Are Electric Cars Necessarily Greener?

Source: Thinkstock
Source: Thinkstock

Why do most people purchase electric or hybrid cars? To save fuel? To help the environment? The answer is probably some blend of both of those reasons, and possibly others. But what if it turned out that these so-called green cars are not much more green than their gasoline- or diesel-powered counterparts?

A new report from The Economist puts that question front and center, with a short report digging into the dirtier-than-expected details. The Economist notes that just a few years ago, the U.S. only had two electric-only models available on the market, and that number has since swelled considerably to 20, as consumer demand and interest has gone up proportionately, as well as ever-increasing stringent environmental regulations.

Despite that interest from consumers, and additional regulations, what actually determines whether or not an electric car is better for the environment boils down to a few simple details: What kind of car an electric vehicle is replacing on the road, where the car is charged, and at what time during the day owners are charging their vehicles.

For the first point, what type of vehicle an all-electric is replacing on the road is fairly easy to grasp. If a driver decides to trade in their gas-guzzling SUV, or older, large pickup truck for a Nissan Leaf or Toyota Prius, then the overall effect on emissions and fuel savings will probably be a net positive. However, if a driver trades in a fairly efficient diesel-powered car, say a Volkswagen, for a Leaf or Prius, there may not actually be all that much of a difference.

Why? The reason can be factored down to how the energy to run the car is actually being produced — whether it be through internal combustion of fossil fuels, or through the electricity that charges a battery.

The final two factors playing into whether or not an electric car is more environmentally-friendly than a gas- or diesel-powered vehicle are closely related. As noted previously, what it all really comes down to is how the energy itself is produced. The Economist says that this typically comes down to the local energy grid, which depends on where drivers and consumers live, more than anything.

If you live in Washington state, for example, where a great deal of the state’s electricity is produced from hydroelectric dams — a clean, renewable resource — then purchasing an electric vehicle to replace a fossil fuel-based vehicle would likely be a more eco-friendly decision. On the other hand, if you live in a state in the midwest or southeast, which largely depends on coal that is imported to generate electricity, then an electric car might not be making much of a difference.

The reason is because electric cars run on electricity, and that electricity is generated through some kind of process. If coal is being burned to generate it, and then charge a battery, it’s not much different than simply burning gas or diesel in your car’s innards. The net benefit, if there is one, isn’t that great.

Also taken into account is the time of day that consumers are charging their vehicles, which would tap into particular power grids that use a combination of methods to generate electricity. This can vary wildly from region to region, so it’s hard to really determine with certainty how this can effect the ultimate outcome in terms of emissions. This is really a local issue, and a blanket generalization can’t be determined with certainty across a giant geographic region — especially the United States.

What The Economist is really getting at is that whether or not an electric car makes a big difference in the overall amount of emissions it produces depends on how the energy your vehicle uses is initially created. Depending on where you live, this can vary. For the truly eco-conscious consumer, researching whether or not an electric car will benefit the environment in the end will require some deeper investigation into your local power grid, and your state’s dependence on fossil fuels.

Will purchasing a Nissan Leaf to replace your 1980s-era pickup truck save you money at the pump? Undoubtedly. Will it end up producing less emissions in the long-run? Most likely. But the point is that things are not as clear-cut as they seem.

There’s another facet to this argument, though, that The Economist didn’t touch on: The density of the power supplied. Inherently, electric cars and hybrids are more efficient than traditional gas-powered cars, and engineers have gotten very good at ensuring that that’s the case. Power that is supplied via a battery has more energy density — that is, an EV can leech out more energy per unit supplied, in comparison to internal combustion engines.

While this has definitely not always been the case, the technology and propulsion systems that are used to power EVs is improving rapidly. A glance at the miles per gallon versus the electric equivalent — MPGe — is an easy way to compare and contrast. An MPGe unit is used to determine the distance traveled by unit of energy consumed. Electric vehicles typically have very high MPGe ratings, oftentimes more than 100, whereas gasoline vehicles typically top out at around 50 miles per gallon, at best. By comparing the two, it’s plain to see that EVs are able to get substantially more bang for their buck out of the energy they consume.

While a bit confusing, it’s one thing The Economist did not address that may actually play into determining how efficient and eco-friendly electric cars can be. Again, it’s simply one part of the overall picture that EVs and the corresponding technology may not be as green as they appear.