The Electric Reliability Council of Texas (ERCOT), the state grid operator and manager of the Texas wholesale electric market, expects to use a variety of resources to meet anticipated electric demands this summer.
That includes nearly 2,000 MW of capacity that had been “mothballed,” or taken off-line for an indefinite period of time. Owners have decided to return those units to service, including about 430 megawatts (MW) of capacity that was not available last summer.
“Even with this additional generation, we expect that there may be some calls for conservation when energy use is particularly high or if generation supplies are impacted by unplanned outages,” said ERCOT CEO Trip Doggett. “Having nearly 2,000 MW of additional generation available this summer will help reduce the likelihood of rotating outages.”
ERCOT released its Seasonal Assessment of Resource Adequacy (SARA) for summer 2012on May 1. As the entity that manages the flow of electric power to 23 million Texas consumers, ERCOT continually looks ahead to determine whether enough electric generation is available to serve projected needs. The quarterly SARA report, which ERCOT initiated in 2011, considers near-term conditions and elements such as weather and economic conditions that can affect generation and demand forecasts.
ERCOT expects to have nearly 74,000 MW of generation resources available to serve summer needs, including some previously mothballed resources. Generators have notified ERCOT that they plan to bring these plants back on-line to meet high summer demand. Additionally, following a federal court ruling late last year, some units that anticipated being unable to run under the U.S. Environmental Protection Agency’s Cross-State Air Pollution Rule (CSAPR) will be able to operate this summer.
“We have taken an ‘all of the above’ approach to meeting Texans’ electricity needs this summer,” said Chairman Donna Nelson of the Public Utility Commission. “I particularly appreciate efforts from generators to bring power plants back on-line to help keep our air conditioners running.”
The summer 2012 assessment assumes weather will be warmer and drier than the 15-year historical average but less extreme than 2011, based on information from the National Weather Service and from Telvent, which provides weather forecasting data for ERCOT. Forecasts also indicate the possibility of tropical storm activity early in the summer and the potential for more variable rain.
Further improving the generation outlook is more than 2,075 MW of wind power in the coastal region, which tends to be available to the grid during the late afternoon when it is needed most in the summer. Wind power generation in the ERCOT region continues to set records, and instantaneous wind power served nearly a quarter of ERCOT load twice in April. Another 48 MW of commercial-scale solar power, including about 20 MW that went on-line this spring, also has been added in ERCOT since last summer.
Additionally, when demand is high and generation tight, some large power users arrange to reduce their demand on the grid in return for compensation. Summer projections include about 1,500 MW of demand response resources, which include energy users that reduce or drop their energy use at ERCOT’s request if generation reserves drop below 1,750 MW.
“From my perspective, making it possible for more loads to respond to tight conditions is one of the most important things we can do in the short term,” said Doggett.
According to new rules adopted by the PUC and new ERCOT market protocols approved by the ERCOT board in April, ERCOT’s Emergency Interruptible Load Service (EILS) program will change on June 1 to Emergency Response Service (ERS) and will add distributed generation to the resources ERCOT may call upon to help stabilize the grid during emergencies. Through EILS, some users previously have provided about 400 MW of capacity during emergencies. Under the new ERS rules designed to increase the potential benefits of the program, smaller loads also will be able to respond to calls for additional capacity.
A megawatt of electricity can power about 200 Texas homes during periods of peak demand. In summer 2011, many residential customers and other smaller consumers helped prevent rotating outages by reducing their energy use when reserves tightened. After seeing the significant benefits of those consumer conservation efforts last summer, Nelson convened market participants to develop a shared plan to encourage conservation when the need arises this summer. Simple actions by consumers, such as raising thermostat settings a couple of degrees on a hot summer afternoon, can make a big difference.
Drought, a concern for power plant reliability in 2011, is not expected to be a large factor in electric reliability this summer as winter and spring rains helped bring most power plant cooling lakes within their operational ranges.
As for a longer-term look, ERCOT will release the semi-annual Capacity, Demand and Reserves report later this month. That report will provide an updated 10-year high-level forecast showing projected energy use and the anticipated generation resources that will serve those needs. That report is based on average long-term temperatures and other conditions and does not consider specific variations that are included in the SARA.