Electric vehicle efficiency still matters, especially with larger cars

One of the most popular strategies for reducing dependence on fossil fuels is to “electricize everything”. Indeed, even with the current energy mix in the United States – according to the Energy Information Administration, 61% of electricity production came from fossil fuels – electric cars and light trucks still have much lower emissions than those of their gasoline equivalents.

But they still have emissions, both from the generation of electricity that powers them and from the initial carbon emissions released when the vehicle is made.

This is why we have often written that three things are necessary for the electric revolution: to reduce demand. clean the electricity, and electrify everything. In homes or cars, size and efficiency are always important because there are only a limited number of clean kilowatts and they are unevenly distributed.

Writing for the American Council for an Energy-Efficient Economy (ACEEE), transportation analyst Peter Huether delved into the issue of efficiency in an article titled “9,000-Pound Electric Hummer Shows We Can’t Ignore Efficiency of EVs”. He compared a small electric car to the Hummer:

“The Chevy Bolt EV is responsible for approximately 92 grams of carbon dioxide (CO2) per mile when factoring in power grid emissions. (CO2 calculations are based on the national average, but grid emissions electric vehicles vary widely across the country.) The gas-powered Chevy Malibu generates over 320 grams per mile. Comparing larger vehicles, the original Hummer H1 emits 889 grams of CO2 per mile and the new Hummer EV produces 341 grams, demonstrating that giant electric vehicles can be even worse for the environment than smaller, conventional vehicles.”

And this without even taking into account the initial or intrinsic carbon emissions of the manufacture of the vehicles. It’s just carbon dioxide (CO2) coming straight out the chimney instead of the tailpipe. Huether also noted these issues:

“The environmental impact of electric vehicles is not just about the electricity generated to travel each kilometer. The manufacturing process also causes the release of greenhouse gases at several stages, known as vehicle embodied emissions. Electric vehicles in particular, with heavy batteries – use minerals that must be mined, processed and turned into batteries The quest for greater range and larger vehicles requires increasing the size of the battery, which which also increases embodied emissions.

Huether called on the Environmental Protection Agency to develop efficiency standards for electric vehicles: “Not all electric vehicles have the same impact on the environment, and our vehicle regulations should reflect that. account.” Efficiency is a function of weight and aerodynamics, with smaller and lighter vehicles being more efficient.

But even between vehicles of the same weight, there can be significant variations; in the 5,000 to 5,500 pound weight range, efficiencies range from 25 kWh/100 miles to nearly 48 kWh/100 miles, just under half the efficiency. The electric Hummer needs 62 kWh to travel 100 miles; that’s a lot of juice, enough to run an average American home for two days.

Huether concluded that we need regulations and standards, just like there are for gas-powered cars, with a greater focus on efficiency. He wrote: “Greater electric vehicle efficiency can reduce driving and vehicle manufacturing emissions, increase range and reduce costs.”

GMC


Huether isn’t alone in questioning the need for these large, inefficient vehicles. James Gilboy and Peter Holderith of The Drive make many of the same points about the importance of efficiency. “Lower efficiency means charging more often. Charging more often means more power consumption,” wrote Gilboy and Holderith. “You can see where this is leading.”

They also do a great job of explaining the importance of embodied carbon, one of the first I’ve seen applied to cars outside of Treehugger. They noted that the companies did not reveal initial carbon data – only Volvo does with the Polestar. They extrapolated from the Polestar to try to estimate the Hummer EV’s initial carbon footprint, with 50.6 metric tons, “more than triple the 15.2 metric tons of Americans’ average CO2 emissions in 2018.” This is another milestone, where they demonstrated the importance of embodied carbon and made it accessible.

They concluded:

“There are two main takeaways from all of this. First, simply being an electric vehicle is not enough to be sustainable. Electric trucks represent a long-term improvement over pure combustion and even hybrid trucks if they can stay on the road, but their resource-intensive manufacturing and sheer size make them less environmentally friendly than small gas-powered cars.And secondly, although we have been able to use what little data we have to better understand the effects of electrification, the lack of information from most of the OEMs we contacted demonstrates that the automotive industry has a transparency problem that we would do well to start taking seriously.”

Ultimately, there’s no question that every electric vehicle is a dramatic improvement over its gasoline counterpart. But just like in gas-powered vehicles, size, weight and efficiency are important for initial and operational carbon emissions. And this Hummer is a climate killer no matter what it’s running on.

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