Electric cars have generated a lot of buzz. The reason is simple: they are very exciting. There are many environmental and socio-economic-political benefits to making electric cars the best they can be, for example:

  • The United States and many other countries put both their general domestic security and well as their energy security at risk by depending heavily upon oil imports (The U.S. imports 12 million barrels of oil a day, more than half our oil.)
  • Oil has a devastating and corrupting influence upon a huge percentage of the countries that produce it as their principal export
  • As electric grids shift towards non-fossil fuel sources like wind, all electric vehicles will be powered entirely by carbon-free energy sources. Domestic fuels already power the majority of the US electric grid.
  • Internal combustion vehicles (gasoline powered engines) emit many pollutants besides the infamous carbon dioxide. Particulates, NOx, SO2, CO, and hydrocarbons are all spewed into the air that cause asthma, acid rain, and other well-quantified ill health effects. And while power plants do this as well, they are a) not located in crowded cities, b) already under emissions controls for many of those pollutants, and c) centralized, so it is easier to develop containment solutions than it is for hundreds of millions of independent vehicles on the road
  • When one accounts for the full life-cycle costs, “well to wheels,” of mining, refining, and combusting fuel, gasoline is arguably the leading environmental scourge when compared with every other kind of fossil fuel (see here for a 2007 report by EPRI and the NRDC)

All that is well and good, but still many people ask, I don’t understand what the deal is with electric cars. How do they work? How does electricity make it go? Here’s the crucial point to understand. Electricity is not a fuel. It is simply a way to transmit and store energy. Batteries do not make power. They store power. So a plug-in-electric car does not get its fuel from a battery. How could it? A battery just stores potential energy from when it was charged. When the battery was charging, it was sucking in energy produced by an actual fuel source: coal power plants, nuclear power plants, wind farms, hydroelectric plants, etc. An electric vehicle draws power from a battery, but the fuel that makes it all possible comes from a coal plant or wind farm far away (or solar panels atop your roof).

So why are we writing about electric cars, besides the fact that they’re very exciting (see above for a refresher)? Well, here at Carbon Lighthouse, we’ve been asked several times recently what’s better for carbon dioxide emissions: a gasoline powered car or an electric car charged from a coal power plant? As an organization with the name Carbon Lighthouse and as supporters of improved energy storage systems – both for transport and the power grid – it was tempting to say: of course the electric car is better. But a proper answer to the question demands accurate calculations. And that’s what we set out to do.

A quick internet search will reveal that many people, both professional and not, both serious and not, have looked at this question. Surprisingly (or unsurprisingly) most of the information out there is not well documented and the assumptions get messy very quickly. We will try to rectify that…. in a post to follow shortly.