Reading Reflection 2

MetabolismofCities.pdf

Home >English homework help >Article writing homework help >Reading Reflection 2

“The Metabolism of Cities” from Creating Sustainable Cities (1999)

Herbert Girardet

Editors’ Introduction

The flow of natural resources into cities and wastes out of them represents one of the largest challenges to urban sustainability. Many argue that cities must “close the resource loop” by recycling, reusing, re-manufac- turing, and otherwise diverting materials from their usual destination in landfills and incinerators. Reducing consumption in the first place is also seen as important. Likewise, more efficient urban uses of energy can be sought to reduce dependence on nonrenewable fossil fuels, and renewable energy sources developed such as wind power (the world’s fastest growing alternative energy source), solar power, geothermal energy, biomass conversion (the burning of organic materials for energy), and cogeneration (the use of waste energy or steam from one industrial process for heat or power).

Herbert Girardet has written eloquently on urban resource flows particularly as they affect the city of London. He has produced many television documentaries on urban sustainability, and has received a United Nations Global 500 Award “for outstanding environmental achievements.” He is the author of Surviving the Century: Facing Climate Change and Other Challenges (London: Earthscan, 2007), Cities People Planet: Urban Development and Climate Change (Hoboken, NJ: Wiley-Academy, 2008), and Creating Regenerative Cities (London: Routledge, 2014). His analysis follows in the footsteps of other “appropriate technology” advocates including the great environmental philosopher E.F. Schumacher, author of Small is Beautiful: Eco- nomics as if People Mattered (New York: Harper & Row, 1973), and energy guru Amory Lovins, author of Soft Energy Paths: Toward a Durable Peace (San Francisco: Friends of the Earth, 1977), Natural Capitalism: Creating the Next Industrial Revolution (with Paul Hawken and L. Hunter Lovins, London: Earthscan, 1999), and Reinventing Fire: Bold Business Solutions for the New Energy Era (White River Junction, VT: Chelsea Green, 2011).

The growing understanding developed by the

natural sciences of the way ecosystems function

has a major contribution to make to solving the

problems of urban sustainability. Cities, like other

assemblies of organisms, have a definable meta-

bolism, consisting of the flow of resources and pro-

ducts through the urban system for the benefit of urban

populations. Given the vast scale of urbanization

cities would be well advised to model themselves

on the functioning of natural ecosystems, such as

forests, to assure their long-term viability. Nature’s own

ecosystems have an essentially circular metabolism

in which every output which is discharged by an

organism also becomes an input which renews and

sustains the continuity of the whole living environ-

ment of which it is a part. The whole web of life

Wheeler, S. M., & Beatley, T. (Eds.). (2014). Sustainable urban development reader. ProQuest Ebook Central <a onclick=window.open('http://ebookcentral.proquest.com','_blank') href='http://ebookcentral.proquest.com' target='_blank' style='cursor: pointer;'>http://ebookcentral.proquest.com</a> Created from asulib-ebooks on 2020-08-19 19:19:53.

C op

yr ig

ht ©

2 01

4. T

ay lo

r &

F ra

nc is

G ro

up . A

ll rig

ht s

re se

rv ed

H E R B E R T G I R A R D E T198

hangs together in a “chain of mutual benefit,”

through the flow of nutrients that pass from one

organism to another.

The metabolism of most modern cities, in

contrast, is essentially linear, with resources being

‘pumped’ through the urban system without much

concern about their origin or about the destination

of wastes, resulting in the discharge of vast amounts

of waste products incompatible with natural systems.

In urban management, inputs and outputs are con-

sidered as largely unconnected. Food is imported

into cities, consumed, and discharged as sewage

into rivers and coastal waters. Raw materials are

extracted from nature, combined and processed

into consumer goods that ultimately end up as

rubbish which can’t be beneficially reabsorbed into

the natural world. More often than not, wastes end

up in some landfill site where organic materials are

mixed indiscriminately with metals, plastics, glass,

and poisonous residues.

This linear model of urban production, consump-

tion, and disposal is unsustainable and undermines

the overall ecological viability of urban systems,

for it has the tendency to disrupt natural cycles. In

the future, cities need to function quite differently.

