AGB 100-INTRODUCTION California is the leading dairy producing

INTRODUCTION California is the leading dairy producing

California is the leading dairy producing state in the United States, with 1,496

dairies and approximately 1.7 million cows producing over 40 million pounds of milk

annually and comprising more than one-fifth of total production in the United States

(California Department of Food and Agriculture, 2013). However, historical shifting

trends in California’s dairy industry have resulted in major changes in its overall industry

structure; the number of California’s dairies continues to decrease, while individual herd

size has increased (Capper, Cady, & Bauman, 2009). Further, there is growing attention

paid to environmental impacts of manure management systems, with stricter

environmental regulations imposed by regulatory agencies (California Department of

Food and Agriculture, 2013).

The California dairy industry’s shift toward fewer dairies is associated with the

economic difficulties faced by small family owned dairies as they try to compete in the

market place. As a result, many family run dairies in California have shutdown,

liquidated their businesses, relocated, or merged to improve efficiencies and/or economies

of scale (California Department of Food and Agriculture, 2013). The closure of small

dairies in California has lead to the merger or acquisition of assets resulting in the

emergence of large scale dairies. In 2000, the average number of cows per dairy

operation was 696 cows; however, by 2012 that number had grown to 1,186 cows per

operation (California Department of Food and Agriculture, 2013).

Dairy farming in general produces a substantial amount of animal waste. The

average lactating dairy cow produces a reported average of 80lbs of wet manure a day, of

which, 80% is realistically recoverable by existing waste management systems (Van

Dyne, 1994). The increase in herd size has concurrently increased the amount of waste

produced at individual California dairy sites, especially those counties located in the

southern San Joaquin Valley; Fresno, Tulare, Kings, and Kern County, respectively

(California Department of Food and Agriculture, 2010). Increasing individual herd size

and regional concentration of dairy livestock operations have led to increased amounts of

potential pollutants from decomposing livestock manure (Capper, Cady, & Bauman,

2009). The large amounts of manure generated, in many cases is applied to crops, must

sit in transit from animal housing to the field or be stored for later use, causing

environmental impacts including: odor emissions, methane emissions, and potential water

quality issues. State and local regulations coupled with limited amount of land base

available for most dairies have made appropriate and efficient waste management an

important issue facing the dairy industry (Hurley & Summers, 2013).

Anaerobic methane digesters, a biogas production and collection technology, has

been around for decades. Methane digesters have the potential to provide the dairy

industry with an apparent solution to the issue of dairy waste management by providing a

ready supply of renewable energy while potentially mitigating some other impacts of

manure management on the environment. Methane digesters can potentially capture a

renewable energy in the form of methane gas, electricity and heat (Hurley & Summers,

2013). They can also create valuable process byproducts, such as fiber solids for animal

bedding material or mulch (USEPA, 2013). Studies have been done on the economic

salinity of methane digesters in recent years; however it’s unclear whether they are yet

economically feasible (Hurley & Summers, 2013).

Several factors can affect the production of renewable energy and potential

pollution prevention of greenhouse gases of anaerobic methane digesters, and depends

largely on the manure handling practices use by dairy producers. Size of the operation,

approach to waste management, regional location and governing regulations coupled with

electricity and carbon reduction prices could influence cost-effectiveness of these systems

(Key & Sneeringer, 2011).

An estimated 1,000 dairies in California would financially benefit from the

installation of a methane digester (Lazarus, 2008). However, despite recent studies

reporting possible positive forecasted economic returns for sale of biogas and biogas

byproducts captured by methane digesters, that could reduce production costs and comply

with regulatory agency goals, especially in California, producers remain unconvinced;

adoption of methane digesters has been slow (Moser, Mattocks, & Moore, 2000; Hurley,

Ahern, & Williams, 2007; Key & Sneeringer, 2011; Meyer & Powers, 2011; USEPA,

2014c).

To determine why this technology has not been widely adopted in California,

information was elicited from producers who have firsthand experience with methane

digester technology. A case study method was used to analyze the data, similar to those

used in the past (Morse, Guthrie, & Mutters, 1996; Lusk, 1998; Moser, Mattocks, &

Moore, 2000; Kramer, 2004), to address the efficacy of methane digesters at the farm

level.

Qualitative case study research has been shown to complement quantitative data

collected for traditional farm management analysis; often uncovering new information

that would not have come to light by traditional methods alone (Howard & MacMillan,

1991). The questions posed in this study utilize qualitative methods, descriptive in

nature, and have been used to form the basis for the development of more general theories

(Babbie, 2007).

Problem Statement

Much research has been done to attest to the viability and economic sustainability

of on-site dairy anaerobic digester technology, and its solution to the issues raised by the

changing dynamic of California’s dairy industry in general; however, the question

remains as to why this technology has not been more widely adopted by California

dairymen. The goal of this project is to address the possible barriers to entry, specifically

the lack of training and technical support as reasons for low adoption rates of this

technology in California.

Hypothesis

Lack of training and technical support of the various mechanical aspects and technical

issues associated with methane digesters have directly contributed to the low adoption of

this technology at the farm level.

Objectives

1) To identify dairy producers reasons why methane digester technology has

not been widely adopted on California dairies.

2) To assess the level of real world successes or failures of this technology on

California dairies.

3) To assess dairy farmer concerns and problems with current

implementation and up-keep of methane digester technology on site.

4) To identify any issues directly or indirectly associated with methane

digester technology specific to California.

Justification

California is the largest dairy producing State in the Nation; subsequently a vast

amount of manure is produced as a result. Dairy producers, if they have the available

land, often store much of the nutrient rich manure produced by their cows to be applied to

production feed crops throughout the year, or they have to contend with the cost of

shipping wet manure to another off-site location. In either case, the resulting emission of

biogas into the air and potential water quality issues provide an environmental and

economic incentive to adoption of methane digesters in California (Hurley & Summers,

2013).

Biogas emitted by decomposing manure is mainly comprised of methane (CH4),

and carbon dioxide (CO2). Recent studies have reported to methane emissions be

approximately 25 times more polluting (heat trapping) than carbon dioxide (CO2) as a

greenhouse gas, thus increasing the importance of capturing this gas at the farm level

instead of releasing it (Yvon-Durocher et al., 2014) .

California dairies vary according to dairy herd size, location, available resources,

production facilities and operational costs. However, despite such differences, they must

all comply with existing and changing waste management programs in their regions, for

example, in May 2007, the Central Valley Regional Water Quality Board adopted a

general Waste Discharge Requirements General Order for Existing Milk Cow Dairies (the

General Order4) requiring commercial dairy’s in the Central Valley to fully implement

their Waste Management Plan by 2011 and Nutrient management plan by 2012 (Central

Valley Region Water Quatlity Control Board, 2010). The cost of compliance with the

General Order is significant with one study estimating annual compliance costs of the

representative groundwater monitoring program to range from

$8,006 to $47,440 with an average cost of $19,136 per dairy (Cady & Francesconi,

2010). New, modified or centralized methane digesters are covered under the General

The Central Valley Water Board first adopted the Waste Discharge Requirements General Order for

Existing Milk Cow Dairies (the General Order) Order No. R5-2007-0035 on May 3, 2007. The Waste

Discharge Regulatory Program for Dairy Manure Digester and Co-Digester Facilities was adopted

December 10, 2010. The Waste Discharge Regulatory Program for Centralized Dairy Manure Anaerobic

Digesters or Centralized Dairy Manure Co-digester Facilities was adopted by the Central Valley Water

Board on 10 June 2011.

Order and the time associated with the permitting processing time streamlined by 75%

(Central Valley Region Water Quatlity Control Board, 2010), thereby providing an

environmental and economic incentive to adoption of methane digesters in California.

Economic incentives may not mitigate all private and social costs associated with

the manure waste in methane digester systems. Despite reported forecasted positive

economic returns from the sale of electricity and carbon emissions reductions (or offsets),

and the offsetting or stabilizing of on farm production costs, adoption of this technology

at the farm level has been scant (Key & Sneeringer, 2011; Morse, Guthrie, & Mutters,

1996).

Table 1. Reported Number of Operational Methane Digesters in the United States by

Farm Type.

Farm Type Number of Digesters

Beef 4

Dairy 193

Mixed 8

Poultry 5

Swine 29

Total 239

Source: (USEPA, 2014b)

The first reported operational methane digester reported by the United States

Environmental Protection Agency (USEPA) in the United States, was installed at

MasonDixon farms in Gettysburg Pennsylvania in 1979. In 2014, the total number of all

farm based methane digesters listed as operational in the United States by the EPA was

239 (See Table 1).

The first methane digester in California was installed in Durham at Langerwerf

dairy located in Butte County, in 1982 (see Table 2). Of the 193 dairy methane digesters

reported operational in the United States, only 26 of these digester systems have been

installed in California, and of those 17 are currently operational (see Table 2; USEPA,

2014b).

Table 2. Reported Operational Methane Digesters by Digester Type, Year Operational

and System End Use(s) on California Dairies.

Year Biogas End

Dairy Name County Digester Type Operational Use(s)

ABEC Bidart-Old

River LLC Bakersfield Complete Mix 2013 Electricity

ABEC Bidart-

StocNO4ale LLC Bakersfield Covered Lagoon 2013 Electricity

ABEC New Hope

LLC Galt Covered Lagoon 2013 Electricity

Antonio Brasil Dairy Merced Complete Mix 2013 Electricity

Bob Giacomini Dairya

Marin Covered Lagoon 2009 Cogeneration

Bullfrog Dairy Imperial Covered Lagoon 2008 Electricity

CAL-Denier Dairy Sacramento Covered Lagoon 2008 Electricity

Castelanelli Bros.

