Category Archives: EV

For many of us who were early adopters of electric vehicles, protecting the environment is an important motivation—to eliminate carbon dioxide emissions from burning fossil fuels that cause climate change and other air pollutants that foul the air.  If we’re concerned about global warming, we should all do our part in cutting emissions, and switching to an electric car seems like an obvious way to be part of the solution.  My first electric car, a 2014 Nissan Leaf, even has a “Zero Emission” emblem on the back.

But is it really zero emissions?  The electricity to charge the battery has to come from somewhere, and isn’t most electricity in the U.S. produced by burning coal?  So when we drive electric cars, are we just moving the emissions from the tailpipe to the smokestack?

Electric cars reduce emissions—and to zero under the right circumstances.

While there is a small element of truth in the skepticism about zero emissions from electric cars, the answer is basically that they do reduce emissions—and to zero under the right circumstances.

Even in the worst case where electricity is generated from polluting sources like coal and natural gas, electric vehicles serve a valuable function in removing the local pollution, moving it to locations where there are fewer people.  If you’ve spent time in an urban area near polluting cars, trucks, and buses, you know how important that is for human health.

Electric cars use energy much more efficiently.

But the benefits in reducing pollution go much further.  Electric vehicles are far more energy efficient than ones powered by internal combustion engines—electric motors are roughly 90 percent efficient compared to about 25 percent for gas-powered internal combustion engines.  Greater efficiency means less use of energy, which translates to less pollution.

One of the best sources of electricity for charging EVs is “negawatts”—energy saved through improved efficiency.

The energy efficiency advantage of electric motors is related to the best source of non-polluting electricity for charging electric vehicle batteries—negawatts.  Negawatts is a term coined by Amory Lovins, founder of the Rocky Mountain Institute.  It represents a watt of energy that you have not used through energy conservation or the use of energy-efficient products.  Instead of kilowatts and megawatts—measures of electricity generation from sources of energy like coal, natural gas, nuclear power, wind, and solar—negawatts are electric power freed up for other uses by more efficient use of existing sources.

Individuals can produce “negawatts” at home by replacing lighting with LED bulbs and getting rid of old, inefficient appliances.

In our case, when we got our Nissan Leaf  EV in 2014, we offset the electricity needed to charge the battery every night by reducing other uses.  By replacing all our lighting with LED bulbs (especially the large number of 60-watt indoor floodlights that are on all the time) and eliminating inefficient appliances like an old refrigerator in the garage, we were able to charge the Leaf without increasing our overall electricity use.  So the Leaf is powered by non-polluting, zero-emissions negawatts.

But even without increasing the need for electricity, the juice going into an electric car still has to come from somewhere.  Doesn’t generating that power still generate emissions?

The electric grid is getting steadily cleaner, making an EV bought today greener every year.

This is really the best part of the zero emissions story.  Our sources of electricity are getting cleaner every year.  The Leaf EV we bought in 2014 has gotten greener every year as the electricity grid has gotten steadily cleaner—something a car powered by an internal combustion engine can never do.

Many EV owners also have solar panels on their homes—giving them a clean power source on the roof.

Many electric vehicle owners also have solar panels on their homes—about one-third according to a 2019 report by CleanTechnica.  So if the vehicle is charging while the sun is shining—no emissions.

Renewable sources like wind and solar now account for almost all the new electrical generating capacity every year, making the grid cleaner each year.

The same thing is true on a larger scale as the electric grid becomes increasingly powered by non-emitting renewable sources.  The use of dirty coal has declined dramatically since the early 2000s, when it accounted for about half of US electrical generating capacity.  It is now down to less than 20 percent and is the fourth largest source—after natural gas (40 percent), nuclear (20 percent), and renewables (20 percent).  And renewables now account for almost all the new generating capacity every year, making the grid cleaner each year.

The future is now in some areas of the country that already have high proportions of renewable or other non-emitting sources of electricity.

The future is now in some areas of the country that already have high proportions of renewable or other non-emitting sources of electricity. 

Vermont currently leads the nation, at nearly 100 percent renewable sources—almost 60 percent hydroelectric, 16 percent wind, and most of the rest from biomass and solar.  So if you’re charging an electric car in Vermont, you’re pretty much zero emissions.

Washington State also generates about 85 percent of its electricity from renewable sources—about 60 percent from hydroelectric.  Neighboring Idaho is at 80 percent with less hydro and more wind.

Iowa gets almost 60 percent of its electricity from wind, and Kansas is nearing half.

New Hampshire and Illinois get about 60 percent of their electricity from nuclear power.  Nuclear provides almost a third of the electricity for my own state of Virginia, so there’s a good chance that my electric cars are being charged from that non-emitting power source at night.

There are exceptions to this pattern, such as West Virginia, which still gets 80 percent of its electricity from coal. 

But overall, the electric grid is getting cleaner every year, driven by a combination of government mandates and powerful economic forces.  Initially, the transition was from dirty coal to cleaner natural gas, a result of the increased production and lower costs of natural gas from advanced drilling methods.  

In recent years, the energy transition has shifted principally toward renewable sources, which now dominate new capacity, a result of the dramatic decline in the costs of renewable sources like wind and solar.

In more recent years, the energy transition has shifted principally toward renewable sources, which now dominate new capacity, a result of the dramatic decline in the costs of renewable sources like wind and solar. 

These trends will continue during the 2020s—during the lifetime of an electric car purchased today.  Costs of wind, solar, and other renewable sources will continue to decline as more solar panels and wind turbines are produced and as new technologies are developed. 

And states are imposing renewable energy mandates on their utilities.  So far, ten states, including the entire West Coast, have enacted mandates for 100 percent renewable and zero-emissions electricity sources between 2040 and 2050.*  And it possible that a Federal mandate of some form will be enacted before the middle of the century.

If electric vehicles and their sources of electricity avoid emissions, what about the manufacturing of the vehicles and their batteries?  And what about the production of the solar panels and wind turbines? 

The solution to the climate crisis is to shift away from fossil fuels by converting our machines to electric motors and producing all our electricity from non-carbon sources.

The answer to that question is the same as the general solution to climate crisis.  The way to eliminate CO2 and other emissions is to transition away from burning fossil fuels by converting our machines to electric motors and producing all our electricity from non-carbon sources.  And that includes not just cars, trucks, and buses, but also the mining vehicles and processing plants and the factories that produce vehicles and batteries.

In sum, electric vehicles can operate with zero emissions today and will move increasingly in that direction as the grid and the overall energy system transitions to efficient electric motors and renewable sources of electricity.

* By 2040, New York and Oregon; by 2045, California, Hawaii, New Mexico, and Washington; by 2050, Colorado, Maine, Nevada, and Virginia.