I think it's all about growing consumer confidence in this as a viable system. Part of it is investment. As renewables continue to gain a foot hold on emerging markets, they become less risky and investor confidence increases. This makes building these things cheaper because money to build them is easier to find. I think the technology - manufacturing and maintenance - is also improving. Yes, the generators are still generators, but they are becoming more efficient. And more companies are producing windmills which creates a competitive market that drives prices down while businesses come online like trades and repairmen that help keep the whole system buoyant.