California is minus a major nuclear power plant and Texas expects hotter than usual weather. This potentially means electricity capacity might not meet demand.
The map shows 14 regional reserve margin estimates and the target reserve margin for summer 2013. The reserve margin estimates exceed the target in every region, except in the Electric Reliability Council of Texas region, which is most of Texas. Although California is above the target reserve margin, it remains an area of concern especially in the southern portion of the system because of its reliance on imported power and the prolonged outage of the San Onofre Nuclear Generation Station.
Both units at the San Onofre plant have been closed since Jan 2012 due to unexpected tube leaks and may never re-open. They had generated upwards of 18% of energy for the area. This means more expensive power needs to be obtained from outside the area.
Texas expects very tight supplies this summer on hot days this summer due to air conditioning use. Wind power is 8.7% of their capacity, which is considerably more than in California.