USA, California:

Opinion: More Renewable Energy Brings New Challenges (Sacramento Bee)

Michael Picker is president of the
California Public Utilities Commission
(Courtesy Sacramento Bee)

Since Gov. Jerry Brown has been in office, California has more than doubled in-state renewable capacity. As of Jan. 1, California leads the nation with an electricity mix composed of one-quarter renewable electricity from sources like the sun and wind.

On some days, the state almost meets its 2020 renewable energy goals. For example, in the 24-hour period on April 12, 2014, renewable generation served almost 32 percent of the ISO power grid load. Between 2 and 3 p.m. that day, a whopping 42 percent of the demand was met with renewable generation (geothermal provided 21,315 MW hours of clean, dependable baseload electricity all that day).

That success, however, is accompanied by a new set of challenges. Over-generation, or producing too much power at certain times of the day when demand for electricity is low, is one of the most significant. And as more renewables are blended into the power mix, the challenge of effectively integrating renewables will grow. Over-generation sounds like a non-problem, but when there is more electricity being generated than places to store or export it, it must be turned off or it threatens reliability of the grid.

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