It might seem intuitive that turbines must produce a lot more power than they consume, but without actual numbers, who really knows? It is fairly easy to find out how much power is being generated by most wind farms. What is so far been impossible is to find out how much power they consume during their operation. So far I’ve looked for information on both wind farm and individual turbine consumption and have found nothing. Without this information it is impossible to know how much of a contribution a wind farm actually makes to the grid, and this in turn affects the calculations of CO2 savings and so on.
The turbines do not use the power they produce to power themselves; instead they are connected to either the existing grid just like any other utility user or to their own distribution system from a substation. I presume the power they use is metered and the project pays the power company for it just like you and I do, so the numbers I’m looking for should be readily available. If the usage isn’t metered (and I’ve read of such cases, amazingly) then pretty much the true value of the entire project is unknown. UPDATE – Early on CanWEA apparently got a deal [there was a nice 30-minute radio program on CKNX but it has been pulled] with the Ontario government that whatever electricity is used by a project is supplied free of charge. Whether it is metered or not I don’t know.
It turns out that turbines might use a surprisingly large amount of power. A quick and probably partial list might include: computers, lights and sensors, motors that control the pitch and direction of the blades, keeping the nacelle at a proper temperature and energizing the electromagnets in the generator. Additionally, it seems that the blades won’t tolerate remaining still for any length of time, so during extended calm periods they must be rotated using power from the grid. I found one guess that this input might be 10% of the rated output; in other words, about a third of the actual output. As I find any real information about this I’ll post it here. In the meantime, if anyone out there has any insights to this, please let me know.
UPDATE, March 24, 2009. I finally saw a number! 15,000kw-hr per turbine per year, which averages out to 1700 watts, roughly equivalent to 2 smaller homes. It was from an economist who works for the Danish Wind Industry, so I’m assuming it is accurate, although I’d (of course) like to see reports of actual measurements. Plus there’s certain other aspects of the article that are problematic and as a result I’m suspicious of the entire thing. Assuming a typical turbine generates 3000-4000 mw-hr in a year this isn’t such a large deal.