Oil-Based Or Coal-Fired? You Decide...

The results are in: MINI E vs. MINI Gas. And the winner is... debatable.

What's better: coal-based electricity or oil-based gasoline?

General Motors is claiming 230 mpg for its Chevy Volt. Nissan is one-upping them to 367 mpg for their Leaf EV. Some say this is the way of the future. Others say that they’re merely swapping oil-based gasoline for coal-based electricity, essentially moving the pollution from one source to the other without actually reducing it at all. Consider this: in per unit of energy delivered to a car's tank or battery, even emissions-stringent California electricity will produce more greenhouse gas emissions than petroleum fuel. On a national average, BTU-per-BTU basis, electricity is 1.7 times as planet-polluting as gasoline.

So what’s the deal here? Isn’t electric drive far more efficient than the old internal combustion engine, no matter how technologically advanced its become?

Well, recent articles on the Web have been looking at the MINI E as a recent example. The MINI E lists its official EPA at 33 kilowatt hours (kWh) per 100 miles in the city and 36 on the highway, for a combined average of 34.4 kWh per 100 miles. These are consumption numbers, not mileage figures, with a lower number corresponding to higher efficiency. So as you would expect, the Mini E is more efficient in the city.

Still, on an energy-equivalency basis, a gallon of gas in the tank is equal to 33.7 kWh of electricity. That's the number EPA uses in a footnote on an EV's window sticker and it can be derived by anyone from a set of basic energy conversion factors. You simply divide 33.7 kWh per gallon by 34.4 kWh per 100 miles and you get 98 miles per gallon, or the gasoline energy-equivalent rating of the MINI E.

Now, the gasoline-powered MINI Cooper Hardtop gets 28 mpg city and 37 highway, for a combined average of 32 mpg. Well, 98 is roughly 3.1 times 32, or in other words, the MINI E is 3.1 times more energy-efficient than its closest gasoline counterpart, right?

When you crunch the numbers for CO2-equivalent per distance driven, the MINI Cooper Hardtop using gasoline results in 357 grams of CO2 per mile, vs. The MINI E at 196 grams per mile, or 45 percent less.

So if you believe that the MINI E is more efficient to run, you’re free to pursue the argument over cold-weather battery charging requiring 220V hook-ups, local availability, vehicle performance, lack of a back seat, and, of course, what to do with all of those batteries when they die.

Discuss…

What's better: coal-based electricity or oil-based gasoline?

General Motors is claiming 230 mpg for its Chevy Volt. Nissan is one-upping them to 367 mpg for their Leaf EV. Some say this is the way of the future. Others say that they’re merely swapping oil-based gasoline for coal-based electricity, essentially moving the pollution from one source to the other without actually reducing it at all. Consider this: in per unit of energy delivered to a car's tank or battery, even emissions-stringent California electricity will produce more greenhouse gas emissions than petroleum fuel. On a national average, BTU-per-BTU basis, electricity is 1.7 times as planet-polluting as gasoline.

So what’s the deal here? Isn’t electric drive far more efficient than the old internal combustion engine, no matter how technologically advanced its become?

Well, recent articles on the Web have been looking at the MINI E as a recent example.The MINI E lists its official EPA at 33 kilowatt hours (kWh) per 100 miles in the city and 36 on the highway, for a combined average of 34.4 kWh per 100 miles. These are consumption numbers, not mileage figures, with a lower number corresponding to higher efficiency. So as you would expect, the Mini E is more efficient in the city.

Still, on an energy-equivalency basis, a gallon of gas in the tank is equal to 33.7 kWh of electricity. That's the number EPA uses in a footnote on an EV's window sticker and it can be derived by anyone from a set of basic energy conversion factors. You simply divide 33.7 kWh per gallon by 34.4 kWh per 100 miles and you get 98 miles per gallon, or the gasoline energy-equivalent rating of the MINI E.

Now, the gasoline-powered MINI Cooper Hardtop gets 28 mpg city and 37 highway, for a combined average of 32 mpg. Well, 98 is roughly 3.1 times 32, or in other words, the MINI E is 3.1 times more energy-efficient than its closest gasoline counterpart, right?

When you crunch the numbers for CO2-equivalent per distance driven, the MINI Cooper Hardtop using gasoline results in 357 grams of CO2 per mile, vs. The MINI E at 196 grams per mile, or 45 percent less.

So if you believe that the MINI E is more efficient to run, you’re free to pursue the argument over cold-weather battery charging requiring 220V hook-ups, local availability, vehicle performance, lack of a back seat, and, of course, what to do with all of those batteries when they die.

Discuss…