Land use of Ethanol vs Solar for Vehicle Fuel

I took a stab at trying to figure out how much land it takes to power an internal combustion engine vehicle with ethanol vs what it takes to power an electric vehicle with solar energy.

The links in the embedded spreadsheet show my data sources. If any of these are inaccurate (or my calculations are wrong) please let me know.

Based on what I’m seeing, it looks like it takes a bit more than an acre of farmland dedicated to growing corn to power a single vehicle. That’s based on the amount of E85 fuel it would take, so it would also take some non-ethanol fuel to make that work.

For the electric car numbers, I used a watts/mile figure found on some Tesla forums and a land use calculation based on typical production of panels in large ground-mount systems. This came to 0.015 acres or 652 sq ft.

It seems like it’s quite a bit more efficient to convert solar energy into electricity, transfer that into car batteries, then use that power to turn an electric engine than it is to convert solar energy into plants, harvest those plants, convert those plants into ethanol, transfer that energy into car tanks, and convert that energy into small explosions to turn an internal combustion engine. If my numbers are correct, it looks like it’s around 70X more efficient from a land needed per vehicle perspective.

While this could be looked at from a “what’s the best use of farmland?” perspective, it’s obviously worth noting that solar panels can be placed on a lot of surfaces other than farmland, including places that don’t consume any land, like rooftops.

Another thing to consider: The cost to power an electric car can be significantly cheaper than what’s shown in the spreadsheet if you take advantage of electric vehicle charging and/or time of day pricing plans. Off-peak electricity rates (when your car is likely sitting in your garage) are far cheaper than standard residential rates.

But, wouldn’t that mean that you wouldn’t be using solar to charge your car? Correct. It looks like the future – at least in Minnesota – will involve powering our homes with solar & wind during the day and charging our vehicles with wind power overnight.