Dairy

San

Joaquin Covered Lagoon 2004 Electricity

Cottonwood Dairyb Merced Covered Lagoon 2004 Cogeneration

Fiscalini Farms Stanislaus Complete Mix 2008 Cogeneration

Hilarides Dairy Tulare Covered Lagoon 2004 Electricity

Langerwerf Dairy Butte Horizontal Plug

Flow 1982 Cogeneration

Meadowbrook Dairy San

Bernardino

Horizontal Plug

Flow 2004 Electricity

New Hope Dairy Galt Complete Mix 2011 Electricity

Straus Family Dairy Marin Covered Lagoon 2004 Cogeneration

Tollenaar Holsteins

Dairy Sacramento Complete Mix 2008 Electricity

Van Warmerdam

Dairy Galt Complete Mix 2011 Electricity

Source: (USEPA, 2014b)

The Bob Giacomini Dairy is also known as Point Reyes Cheese Company.

b Cottonwood Dairy is part of a five dairy conglomerate owned by Joseph Gallo

Farms. Joseph Farms Cheese Company operates the digester at Cottonwood Dairy.

The remaining seven digesters reported as having shutdown or non-operational are

reported in Table 3 (Table 3; USEPA, 2014b).

In recent years dairy producers in California have been investigating the

feasibility of implementing and operating methane digesters that allow them to convert

methane into a renewable energy source. Engineers have developed system designs

suitable to California, relating to component configuration, dairy waste collection and

removal, along with other factors influencing efficiency. However, dairy producers

Table 3. Reported Non-Operational Methane Digesters by Digester Type, Year

Operational and System End Use(s) on California Dairies.

Year Biogas End

Dairy Name County Digester Type Operational Use(s)

Cal Poly Dairy San Luis

Obispo Covered Lagoon 1998 Electricity

Eden-Vale Dairy Kings Horizontal Plug

Flow 2006 Cogeneration

Inland Empire Utilities

Agency - Regional Plant

San

Bernardino Complete Mix 2003 Electricity

Inland Empire Utilities

Agency - Regional Plant

San

Bernardino

Horizontal Plug

Flow 2001 Electricity

Koetsier Dairy Tulare Horizontal Plug

Flow 2005 Electricity

Lourenco Dairy Tulare Covered Lagoon 2006 Flared Time

Gas

St. Anthony Farm Sonoma Covered Lagoon 2007 Cogeneration

Van Ommering Dairy San Diego Horizontal Plug

Flow 2004 Electricity

Vintage Dairy Fresno Covered Lagoon 2008 Pipeline Gas

Source: (USEPA, 2014b) must be able to compensate for the time it takes to implement a

digester and the associated time and cost of installing and maintaining the system and for

the performance of digester to be cost-effective for them to invest in a technology that

will allow them to generate electricity from the methane produced. Additional research,

besides environmental and economic factors into the qualitative issues associated with

implementing and operating a methane digester by the dairy producer is needed to better

understand the all aspects of implementing and operating a methane digester.

CHAPTER II

LITERATURE REVIEW

Methane Digestion Technology

Methane digesters, also known as bio-digesters, enable biogas recovery systems

via anaerobic digestion—a biological process of decay by which bacteria (methanogens)

breakdown organic waste material in the absence of oxygen. The California Energy

Commission (CEC) defines anaerobic digestion as a biological gasification process that

produces a renewable energy source from organic wastes such as livestock manure and

food processing waste, which is composed of 60% methane (CH4) and 40% carbon

dioxide (CO2) and 0.2-0.4% hydrogen sulfide (H2S) gasses are collectively known as

biogas. However, methane digesters can provide numerous benefits to dairy producers

and the environment besides a renewable energy source through the gasification process

of anaerobic digestion (Wright, 2001; Borjesson, 2006).

This technology first gained notice as an energy source in the 1970’s, due to the

high cost of petroleum. At the time there existed many design obstacles and economic

issues which prevented widespread adoption (Van Dyne, 1994). In recent years,

anaerobic digestion systems utilizing primarily livestock manure for on-farm or off-farm

use, have again received attention because of their ability to produce renewable energy, as

energy prices soared.

Reasons for low adoption rates identified in past studies included: prohibitive

financial cost associated with the construction and installation prevented many farms

from adopting (Key & Sneeringer, 2011). Factors of design incompatibility, failed

revenue streams, prohibitive operating and maintenance costs, and scant support services

available also decreased adoption (Morse, Guthrie, & Mutters, 1996; Wright, 2001).

Other disincentives include labor costs, delays, and costs associated with operation and

maintenance of these digester systems (Morse, Guthrie, & Mutters, 1996). One study

found 80 % of the cost of maintenance was associated with post-digester components

comprised of engine repair, maintenance, and dealing with utilities, not daily operation

and management of the system (Moser, Mattocks, & Moore, 2000).

System Designs

There are approximately 1.8 million lactating cows in California and dairy cow

manure contains approximately 12-13% solids as excreted (Wright, 2001), which

generates annual quantities of 7 million tons of volatile solids (VS). Methane digesters

systems of various designs have been reported to produce a substantial amount of energy

in the form of biogas or in the form of energy and heat from all this animal waste

(Summers & Williams, 2013). Depending upon the state and region they are located,

methane digestion systems can utilize a wide range of configurations including; variations

in scale and configuration, a range of temperature, pH, organic loading rates and methane

recovery potential (Borjesson, 2006), and the resulting differences in composition and

distribution of manure have been reported to have some affect on levels of bioconversion

(Wright, 2001). However, the quality of the biogas or methane produced, regardless of

system design or facility was reported to be consistent, meaning their heating value was

the same (Summers and Williams, 2013). The three digester systems that are reported to

exist in California are ambient-temperature covered-lagoon, complete-mix, and horizontal

plug-flow digesters (Krich, et al., 2005).

Covered lagoons are anaerobic lagoons which are sealed and operate at ambient

temperatures, meaning they are not heated. These systems utilize a flexible fitted cover

for biogas recovery and are fitted with a pipe to the combustion device. Covered lagoons

are reported to be the most popular digester design in California (USEPA, 2014b).

Covered lagoons are comprised of diluted wastes from dairy parlors and housing sheds

wash using a flush dairy manure system. Lagoon style digesters have the potential to

reduce manure solids by 26% (Summers & Williams 2013).

Complete-mix digesters are designed as enclosed aboveground tanks that are

usually heated and insulated. Complete-mix systems utilize hydraulic or mechanical

agitators or some sort of gas mixing system to mix the excreted manure. This agitation is

used to keep the material in consistent slurry with 2% to 10% solids. Complete mix

digesters are reported to work best when the excreted manure is diluted with water

(USEPA 2014d). Material leaving the digester digestate will contain a fraction of the just

added manure (Wright, 2001).

Plug flow digesters are reportedly used only at dairy operations that collect

manure by scraping Plug-flow anaerobic digester systems and are found in greater

numbers in cooler climates other than California. A plug flow digester is designed with a

long, narrow concrete chamber or tank with a rigid or flexible cover, and is built partially

or completely below ground to limit the demand for supplemental heat (USEPA, 2014d).

Plug-flow digesters consist of unmixed, heated rectangular tanks that function by

horizontally displacing old material with new material. Plug-flow digesters are used to

digest thicker wastes of 11% to 13% solids, and are best suited for manure handling

systems that do not contain less than 10% solids which is what flushed manure or dry lots

to lagoon system do, thus rendering them unsuitable for most California dairies (Moser,

Mattocks, & Moore, 2000). Manure is collected using either a flush system or scrap

system and is added to one end of an insulated holding container, which flows into the

main digester. The manure added forces out an equal amount of effluent from the other

end of the digester as digested effluent (Wright, 2001).

Anaerobic covered lagoons have seasonal variation in gas production due to the

variation in ambient temperature and are best suited for dairies in the West (Moser,

Mattocks, & Moore, 2000). Gas production from complete-mix and plug-flow digesters

are impacted less by ambient temperature variation since they are usually heated. Once

the digester captures the biogas, the gas is usually transferred to another point to be

processed prior to its intended end point. This generally means the gas has been to be

scrubbed to remove impurities, to be used to power a combustion engine or generator

unit, or for injection in to a natural gas pipeline. The remaining effluent inside the

digester is made up of salts, nutrients and the leftover organic matter that was initially

present in the animal feed and can dried for further use (Meyer & Powers, 2011).

Design Trends

Many of the problems associated with methane digesters in the 1970’s were due to

a lack of understanding of the biological system used. The result was that the digester

was treated more as a physical process that could be started and stopped by turning on or

shutting off the waste flow instead of a complex bio-mechanical system (Wright, 2001).

According to the USEPA (2014) methane digester project database, from the 1980’s to the

1990’s approximately thirty methane digesters were installed on various types of

agricultural operations across the U.S., though these systems had a better performance

rate than previous systems, due to a more simplified design (Wright, 2001), nearly half of

these systems failed or were shutdown according to the EPA methane digester database.

Prior to 2000, only fourteen digesters were reported operational according to the

EPA, however, from 2000 to 2011, a reported 176 methane digesters, most of these at the

farm level, were installed across the U.S. In California, prior to 2000 only two methane

digesters were in existence, one operating and one shutdown.

In 2011, nearly 50% of anaerobic digesters installed in the United States were

complete mix, with mixed plug flow digesters comprising another 40%. These systems

continue to be the dominant technology designs in relation to all operating anaerobic

digester systems in the U.S. The remaining 10% of new digester systems were covered

lagoons. In contrast, from 2000 to 2011, California reported 50% of the digestion

systems in existence were covered lagoon systems, 30% were complete mix, and 20%

were horizontal plug flow systems (see Table 1 and 2) (USEPA, 2014b).

Although the majority of systems use only livestock manure and are farm-owned

and operated, other approaches are emerging. In Europe, a study done in Sweden showed

large potential for anaerobic digestion and methane digestion in proper waste ratios at

large centralized wastewater treatment plants. These facilities are reported to show great

potential for co-digestion of livestock manure and clean organic urban and industrial

wastes (Davidsson, et al., 2007).

