As California prepares to transition to electric vehicles (EVs), its grid is facing a significant challenge: how to handle the increased demand for electricity that will come with the state’s ambitious goal of having all passenger vehicles be electric by 2035. Two researchers at the University of California, Davis—Yanning Li and Alan Jenn—have examined the state’s existing grid infrastructure and found that nearly two-thirds of its feeder lines do not have the capacity to meet the anticipated demand.

The researchers analyzed data on every substation, feeder line, and transformer that delivers electrons to customers of the state’s three largest utilities, which cover nearly 90 percent of the state’s population. They used this information to estimate where charging is taking place and how much electricity will be needed per charge. They then compared this need to what the existing grid has the capacity to deliver.

Their findings are concerning: by 2025, only about 7 percent of the feeders will experience periods of overload, but by 2030, that figure will grow to 27 percent, and by 2035—only about a decade away—about half of the feeders will be overloaded. The problems will continue to grow, with two-thirds of the feeders overloaded by 2045, just ten years after all cars sold in California will be EVs. At that point, total electrical demand will be close to twice the existing capacity.

The researchers’ findings suggest that updating the grid to handle the rising demand could set its utilities back as much as 40 percent of the existing grid’s capital cost. This is a significant investment, and it raises questions about whether the state’s goals for EV adoption are realistic given the current state of the grid.

However, the researchers also note that there are ways to address these challenges. For example, utilities could upgrade transmission lines, add new substations, and install more advanced technologies like smart meters and energy storage systems. Additionally, the state could encourage the development of more distributed energy resources (DERs), such as rooftop solar and energy storage systems, which could help to reduce the strain on the grid.

In conclusion, California’s transition to electric vehicles will require a significant investment in its grid infrastructure. While the challenges are daunting, they are not insurmountable. With careful planning and strategic investments, it is possible for California to achieve its goal of having all passenger vehicles be electric by 2035 while ensuring a reliable and resilient energy supply.