California ISO Study Affirms Grid Can Reliably Integrate 20% RPS


The California Independent System Operator Corp. (California ISO) has released a renewable portfolio standard (RPS) integration study.

California ISO and its study partners, including GE Energy Consulting, gained insights about grid dynamics through the ‘Integration of Renewable Resources – Operational Requirements and Generation Fleet Capability at 20% RPS.’ The study assumes California will add 6,686 MW of wind 2,246 MW of solar resources by 2012.

Findings of the report include the following:

– Green power can swing in output by several thousand megawatts in as little as 20 minutes.

– Wind and solar power can offset each other's variable output because wind is plentiful at night and during early mornings, while solar power generates best on hot, sunny afternoons;

– Over generation resulting from high winds and high hydro can lead to too much power during periods when demand is low, which raises economic and reliability concerns; and

– Flexibility is important, and conventional power plants are needed to provide quick ‘ramp up’ and ‘ramp down’ capabilities to compensate for intermittent resources.

The full study is available at

SOURCE: California Independent System Operator Corp.

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