In the United States, centralized systems are an area of growing consideration

where dairy, swine, or poultry farms are too small to support a cost-effective on-farm

facility (Hurley, Ahern, & Williams, 2007; Lusk, 1998). Approximately 30% of project

operators reported co-digestion systems running “high-strength” organic wastes, such as

cheese whey in those dairies in close proximity to a cheese making facility, and urban

waste (Lehtomaki, 2007; USEPA, 2014c). Regardless of design, an anaerobic digester

requires an oxygen free, closed environment; therefore the digester design is based on the

system of animal waste collection used (Meyer & Powers, 2011).

Dairy Waste Collection and Removal

Engineers have designed a number of manure waste handling and collection

systems. These systems vary greatly, and each method or system has its own set of

benefits and drawbacks. However, the purpose is the same, moving manure away from

the cattle into some collection end point. The three primary manure collection methods

used on California dairies are scraper systems (integrated mechanical or tractor scrapers),

flush water system, and vacuum systems. Nearly two-thirds of California dairies use a

flush water management system and the remaining use a scrape system. Flush dairies are

the best candidates for biogas production compared to other methods where manure is

scraped and stored and will decomposes aerobically, inhibiting the development of the

bacteria that create biogas (Krich et al., 2005).

Factors Influencing Efficiency

The three digester systems in use on California dairies are ambient-temperature

covered-lagoon, complete-mix, and horizontal plug-flow digesters (Krich, et al., 2005;

USEPA, 2014b). Of the 26 California dairy digesters, half are covered lagoon systems

(USEPA, 2014b). The three temperature ranges that methanogens produce methane are

psychrophilic, mesophilic and thermophilic (Rico, 2006). Bioconversion of waste (liquid

manure) to methane gas produced depends on several factors including temperature, and

pH level.

A covered lagoon system operates (psychrophilic conditions) at 68 degrees or less,

and thus significantly effects the rate of anaerobic digestion and amount of methane gas

produced (Wright, 2001). Most complete-mix and plug-flow digester systems operate at

either mesophilic or thermophilic temperatures. The optimal ranges for anaerobic

digestion are between 125 to 135° F (thermophilic conditions) and between 95 to 105° F

(mesophilic conditions) (Rico, 2006).

Mesophilic temperature systems are reported to be the prevailing temperature

design in relation to all operating digester systems in the U.S. (Nishio, 2007; USEPA,

2014c), though drainage of solid and semisolid material through the digester becomes

difficult in mesophilic concentrations with greater than 10% solids (Nishio, 2007).

Under thermophilic conditions, digester systems can generate gas in a shorter

amount of time than anaerobic digestion under mesophilic conditions. A trade off

however, is that more energy is required to maintain thermophilic conditions within the

reactor. The additional heat could be captured from excess heat from the generator

engine or another outside source (Krich, et al., 2005).

In all three of the temperature ranges, methanogens breakdown the solids in

manure, refered to as total solids (TS), into volatile solids (VS), which typically comprise

70% of TS, while the remaining 30% is inorganaic matter. VS are then further divided

into biodegradable and non-biodegradable VS, with the biodegradable portion of VS

(approximatly half) converted into carbon monoxide and methane gas (Wright, 2001).

The bioconversion rate of any methane digestion systems may differ by a factor of

2-4% for CH4 and by 11% for SO2 depending on the properties of the raw material

digested. The raw organic properties of various wastes effect production of methane

digestion systems especially for manure (Borjesson, 2006). The production of CH4 can

take 18 to 24 days in an anaerobic digestion system containing dairy manure to produce a

90% of the potential biogas yield (Rico, 2006).

U.S. Policies in Support of Methane Digesters

Policy makers, government agencies and environmental groups have created a

great deal of support in the form of programs and incentives for biogas recovery

technology at the state and federal level (USEPA, 2014d). There are a number of factors

that have driven policy makers to pass legislation in favor of methane digesters and other

renewable energies (Duncan, 2004). Over the last decade, several policies have been

implemented for methane digesters at the farm level, which provide financial incentives

for dairy farmers to use digester technology to reduce methane emissions and

environmental impacts. These programs include educational and technical support,

grants and loans for capital items, feasibility studies, environmental policy and research

(USEPA, 2014d).

There have been approximately 22 current, expired or pending federal programs

that have provided direct or indirect support for biofuels (Yacobucci, 2012). One

example is the AgSTAR program, a collaborative venture of federal agencies including

the USDA, USEPA and USDOE which provides educational materials and online project

evaluation tools and funding options (USEPA, 2014d).

Over the last decade, support in favor of renewable biofuels has been evident in

key pieces of legislation that have made methane digester technology appealing, most

notably the 2008 Farm Bill—The Food, Conservation, and Energy Act of 2008, which

established several biofuel incentives, including several new grant and loan programs, in

support of anaerobic digesters at the farm level (Yacobucci, 2012), and effectively

reinvigorated the push for adoption of methane digesters at the farm level. The renewable

Fuel Standard (RFS) established by The Energy Policy Act of 2005, which in 2009 was

expanded upon to specifically mandate the use of advanced biofuels (like those produced

by methane digesters) on livestock operations (Yacobucci, 2012).

More recently, in 2010, the USEPA and the USDA earmarked $3.9 million in

funds to encourage adoption of methane digesters on conventional livestock operations

(USEPA, 2014c). Political support from the dairy industry itself has been evident with its

goal to voluntarily reduce greenhouse gas emissions by 25% by 2020 coupled with a

partnership with the USDA in 2009, and renewed again in May 2013 (USDA, USEPA,

and USDOE, 2014).

In March of 2014, the current administration released The Climate Action Plan

(CAP) formulated by a consortium consisting of USDA, USEPA, USDOE (2014), and

dairy industry representatives. In August 2014, President Obama released the Biogas

Opportunities Roadmap, outlining voluntary measures that dairy farmers and producers

can implement to increase the adoption of methane digesters.

Funding and support for these machines at the State level depends on location and

other factors. Ultimately, the funding of projects at the farm level comes from a

combination of sources including: the farmers themselves, private investors, grant and

loan programs and regional utility companies. In California, the regional Sacramento

Municipal Utilities Department (SMUD) for example, in accordance with greenhouse gas

reduction goals of the California Municipal Utilities Association, received millions in

funding from the DOE and the CEC, to help fund the construction of methane digesters in

their district (Sacramento Municipal Utilities District, 2014). A great deal of support at

the state and federal levels was evident in policies then applied to methane digester

technology as prices of energy rose.

Opportunities for Methane Digesters

Potential revenue sources for methane digesters on California dairies include the

collection and sale of biogas, heat and electricity generation. However, each potential

end use has its pros and cons. Federal and State support for renewable energies has

helped create a market for the sale of biogas and facilitated the sale of electricity from

anaerobic digesters by prompting contractual arrangements between the regional utilities

and dairies with methane digesters or those considering implementing one. Alternatively,

biogas collected from a methane digester can be piped back into the gas pipeline,

however, it requires a secondary treatment as it contains between 0.2-0.4% hydrogen

sulfide (H2S), which converts to sulfuric acid, and is highly corrosive to engine generators

(Wright, 2001).

Most methane digestion systems installed on dairies in California are designed to

generate electricity as their final energy output (USEPA, 2014b). The generation of

electricity from biogas for profit is determined by the contractual arrangement of the

regional utility company. Electrical energy contracts for dairies with methane digesters in

California are usually negotiated in one of three ways: a buy-all-sell-all, a net metering

agreement or a surplus sale arrangement (California Public Utilities Commission, 2014).

A buy-all-sell-all contract allows the utility company to sell a dairy all electricity

requirements, and buys all the generator output. A net metering contract allow for

electricity produced to be offset on a monthly or yearly basis against consumption, and

the surplus energy produced to then be purchased by the utility company and shortages

purchased by the dairy. A surplus sale contract allows the electricity produced by a

digester to be sold at avoided cost and excess consumption at the retail rate (USEPA,

2014c). However, this means that electrical prices are locked in at the time of the

negotiated contract, essentially forecasting future electricity prices, which has been

shown to be variable. Interconnection to the grid can also be variable and associated

costs and logistics can be challenging (Gloy & Dressler, 2010).

Carbon credits, or emission reduction credits, are derived from the biogas

collection device or gas treatment system before either flare (burn-off) or other end use

(USEPA, 2014c). A gas treatment system is needed to remove high concentrations of

hydrogen sulfide in dairy manure in order to prevent corrosion of the combustion device

(Wright, 2001). According to the EPA, carbon credits are based on “baseline emissions”,

that is how much methane a given dairy produced prior to the installation of a methane

digester. Currently, dairy producers in California have the option to sell carbon credits in

regional or voluntary markets when a given amount of carbon emissions allowed for a

dairy is not used, they can be traded for a profit (USEPA, 2014c). One study showed

sales of carbon credits to be profitable with herds in excess of 600 head (Key &

Sneeringer, 2011). However, voluntary market prices tend to be low and variable, and

often require a third-party offset verification company in order to sell the emission

reductions leaving most farmers to consider the process too costly to sell carbon credits

(Gloy & Dressler, 2010).

The Dennis Haubenschild Dairy near Princeton, MN, was one of the pioneers in

trading carbon credits from captured methane. These carbon credits were sold on the

Chicago Climate Exchange, at the time, the only market for greenhouse emissions credits.

The dairy was the first to run a methane digester in Minnesota, and the first digester in the

world to run a hydrogen fuel cell off of biogas (Bilek, 2006).

Case Study Research

There are a number of qualitative methods that can be used to collect primary data

to then be used in a structured study with quantifiable results. Qualitative data collected

from surveys is the most common method used for exploratory purposes (Kumar, Aaker

& Day, 2001; Babbie, 2007). Exploratory research obtained through surveys can be used

for defining problems in more detail, for generating new ideas or production concepts, to

finding solutions to problems, and for suggesting interesting questions or concepts to be

examined in subsequent research. Feelings, thoughts, insights, behaviors and intentions

are examples of data that can be obtained through qualitative survey data collection

(Kumar, Aaker & Day, 2001).

