# How many birds must die while you pour refrigerated soy milk on your granola?

According to The Province:

More than 300 sea birds, mostly brown pelicans and northern gannets, have been found dead along the U.S. Gulf Coast during the first five weeks of BP’s huge oil spill off Louisiana, wildlife officials reported Monday.

Tragic. Poor birds.

According to another report:

While generating megawatts of electricity, windmills on the Tug Hill Plateau in northern New York are also killing hundreds of bats and birds, according to a recent study.

The consultantsâ€™ report for PPM Energy and Horizon Energy identified 123 birds, mostly night migrants, and 326 bats found dead over the course of five months last year beneath 50 wind turbines on the plateau between Lake Ontario and the western Adirondacks.

Those poor birds and bats, done in by some windmills. The article describes 123 birds and 326 bats killed by 50 windmills over 5 months. While the other article explains that about 300 birds killed. This by about 37 million gallons of oil over 5 weeks.

The wind-watch article also mentions that those 50 turbines produce 900,000 megawatt hours per year.

Let’s only consider the number of birds killed.

Oil:
1.7 MWh per barrel of oil x 37,000,000 barrels = 62,900,000 MWh of energy in the oil spill to date
62,900,000 MWh / 300 birds = 209667 MWh per bird killed

Wind:
50 turbines produce 900,000 MWh per year
4.35 weeks/month * 5 months = 21.75 weeks
21.75 weeks / 52 weeks/year = 0.42 years
0.42 years * 900,000 MWh/year = 376442 MWh produced by windmills over 5 month period
376442 MWh / 123 birds = 3061 MWh per bird killed

Oil vs. Wind
209667 MWh per bird killed (oil) / 3061 MWh per bird killed (wind) ~= 68

What does this mean?

In terms of environmental impact measured by one factor (birds killed), windmills are about 68x more efficient at killing birds per unit energy derived. To garner the same amount of energy needed from wind than from oil, we’d have to operate the windmills 68x longer or increase the number of windmills by 68x in order to get the same amount of energy. This means that about 68x more birds will die if we wanted to match the energy we’d get from oil. This would result in 68 * 123 birds = 8425 birds dead compared to the 300 dead from the oil spill for the same amount of energy derived.

There is, of course, one major flaw in the calculation above (besides my wanton disregard for sig figs). We’ve only considered oil spilled in the gulf. Alas, the vast majority (ie. 99.9999%) of oil isn’t spilled. When oil isn’t spilled, its efficiency in killing birds goes way down. Further, the wind energy we consider above is the norm not the exception; this is the rate of bird death during normal operation of wind turbines.

Clearly, when considering the environmental impact of oil by showing dead oil slicked birds on cable news, oil actually isn’t comparatively bad. In fact, it is a less efficient killer of birds per unit energy derived.

The champ?