Electric vehicles can’t help the planet without a smarter power grid

Electric vehicles (EVs) are often touted as a climate solution. But new research shows that even if every gas-powered car in the U.S. were swapped for an EV, the country wouldn’t see the full benefit – unless we also fix a hidden but critical part of the equation: the power grid.

This is the conclusion of a new study by a team of scientists at Northwestern University. The research reveals a surprising roadblock in the race to cut emissions. Electricity is not always able to travel from where it’s generated to where it’s needed.

Electric vehicles using dirty power

The power grid is overloaded. And that bottleneck could make electric vehicles far dirtier than expected.

“Vehicle electrification, alongside renewable energy integration, is a long-term strategy toward zero carbon emissions. However, transitioning to fully renewable electricity may take decades – during which electric vehicles may still rely on carbon-intensive electricity,” wrote the researchers.

Adilson Motter, who led the study, noted that even if the U.S. fully adopts EVs and generates enough renewable electricity to charge them, it still won’t be enough.

Power grid strained by EV demand

The power grid functions like a highway system. Electricity is generated at power plants, moves across long-distance transmission lines, then drops into local networks to serve homes, businesses, and charging stations.

But as EV adoption ramps up, so does the demand for electricity – especially in densely populated areas.

That’s a problem, because the cleanest power sources, like wind and solar, tend to be far from where most people live. These renewable energy sources include rural wind farms in the Midwest and massive solar installations in the Southwest.

The team modeled different scenarios of vehicle electrification and renewable energy generation. In every scenario where electric vehicles played a major role, one thing stood out: the grid kept getting in the way.

In places where the grid couldn’t deliver clean power from distant wind or solar farms, local utilities had to rely on whatever was nearby. Often, that meant fossil fuel plants. The emissions savings from EVs were wiped out – sometimes by as much as a third.

Smart charging is not enough

Planners and automakers often tout “smart charging,” where EVs juice up at times that align with wind and solar production. But that approach only works if clean power can get where it’s needed.

“The charging schedule of EVs can be optimized to align with intermittent renewable generation,” Motter said.

“But even with smart charging, efficient use of clean energy still depends on having enough transmission capacity to deliver it where it’s needed.”

Modest grid boost cuts emissions

The good news? The solution is surprisingly modest. According to the study, increasing the grid’s transmission capacity by just three to 13 percent would open up access to far more clean energy.

That’s enough to cut congestion and avoid losing much of the emissions savings. The upgrades could involve adding new high-voltage lines or improving existing ones. There’s no need to tear it all down and start over.

“Power grids began as local networks, where consumption was close to generation,” Motter said. “Over time, they evolved into nationwide – even continent-wide – systems.”

“It was a gradual growth process built on existing infrastructure. No one wants to redesign it from scratch, but we do need targeted upgrades that reflect the large-scale reach of today’s grid.”

A cleaner future with electric vehicles

The U.S. power grid is divided into three primary regions – the Eastern, Western, and Texas grids – which function largely independently from one another. In other words, we have limited ability to transfer electricity across these regional boundaries.

Improving the connections between them would allow clean energy to flow where it’s needed most, regardless of regional boundaries.

Switching to electric vehicles is necessary, and so is scaling up wind and solar. But without investing in the power lines that connect it all, the U.S. won’t get the full climate benefit.

A cleaner future isn’t just about what we drive – it’s about how power gets from point A to point B.

The full study was published in the journal Nature Communications.

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