Qualitative interview methods and field research techniques allow for exploratory

and conceptual in-depth discussions between the researcher and participant rather than

quantitative analysis of financial and/or survey data (Howard & MacMillan, 1991). A

main strength of this approach is open ended, in-depth interviews often yield observations

not easily reduced to numbers. Researches may recognize nuances of attitude and

behavior that might escape research using other methods (Babbie, 2007). This setting

allows for the study of those attitudes and behaviors best understood within their natural

surroundings as opposed to an artificial setting and can lead the researcher to develop a

deeper and fuller understanding of meaningful comments, suggestions and insights

(Babbie, 2007).

A case study approach and multiple case study approach use qualitative field

research interview techniques to examine an instances or separate instances. The

individual case study inquire copes with the technically distinctive situation in which

several variables of interest are present than data points. Similarly, the researcher relies

on multiple cases of evidence with multiple sources of data and increasing variables

needing to converge in a cohesive manner in order to guide data collection and

metaanalysis. Both the individual and multiple case study designs require researchers

entering the field with full knowledge of existing theories that aim to uncover

contradictions that require modification of those theories (Babbie, 2007). Previous case

study research which addressed the efficacy of anaerobic digesters on dairy farms (Morse,

Guthrie, & Mutters, 1996; Kramer, 2004; Lazarus, 2008) had used qualitative interview

methods to obtain primary data points from producers who have firsthand experience

with methane digester technology, and thus provided the logical starting point for this

study.

Multiple case study planning begins with the creation of a discussion guide or

agenda. The purpose of the research is set into questions to address the research

objectives. The discussion guide is comprised of a base set of topics selected ahead of

time to be discussed in-depth, rather than specific formalized questions during each

interview. The interviewer proceeds with a logical flow from general questions to key

questions or specific issues (Kumar, Aaker & Day, 2001; Babbie, 2007).

When recruiting participants it is appropriate to incorporate similarities and

contrasts within a given group. The participants may all be dairymen for example, but

they may differ by geographical region, dairy size, by levels of education and waste

collection method. Scheduling individual interviews to accommodate the participant is

also important, and should take place within a relatively limited area and time frame

(Babbie, 2007).

Critical to the quality of commentary collected from each participant is the level

of ease the participant has with the researcher, established by rapport. The researcher

should give an introduction about the purpose of the study, the general approach to the

topic, what can be expected from the interview and the expected time frame of the

interview. In addition, the researcher should ensure that the information obtained during

discussion will be kept confidential (Babbie, 2007).

In addition the researcher should encourage discussion of attitudes and

perceptions of issues related to the topic as well as feelings, anxieties, and frustrations

without bias or pressure. The researcher should dress appropriately, be respectful and

show great interest in the topic by listening carefully to commentary. The researcher

should be flexible and have the ability to control conversations in a smooth flow by

redirecting a participants’ wandering commentary back to key topics and know when a

topic is becoming uncomfortable or exhausted (Kumar, Aaker & Day, 2001). Field

research guidelines for conducting case study interviews include: preparing for the field,

identifying appropriate topics for field research discussion, tools for analyzing social

situations, the various roles of the observer, and how to correctly managing the relation to

subjects by establishing a rapport (Babbie, 2007).

When writing the report the analyst would give background and purpose of the

study and organize the data in an accessible and relative manner, which means organizing

responses into categorical tables that would become the worksheets for writing the report.

The researcher would also provide transcripts for each of the participating dairies

(Babbie, 2007).

CHAPTER III

METHODOLOGY

Data

Eighteen dairies were identified through the USEPA’s AgSTAR website, through

discussions with dairymen, and through advising Cal Poly faculty contacts as possible

candidates for this study. The sample criterion was based on available data. Budgetary

restrictions of the study limited the available sample to coastal Northern and Central

California dairy producers and any non-response bias of producers in those two regions.

The regional sample population (n=18), criteria included; having had experience with

methane digesters or interest in implementing this technology. Those eighteen dairies

meeting the aforementioned criteria were contacted by telephone to determine their

willingness to participate in the case study, and to schedule a time of their choosing to

conduct an in-depth interview at their facility, or agreed upon location. The age, gender

and ethnicity of the subjects were predominantly male, Caucasians, and approximately

30-65 years of age.

Of the dairies contacted, twelve responded and agreed to participate in this study.

The twelve subjects who participated in the study fell into one of three categories; dairy

producers who have installed a methane digester is currently operational (n1 = 4), dairy

producers who have installed a methane digester in the past that was currently

nonoperational (n2 = 4), and dairy producers who are considering implementing a digester

on their farm (n3 = 4).

Personal interviews were conducted in person, and one on one, with dairy owners

or employee representatives. The interviews were spread out over a 12 month period,

from August 2013 through August 2014. A copy of the questions included in the

discussion guide (see Appendix A) was sent by email to each participant a week ahead of

time, for them to review, prior to the scheduled interview. Each interview held was taped

with the use of a portable audio recorder, and transcripts were made available to each

survey participant. Consent for the interview and participation in the study was obtained

at the beginning of each interview with the provided consent form (see Appendix C). The

names of the participating parties and the dairies were then given an option of

confidentiality, so as to elicit fuller commentary or response. Participants were told the

purpose of the study and were given the option to omit or not answer any question asked

by the interviewer.

The discussion guide used during the interviews is included in Appendix A. The

guide consisted of 24 open-ended questions, designed to encourage the participants to be

as descriptive as possible in their responses. Ice-breaker and background questions were

asked to lead into the main topic of methane digesters. Introductory questions about the

history of each dairy, number of family members working there and highest level of

education were discussed. Further background questions relating to overall agricultural

production and operation, crops farmed, number of employees, relationship with

processors and any consultants they contracted with, were then discussed. Participants

were then questioned about their decision to install a digester on their dairy, company

chosen (or considered) to design and install the digester, troubleshooting services offered,

and approximate cost to install the digester, any financial incentives, and how long they

had considered this technology.

Participants were then questioned about their knowledge and experience with

methane digesters or possible installation. Exploratory questions eliciting reasoning for

installing this technology include; how the digester fit (or would fit) into their daily

operation, the time spent operating and maintaining it, who operates and maintains the

digesters (or would) when problems arise and any training they received were discussed.

The interviewer then asked questions relating to the performance evaluation and

expectation of the methane digester. Participants were asked to explain reasons why

expectations were or were not met, how the performance of this technology differed from

their initial expectations (or what the initial performance expectations were), in hindsight

what they would have done differently (or their assessments for the technologic future),

and reasons why they would or would not reinvest in this technology again (or what help

form their opinion of the adoption of this technology). Finally, to wrap up, participants

were provided the opportunity to discuss any question asked further, provide any an

additional comments or suggestions or “take away advice” on their experiences or

thoughts that had not been brought up.

The qualitative or textual data analyzed in this study utilized qualitative data

processing methods to objectively categorize all textual data by using coding units

(Babbie, 2007), with the aim of discovering patterns among the responses to questions

pertaining to experience with methane digesters. The twelve interviews were analyzed

for such content, specific insights, and consistency. The responses derived from each

interview were then transcribed into text. Coding labels were assigned to primary

themes, once all the data was transcribed, organized, analyzed several times over to

insure confidence in data assessment (see Figure 1).

Figure 1. Coding Categories for Hypothesis Testing

Category Definition Examples Coding

Rules

C1: high competence

or confidence or

positive

experience/opinion

High subjective

conviction to have

successfully maintained a

digester, to be confident in

the demands or

expectations of the

digester and to have had a

positive, hopeful feeling

in about this technology.

“Of course there

had been some

little problems, but

we solved them all,

either I was to fix it

or was able to

get help to fix the

problem”.

All three

aspects of

the

definition

have to point

to "high" self

confidence

no aspect

only

"middle".

Otherwise

C2: middle

self

confidence

Category Definition Examples Coding

Rules

C2: middle

competence or

confidence or

midlevel

experience/fluctuating

opinion

Only partly or fluctuating

conviction to have

successfully coped with

the digester demands.

Ambivalent experiences

or expectations. They are

of two minds or

undecided about this

technology.

"Quite often I

found it hard to

maneuver through

the initial problems

with the digester,

but finally I made

it work." Or "In

time everything

got better, but I

couldn't you if it

was worth it."

If not all

aspects of

definition

point to

"High" or

"low"

Category Definition Examples Coding

Rules

K3: low understanding

competence or have a

negative

experience/opinion

Conviction to have badly

coped with the digesters

operational/maintenance

demands, or to have a

negative, pessimistic

feeling or experience with

the digester, to be

pessimistic, negative

about this technology.

"I thought it

wouldn't be that

hard to manage,

but it was over my

head."

All three

aspects of

definition

point to low

confidence,

or negative

experience,

fluctuations

recognizable

Source: (Mayring, 2000)

A coding label triage sorted responses into three categories: high competence or

confidence or positive experience/opinion (C1), mid-level competence or confidence or

fluctuating opinion (C2), and low level competence or confidence or having a negative

opinion of methane digester technology (C3). The coding categories were defined and

coding rules were formed. An example of a C1 category response read “Of course there

had been a few initial problems with the digester, but we solved them all, either I was

able to fix it or had someone help fix the problem”. An example of C2 responses were

“Quite often I found it hard to maneuver through the problems with the digester, but

finally figured something out.” Or “In time everything sort of got better, but I couldn’t

tell you if it was worth it” and a C3 response would read “I thought it wouldn't be that

hard to manage, but it was over my head” and “I just don’t see a future for this

technology”.

The responses to the primary questions that addressed the use or planned

implementation of methane digesters were analyzed and reemerging themes or topics

were identified in the textual data. Representative sample responses were selected to

illustrate typical view points. Primary topics or issues were grouped into heading

categories: troubleshooting, training, operation and maintenance, funding, time

commitments and constraints, motivational factors and expectations and performances of

the methane digester.