On a predominantly urban planet, cities will need

to adopt circular metabolic systems to assure their

own long-term viability and that of the rural envi-

ronments on whose sustained productivity they

depend. To improve the urban metabolism, and

to reduce the ecological footprint of cities, the

application of ecological systems thinking needs

to become prominent on the urban agenda. Outputs

will also need to be inputs into the production system,

with routine recycling of paper, metals, plastic and

glass, and the conversion of organic materials, includ-

ing sewage, into compost, returning plant nutrients

back to the farmland that feeds the cities.

The local effects of the resource use of cities

also need to be better understood. Urban systems

accumulate vast quantities of materials. Vienna,

for instance, with 1.6 million inhabitants, every day

increases its actual weight by some 25,000 tons.1

Much of this is relatively inert materials, such as

concrete and tarmac which are part of the built

fabric of the city. Other materials, such as lead,

cadmium metals, nitrates, phosphates, or chlorinated

hydrocarbons, build up and leach into the local

environment in small, even minute quantities, with

discernible environmental effects: they accumulate

in water and in the soil over time, with potential

consequences for the health of present and future

inhabitants. The water table under large parts of

London, for instance, has become unusable for

drinking water because of accumulations of toxins

over the last 200 years. Much of its soil is polluted

by the accumulation of heavy metals during the

last 50 years.

The critical question today, as humanity moves

to “full scale” urbanization, is whether living stand-

ards in our cities can be maintained whilst curbing

their local and global environmental impacts. To

answer this question, it helps to draw up balance

sheets quantifying the environmental impacts of

urbanization. We now need figures to compare

the resource use by different cities. It is becoming

apparent that similar-sized cities supply their needs

with a greatly varying throughput of resources, and

local pollution levels. The critical point is that

cities and their people could massively reduce their

throughput of resources, maintaining a good stand-

ard of living creating much needed local jobs in

1 Inputs (tons per year)

Total tons of fuel, oil equivalent 20,000,000

Oxygen 40,000,000

Water 1,002,000,000

Food 2,400,000

Timber 1,200,000

Paper 2,200,000

Plastics 2,100,000

Glass 360,000

Cement 1,940,000

Bricks, blocks, sand, and tarmac 6,000,000

Metals (total) 1,200,000

2 Wastes

CO2 60,000,000

SO2 400,000

NOX 280,000

Wet, digested sewage sludge 7,500,000

Industrial and demolition wastes 11,400,000

Household, civic, and

commercial wastes

3,900,000

Source: Compiled by Herbert Girardet (1995, 1996); sources available from author.

Table 1 The metabolism of Greater London (population 7 million).

C op

yr ig

ht ©

2 01

4. T

ay lo

r &

F ra

nc is

G ro

up . A

ll rig

ht s

re se

rv ed

199“ T H E M E T A B O L I S M O F C I T I E S ”

T W O

the process. I shall now discuss aspects of urban

use of resources and energy in more detail.

WATER AND SEWAGE

Our cities consume vast amounts of water: in the

UK, typically, some 400 liters per person per day.

In the US the figure is as high as 600 litres. In older

cities, such as London, water has to be pumped in

from elsewhere because it is exceedingly costly to

clean it to drinking water standards. Cities extern-

alize the problem. The abstraction of river water,

often many miles away from cities, has caused the

destruction of river habitats and fisheries; today,

many rivers’ supply are a pale shadow of their

former selves.

Water supplied to households, even if supplied

from outside cities, goes through various treatment

processes. River water, a source of supply in most

countries, has to be cleaned of impurities, including

pesticides, phosphates and nitrates from farming.

The water is percolated through sand and charcoal

filter beds before it is pumped into a city’s network

of water pipes. Chlorination, which is common-

place, disinfects drinking water, but its unpleasant

taste causes many people to switch to bottled drink-

ing water instead. This does not make financial

sense, since bottled water, at up to 60p per litre,

is often more expensive than the petrol we put in

the tanks of our cars. Neither does it make sense

environmentally, with vast quantities of bottled

water being trucked in from hundreds or even thou-

sands of miles away at great energy cost. It would

be desirable to ensure that the quality of urban

water could be high enough for it to be commonly

used for drinking once again.

