The California power supply may be stretched to its limits this summer.
It all started with the indefinite loss of the 2,250-MW San Onofre nuclear plant nearly 18 months ago. The plant went and remains offline because of premature wear on reactor steam tubes at both units. The loss of such a large asset to a state-wide or regional power system is the kind of worst-case scenario that grid operators plan for on a short-term basis.
On top of that, it’s barely snowed in the mountains whose spring runoff supplies much of the “fuel” for the state’s hydropower. In the 2013 summer assessment released Monday by the California independent system operator, Cal-ISO, the report said that “snowpack water content on May 2, was 17% of average statewide for that date, 16% for northern portions, 23% for central California and 9% for the southern region.” As a result of that, the ISO projection assumes a 1,022-MW “derating” on the hydro resources in the ISO system. And the report also noted that, not surprisingly, the drop could be bigger if the summer is hotter and dryer than normal.