Assignment
iMozzie
EECS54609A9.22.21.pptx
Power System Management
EECS 4460/5460-901
Lecture #9A
Power Generation Alternatives –
Update on the 2021 Winter Event in Texas
1
Recap - Generation Resource Adequacy “Conventional Wisdom”
Provide Sufficient Resources to meet 20% Reserve Margin over the Peak Load
Continue to Improve Efficiency and Lower Costs –
Advance Technologies to do so.
Provide Fuel Security and Diversity
Build Transmission necessary to support reliability
Operate the System Economically and Reliably
Include Operating Reserves
Dispatch Units based on Costs and Heat Rate
Major winter storm (“Uri”) develops on February 13 in the Pacific Northwest and moves southeast toward Oklahoma and Texas
Heavy snow and record cold temperatures
Of the roughly 700 generating units in Texas, 185 units had tripped off by Monday morning February 14
Gas supplies, frozen wind turbines, pipes, water systems and instrumentation
At one point, over 52,000 MW of generation was out of service
30,000 MW Thermal; 20,000 wind and solar
49% of 107,514MW of total installed capacity
About 2800MW had been out of service for planned outages
Estimated demand approached all-time peak demand 74,820MW (8/12/19)
Capacity: 51% Nat Gas, 25% wind, 13% coal, 5% nuclear, 4% solar
ERCOT ordered rapid and systematic load shedding – about 16,500 MW of customer load shed at highest point
At peak, 4.5MIllion customer outages - lasting several days
Estimated $159Billion in losses, water system failures, fatalities
Texas PUC establishes wholesale market cap price of $9000/MWhr
The Event
The Winter Storm Map – “Arctic Outbreak”
National Weather Service – February 15,2021
Generation Losses Throughout the ERCOT Footprint
Source: ERCOT
February 7-18 ERCOT Forecasted Demand vs. Actual
ERCOT Frequency Chart: 1:23-2:03 am February 15,2021
Source: ERCOT
Texas Natural Gas Production Fell by Almost Half
Source: EIA February 25, 2021
Decline due mostly to “freeze-offs”: water and other liquids in the gas stream freeze at the wellhead or in the lines
Power generation must be available to cover the peak load
Historical planning criteria is Reserve Margin – the percent of available capacity over the peak load -ties to probability of loss of firm load
Fuel diversity and fuel security are changing:
Coal and nuclear plants are shutting down
Most “new” generation is renewable and natural gas
Renewable generation does not coincide with the peak load
Other resources, typically natural gas generation, are called on when renewables are unavailable.
Generation and load must match every second
Figure of merit: Frequency @ 60Hertz (exactly)
Frequency control is inertia based; voltage control also important
Loss of generation can result in automatic under-frequency tripping and load separation
Transmission operators apply “situational awareness” and respond
Background: Technical Reminders
9
Weather is a major driver of the electric load
Substantial variations and extremes, seasonal and daily
Generation availability can also be a function of the weather
Weather often drives natural gas consumption
Most facilities are designed for normal weather, including power plants, gas wellheads, and gas field equipment.
Many gas field facilities require electric service
Natural gas power generation depends on “just-in-time” gas delivery
Gas storage is large scale and often remote from the plants
Fuel supply depends on pipeline capacity
Gas for residential, commercial and many industrial customers, is contractually “firm”
Power plants typically “live off the spot market” for natural gas
Background: More Technical Reminders
10
Power generation in many parts of the U.S. is “unregulated” (restructured)
Since the mid 1990’s, power plants could decouple from state regulation and become “merchant generators ‘
They receive revenue through wholesale power markets
Generally, markets are managed by ISO/RTO’s
FERC has regulatory jurisdiction over most wholesale markets
The responsibility for resource adequacy varies widely
Some states still have traditional rate-making for generation and “regulate” resource adequacy
Also, many states have “retail choice”
Customers can choose their generation supplier
Typically, through third party “energy companies”
Pricing arrangements vary widely
Background: Regulatory & Market Reminders
ERCOT Wholesale Power Prices During the Event
From Lecture 6: Retail Choice
13
Three Major Interconnections in the U.S.