Unfortunately, a major function of urban water

supply is as a carrier for household and commercial

sewage. For this and other reasons, urban sewage

systems are of an important issue in the quest

for urban sustainability. Their main purpose is to

collect human faeces and to separate it from

people, to help prevent outbreaks of diseases such

as cholera or typhoid. As a result, vast quantities

of sewage are flushed away into rivers and coastal

waters downstream from population centers.

Coastal waters the world over are enriched both

with human sewage and toxic effluents, as well

as the run-off of mineral fertilizer and pesticides

applied to the farmland feeding cities. The fertility

taken from farms in the form of crops used to feed

city people is not returned to the land. This open

loop is not sustainable.

Whilst it is clear that cities need to have efficient

sewerage systems, we need to redefine their pur-

pose. Instead of building disposal systems we should

construct recycling facilities in which sewage can

be treated so that the main output is fertilizers

suitable for farms, orchards, and market gardens.

It has been too readily forgotten that sewage con-

tains an abundance of valuable nutrients such as

nitrates, potash, and phosphates. Returning these

from cities to the land is an essential aspect of

sustainable urban development.

A variety of new sewerage systems have been

developed for this purpose using several new tech-

nologies: membrane systems that separate sewage

from any contaminants; so-called “living machines”

that purify sewage by biological methods; and dry-

ing technology which converts sewage into granules

that can be used as fertilizer. These technologies

can be used in combination with each other, making

sewerage facilities into efficient fertilizer factories.

These sorts of systems are now beginning to be

used in cities all over the world.

In Bristol, the water and sewage company

Wessex Water now dries and granulates all of the

city’s sewage. The annual sewage output of 600,000

people is turned into 10,000 tons of fertilizer granules.

Most of it is currently used to revitalize the bleak

slag heaps around former mining towns such as

Merthyr Tydfil in South East Wales. In contrast,

Thames Water in London is currently constructing

incinerators for burning the sewage sludge produced

by 4 million Londoners. This is a decision of

historic short-sightedness given that phosphates –

only available from North Africa and Russia –

are likely to be in short supply within decades.

Crops for feeding cities cannot be grown without

phosphates.

There is an acknowledged problem with the

contamination of sewage with heavy metals and

chlorinated hydrocarbons. For this reason, there is

growing concern about using sewage-derived fertilizer

on farmland. However, the reduction of the use of

lead in vehicle fuel and the de-industrialization of

our cities is reducing this problem, lessening the load

of contaminants that are flushed into sewage pipes.

Also, more stringent environmental legislation is

C op

yr ig

ht ©

2 01

4. T

ay lo

r &

F ra

nc is

G ro

up . A

ll rig

ht s

re se

rv ed

H E R B E R T G I R A R D E T200

further reducing contamination of sewage. The

quest for greater urban sustainability will certainly

lead to a significant rethink on how we design sew-

erage systems. The aim should be to build systems

to intercept the nutrients contained in sewage whilst

assuring that it can be turned into safe fertilizers

for the farmland feeding cities.

SOLID WASTE

Solid waste is the most visible output by cities.

In recent decades there has been a substantial

increase in solid waste produced per head, and

the waste mix has become ever more complex.

Today’s “garbologists” see a vast difference between

early and late twentieth century rubbish dumps.

The former contain objects such as horse shoes,

enamelled saucepans, pottery fragments and leather

straps. The latter contain food wastes, plastic bags

and containers, disposable nappies, mattresses,

newspapers, magazines and transistor radios. But

garbologists will also find plenty of discarded

building materials, and crushed canisters containing

various undefined, sometimes highly poisonous,

liquids.

Urban wastes used to be dumped primarily in

holes in the ground. Much of London’s waste, for

instance, is dumped in a few huge tips, such as at

Mucking on the Thames in Essex. Household waste,

as well as commercial and industrial waste, is taken

here by central London, and “co-disposed” in pits

lined with clay. The compacted rubbish is, eventu-

ally, sealed with a top layer of clay, which is then

covered with soil and seeded with grass. Inside the

dump, methane gas from the rotting waste is

now intercepted in plastic pipes and used to run

small power stations. However, their output is quite

insignificant. Mucking receives the rubbish of some

2 million people, but its methane-powered genera-

tors supply electricity to just 30,000 people.2

More and more cities, including London, are

seeing growing resistance from people in adjoining

counties on receiving urban wastes; all the envir-

onmental implications of fleets of rubbish trucks,

potential groundwater contamination, and stench

in the vicinity of waste dumps are a growing con-

cern. As the unwillingness to receive rubbish grows,

other waste disposal options are urgently required.

