Some numbers to argue about
Which is more efficient, electricity or gasoline? A complicated and surprising answer...?
I've been waxing nostalgic lately over the placidity of my blog in comparison to the knock-down, drag-out free-for-all that is Charlie Stross's (where I guest-blogged for a couple of weeks this summer). So I thought I'd share an interesting bit of data that came across the twitterverse yesterday and (while it may not be news to you, is news to me) bears some contemplation. It is simply this:
According to various sources, including apparently the United States Department of Energy, it takes between 4 and 7.5 kWh of energy to refine one gallon of gasoline. To drill and transport that gas takes another 1.5-3 kWh. So, the average energy cost of one gallon of gas is roughly 8 kWh, or even more.
A lot of that energy is provided by fossil fuels, chiefly natural gas; but a big proportion of it is provided in the form of electricity. Those who have totaled it up find that a gasoline-powered automobile uses more electricity to run per mile than a comparable electric vehicle. The total energy cost of the gasoline economy is therefore at least double that of an electric economy.
A corollary to this is that a complete conversion to electric vehicles would not place any more strain on the grid than there is now; it would simply distribute it (because right now much of that energy is going to fixed installations, and with an EV economy it would be going, at least potentially, to millions of individual houses). So a 100% EV economy would not require any increase in electricity production, only an upgrade to the grid (and lots of companies, such as GM, are designing that grid). In fact, all things being equal, in a 100% EV world, electricity demand should go down somewhat.
The remaining issue for electric vehicles, then, would be battery disposal, because their toxicity is high when they contain lead, but with Li batteries is becoming lower and lower.
This isn't quite the whole story. What remains to be factored in here is the electricity cost of manufacturing the EV's batteries. I haven't yet found numbers for this cost; if anybody can supply it, that would be helpful.
And while we're at it, we should do a complete parts count for the additional complexity and wear-out rate of internal combustion engines, and factor in the electricity cost of those components...
...And round and round we go.