Monday, October 09, 2006

Wind Power Doesn't Reduce Emissions?????

Wind generators operate mechanically to convert the kinetic energy in the wind into electricity. No fuel is burned and nothing is emitted--no air pollution or global warming pollution. Therefore, greater use of wind-generated electricity, if it substitutes for fossil fuels, will reduce a utility system's emissions. Right?

No, not according to anti-wind zealots, who seemingly will believe most anything, no matter how outlandish or contrary to common sense, provided it criticizes the energy source they oppose.

The no-emissions-benefit theory is nicely discussed and disposed of in a Frequently Asked Question (FAQ) from the Yes2Wind Web site, which is a joint project of the major environmental groups Friends of the Earth, Greenpeace and the World Wildlife Fund, all of whom share a common concern about global warming.

It rests on three pillars, all of which turn out to be made of sand:

(1) Because the wind is variable and sometimes does not blow, backup generation must be kept ready at all times to replace it. The backup power plants emit pollution anyway, so no pollution is avoided.

(2) Because the wind is variable, when it displaces coal-fired generation, the coal power plants are forced to adjust their electricity output. When they do, they are less efficient than if they can run at constant output, and the extra emissions that result from this reduced efficiency more than offset the gains from using wind.

(3), not mentioned at the Yes2Wind site: The country of Denmark, which currently obtains about 20% of its electricity from wind, has not experienced a reduction in carbon dioxide (CO2) emissions as a result. See, for example, the TurbineAction anti-wind site in the U.K., where the following bald-faced statement is made: "Denmark, which has more wind turbines per capita than any other country, has publicly admitted that there has been no savings in carbon dioxide emissions." (This statement was excerpted from the site today, 9 October 2006.)

With regard to (1), the Yes2Wind site correctly notes that backup is needed for the whole system anyway, in case other power plants experience unexpected outages (in fact, the largest part of backup requirements is often for nuclear reactors, which are larger than other power plants). A bit more must be added for wind, but only a bit.

With regard to (2), coal-fired power plants do indeed run at slightly lower efficiency, but this effect is trivial. See, for example, Assessment of Greenhouse Gas Abatement from Wind Farms in Victoria, a recent study that explicitly takes this issue into account yet still finds large CO2 offsets from adding wind to the utility system.

And finally, with regard to (3), the latest emissions data from the Danish Energy Authority show CO2 emissions--after adjustment for weather variations and exports or imports of electricity--peaking at about 62 million metric tons in 1991 and then declining steadily to approximately 51 million metric tons in 2004.

Says the Energy Authority, "Gross energy consumption has been more or less constant over the last 10 years; however, the fuels used have changed considerably. The shift from coal to natural gas and renewable energy etc. has meant that, year by year, less CO2 is linked to each unit of fuel consumed. Thus, in 2004 each GJ of adjusted gross energy consumption was linked to 61.2 kg CO2, against 74.2 kg in 1990. This corresponds to a 17.5 per cent reduction.

"One kWh of electricity sold in Denmark caused 526 grams of CO2 emissions in 2004. In 1990, CO2 emissions were 937 grams per kWh of electricity sold. This corresponds to a reduction of almost 44 per cent. This large reduction is attributable to fuel conversions in electricity production and the growing significance of CHP [combined heat and power] production and wind power." [emphasis added]

I sincerely hope this drives a stake through the heart of this particular piece of disinformation.

1 comment:

WattHead said...

Hey Tom. You didn't mention in your comments on my blog that you had started your own blog. I've added it to my RSS feed and will keep up on it regularly. I'll add your blog to my blogroll as well. Welcome to the blogosphere.