Dumping ever growing mounds of waste outside

the cities where they originate is a waste of both

space and resources that be used more beneficially.

We need to think again about the ways in which

urban waste management systems work. Many

cities all over the world have chosen incineration

as the most convenient route for “modern” waste

management. Incineration has the advantages of

reducing waste materials to a small percentage of

their original volume. Energy recovery can be an

added bonus. But incineration is certainly not the

main option for solving urban waste problems. The

release of dioxins and other poisonous gases from

the smokestacks of waste incinerators has given

them a bad name. There have been great improve-

ments in incineration and pollution control tech-

niques, but only those wastes that cannot be

recycled should be considered for incineration.

Recently, new objections to incinerators have

been voiced in the United States because research

has shown conclusively that incinerators compare

badly with recycling in terms of energy conserva-

tion. Because of the high energy content of many

manufactured products that end up in the rubbish

bin, recycling paper, plastics, rubber and textiles

is three to six [times] more energy-efficient than

incineration. These are very significant figures,

given that the energy and resource efficiency of

urban systems is regarded as critical for future

urban sustainability.3 Many European cities are now

deciding against investing in new incinerators, and

in favor of a combination of recycling and compost-

ing facilities instead, with minimal incineration for

waste products that cannot be further recycled.

It has been said that recycling is a red herring

because it is so difficult to match the supply

of materials to be recycled with regular demand

for recycled products. But experiences in many

European cities indicate that market incentives

can make recycling economically advantageous

and that the right policy signals and incentives at

national and local level can transform prospects.

Whilst not all waste materials can be recycled,

much can be done to move in this direction. As

concern grows about the continuing viability of the

environments on which cities depend, the reuse

and recycling of solid wastes is likely to become

the rule rather than the exception. Deliberately

constructing ‘chains of use’ that mimic natural eco-

systems will be an important step forward for both

industrial and urban ecology.

C op

yr ig

ht ©

2 01

4. T

ay lo

r &

F ra

nc is

G ro

up . A

ll rig

ht s

re se

rv ed

201“ T H E M E T A B O L I S M O F C I T I E S ”

T W O

Some modern cities have already made this

a top priority. Cities across Europe are installing

waste recycling and composting equipment. In

German towns and cities, for instance, dozens of

new composting plants are being constructed. In

Sweden, Gothenburg has taken matters even further

by setting up an ambitious program for developing

“eco-cycles,” minimizing the leakage of toxic sub-

stances into the local environment by helping com-

panies develop advanced non-polluting production

processes.4 Vienna also has an impressive track

record, currently recycling 43 percent of its domestic

wastes.5 This sort of figure is common to a growing

number of European and American cities.

Most European cities exceed the household

waste recycling performance of cities in the UK.6

In some British cities, such as Bath and Leicester,

where recycling has advanced a great deal, the

benefits for people and the local environment are

clearly apparent. The UK landfill tax, introduced

in 1996, has increased recycling throughout the

UK, helping to achieve the government target of

25 percent household waste recycling by 2000. This

taxation should be extended to approximate a

recycling rate of 50 percent, which is the target in

other European countries.

In London, where currently only 7 percent of

household waste is recycled, a proposal by the

London Planning Advisory Council is intended to

bring recycling up to unprecedented levels. By

2000, every London home would have a recycling

box with separate compartments instead of con-

ventional dustbins. Progressively more and more

municipal waste would be recycled, establishing new

reprocessing industries and creating 1,500 new jobs.7

Early in the new century, this figure would increase

further. Meanwhile, the composting of organic

wastes is advancing well, with ‘timber stations’ that

compost shredded branches of pruned trees and

leaf litter being established in various locations.

Throughout the developing world, too, cities

have made it their business to encourage recycling

and composting of wastes.8 Cairo, Manila, and

Calcutta are interesting cases in point.

