Math suggests land area need for wind turbines

Re: “What’s the math on wind power?” letter, Dec. 20.

The letter-writer asked what would be the environmental impacts of proposed alternatives to Site C, specifically wind power.

I found a 2009 study by the National Renewable Energy Laboratory specifically on land-use requirements of modern wind-power plants in the U.S., based on 172 actual projects. There are permanent impacts, which include turbine-pad area, permanent clearing, permanent service roads, substations and service buildings, and temporary impacts such as roads and lay-down areas needed for construction (which can be reclaimed). The combined number for these two impacts is about one hectare per megawatt of peak capacity.

B.C. Hydro did a study in 2009 that looked at capacity factors in four areas of the province, and found a range of likely capacity factors between 19 and 41 per cent, depending on wind strengths. By comparison, the Site C dam is 53 per cent.

Combining the two sources, I calculate that for wind power, the amount of direct land area needed to produce the same 5,100 GWh that is forecast from Site C would range between 35.1 and 75.7 square kilometres. This is in the same ballpark as the area flooded by the Site C reservoir, 55.5 square kilometres.

If all the wind power sites identified in the Hydro study were developed, they would provide from five to 11 times more energy annually than Site C. This, of course, does not address intermittency or cost, which are whole other discussions. Alex Zimmerman Victoria