Energy Storage Smooths the Duck Curve
The stability of the electric grid affects millions of residential and business customers. One blip—amounting to just seconds—can interrupt critical systems across a city or an entire region.
Maintaining grid stability is a challenge as utilities rush to add renewable power to their generating portfolio. The business case for renewables is undeniable: as prices for wind turbines and solar panels keep dropping and the costs of installation go down, renewable electricity becomes some of the cheapest power available. But the inherently inconsistent nature of solar and wind energy has grid operators looking for new ways to seamlessly integrate their output into the system.
This challenge is being faced around the world, and in the U.S. it is playing out initially in California. A law passed by the California legislature in 2015 mandated utilities to reduce greenhouse gas emissions and increase the capacity of renewable projects. In response, the California Independent System Operator, CAISO, began seeing solar power provide an increasing share of electricity in the middle of sunny days. By 3:00 PM each day, however, the sun begins to sink toward the horizon and the power provided by the state’s solar projects also starts to fall off—and this loss in power happens just as daily electricity demand starts to rise.
To meet that demand, California utilities figured they would turn to natural gas-fired peaking plants that could ramp up quickly. Southern California Edison, one of the state’s three major electric utilities, owns five such peaking plants.
