May 16 (Reuters) - North America should have enough power to meet electricity demands this summer, the region's electric reliability organization said on Thursday.
But continued growth in power demand with only a small increase in power resources could cause problems in Texas, and a prolonged nuclear plant outage could keep power supplies tight in California, the North American Electric Reliability Corp (NERC) said.
NERC is a not-for-profit entity that develops and enforces power reliability standards in the United States. Its territory covers the continental United States, Canada and the northern portion of Baja California in Mexico.
"We expect the bulk power system will be able to meet the electricity demands this summer," John Moura, director of Reliability Assessment at NERC, said in a release.
"However, continued peak demand growth in Texas coupled with only a small amount of new resources made available this summer is causing resource adequacy projections to fall below targets," he said.
NERC said it will closely monitor the situation in the Electric Reliability Council of Texas (ERCOT), which oversees the power grid in most of Texas, as well as impacts from persisting drought conditions in the west.
In ERCOT, NERC said the anticipated reserve margin is 12.88 percent for this summer, which is below NERC's 13.75 percent target for the area.
NERC warned that insufficient reserves during peak hours could lead to increased risk of emergency operating conditions, including curtailment of interruptible load and even rotating outages.
Interruptible load includes mostly industrial companies that pay less for power with the understanding that their supplies may be reduced or cut off if needed.
ERCOT, Texas regulators and Texas power companies have long been aware of the potential shortfall and have been taking action to tackle the problem for this summer and in the long term.
NERC also warned of tight power supplies in Southern California that may lead to "operational challenges" due to the continued shutdown of the San Onofre nuclear power plant since January 2012.
"A prolonged or extreme heat wave could result in localized controlled load shedding in San Diego and Los Angeles Basin to maintain integrity of the system," NERC said.
Power companies in California expect several system enhancements to be in service by the summer peak, which "should relieve some operational issues and support system flexibility during conditions of stress," NERC said.
NERC warned that increased reliance on wind and solar power resources in regions with a lot of renewable generation could pose challenges for some operators to get other plants online when the sun stops shining and the wind stops blowing.
NERC also said drought conditions west of Mississippi River could pose localized problems for some generators.
The retirement and retrofit of power plants to meet environmental regulations is not expected to cause immediate reliability concerns, NERC said.
NERC also said it was watching for above-average growth in peak demand in Texas and the West, that it was expecting an active hurricane season this summer, and that it was keeping an eye on increasing dependence on natural gas to fuel power plants across the country as coal units retire.