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The US Energy Grid Is Making Electric Cars Dirtier Than They Should Be

Electric cars still run on coal, gas, and nuclear power.
Image: Shutterstock

A future full of electric cars is getting closer to becoming a reality, but we won’t be able to save the environment by simply eliminating the combustion engine from the American landscape. To fix the future of transportation, we need to fix the electrical grid it will run on.

In the past year, transportation has become the leading cause of pollution in the United States, ending power plants’ 40-year reign as the top producer of greenhouse gases (GHG).


According to Costa Samaras, an assistant professor of civil and environmental engineering at Carnegie Mellon University, the carbon intensity of power generation has fallen 24 percent since 2005. During that same time, however, transportation’s GHG emissions have remained fairly stable (as seen in the graph below).

Image: EPA

If everyone in the US switched to electric vehicles (EVs) tomorrow, of course there’d be environmental benefits. The US Energy Information Administration reported gas-guzzling vehicles pumped out 1.5 billion metric tons of CO2 in 2016 alone.

But it’s important to remember that coal still produces just under a third of the US’s energy—and in 2016, about 68 percent (1.2 billion metric tons) of the energy sector’s CO2 emissions. It’s that grid that will power EVs.

Read More: It’s Way Too Hard to Buy an Electric Car in Canada

“We need a dramatically decarbonized grid and we need any possible solution to get there,” Carnegie’s Samaras told Motherboard. In addition to his professorial duties, he’s also co-director on, which will soon provide public quarterly US carbon emissions data.

The two top energy sources besides coal are natural gas and nuclear, both of which are low GHG emissions but are still not great for people or the planet due to fracking, mining, and radioactive waste. Meanwhile, renewable forms of energy—namely hydro, wind, and solar—only make up a combined 15 percent of electricity production. That means your electric car still has a high likelihood of being powered by fossil fuels or uranium for the foreseeable future.


For some context, a recent study from Belgium’s VUB University concluded that even in a country highly dependent on coal power—Poland, in this case—switching from diesel cars to electric reduces emissions by 25 percent over the course of a vehicle’s life. That includes manufacturing and the electricity to power them.

A lot of progress on cleaning up the grid has been made in the past decade, Samaras noted, pointing to a major drop in the cost of generating solar and wind power. But this rate of change may still be too slow. “In order to reduce the most severe effects of climate change,” he said, “we’ll have to have dramatic reductions in CO2 (carbon dioxide) in all sectors, and this includes the transportation and electric sectors.”

“If we electrify [transportation], people in cities will be healthier"

California has long been a leader in cleaner transportation and cleaner energy, and is actively pursuing both through a series of aggressive measures. Its ambitious action plan for zero-emissions vehicles (ZEVs) includes up to $5,000 in rebates for buying or leasing an electric car, carpool lane access, and expanding the EV charger network. The intent is to have 1.5 million ZEVs on California roads by 2025.

With four million customers, the Los Angeles Department of Water and Power (LADWP) is the largest municipal utility in the US—and will be responsible for powering many of the region’s EVs. However, it still gets 15.4 percent of its power from coal.


Marvin Moon, LADWP’s director of power systems, told me over the phone that will change in 2025 when the contract with its only remaining coal plant expires. By then, the utility aims to have 50 percent of its power from renewable sources.

Even with its single coal plant, though, Moon said GHGs would go down by 60 percent if everyone in the utility’s territory suddenly switched from gas-powered cars to EVs tomorrow. “If all the cars in LA switched to electric, our electricity sales would go up 50 percent,” he added.

So far with EV usage—about 32,000 cars in LA—LADWP hasn’t had to make any upgrades to its infrastructure. Jason Hills, the department’s EV program manager, said that’s largely because most users charge in off-peak times. But if the utility makes good on its target of having the equivalent of 137,000 EVs (1 bus = 20 cars) by 2020, that could require equipment upgrades and modifying peak hours. For that, Moon said the state needs to do better with its state credits for utilities working toward cleaner grids and transport.

Even for states that can’t, or won’t, divest entirely from coal, electrifying most transport will have a dramatic effect, said Samaras of Carnegie Mellon. Moving pollution from millions of tailpipes in a metropolitan area to a more remote generator—even if it’s not super clean—would still have some benefit.

“If we electrify [transportation], people in cities will be healthier,” said Samaras. “If we do it with a cleaned-up grid, the planet will be healthier.”

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