Thursday, July 3, 2008

Houston powers city with hot air


The city of Houston has signed a contract to get a quarter of its municipal government power needs from wind farms. This is significant not only because Houston is the oil and gas capital of the country, but because it needs a lot of power. It’s the fourth-largest city in the nation, and it’s built on a swamp near the tropics. Those government air conditioning needs are not small.

Houston officials have contracted with Goldman Sachs and Reliant Energy to provide 40 MW of power at 7.5 cents per kilowatt hour for the next five years. The city uses an average of 160 MW to power its municipal buildings (this doesn’t include residential or business users in the city). The cost is less than the current 9.5 cents per kilowatt hour that natural gas providers are offering.

But here’s where it gets really interesting. The Wall Street Journal, in reporting on this deal, said:

The power that the city buys won’t necessarily come directly from wind turbines. Because wind power is intermittent — it is produced only when the wind blows hard enough — the city’s contract calls for back-up power to come from conventional sources. But the energy companies will certify that an equal and offsetting amount of power will be produced by Texas wind farms.

This essentially promises that any conventional power used for Houston’s “clean” 40 MW will be offset by using the same amount of clean energy in other places. We’ve all seen the tenuous nature of carbon offsets, and we’re wondering if these certifications might become more tenuous as the demand for wind power exceeds the ability to produce it.

If the wind doesn’t blow or wind power is pledged for other resources, then finding wind power for an offset could be a challenge — and an expensive one.

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