Key questions and their responses were systematically sorted into rule guided

qualitative text within a framework of the three previously defined categories (Mayring,

2000), to test the hypothesis (see Figure 1). Primary concepts or themes were then

identified and sorted into categories that satisfied the four objectives. Data collected from

the responses underwent cross-case analysis, using an open coding and “axial coding “

and meta-analysis identifying core concepts or primary issues that best address the

objectives and test the hypothesis of the study. (Babbie, 2007) .

Assumptions and Limitations

The manner in which a qualitative interview question is asked can greatly affect

the measure of openness in answers given by participants. The asking of questions

relating to the management and operation of any business can be perceived as invasive

and can elicit responses such as; “why do you want to know?” and “what are you going to

do with this information?”. Careful consideration was taken to make sure any question

asked was neutral in context, with no positive or negative bias. However, often the

interviewer must make careful behavioral decisions during the interview to negate any

suspicions held by the participant and to establish a rapport with the interviewee in order

to obtain more candid insights and opinions during (Babbie, 2007). Slight adjustments on

behalf of the researcher were made over the course of the interviews; however the order

of questions asked was maintained to elicit a logical smooth flow from one topic to the

next (Kumar, Aaker & Day, 2001).

Given the size and differences in the regions—no two dairies are alike. There

were too many variables to include in the scope of this study, and combined with the

reality of so few examples of methane digesters on dairy farms, gives good reason to

interpret any data cautiously. The responses given are those of the participating dairies,

and my not represent those of the dairy industry as a whole.

CHAPTER IV

RESULTS

Primary topics or issues that addressed the adoption of methane digester at the

farm level were identified in the response data. These issues consisted of recurring

themes that consistently appeared throughout the interview response analysis. Primary

issues and corresponding groups include: troubleshooting, training, operation and

maintenance, funding, time commitments and constraints, motivational factors,

expectations, and performances of methane digesters. The primary topics or issues

addressed dairy farmers concerns and problems with installation and up-keep of methane

digester technology at the farm level. To better illustrate these primary issues,

respondents were separated into two groups; those who had firsthand experience with

methane digester technology and those who considered adopting. Participants that had

firsthand knowledge along with a summary of their background information are

represented in Table 5. Generalizations, commonalities and differences were then

discussed to further illustrate the extremes, median and deviations within the two groups.

The four dairies with operational digesters were labeled as operational 1 (O1),

operational 2 (O2), operational 3 (O3) and operational 4 (O4). The four dairies with

nonoperating digesters were labeled non-operating (NO1), non-operating (NO2),

nonoperating (NO3) and non-operating (NO4). The four remaining dairies who had

considered adopting this technology were labeled as considering adoption 1 (CA1),

considering adoption 2 (CA2), considering adoption 3 (CA3) and considering adoption 4

(CA4).

Table 4. Summary of Background Data for Operating and Non Operating Methane

Digesters.

Dairy Producer

O1 O2 O3 O4 NO1 NO2 NO3 NO4

Years 2009 to

Present

2008 to

Present

2004 to

Present

2011 to

Present

1998 to

2005

2007 to

2008

2008 to

2012

1985 to

1986,

2002 to

2009,

Fall of

2014

Herd

Size

<300 2600 5000 1500 <300 <300 2800 2000

Baseline

System

Lagoon Complete

Mix

Lagoon Complete

Mix

Lagoon Lagoon Lagoon Lagoon

Digester

Operator

Employee 3rd Party Employee 3rd Party Resident

designer

and P.E.

Employee Employee

3rd

Party

Cheese

Plant/

Creamery

Yes Yes Yes Yes

Troubleshooting

When asked about troubleshooting issues nearly all the participants reported

facing issues that required technical support from a knowledgeable source.

Troubleshooting services were reported to mean telephone consultation with a technician

and online support. Most of the participants reported having limited initial support during

the installation process. However, once installation was complete, most participants

reported no support services were made available by the supplier or installation company.

Although, when pressed further, most participants reported they were able to reach out to

contacts in that industry for some friendly assistance and troubleshooting advice.

O1, O2 were the only two producers that reported having an initial telephone and

online troubleshooting support package when the methane digester was installed.

However, their experiences were very different. O1 dairy attributed much of their success

with their digester to a three year mandatory service agreement with the company that

installed the digester, Martin Machinery, which was required by PG&E. O1 dairy

operated and managed the methane digester themselves but when problems arouse, they

were able to contact the installation service technician for troubleshooting by telephone

and online remote access. The participant mentioned that online monitoring allowed the

producer to identify any problems that would arise during off hours. In addition, the

installation service technician would then utilize the online remote access to diagnose the

problem and make recommend adjustments to resolve the issue. The ability to diagnose

an issue quickly without having to schedule a service representative to visit and/or have

the producer (or an employee) onsite was seen as the primary reason by the producer for

the success of their methane digestion system. O1 went on to say that in the first year of

operation, the online service saved their generator engine from having to be replaced

more than once.

In contrast, O2 (prior to contracting with a third party management company) was

able to utilize limited troubleshooting technical support through an online screen sharing

remote access (team viewer program) with the manufacturing company for the first year,

as part of the methane digester’s installation package. However, O2 reported that because

the company was located in Germany, the time difference made scheduling an online

interface difficult and therefore was not helpful in diagnosing issues quickly.

When asked about particular troubleshooting services offered, three of the eight

participants-- O2, O4 and NO4-- reported that they had decided to contract with a third

party management company rather than deal with the digester themselves. The third

party management company, for all three cases, had a service representative come out to

perform routine engine/generator maintenance every 10 days or two weeks. O4 further

mentioned that should any issues arise the third party operative would send out a text

alert informing the owners about the issue.

The two exceptions with regard to troubleshooting and or available maintenance

services were NO1 and NO3. NO1 was a pilot project by a resident professional designer

Professor Douglas Williams, at Cal Poly State University, where the methane digester

was located, who at the time provided troubleshooting and maintenance with the aid of

student workers. NO3 was a pilot project of the bio-energy firm, Energy Solutions LLC

(now closed after filing for bankruptcy in 2012), and as such, could not comment on

whether or not they would have offered support services to future clients.

Training

When asked about the amount of training involved in the operation and

maintenance of the digester, most participants reported that no formal training was

provided by the supplier beyond the initial startup. One participant that had contracted

with a third party operative, (O4) stated that they received around 20 hours of instruction

on how to run a weekly test on the bacterial health of the digester, as part of the

contractual agreement.

As previously mentioned, NO1 and NO3 were again the exception with regard to

needing any training, as they were both experimental pilot projects by industry

professionals; NO1 was part of the curriculum to instruct University students in

biotechnology and engineering, and NO3 was the pilot project of a bio-technology startup

firm. However, both participants reported giving a significant amount of

instruction/training to those employees or students operating the methane digester.

Coincidently, NO3 reported that there was one primary employee who received a

significant amount of training from the company, a graduate of Cal Poly State University

(previously mentioned) and former student of resident designer Williams, who was

employed by the bio-tech firm, and was instrumental in the installation of NO2 and once

installed chiefly in charge of monitoring the digester daily and performed any

maintenance required.

NO4 was a unique case, although they had reported receiving no training at all

with their first digester, saying “there were components to it that they had no idea what

they were or what they did”. However NO4 did receive some initial training with their

second methane digester on how to check the pH, gas contents and perform some analysis

on a regular basis. NO4 went on to mention that they thought the digester was very time

consuming and that it was another thing he had to constantly think about, watch and

maintain.

Operation and Maintenance Issues

When asked about operating and maintaining the methane digester, all participants

with methane digesters, reported that repairs were a common issue of concern, and 50%

reported having issues with sourcing replacement parts. Most participants reported

having to make numerous technical repairs that required some measure of skill. Most

attributed the reason for these occurrences to either basic maintenance issues resulting

from normal wear and tear and or poor design.

The issue of sourcing parts was mentioned as a significant concern among

producers. Many participants remarked that parts and components needed for repairs

were not easily sourced, meaning they were not available at local hardware stores. NO2

dairy for example, upon closure in 2008, sold off many of the digester components and

parts as replacement parts to Straus Dairy in Sonoma County (which declined to

participate in this study), who operated a methane digester.

Interestingly, all participants, including those with a third party operative,

commented that it was a “learning experience.” Despite the number of differences and

levels or competency in working with this technology, every participant in the study

expressed the sentiment that methane digester systems were not instantaneously

successful, and required more effort than originally anticipated.

Six of the eight participants had reported numerous technical issues associated

with operating their methane digesters. These six participants went on to say that those

issues resulted in poor output by the digester and were attributed to design flaws. Four of

the six participants, who reported having experienced several technical issues, stated that

design flaws had directly affected their decision to continue to run their digester.

NO4 dairy stated that they had experienced numerous similar technical and design

issues with the first and second start up, and stated a lack of troubleshooting support,

available parts, daily maintenance, emissions regulations by the Air Quality Control

Board (with regard to the engine), and overall design (they had used a vacuum manure

collection method which resulted in a dirt plug) were the main reasons why the first two

startups failed.

The three dairies contracted with a third party management company reported

overall very satisfied with the arrangement. They felt their time could be used more

wisely tending to their herds and running their dairy, and having little direct responsibility

for the digester was reported as a most beneficial aspect. It should be noted that in each

of the three cases, technical modifications and upgrades were made that allowed for co-

digestion of garden waste and food waste what were additionally fed into the digester.

Two of those producers, O2 and NO4, who had contracted with a third party, had

initially maintained their digesters themselves, but after years of dealing with numerous

maintenance and repairs issues, limited troubleshooting support, and decreased digester

output, they decided to contract with a third party management company. NO4 dairy was

the only participant with a non-operating methane digester that was planning to restart the

system in Fall 2014, and said the third startup would not have been considered without

the aid of a third party management company.

