Saturday, February 2, 2008

Carbon Offsets

Do carbon offsets work? They can work, but won't necessarily. There are companies ready to take your money and grant expiation in return. No doubt some of them are honest, but it's up to you to check them out. There aren't any agencies that regulate them.

Another issue is, what kind of carbon-offset schemes work? Some offer tree planting, maybe in some exotic place. But planting trees won't work, because trees all die eventually and give back all the carbon they've absorbed. It only could work if land was set aside permanently for new forests and if somehow it could be guaranteed that the land would never be cleared. There's no way such a guarantee could be made. At the rate the world population is growing, all the arable land will be needed for growing biofuel, not to mention food. In fact, global warming is likely to reduce land productivity.

But a different scheme could work. Non-fossil energy costs more than fossil energy. That's why we use so much fossil fuel, especially coal. So you could pay your local utility to buy your share of electricity from non-fossil sources, with you paying the difference in cost voluntarily. If this plan were structured properly, nuclear would be one of the non-fossil sources. It never is, though. All or nearly all the energy will come from wind turbines.

If you do that much, why couldn't you pay extra to make up for other CO2 emissions?

Here's some CO2 emission rates you can get from the US EPA's website.

For each KWH of electricity, you generate 1.37 lbs of CO2.
For each gallon of gasoline, you generate 20.4 lbs of CO2.
For each gallon of diesel fuel or heating fuel, you generate 22.3 lbs of CO2.
For each 1000 cubic feet of natural gas, you generate 120.6 lbs of CO2.

The EPA doesn't give this figure, but for commercial air travel, figure 50 passenger miles per gallon, or 1000 / 50 * 20.4 = 408 lbs of CO2 per 1000 passenger miles.

Now you can calculate your footprint in pounds of CO2 per year. If your utility has a green-energy program, ask what the premium per KWH is for green energy. At my utility, the rate is 1.25 cents, so the cost of becoming carbon neutral is 1.25/1.37 = 0.91 cents/pound.


Electricity 5000 KWH 6850 lbs
Gasoline 1000 gallons 20,400 lbs
TOTAL 27,250 lbs

Cost of offset = 27,250 * 0.91/100 = $248/year, or $21/month.

So if our example consumer donated $21/month to the green energy program, he'd be carbon neutral, just like former US VP Gore. If your utility doesn't offer such a program, find one of those companies you have confidence in and donate it there. Just don't pay to plant trees.

Now that you're guilt free, let's discuss this sensibly. The only reason carbon offsets work is that we generate electricity in the most stupid way possible. As we move toward non-fossil energy sources, this system will break down. If all the electricity came from nuclear power plants and windfarms, there'd be no way to offset motor and aviation fuels. That means the world has to shift toward hydrogen, battery-powered cars, and electrified rail transit.

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