By: Martin Coyne |
The summer planning reserve margin for the Texas power supply is projected to be below that recommended by the North American Electric Reliability Corp, NERC said Wednesday in its 2013 Summer Reliability Assessment.
NERC anticipated that ERCOT will have a 12.88% reserve margin for the summer, a figure which equates to 6,780 MW. That’s down from a 7,258-MW margin in 2012 and a 8,397-MW margin in 2011.
ERCOT has taken steps to shore up the Texas grid for this summer, said John Moura, NERC’s director of reliability.
“There are a lot of demand-response programs in place that are not accounted for in our assessment because they are pilots,” Moura said.
He also said the Texas Public Utility Commission is talking with energy market participants about the best ways to encouragethe construction of power plants.
Besides Texas, NERC also singled out southern California as a part of the country where “tight supply resources may lead to operational challenges.”
While the California Independent System Operator will be above NERC’s recommended reserve margin of 15%, the electricity market “will be tight in extreme weather and adverse supply conditions,” NERC said.
But the ISO has taken a number of steps in response to the indefinite loss of the 2,250-MW San Onofre nuclear power plant, NERC said.
The reliability group also pointed to the conversion of Huntington Beach units 3 and 4 into synchronous condensors for much-needed voltage support in the Los Angeles and San Diego areas, the addition of about 1,900 MW of new generation and the continued use of curtailment and demand response programs.
Throughout North America, increased wind and solar capacity since the summer of 2012 “adds more supply uncertainty,” NERC said.
NERC’s focus on renewables is two-fold, Moura explained.
Renewables require more flexible resources capable of fast ramping to offset the variable output of wind and solar.
Operationally, renewables also create the need for grid operators to see large weather fronts that can change generation forecasts every five minutes or within the next hour, Moura said.
NERC, which coupled the summer outlook with its 2013 State of Reliability report, believes that by several measurements the reliability of the grid has improved substantially since 2008, said Jessica Bian, NERC’s director of performance analysis.
For example, transmission-related events caused by human error and resulting in load loss on the bulk power system dropped from nine in 2011 to two in 2012, Bian said.
The 10 “highest stress days” for the grid since 2008 are all weather related events including Hurricane Sandy and last year’s severe wind storm in the eastern half of the country, she said.
Since the first quarter of 2008, the compliance rate with NERC standards has increased from about 70% to around 98%, Bian said.
