The average capacity factor of all wind turbines currently supported by the ecoENERGY program is about 33%, and that's considered to be quite high. Generally, on your threshold, you have to start having a 30% capacity factor to make it viable. The North Cape wind farm in Prince Edward Island has this cranking wind and it's been sitting at about a 41% capacity factor. So it does change the economics, you're right, and it's a matter of picking the right spot. It's quite an art to finding that spot where you have a capacity factor that makes your economics work.
On March 24th, 2009. See this statement in context.