Editor’s note: This Q&A is a part of a survey conducted by Scientific American of executives at companies engaged in developing and implementing non-fossil fuel energy technologies. What technical obstacles currently most curtail the growth of wind power? What are the prospects for overcoming them in the near future and the longer-term? Whether they are built on land or at sea, nearly all wind turbines have the same technical issues related to the fact that wind is naturally variable. Today the best machines in the best spots now offer about a 35 percent ‘load factor,’ or efficiency level. The largest problem in turbine design is not the blades, but what we can’t see. It’s the guts of the machine-the engineering components housed in the nacelle, or body, of the turbine, which convert that kinetic energy into electricity-that need improvement. The main workhorse of the nacelle is the generator. First developed in 1831 for the coal industry, these machines move copper wires past magnets to convert mechanical energy into electricity. The basic premise of the system hasn’t changed very much. Generators thrive on a stable input energy source, such as coal or hydroelectric power, and with this stable prime […]