Newsletter: How clean is your ride?

It’s already possible to lower carbon emissions from EV charging based on when you charge.
By Julian Spector

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A white and red Tesla EV charger
(Bill Clark/Getty Images)

I like to keep track of the most common questions I get from folks who don’t live and breathe clean energy every day.

Energy wonks ask things like, How bullish are you on V2G?” Normal people often question the underlying cleanliness of clean energy, as in:

  • Don’t the materials used to build solar panels actually have a big environmental impact?”
  • Electric cars aren’t that clean because they charge from dirty power, right?”

The reflexive skepticism can be counterintuitive, given that status-quo power production kills people with air pollution, and solar panels and electric cars clearly do not. But that’s a wariness that the industry needs to have an answer for.

One answer is that we get to choose how much environmental impact the energy transition will have.

In the case of electric vehicles, technology provides an increasingly granular understanding of the emissions impact of when you charge, making it possible to decide accordingly. Jeff St. John explores that topic in his latest story for Canary Media.

Even if you charge an EV from coal power alone, it’s cleaner to drive than an internal combustion car at this point. But, not surprisingly, charging at times when the grid is cleaner reduces the carbon emissions from driving an electric-powered car.

A startup called WattTime crunches real-time data from power plants to tell people the emissions status of a local grid at a particular point in time. (Like Canary Media, WattTime is an independent subsidiary of RMI.)

  • EV charging companies such as Amply and Enel X have integrated that data stream into their offerings. 
  • That means customers can request to charge during periods of lower emissions, within the parameters of ensuring enough charge in the battery for when they have to drive.

There are some limitations to this approach. Drivers are ultimately at the mercy of the supply mix in whatever grid territory they live in. If cleaner-energy hours don’t align with a driver’s schedule, there’s only so much you can do.

This system is also entirely voluntary. Absent the imposition of a price on carbon, it’s up to individuals to prioritize cleaner charging. In some regions, cleaner power often coincides with cheaper power (think California at noon), but there won’t always be a price signal pushing for lower-emissions electricity without broader policy decisions.

But marginal improvements add up. WattTime found that aligning charging schedules with emissions data reduced annual charging emissions by 20 percent. But it could reduce emissions up to 90 percent on particular days with pronounced swings in clean energy production.

When thinking about the hidden environmental impacts of electric vehicles, then, we already have a way to mitigate emissions from charging. But that’s happening against the backdrop of clean energy gaining market share and pushing fossil-fueled plants out. You don’t have to worry about when you’re charging if the electricity is clean all day.

Julian Spector is a senior reporter at Canary Media. He reports on batteries, long-duration energy storage, low-carbon hydrogen and clean energy breakthroughs around the world.