Source: ERCOT
U.S. Transmission System Map
ERCOT (Electric Reliability Council of Texas)
Manages flow of electric power for more than 26 million customers – about 90% of the Texas load – Texas produces more electricity than any other state
History includes the 1930s when FDR signed the Federal Power Act
46,500 miles of transmission lines; 700+ generating units
A nonprofit company; governed by a Board of Directors and subject to oversight by the Public Utility Commission of Texas and the Texas Legislature
Commissioners are appointed by the Governor and have broad authority
Local utilities provide distribution services; most are investor owned
ERCOT Control Room Images
ERCOT Operates the Wholesale Electricity Market
Texas established their independent power market in the1990s. ERCOT controls 75% of the state, 90% of the load
Power generation is “unregulated”, i.e., not part of the utilities that serve the retail customer, but separate “merchant generation” companies
Generators get paid based on a real-time market, where price fluctuates based on supply and demand
Prices are established at transmission nodes, and are called Locational Marginal prices (LMP’s)
Most retail customers pay for generation separately, with wide variation on the business models and contracts
There are over 100 co-ops and municipal systems, many of which do not offer “choice”
The Texas PUC establishes the electricity market “rules of the road” and the Texas market is not subject to FERC jurisdiction
Texas Power Generation and Home Heating
Cold waves are very rare, but they have occurred
In 2011, record-breaking subfreezing temperatures in New Mexico, moving into Central Texas (7 to 9 degrees F)
Known as the “The Groundhog Day Blizzard”
210 generating units impacted, including some affected during the 1989 event; 3.2m customers lost power
History: Cold Waves in Texas: 1989 and 2011
A follow-up report by FERC and NERC identified causes and provided recommended corrective actions, including improved procedures and equipment winterization. NERC published guidelines for winterization.
19
Comparison Between 2011 and 2021
| 2011 | 2021 | |
| Max generation out at any one time (MW) | 14,702 | 52,277 |
| Cumulative generation forced out through the event (MW) | 29,729 | 46,249 |
| Cumulative number of generators unable to perform | 193 | 356 |
| Cumulative gas generation de-rated due to supply issues | 1,282 | 9,323 |
| Lowest frequency (Hz) | 59.58 | 59.30 |
| Maximum load shed requested (MW) | 4,000 | 20,000 |
| Duration of load shed requested (hours) | 7.5 | 70.5 |
| Estimated peak load without load shedding (MW) | 59,000 | 76,818 |
| Number of consecutive hours below freezing (Dallas) | 101 | 140 |
Heat Waves More Common: August 2019
New Peak:
74,820 MW (8/12/19)
$9000/Mwhr
Demand response
@ 1750Mw
Rotating outages
@ 1000Mw
Planning Reserve 8.6%
21
Immediate Leadership Changes
PUC Chair DeAnn Walker resigned
PUC Commissioner Shelly Bortkin resigned
ERCOT Board members from outside Texas resigned
ERCOT CEO Bill Magness was fired
Immediate financial outcomes
Brazos Electric Co-op filed for Chapter 11 bankruptcy protection; their bill from ERCOT was $2.1B; normal annual revenue is $1B
Some retail customers got billed at price cap, e.g., Griddy Energy LLC provides customers direct access to wholesale prices
Griddy Energy subsequently filed for Bankruptcy
NRG Energy $1B cash loss and financial uncertainty
Regulatory and Political Activity
FERC/NERC Investigation, NERC Standards development for winterization
Congressional Hearings
Market Design Challenges
Independent market monitor reported that wholesale prices were kept artificially high 30 hours longer than necessary creating $16B of “overcharges”
Debate ongoing about “repricing” after the fact and settlements
The Aftermath … the death doll was over 100
In Lecture 9, we noted that outages due to inadequate generation resources are “almost non-existent”
The world is changing:
California renewable integration challenges
Texas cold weather event impact on supply
What’s next?
Summary
Power Generation Alternatives
Generation Costs
Alternatives and Decision Making
Next Lecture(s)
