An upcoming California ban on the sale of gas-powered cars could cost taxpayers as much as $20 billion, according to research from the University of California, Berkeley.

The state has set itself the ambitious goal of making 100% of all passenger vehicles sold be electric by 2035. This goal will place substantial demand on the state’s electric grid, researchers wrote, and will require significant upgrades to be made feasible.

Increased EV charging demand in California has already begun to overwhelm the capacity of its feeders, which deliver power to consumers after it is taken from high to low voltage. A majority of the state’s feeders will become overloaded by 2045, with remaining feeders being “very close” to overloading, study authors wrote.

To accommodate this, the state must invest heavily in its electric grid, the study reads. Such rapid growth could mean taxpayers will be held responsible for fronting the bill.