ENERGY

Looking down on the Earth from space at night,

astronauts see an illuminated planet – vast city

BOX 1 How Cairo recycles its waste

Cities in the developing world usually make highly efficient use of resources, particularly if people are supported in their recycling activities. Cairo and Manila actively encourage recycling and composting of wastes. There are a growing number of cities that are actually moving to- wards being zero-waste systems. Cairo, with 15 million people one of the world’s largest cities, reuses and recycles most of its solid waste. Much of it is handled by a community of Coptic Christians called the Zaballeen. With the active support of the city authorities, the Zaballeen were able to acquire recycling and composting equipment. Metals and plastics are remanufactured into new products. Waste paper is reprocessed into new paper and card- board. Rags are shredded and made into sacks and other products. Organic matter is compos- ted and returned to the surrounding farmland as fertilizer.

The Zaballeen Environment and Development Programme has enabled the 10,000 strong community to substantially increase its income from its recycling and remanufacturing activities. In that way, social and environmental problems affecting Cairo are tackled simultaneously. Had the waste management of the city been given over to a conventional waste management com- pany, thousands of waste collectors would have been out of work. By helping the Zaballeen with appropriate technology, they were able to improve on their traditional waste-handling methods, while Cairo could avoid putting vast waste dumps on the periphery of the city.

In the case of solid waste management, cities in the North have much to learn from the ingenuity of waste recycling in the South. Meanwhile, cities in the South could greatly benefit from the transfer of improved recycling technologies now available in the North.

C op

yr ig

ht ©

2 01

4. T

ay lo

r &

F ra

nc is

G ro

up . A

ll rig

ht s

re se

rv ed

H E R B E R T G I R A R D E T202

clusters lit up by millions of light bulbs as well as

the flares of oil wells and refineries. Fossil fuels

have made us what we are today – an urban–

industrial species. Without the power stations they

supply and the vehicles they power, our urban life-

styles and our astonishing physical mobility would

not have developed.

Worldwide, fossil fuel use in the last 50 years

has gone up nearly five times, from 1.715 billion

tons of oil equivalent in 1950 to well over 8 billion

tons today. Fossil fuels provide some 85 percent of

the world’s commercial energy, of which oil cur-

rently amounts to around 40 percent. The bulk of

the world’s energy consumption is within cities, and

much of the rest is used for producing and trans-

porting goods and people to and from cities. This

realization is crucial for developing strategies for

sustainable use of energy, particularly in the con-

text of global warming.

Energy use is something most of us take for

granted. As we switch on electric or gas appliances,

we are hardly aware of the refinery, gas field, or

the power station that supplies us. And despite

publicity about acid rain and climate change, we

rarely reflect on the impacts of our energy use on

the environment because they are not experienced

directly, except when we inhale exhaust fumes on

a busy street.

Yet reducing urban energy consumption could

make a major contribution to solving the world’s

air pollution problems. At the 1997 Kyoto confer-

ence on climate change, the industrialized nations

agreed to cut CO2 emissions by 5 percent by 2010,

but a worldwide cut of some 60 percent is needed

to actually halt global warming. As indicated in the

Introduction, large cities and high levels of energy

consumption are closely connected, particularly

where routine use of motor cars, urban sprawl and

air travel define urban lifestyles. Yet the potential

exists for cities to be efficient users of energy.

London’s 7 million people, for instance, use

20 million tons of oil equivalent per year (two

supertankers a week), and discharge some 60 million

tons of carbon dioxide. All in all, the per capita

energy consumption of Londoners is amongst

the highest in Europe. The city’s electricity supply

system, relying on remote power stations and long

distance transmission lines, is no more than 30 to

35 percent efficient. The know-how exists to bring

down London’s energy use by between 30 and

50 percent without affecting living standards, and

with the potential of creating tens of thousands of

jobs in the coming decades. Significant energy con-

servation can be achieved by a combination of energy

efficiency and by more efficient energy supply systems.

In the UK, national planning regulations have

already substantially improved the energy efficiency

of homes, but much more can be done. At the

domestic level, two out of three low-income families

lack even the most basic insulation in their homes.

Eight million families cannot afford the warmth they

need in the winter months. Treating cold-related

illnesses costs the National Health Service over £l

billion per year.9 Only one in twelve domestic prop-

erties in Britain have the level of energy efficiency

currently required by law.10 Yet energy efficiency’s

advantages are impressive:

■ reduced fuel bills for everyone;

■ benefits to the trade balance through curbing

the need for imports;

■ the creation of new jobs in the energy efficiency

industry;

■ the preservation of fossil fuel reserves;

■ the alleviation of environmental problems, such

as air pollution and global warming, contributed

to by energy generation.