O4 was the only participant who had never planned to maintain the digester

themselves; from the onset they planned to have a third party company manage the

system. From the dairy startup planned on installing a methane digester system primarily

as a waste management system. The ability of the methane digester system to create

renewable energy in the form of natural gas was what made it feasible to contract with a

third party management company.

Funding the Project

The reported costs for the methane digesters varied from approximately $1 million

to $4.5 million among the respondents. The reason for this cost variation was not directly

addressed in this study. However, a summary of approximate costs associated with the

digester and installation along with any grant funding that was utilized is reported in

Table 5.

Table 5. Summary of Installation Costs for Operating and Non Opera

Digesters.

ting

Methane

O1 O2 O3

Dairy Producer

O4 NO1 NO2 NO3 NO4

Associated

Costs

Cost to

the

producer

$700,000

Total project

cost $4.5

million.

Cost to

producer

$2.5 million.

Total

cost

$3.2

million.

Total cost

million.

Initial

support

and

partial

funding

from the

Univ.

$650,000-

$700,000

initially;

further

costs

overlap

with new

creamery

MD was

funded

private

capital;

refused

comment

further

on costs

$1 million

for 1st

startup;

$300,000

for 2nd

startup;

$3-4

million

for 3rd

startup

Grants Grants 50% of

provided construction

2/3 of and

total cost. installation.

50% of

the

total

cost

Grants Grant

provided funds 2/3

of obtained

total cost.

No grant

funds

obtained

No grant

funds

obtained

Grant

funds

obtained

in 2nd

startup

When asked about initial costs, the numbers varied from all four dairies with operational

digesters, O1, O2, O3 and O4; however, all four explained that they received grants from

the state and federal government that covered at least 50% of the initial cost of the

digester. O1 and O4 stated that 2/3rds of the cost of the digester was covered by grants.

The remaining cost was covered by the dairy. Grant funding was a factor that most

participants reported was essential to the decision of installing a methane digester. Six of

the eight participants with digesters, O1, O2, O3, O4, NO1 and NO4 reported they would

not have implemented this technology without substantial grant funding.

Two of four dairies with non-operating digesters, NO1 and NO4, had received

grants that covered some portion of the digester. NO2 dairy stated that their personnel

did not recall receiving any grant funding to build the digester, and that those sorts of

incentives were not available or known to them at the time (2006-2007). NO3 dairy

declined to talk about the cost of the digester, but did state that they did not receive any

grants funds, that it was all private capital.

Unforeseen Costs

Seven of the eight respondents reported the total cost of installing a digester

exceeded initial estimates. The reasons for the increase in cost varied, although most

attributed these extra costs to site-specific configuration or design issues, extended

installation timelines and additional labor costs. Examples of reported site specific

installation costs included; topography of the dairy (having the digester located below the

overflow ponds), high ground water, poor stabilizing soil, the relining of a pond, the

addition of a second pond, and several system reconfigurations, all of which cumulatively

added several months of additional labor and dirt excavation work. The one exception

was NO1, which stated that they could not recall (due to the 16 year laps in time) if the

digester project cost more than initially anticipated.

Although the circumstances were different, similar configuration and design

related installation costs were reported by seven of the eight participants. A few examples

of design issues reported were inadequate piping configurations (too few moisture trap-

filters were used to reduce the amount of hot moist air captured from a lagoon methane

digester systems in route to the generator/engine) and the wear and tear of daily startups

and shutdowns of the generator or diesel engine). These issues resulted in poor output by

the digester and subsequent shutdowns.

Additional labor costs incurred during installation were reported by more than half

of the participants. Poor communication between different industries and fields that often

converge when installing digester systems was reported by one participant as a reason

digester projects fail or incur unforeseen installation costs. One participant mentioned

one reason digester products fail or incur unforeseen installation costs are the

communication between the digester engineers, project managers and the dairyman or

herdsman is mired in disagreement, meaning they are not effective at communicating

both ways, resulting in project delays and additional expense. Most notable was the

experience O2 reported; their methane digester was expected to cost around $2 million

but by the end of the extended site preparation and construction timeline, the total cost

was $4.5 million dollars.

Half of the participants reported installing a digester to complement the

redirection of their overall production with the addition of a cheese making facility or

creamery and/or switching to organic practices. An extreme example of this was NO2,

which reportedly had decided to redirect their entire conventional production operation to

an organic operation, build a creamery and launch a new product line in partnership with

the milk processor Clover Stornetta LLC, (Petaluma). The participant reported that the

initial installation of the methane digestion system incurred many unforeseen costs

including; additional ground excavation costs, site configuration issues, and additional

labor costs to help maintain the digester. The participant further reported mounting costs

to operate and maintain the digester and creamery along with a poor economy were

reported to have led to the closure of the dairy in 2008.

In an extreme case, NO4 reported poor planning and additional labor costs were

believed to be the reasons why their first two methane digesters failed. The participant

reported that a manure vacuum collection method was used in conjunction with a lagoon

digester design, which was said to be incongruous and ultimately problematic. The

producer stated that a significant amount of dirt was collected (along with the manure and

waste water) and transferred to their lagoon methane digester, which resulted in poor

system output. NO4 reportedly did not switch over their waste collection system from a

manure vacuum to a scrape system (as suggested by the manufacturer) believing it would

be too costly at that time. The participant reported that that decision ultimately resulted

in the same problematic plugging in both their first and second methane digesters. The

producer went on to say that unforeseen cost associated with parts and labor to maintain

the generator and the hiring of additional part-time labor to conduct repairs (help clean

out the dirt that plugged up the system) proved too costly and also contributed to the

failure of the first and second digester. NO4 further mentioned that, additional system

upgrades and the assistance of grant funding to mitigate those costs made the second

startup more successful, despite continuing to use a manure vacuum system. However,

NO4 reportedly had to walk away from those grants because the methane digester did not

meet emission standards of the Central Valley Regional Water Quality Control Board.

NO4 concluded that a scrape system was to be part of the third methane digesters system

upgrades, and would be installed by the third party operative (NO4’s third system would

be run exclusively by a third party operative).

Five of the eight participants reported having to hire additional labor to manage

their digester and further stated that the additional expense was not originally factored

into the total cost of owning and operating their methane digester system. The increase in

labor cost reported by O1, O2, O3, NO2 and NO4, coupled with the time and cost to

maintain the required energy output from their methane digester over time (often

attributed to design or normal wear and tear) created unforeseen costs that undermined

the economic feasibility of those of those systems.

Of those participants who reported having to hire a person to manage their

methane digester, most said that hiring someone with a mechanical background rather

than a dairy background was of greater priority (given the technical nature of the system).

A best case scenario can be made for O1, who was able to hire the digester operator at

NO2 (once NO2 was closed and liquidated) to manage the installation and daily

maintenance of their digester fulltime. The methane digester operator at NO2 had been

involved with the installation, and possessed both technical experience and a dairy

management background.

The operator of O1 (formally NO2) was said to be pleased with how the digester

system had performed. However, the producer was not as optimistic in his assessment of

their methane digester, stating that it was hard to put an exact number to how much the

digester was saving the dairy (electricity costs, propane costs, and sourcing and storage of

hot water required) but said he was satisfied none the less. The producer went on to

mention that the mandatory service contract required by PG&E (mentioned previously)

was an additional unforeseen costs that was not originally factored into the decision to

own and operate a methane digester; however this unforeseen cost was considered

fortunate in that the service provided had reportedly contributed to the success of their

digester.

Participants O2, O3 and NO4 shared a similar negative viewpoint with regard to

incurred unforeseen costs and the hiring of additional labor to manage the digester. All

three experienced significant increase in costs associated with initial construction, site

preparation and the increased labor costs with hiring part-time or full-time help to manage

their methane digesters. The personnel hired by those three participants were reported to

have a background in mechanics and little or no experience in the dairy industry.

Ultimately, all three participants referred to their methane digester as being a “bog

project” meaning the initial investment and continuous cost of operating and maintaining

the system along with the decrease in output by the methane digester was considered to

be an ever increasing loss. An extreme case was reported by O2, which in addition to

having to hire a full-time employee to operate the digester after the first year, also

reported having to acquire parts from overseas (their supplier was a German company),

having to arrange shipping for replacement parts, and contend with customs delays,

which amounted to substantial unforeseen costs. The producer went on to say that the

system became a burden because it cost more to operate and maintain than the system

was contributing to their operation. The producer further explained that the expenditure

incurred with the initial investment of O2, together with monthly loan payments and labor

costs and increased hours spent to manage the system, could not be recovered, and by its

second year in operation, hiring a third party operator was the only viable option for

recovering at least some of their loss.

Time Constraints and Commitments

When asked about time constraints and commitments relating to any aspect of

how operating a digester fit into the everyday production schedule of the participants, the

amount of time varied. Half of the participants reported spending anywhere from 20-45

minutes a day on average checking on the digester, and every two to three weeks

spending more time on basic engine maintenance. The other half reportedly spent two to

three hours a day checking and monitoring their methane digester. Two participants, O2

and NO4 went on to say that over a period of years, that amount of time increased to four

to five hours/day spent maintaining their digester. The participants reported the reason

for this was a decrease digester output over time, eventually leading to contract with a

third party operator. Similarly, O3 reported that it was necessary to hire a fulltime

employee to run the four engines needed to handle the seven acre lagoon digester’s gas

production.

When asked how much time was taken to consider installing this technology, all

eight participants with digesters reported that it took a year or more to fully research the

topic and come to a decision. O1 reported that they had considered the idea of a methane

digester for awhile, ever since the installation of a methane digester system at nearby

dairy, Straus Family Creamery Dairy (Marshall), but not until they had visited several

dairies with digesters, conducted an energy audit, and determined that a methane digester

would best suit their needs, did they implement one.

