Electric vehicles could become a vital asset for California grid operators who are struggling to bring more renewables online. The state’s rapid adoption of solar power is contributing to a problem known as the “duck curve” — a deep dip in demand during solar-saturated midday hours, followed by a steep ramp in the evening as solar power fades away. Regulators have responded by mandating that the state’s three biggest utilities procure a total of 1.3 gigawatts of energy storage by 2020. But researchers say they’ve found a more effective way to mitigate the duck curve using strategic EV charging.