Friday, March 13, 2009

Well, Blow Me Down!

A couple of follow-ups to my post on alternative energy from Monday. Leading off is an informative e-mail sent by Tim from Colorado:

Many states have now passed legislation requiring power companies to provide a certain "Renewable Portfolio Standard" or RPS as wind or solar energy, usually 10-20% by 2010 or 2020 (California's is 20% by the end of 2010, and 33% by the end of 2020). Now, that's just an average and every state has slightly different requirements.

I quibble a little with Mr. Bryce's numbers; I think he's one decimal place too high, so I'm going to adjust my discussion, and then we'll figure in Mr. Bryce's error at the end. According to the US Energy Information Administration, the peak electricity production last year was mid-July at 400 terawatt hours (400 x 10^12).

For the sake of argument, let's say the average RPS number for wind or solar is 3% of the US' total generation, so we'll split that 3% evenly 50-50 between wind and solar, and assume that every state in the Union has passed an RPS bill. Nationally, three percent of 400 terawatts is 12 terawatts that will have to come from wind or solar; sticking with our assumption that's 6 terawatts from wind, and 6 terawatts from solar.

The average output of a land-based wind turbine is 3-4 megawatts (10^6 watts); I'll be generous and use 4 megawatts. 6 terawatts divided by 4 megawatts per wind turbine equals 1.5 million wind turbines needed to meet a national average of 6 terawatts of wind generation. Do you know how many wind generators were installed last year? 8,300 megawatts of wind generation; dividing by my average of 4 megawatts per turbine means about 2,000 turbines were installed last year; 2,700 if we use 3 megawatts per turbine. At that rate it will take 500-750 years to install all of the 1.5 million wind turbines we'll need. Multiply those numbers by ten if we use Mr. Bryce's numbers.

If you factor in this information we're going to need more than 1.5 million turbines. The overall availability of wind turbines currently in service is somewhere around 30%; this includes maintenance downtime, and periods where the wind speed is too high or too low to operate.

What they don't tell you is that for every megawatt of wind or solar generation a power company has, that megawatt has to be backed up by conventional generation, usually in the form of a gas turbine, because the sun doesn't always shine and the wind doesn't always blow.

As we all saw happen over the last couple of years, natural gas futures tend to rise unpredictably at times. Another fact that is not shared is that wind generation is subsidized, which means we pay for it up front, and the subsidized cost is still higher per kilowatt than coal-fired power and nuclear power, so we pay again on the back end.

On the subject of Renewable Portfolio Standards, Paul Chesser notes some trouble in the Tar Heel state:

Today's News & Observer of Raleigh (one of McClatchy's tanking newspapers) reports that one of North Carolina's two investor-owned utilities, Progress Energy (Duke Energy is the other major one), has announced that it will not be able to meet renewable portfolio standard mandates enacted by the state a couple of years ago.

The story includes a good quote from the Progress Energy CEO:

"If renewables were easy, effective and plentiful, we'd be doing them," he said.

Exactly. And pouring billions even trillions of dollars into them is not going to change that simple fact any time soon.

No comments:

Post a Comment