While wind power has become the most economically competitive renewable energy source globally, future US growth faces a hurdle in the form of a supply chain bottleneck for turbines.

Market share for turbines has become increasingly consolidated in the hands of a few producers, putting pressure on domestic wind developers and creating an opportunity for more vertically integrated foreign utilities to acquire US assets. Throw in the fickle production tax credit for wind power with its two-year lifespan, and the US outlook for more wind power does indeed look shaky.

On the positive side, more and more states are increasing their renewable portfolio standards, the price of oil continues to rise, demand for energy is expected to grow and energy independence from foreign producers is still an attractive proposition to law makers.

For these reasons, wind still remains an indispensable piece of the energy and climate change puzzle. KLD’s Global Climate 100 Index includes three of the top five turbine manufacturers and four of the top five wind utilities referenced in this fascinating article from the front page of today’s Wall Street Journal.