Electric vehicles are often dubbed “zero-emission.” You’ve probably seen the phrase sported on the back of a new Tesla. But is an entire electric vehicle fleet really zero emissions? In this article, we will dig into what it means for a vehicle to be zero emissions, and how electric vehicle drivers can go beyond zero-emission to truly decarbonize their transportation.
Are electric vehicles really zero emission?
The short answer is yes. An electric vehicle does not have tailpipe emissions or an exhaust system, so zero emissions are coming from the back of an EV. This means they do not emit local pollutants such as volatile organic compounds, hydrocarbons, carbon monoxide, ozone, and lead.
And yet, a car’s energy must come from somewhere. In most cases, electric cars pull energy from the power grid, just like any appliance in your home. In this scenario, the amount of carbon emissions required to power an electric vehicle depends on two things: 1) The efficiency of the engine and 2) The electricity mix provided by the local power operator.
When it comes to efficiency, traditional internal combustion engines (ICE) don’t hold a candle to battery-powered engines (BPE). BPEs are over 4X more efficient than ICEs. They convert between 60 – 77% of the energy available, compared to gas cars, which only convert 21 – 40% of the available energy. This fact alone makes EVs much cleaner than a traditional vehicle. Given these efficiency advantages, the average EV in the US produces global warming pollution equal to a gasoline vehicle that gets 88 miles per gallon fuel economy. That’s significantly better than the most efficient gas car available in the United States, which gets 58 miles to the gallon.
Now let’s consider the second factor in determining the carbon emissions of an EV: the electricity mix of powering the vehicle. What we mean by electricity mix is the mix of electricity sources powering the electric grid in your community. Depending how much renewable energy is in that mix, an electric car’s emissions will vary. Nationally, the US gets around 17% of its energy from renewables, a number that is increasing steadily. And in some regions of the US, the grid is already extremely clean. For instance, Washington state, which relies heavily on hydropower as an electricity source, gets around 90% of its electricity from renewable resources. The more renewables you have in your local electricity mix, the cleaner your electric vehicle will be. Many utilities and cooperatives now offer options enabling their customers to choose whether to source all or a percentage of their electricity from renewable sources.