Similarly, O2 dairy stated they visited several dairies with methane digesters in

California and the Midwest and considered many different designs, including those used

in Europe. Eventually, they reportedly decided on a German company because of it its

simplistic design (an above ground configuration), overall efficiency, and fewer moving

parts. In contrast, O4 dairy stated they knew they wanted to incorporate the use of a

digester eight years before (when they acquired the dairy). O4 reported the main reason

for installing a methane digestion system was that they felt it would best integrate their

waste management and soil nutrient management programs.

One participant, an environmental law attorney with family ties to the dairy

industry and CEO of the bio-tech firm Energy Solutions LLC, when asked how long he

had considered implementing this technology, replied that it took years to learn about

how digesters work, eight months to negotiate a contract with the utilities, another nine

months to figure out how to build one, and then another nine months to actually build a

methane digester. More than most people wanted to know.

Motivation for Adoption

Seven of the eight participants reported the aim of incorporating environmentally

friendly and renewable energy practices was a primary motivation for adoption of this

technology, meaning those respondents reported a desire to both introduce green energy

practices and reduce their on-site energy costs as the primary motivators. Limited

facilities and land was also reported by every participant in the group to be another

important reason to implement this technology since a digester would reduce the amount

of land needed to store manure waste for later for application to pasture and/or crops or

for transport to an off-site location.

Although, almost all participants stated that a desire to produce renewable energy

was the primary reason for implementing this technology. O4 was an exception to this

because the motivation to install their digester system first to improve their nutrient and

waste management system and second to generate renewable energy. The lack of

available land was reported to be problematic, because they had no place to treat and

store their manure waste, and that prior to installing the methane digester they had

shipped wet manure to an off-site location. The producer went on explain that shipping

wet manure was costly (and messy) and more importantly, posed additional nutrient

management issues. The participant then stated that in their case, a fortunate combination

of their dairy’s layout characteristics; an above ground tank configuration, with a scrape

waste removal system, that slopes downhill from the barns and sits alongside a natural

gas line allowing easy access to the grid, was said to be the reason for their digester

success.

Four participants, O1, O2, O3 and NO2, reported partial motivation to install a

digester came from a desire to better address the needs of their cheese making or

creamery facilities. Producers reported the additional waste produced by the cheese

making or creamery facility was fed to the digester as an input instead of sold as another

product, due to smaller economies of scale, and the waste water and cheese byproducts

(curds and whey) from the cheese making facility and milk fats from the creamery was

then converted into energy as an output. Participants reported that all the energy output

from their digester was then used for either electricity, for sourcing and collecting heat for

a boiler used in the cheese making plant, and for nutrient management in their pastures.

The four participants went on to say that they had also utilized the separated solids left

over from anaerobic digestion, for bedding for cows and/or to sell peat moss or fertilizer

to local nurseries.

Two participants, NO1 and NO3, also reported entrepreneurial motivation for

installing a digester. NO1 was a pilot project by a resident professional designer Doug

Williams P.E., PhD, a leader in anaerobic digester research, at Cal Poly State University

(previously mentioned), who stated that the University methane digester pilot project was

the impetus to later found Williams Engineering Associates an engineering service

company that has designed digesters throughout California. NO3 was a flagship project

for BioEnergy Solutions (Bakersfield) in 2008 (previously mentioned). The firms CEO

possessed a degree in environmental law who had over 10 years of experience negotiating

contracts between utilities and dairies looking to implement digesters.

Issues Related to Expectations and Performance

When participants were asked about their initial expectations and performance of

their digester, six of the eight participants reported that their initial expectations were met

with regard to digester performance and energy output, but that’s where the similarities

ended. The two participants, NO2 and NO4 who experienced performance issues from

the start, explained that as a result would operate their methane digesters intermittently,

which was hard on their generator/engine causing excess wear. This problem was

reportedly further exacerbated by increased load levels, from too much manure waste

added at one time, when their methane digester was operating.

NO4 went on to report that they were dismayed with regard to expectations and

performance of the digester during both startups. The producer stated that he anticipated

being able to operate their methane digester without much trouble, however once their

methane digester was installed, the producer reported that he was unable understand the

components, chiefly the complexity of the gages and control levers, and further stated that

he was completely in over his head following the installation of their first digester in

1985. NO4 further explained that technical and management issues with the amount of

management time required to operate the methane digester, and not meeting emission

regulations, coupled with their decision to use a vacuum system instead of replacing it

with a scrape system (as previously mentioned), added to the overall poor performance of

the first two startups.

Two participants reported that for the first 6-12 months expectations were met, but

were ultimately dissatisfied. Reported the performances of O2 and O3 diminished after

the first year. The operational and maintenance costs specific to the design of O2 (a

German company designed the digester), configured to meet Germany’s emission

regulation standards were different from those in California. As a result producer became

disenchanted with the technology in general and handed it over to a third party to

manage. Similar performance issues were reported in O3 with regard to diminishing

energy output and increasing operational and maintenance costs over time. The operator

explained that the seven acre lagoon style digester had reportedly filled with too many

solids and as a result may soon be shut down permanently due to insufficient solid

separation. Technical issues and maintenance costs required to keep the digester

operational were considered prohibitive. These costs were reported to include a new

cover, clearing out the system of dirt, and technical issues with the circulation pump. The

participant went on to explain that these costs combined with the dairy’s change in

leadership, meaning those who originally advocated for the adoption of the digester are

no longer there, has led to an overall feeling of dissatisfaction.

When given the opportunity to further explain any additional performance

exceptions, six of the eight participants reportedly thought their digesters would be able

to accomplish more than they did. One participant (O4) reportedly met all expectations

as a waste management and nutrient management tool, but the participant further

mentioned that they thought the methane digester would have delivered a more

significant byproduct revenue stream. They had hoped to sell the separated solids from

the digester as compost to local plant nurseries. Similarly, O1 was reported to have met

expectations as an environmentally friendly renewable energy source, as a nutrient waste

management tool and by providing usable by-products, such as bedding; however, the

producer was disappointed to find the methane digester covered many, but not all of the

dairy’s energy needs.

NO3 was the only system which reportedly exceeded expectations with regard to

digester output; however, poor communication resulted in two project expectations that

were not met. The first was the problematic communication issues during the planning

and installation process. The second issue was the poor communication between the

dairy and the utility company. The participant explained that their project engineers did

not configure the layout of the methane digester system properly, and instead positioned

the overflow pipe from the digester to the lagoon in such a way as to move the manure

uphill, which is counterintuitive to most dairy industry people. Similarly, the

communication between the utilities was also reported to be problematic, seven different

times, a lower than usual output from the digester was detected by PG&E, and when

investigated by the dairy, the digester was found to be operating effectively. The

participant went on to explain that the issue was with PG&E’s faulty stop values, which

had malfunctioned, and would not allow the gas to enter into the utility gas pipeline. The

participant stated that PG&E was not required to maintain their system to the same

standards as the dairy.

Somewhat surprisingly five of the eight participants, O1, O4, NO1, NO3 and

NO4, reported that they would reinvest in this technology again, while O2, O3 and NO2,

reported that they would not reinvest in this technology and would have preferred to

invest in traditional waste management systems. The participants who reported that they

would reinvest further stated that they believed in this technology, and felt that it made

the most sense for the future of the dairy industry. However, many qualified their

response by further recommended that anyone looking to adopt this technology should do

their homework, meaning they should visit as many digesters as possible—all over the

world, study their financial requirements, make use of available grant funding, research

emerging technologies, understand the geographic location and relation to certain

utilities, and be familiar with the regulations in that area.

Issues for Considering Adoption

We now switch gears and examine the results of the group of dairies considering

methane digesters. The reported impetus for considering adoption varies, but some

similarities were noted. Those participants considering adopting methane digester

technology were asked to comment on the amount of time considering installing a

digester, economic feasibility, expectations for operating and maintaining this technology,

and any other issues. A summary of background information collected from those

participants considering adoption were reported in Table 6.

When asked about the amount of time the participant spent considering and/or

researching this technology, most had done little research. One producer explained that

the process was time consuming and estimated that it would take two or more hours a

day, for two weeks to research this technology properly, on top of all the daily production

requirements. The producer then went on to explain that regardless of their decision,

whether to install a digester or not, the banks were not too friendly to dairymen and that

as a small dairy with less than 300 head (small by California dairy farm standards), they

could not afford such a capital intensive investment.

Table 6. Summary of Background Data Collected from Participants Considering

Adoption.

Dairy Producer

CA1 CA2 CA3 CA4

Herd Size 240 1500 800 700

Intended

Digester

Operator

Owner Owner &

Employee

Employee Employee

Primary

Issues/

Motivation

Renewable

Energy

Waste

Management &

Organics

Organics Renewable

Energy &

Organics

Expectations Feasible at

<300

Economically

Feasible &

Income

Generating

Economically

Feasible

Economically

Feasible

All four of the participants in this group stated that they were interested in the

future of this technology, but found cost to be the most prohibitive barrier. One

participant stated that they would expect methane digester technology to be able to pay

for itself within a few years, and further stated that sustainability depended on energy

rates greatly improving. Another participant mentioned that they would expect such a

significant investment of capital and space (not all dairies have the space for it) should be

economically feasible and income generating.

When questioned about the possibility of contracting with a third party operative,

all four participants seemed open to the notion of having less responsibility and said

further they would rather tend to their cows. One participant reported that the first

digester he had known about was at the Grossi dairy (installed in Marin in the 1970’s),

and said that it was extremely time consuming, and that there was not enough time in the

day to add a labor intensive technology.

Most of the participants commented that they expected a digester to require little

maintenance and minimal supervision. Two of the four participants, CA2 and CA3

commented that manure is a highly caustic and corrosive substance that quickly erodes

machinery, and felt that a methane digestion system and had the potential to breakdown

often. CA2 further stated that they had installed a manure separator to produce much and

bedding, a component that is part of most digester designs, and was not happy with the

machinery. The participant explained that the separator was always breaking down and

required constant maintenance and felt a methane digestion system would be no different.

