California energy officials issued a sobering warning this month, telling residents to brace for potential blackouts as the state’s energy grid faces capacity constraints heading into the summer months.

In Sacramento, officials said California’s grid could face a potential shortfall of roughly 1,700 megawatts, which would affect the power supply of between 1 million and 4 million people this summer. That number would likely be exacerbated by an additional shortfall of 5,000 megawatts in the case of extreme heat and further fire damage to existing power lines.

And since the state has committed to phase out all new gas-powered vehicles by 2035 — well ahead of federal targets — the additional load from electric vehicle (EV) charging could add more strain to the electric grid.

“Let’s say we were to have a substantial number of [electric] vehicles charging at home as everybody dreams,” Ram Rajagopal, an associate professor of Civil and Environmental Engineering at Stanford University, who authored a recent study looking at the strain electric vehicle adoption is expected to place on the power grid, told Yahoo Finance. “Today’s grid may not be able to support it. It all boils down to: Are you charging during the time solar power is on?”