A Federal Electric Reliability Commission (FERC)’s task force looking into the causes of rolling blackouts during cold weather in February 2011 said that grid operators and power plant operators should have better prepared for extreme winter weather.
The task force said the Electric Reliability Council of Texas (ERCOT) region experienced a similar event in 1989 when it also shed firm load, but the lessons learned from that event were not used to prevent outages during the 2011 event.
The task force offered 26 recommendations to ERCOT covering load shedding, winterizing, planning, the natural gas industry and plant design.
The task force said the outages could have been minimized if generators had proactively executed winterization procedures such as inspecting and maintaining heat tracing and thermal insulation, and installing wind breaks and enclosures to protect equipment and lines vulnerable to freezing. It said the event emphasized the lack of any reliability standard that directly requires generators to develop, maintain and implement plans to winterize their units. The North American Electric Reliability Corp. agreed to begin the process of developing such a standard. A standard could be in place before winter 2012.
The task force also said the balancing authorities could have been better prepared by requiring accurate information about temperature design limits from generators, not allowing planned outages when extreme weather is expected, raising reserve levels when extreme weather is expected, and having procedures that would allow them to order some units to warm up before extreme weather hits.
The task force report also recommended taking steps to ensure that black start units can be utilized during extreme weather, designing new power plants to perform at the lowest recorded temperature for the nearest city, improve communications with transmission owners and operators and exempting critical natural gas facilities from rolling blackouts. The report also recommended that local distribution companies should determine if their distribution systems can be improved so curtailments can be implemented if necessary to help speed the restoration process.
Rolling blackouts February 2 and 3 shut down 7,000 MW, or 210 generating units, of capacity across Texas. Nearly half of ERCOT’s black start units were either on planned outages or failed to load during the event, the report said. For the Southwest as a whole, 67 percent of generator failures were due directly to weather-related causes, including frozen sensor lines, equipment, valves or low temperature cutoff limits.
The electricity shortages caused spot power prices to reach $3,000/MWh on February 2.
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