Grid needs help this decade to charge EVs — study

Source: By David Ferris, E&E News reporter • Posted: Wednesday, July 29, 2020

The U.S. grid will be able to handle a growing herd of electric vehicles for the next eight years, but after that, its reliability will depend on either costly upgrades or a smarter charging network, according to a study out today.

Scientists from Pacific Northwest National Laboratory in Washington state examined how the power system will cope, a topic of growing urgency as EVs become more common.

The grid as it stands today could serve up to 24 million electric vehicles, the study concluded, a milestone that it pegged to 2028. Currently U.S. roads have about 1.5 million EVs.

By the end of the decade, utilities may need to build new transmission lines and power plants fueled by natural gas to keep up with EVs — a problem for states and energy companies with zero-emissions goals.

Furthermore, “the ‘last mile’ in utility distribution systems will see bottlenecks and equipment failures in some areas due to lack of local infrastructure capable of supporting transportation electrification,” the report said.

Those outcomes are, however, just one possible path.

The study looked at two scenarios: One is similar to today, when most charging sessions begin at the end of the day, with drivers plugging in and drawing electrons at the same time in the evening.

The other imagined a smarter system where the EV’s battery-filling schedule is coordinated with the needs of the electric grid, via technologies that are in development but unproved.

In the first scenario, if the U.S. electric fleet exceeded 24 million units, utilities would need to build a lot more infrastructure. In the second, smart-charging scenario, the number of vehicles that today’s grid could manage more than doubles, to 65 million vehicles.

The study was based on information from the Western Electricity Coordinating Council, the federally designated grid authority on the west side of the Rockies, because it already has a rich, future-looking set of EV data.

The study is the first to consider not just light-duty vehicles, but also medium- and heavy-duty trucks. It projected that by 2028, there will be 24 million electric passenger cars, 200,000 medium-duty trucks and 150,000 heavy-duty trucks.

Without careful management, the authors said, EVs could aggravate a renewable energy phenomenon known as the duck curve (Energywire, May 2, 2014). The center of the duck curve is a midday crater of energy demand when solar power production is at its peak at the same time as homes and businesses need less electricity.

EV charging could make the duck curve steeper and increase costs to consumers if it isn’t adroitly managed, the study said.

On a massive scale, EV charging could reduce renewable energy curtailments, when electricity is shed without being used when sunshine or wind is super-abundant.

These curtailments could be cut by as much as 75% by the expected growth in EVs this decade, the study said, and managed charging could reduce that by an additional 16%.