There are many examples, particularly from

Scandinavia, of how energy efficiency combined with

efficient supply systems can dramatically reduce

the energy dependence of cities. There is no doubt

that the energy supply systems in many cities of

the world can be vastly improved. Take electricity:

most cities are supplied by power stations located

a long way away, fired mainly by coal, with electric-

ity being transferred along high-voltage power lines.

On average, these stations are only 34 percent

efficient. Modern gas-fired stations are slightly

better, at 40–50 percent efficiency. Combined heat

and power (CHP) stations, in contrast, are about

80 percent efficient, because instead of wasting

heat from combustion, they capture and distribute

it through district heating systems.11

CHP systems are a very significant technology

indeed. They can be fueled by a wide variety of

sources – gas, geothermal energy, or even wood

chips. CHP systems provide heat and chilled

water, as well as electricity to urban buildings and

factories. They are now commonplace in many

C op

yr ig

ht ©

2 01

4. T

ay lo

r &

F ra

nc is

G ro

up . A

ll rig

ht s

re se

rv ed

203“ T H E M E T A B O L I S M O F C I T I E S ”

T W O

European cities. In Denmark 40 percent of electric-

ity is produced by CHP; in Finland 34 percent, and

in Holland 30 percent.

Helsinki has taken the development of CHP

further than most cities. Waste heat from local coal-

fired power stations is used to heat 90 percent of

its buildings and homes. Its overall level of energy

efficiency of 68 percent was achieved because its

compact land use patterns made district heating a

viable option. The compactness of the city also

made the development of a highly effective public

transport system economically viable.

In the development of CHP, the UK has been

off to a slow start. Small-scale systems are being

installed in some office blocks, schools, hospitals,

and hotels, improving their energy efficiency con-

siderably. All have the same high level of efficiency

as large-scale systems.

The challenge for national governments and

local authorities in the developed world is to put in

place new energy policies, particularly to improve

urban energy efficiency. The scenario includes

the creation of municipally owned and operated

energy systems. In some cities, such as Vienna and

Stockholm, energy systems are operated by the

“city works,” which also supply water and run

the transport and waste management systems. The

synergies possible between these services are much

harder to achieve in cities where privatization of

services is the norm. It appears that the largest

improvements in power distribution and consump-

tion are realized by cities with a municipality-owned

electricity company, such as Toronto and Amsterdam.12

The UK is just seeing the first schemes where

greenhouse cultivation is being combined with CHP,

utilizing their hot water and waste CO2 to enhance

crop growth for year-round cultivation.13 Policies

for encouraging CHP could thus also be used for

enhancing urban agriculture, bringing producers

closer to their markets instead of flying and truck-

ing in vegetables from long distances. Once again,

local job creation would result.

In addition to CHP, other significant new energy

technologies are becoming available for use in

cities. These include heat pumps, fuel cells, solar

hot water systems and photovoltaic (PV) modules.

In the near future, enormous reductions in fossil

fuel use can be achieved by the use of PV systems,

a technology particularly suited to cities. In the late

1990s there are only a few thousand buildings

around the world using electricity from solar panels

on their roofs or facades. Solar electricity could

meet some of a building’s requirements, with the

rest of the power coming from the grid.

According to calculations by the oil company

BP, London could supply most of its current

summer electricity consumption from photovoltaic

modules on the roofs and walls of its buildings.

While this technology is still expensive, large scale

automated production will dramatically reduce unit

costs. And the only maintenance they require is

cleaning once or twice a year.

Currently, solar energy is about eight times more

expensive than conventional, but it is expected to

be competitive as early as 2010 as the technology

develops and the market grows. Major development

programs have been announced in Japan, the USA,

the Netherlands and the European Union to stimulate

market growth. The technical potential for the gener-

ation of electricity from building integrated solar

systems is very large indeed and could contribute

significantly to the building energy requirements, even

in a northerly climate like that in the UK. Of course,

not all buildings will be suitable for the installation

of a solar roof or facade, and adoption will be more

rapid in countries with the highest sunshine level.

