Tesla Motors has received more than 325,000 early orders for its attractive new “Model 3” electric cars, even though the car will not be available in the market for at least another year. This number is roughly equal to the 340,000 electric and hybrid cars running on American streets now.
Tesla has declared its cars to be zero-emissions, which helps borrow the obsession with driving pleasure, but that isn’t necessarily true. Although a car powered by a battery itself does not generate any emissions, the power plant used to charge those batteries is likely to emit emissions. Low emissions – not to mention zero emissions – are only real in certain places where most of the electricity comes from a mixture of low-carbon sources such as the sun, wind or nuclear reactors.
Electric cars are an excellent option for eliminating the use of oil in transportation, given that very limited electricity in the United States is generated by burning petroleum. However, electric cars may or may not help the country to combat climate change, and it all depends on where the electricity comes from.
Cars and trucks are responsible for about 24% of the greenhouse gas pollution in the United States, meaning about 1.7 billion metric tons per year. And since these emissions come from hundreds of millions of car exhaust emission tubes, and it seems that it is difficult to control this source of pollution, and then converting it to hundreds of chimneys in power plants that provide electricity to charge electric cars seems a more effective way to clean up a fleet. Country cars.
And those chimneys – many of which are found in coal-fired power plants – are the largest single source of greenhouse gas pollution in the United States, releasing two billion metric tons of carbon dioxide annually.
Emissions from that source could increase with the increase in electricity demand due to electric cars, unless more stringent pollution controls are imposed on power plants, or electricity utilities shift to less polluting sources such as solar energy.
Currently, the regular Toyota Prius hybrid that burns gasoline when its battery is disconnected, and an all-electric Nissan LEAF generate roughly the same amount of greenhouse gas pollution: 200 grams per mile, according to US Department of Energy data.
And that’s an average value for the United States. In California, which has one of the highest levels of clean electricity in the United States, an electric vehicle can only produce roughly 100 grams per mile – half the amount a hybrid car can generate. The same applies to Texas and even Florida.
In the midwestern and southern United States, where coal is responsible for generating most of the electricity, hybrid cars generate less carbon dioxide than electric cars. And in Minnesota, which relies on fossil fuels, an electric vehicle actually emits 300 grams per mile of greenhouse gases.
As a result, some researchers suggest that using a regional approach to clean vehicle standards would make more sense than using nationwide standards that practically require electric vehicles to be used throughout the United States. Hence, Minnesota could choose to use hybrid cars, while California would choose electric cars.
The time when recharging electrons flow from the wall socket into electric vehicle batteries can also play a role in these calculations. Night is often the time when the wind blows, but it is also the time when electricity utilities prefer to operate only coal-fired plants.
And a recent study found that electric cars that are charged with electricity at night from the regional grid that covers Ohio, Delaware, Pennsylvania and Virginia cause more greenhouse gas pollution than if car owners charge their car batteries at random times throughout the day when the fuel sources are more diverse.
The same logic applies to different parts of the world as well. Driving an electric car in China – where coal is the largest source of fuel for power plants – has catastrophic consequences for climate change.
If a coal-fired power plant lacks pollution control or fails to operate, this would amplify the range of smog, acid rain, lung-damaging micro-soot, and other diseases that result from burning fossil fuels. The same applies to all other countries that depend on burning coal, including Australia, India and South Africa.
The positive news is that the United States is in the midst of a fundamental shift from using coal to produce the most electricity to cleaner natural gas. This change results in the production of less carbon dioxide, making electric cars cleaner across the country, roughly equivalent to hybrids.
But on the other hand, the main component of natural gas – methane – is a powerful greenhouse gas. If methane leaks from the wells in which it is extracted, or the pipes that transport it or the power plants that burn it, the climate will not benefit.
In short, electric cars are only as good as the electricity they charge. (The fuel source also plays a role in the case of regular cars. For example, gasoline derived from tar sands is more air pollutant than that derived from most other petroleum sources.) In the absence of clean electricity, hybrid cars that can drive 50 miles or more with a gallon of gasoline generate the fewest emissions.
However, electric cars still represent less than 1% of car sales in the United States of America, and a smaller percentage of that of the global car fleet, which today approaches two billion cars.
So, there is no reason to worry about its environmental benefits, which are in doubt until now until more power plants give up the use of coal.
The current return to SUVs that consume much more fuel than other cars, urged by lower gasoline prices, is an even more alarming indicator of future climate change. But perhaps by the time electric cars become widespread, the pollution from electricity generation will be zero.