One participant reportedly received a proposal from RCM Digesters, an anaerobic

digester design and manufacturing company a year ago, but was not confident that the

technology would be able to meet their expectations of being able to pay for itself and

then some. They then decided that it was not worth considering further. The estimated

costs were approximately $3.5-4 million, and after deducting qualifying grants would

cost the dairy around $600,000 out of pocket. The producer went on to say that they

already had a separator that converts their manure into dry bedding that they were not

completely satisfied with it. The producers reported to be very interested in a smarter

way to handle their waste, but in regard to methane digesters felt that economically the

technology didn’t make sense.

One participant noted that regional differences could impact the feasibility of

methane digesters. Coastal Northern California dairies, for example, were reported to be

very different from those in the Central Valley, where the majority of digesters have been

implemented, because of regional climate differences and/or economies of scale. Dairies

in the Central Valley are regionally drier with little to no pasture available, herds are

larger and cows are typically kept in housing sheds and on dry lots. In contrast, coastal

Northern California dairies experience greater rainfall and precipitation providing pasture

throughout the year, herds are smaller and cows are kept out on pasture most of the time.

These separate conditions create different economies of scale between the two regions

and participants believed further development of this technology would be needed to

improve economic feasibility of methane digestion systems on coastal Northern

California Dairies.

Most participants considered the integration of methane digester and organic

practices an issue of significant importance, since coastal Northern California dairies

provide most of the organic milk produced in California, when they considered adopting

this technology. Three of the four participants were interested in how a digester system

would fit into current organic pasture management standards. One participant

commented on the fact that organic herds are required to remain out on pasture for a

certain number of days, and that methane digesters seemed counterproductive to the idea

of a digester, meaning there wouldn’t be enough volume to make the amount of energy

required to be feasible as a renewable energy source. Another participant motivated by

the renewable energy aspect and possible application to organic dairy practices reported

that after researching the issues decided there were other “green,” but less capital

intensive ways of handling manure that better fit their production needs.

All four dairies said they would not invest in this technology at this time.

Hypothesis Testing

Participant response were analyzed, sorted and objectively categorize which

allowed for the researcher to discover patterns among the responses and to identify

specific insights, and response consistency. A coding label triage sorted responses into

three categories that allowed the researcher to test the hypothesis and are reported in

Table 7. The sorted response were placed into three categories; those participants who

reported a high competence or confidence and/or positive experience/opinion (C1), those

participants who reported a mid-level competence or confidence or fluctuating opinion

(C2), and those with a low level competence or confidence or having a negative opinion

of MD technology (C3).

Table 7. Summation of Category Coding of Responses Used in the Analysis data for of

the Adoption of Methane Digestions on California Dairies.

Dairy Category Response Summary

O1 C1 Digester Operational. Reinvest as long as grants were available. Confident and

competent at troubleshooting and maintenance. Adoption mostly positive outlook.

O2 C3 Digester Operational. 3rd party contract. Would not reinvest. Not confident or

competent with troubleshooting and technology. Mostly middle or negative

outlook on adoption.

O3 C3 Digester Operational. Considering Shutdown. Would not reinvest. Not confident,

but competent with troubleshooting and technology. Adoption mostly negative

outlook.

O4 C1 Digester Operational. 3rd party contract. Would reinvest. Confident at

troubleshooting and technology. Adoption mostly positive outlook.

NO1 C2 Digester Non-operational. Would tentatively reinvest. Confident and competent

at troubleshooting and technology. Designer is optimistic but university cautious

due to funding.

NO2 C3

Digester Non-operational, dairy closed. Would not reinvest. Not confident or

competent at troubleshooting and technology. Adoption mostly mid-level outlook.

NO3 C2 Digester Non-operational, dairy is closed. Would reinvest. Confident and

competent at troubleshooting and technology. Adoption mostly positive outlook.

NO4 C2 Digester Non-operational. Restart Pending with 3rd party contract. Would

reinvest. Confident but not competent at troubleshooting and maintenance. Very

negative about regulatory burdens. Adoption mostly middle level outlook.

CA1 C3 Considering, but would not invest. Not confident at troubleshooting and

maintenance. Interest in renewable energy. Adoption mid-level outlook.

CA2 C3 Considering, but would not invest. Confident and competent at troubleshooting

and maintenance. Interest in waste management and organics. Adoption negative

outlook.

CA3 C3 Considering, but would not invest. Not confident at troubleshooting and

technology. Interest in organics. Adoption negative outlook.

CA4 C3 Considering, but would not invest. Confident but not competent at

troubleshooting and technology. Interest in renewable energy and organics.

Adoption mid-level outlook.

CHAPTER V

SUMMARY, CONCLUSIONS AND RECOMMENDATIONS

Summary

The objective of this study was to identify qualitative reasons why methane

digester technology has not been widely adopted on California dairies, and to determine

whether or not a lack of training and technical support in the operation and maintenance

of methane digesters technology has resulted in low adoption rates at the farm level.

Additional objectives were to assess the level of real world feasibility of this technology

and to assess dairy farmers’ concerns and problems with installation, operation and

maintenance of these systems. The final objective was to identify any issues associated

with digester technology specific to California. The most compelling results of the study

showed that a lack of training and support has contributed to low success rates and thus

low adoption rates at the farm level. In order for widespread adoption to be feasible, a

long-term service plan or third party operative would need to be in place prior to

implementation.

Similar to past studies, hefty initial costs of installing a methane digester system,

combined with low negotiated energy prices and changing emissions regulations were

said to be the main economic reasons for a lack of adoption in California. Further, it was

observed that most opinions of widespread adoption at the farm level to be negative,

regardless of whether or not a dairy would invest or reinvest in the technology. Producers

understand that the price of this technology, even with grant funding, is more costly and

time consuming then they are willing to take on. In addition, the decreasing numbers of

dairies—particularly small family run dairies in the State of California leave many

reluctant to take on such large capital investment in a system that would take up valuable

space on a dairy and would ultimately require a decades-long commitment. Producers

were clear about not wanting to take on more debt or additional projects requiring any

major time commitment.

Regarding the level of real world apparent success or failure of this technology, a

low level of understanding and communication with regard to ongoing time and labor

costs or competence in the degree of training and support required in the installation and

long-term operation and maintenance of methane digesters was observed. Producers

consistently report a lack of long term technical support as an issue that affects those

methane digesters in operation, and as a primary contributor to the failure of non

operational systems, which has further contributed to the lack of wide spread adoption at

the farm level.

In addition, it was observed that a dairy’s primary motivation for implementing a

methane digester was for renewable energy production at the farm level, but what they

actually implemented was a 24 hour, seven day a week, entirely new waste management

system with limited or no training or support services; it would be similar to adding a

whole new department or product line. Dairymen want to tend their cows rather than

learn and manage a potentially time intensive technical and biological system. This leads

the researcher to believe that if methane digesters were projected as a whole new waste

management system or field of operation, rather than focusing primarily on the renewable

energy aspect, dairies would have a better understanding of what would be required to

successfully incorporate a methane digester into their operation. Further, it was observed

that participants with a third party management contract were the most content and

successful with their digester systems.

Issues directly and indirectly associated with preventing methane digester

technology from being widely adopted at the farm level include region specific dairy

management approaches to production and changing emissions regulations. The

Regional Water Quality Control Boards General Order in the Central Valley is an example

of a regulation policy specific to one region of California that encourages the adoption of

methane digester on conventional dairies (those with high animal density), but does not

apply to coastal milk producing counties. Participants felt the two regions and their

requirements to be separate, with methane digesters perceived to be counterproductive to

organic dairy practices, in part because of the required amount of days on pasture. In

addition, in coastal Northern California dairies, where the majority of organic milk is

sourced, participants consider digesters most beneficial to dairies with multiple energy

end uses, such as those with a cheese making plant or creamery.

Producers considering this technology were specifically interested in the

renewable energy aspect of this technology and its possible pairing with the organic dairy

market. Waste management was also thought to be another issue driving the

consideration of this technology, and interest in adoption of this technology increased

when the involvement of a third party management company was discussed as an option.

Conclusions

The purpose of this study was to determine if a lack of training and technical

support of the various mechanical and management issues associated with methane

digesters had directly contributed to the lack of widespread adoption of this technology at

the farm level. The finding of this study is that the qualitative data collected is persuasive

enough to conclude that a lack of training and technical support of the various mechanical

and management issues associated with methane digesters, has directly contributed to the

low widespread adoption of this technology at the farm level.

Recommendations

The findings of this study emphasize the overall impression of a lack of

comprehensive technical and biological competence required to operate and maintain a

digester over the long-run is complex and was not fully understood by most participants

with firsthand knowledge. Dairymen with operational and non-operational methane

digesters did not know what they were getting themselves into, and that a lack of

troubleshooting tools and technical support directly contributed to the non-operative

status of most shut down systems.

Methane digesters were shown to require more time and knowledge than

anecdotal evidence provides to an industry that has traditionally been conservative and

which is now evolving rapidly. It is the recommendation of this study is to address

underlying issues related to a lack of troubleshooting services available, such as online

monitoring and 24 hour tech support.

Any proposal to implement a methane digester should have a plausible

comprehensive service agreement, for the life of the machine or system. This may come

in the form of a third party service contract or lease agreement between the dairy and an

outside digester management company, for the estimated life of the machine.

Technical research on methane digester operations should be ongoing and done in

a way to encourage adoption of an innovative waste management system, and then

secondly as a renewable energy source. In addition, important issues that would need to

be addressed in future studies on costs associated with digester system update(s) or

repairs including: any and all engine or digester replacement parts, shipping costs, labor

costs, an alternate waste management plan for times when the digester is being serviced

or updated, should be incorporated into the assessment of any feasibility study, cost

benefit analysis or contractual service agreement.

Possible implications of this study point to the emergence of a third party

management company market, as a industry service sector that could provide many of the

technical and biological competence could contribute to the widespread adoption of

methane digesters in California.

AGB 100-INTRODUCTION California is the leading dairy producing

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