BOX 2 Solar energy in Saarbrücken, Germany

Saarbrücken, a city of 190,000 people, has a major investment program in solar energy. Since 1986 US$1.7 million has been spent on solar heating, PV systems, and other renewable energy sources. The state offers a 50 percent subsidy for technical assistance, and the local savings bank offers residential energy users favorable lending terms for the installations. The local energy utility owns the PV array, but the inhabitants of each house benefit from the solar electricity supply. In addition to domestic systems, there are also municipal PV installations, incorporated into high- way noise barriers. The solar initiative has the support of the entire community because it is helping to lay the foundation for a sustainable future. A former coal-mining center, Saarbrücken has now become a center for the development of urban applications of solar energy systems.

C op

yr ig

ht ©

2 01

4. T

ay lo

r &

F ra

nc is

G ro

up . A

ll rig

ht s

re se

rv ed

H E R B E R T G I R A R D E T204

Experimental solar buildings are springing up

all over Europe. The new German government,

elected in 1998, has a national program for install-

ing 100,000 PV modules. PV programs in Japan

and the USA are on a similar scale. In the UK,

experimental systems have proved to be very

promising. The Photovoltaics Centre at Newcastle

University, a 1960s building recently clad with PV

panels, has proved to be a great success. In Doxford,

near Newcastle, Europe’s largest solar-powered

office building was completed in 1998.

In the new millennium, building designers will

routinely incorporate this technology when design-

ing a new building or refurbishing an existing one.

In the meantime, to get experience with the tech-

nology, governments and urban authorities should

vigorously encourage the installation of PV modules

in our cities, enhancing the capacity to install PV

systems. Every city should have buildings to test the

potential of PV and to develop the local know-how.

Another energy technology of great promise,

fuel cells, is fast coming of age. Fuel cells convert

hydrogen, natural gas, or methanol into electricity

by a chemical process without involving combus-

tion. Fuel cells, like photovoltaic cells, have taken

a long time to become commercially viable. Their

development is now accelerating as the world

searches for practical ways to produce cleaner elec-

tricity. Several companies have made great strides

in making fuel cells competitive, in a variety of

applications: from running generators and power

stations, to buses, trucks and cars. Large-scale com-

mercial production of fuel cells will be getting under

way early in the new millennium. The combination

of photovoltaic cells and fuel cells is a particularly

compelling option. Electric energy from PV cells

could split water into oxygen and hydrogen, and

the latter could be stored and then used to run fuel

cell power stations, or generators for individual

buildings.

It is plausible that even large cities, whose gen-

esis depended on the routine use of fossil fuels in

the first place, may be able to make significant use

of renewable energy in the future. To make their

energy systems more sustainable, cities will require

a combination of energy-efficient systems such as

CHP with heat pumps, fuel cells and photovoltaic

modules, and the efficient use of energy. Regulating

the energy industry to improve generating efficiency,

reduce discharge of waste gases and to adopt

renewables will profoundly reduce the environmental

impact of urban energy systems.

NOTES

1 Prof. Paul Brunner, TU, Vienna, personal

communication.

2 Western Riverside Authority. 1991–2. Annual

Report.

3 Worldwatch Institute. 1994. Worldwatch Paper

121. Washington, DC.

4 International Council on Local Government

Initiatives. 1996. The Local Agenda 21 Planning

Guide. Toronto.

5 Dr. Gerhard Gilnreiner, Vienna, personal

communication.

6 Prof. Gerhard Vogel, Vienna, personal

communication.

7 Evening Standard. 30 December 1996. London.

8 Warmer Bulletin. Summer 1995. London.

9 National Energy Action. 1997. Newcastle.

10 Energy Savings Trust. 1992. Meeting the

Challenge to Safeguard Our Future. London.

11 Combined Heating and Power Association.

1998. London.

12 Nijkamp, Peter and Adriaan Perrels. 1994.

Sustainable Cities in Europe. London: Earthscan.

13 Energy Savings Trust. 1992. Meeting the

Challenge to Safeguard Our Future. London.

C op

yr ig

ht ©

2 01

4. T

ay lo

r &

F ra

nc is

G ro

up . A

ll rig

ht s

re se

rv ed