3.8 Million New Wind Turbines by 2030?

3,800,000 new wind turbines, 1,700,000,000 rooftop solar cells, 49,000 concentrated solar plants, 490,000 tidal turbines, 49,000 wave converters 5,350 geothermal plants, 40,0000 photovoltaic power plants and 900 hydroelectric power plants are all that is needed to supply 100% of the world's energy demand by 2030, according to a recent article in Scientific American. According to the authors, Mark Z. Jacobson of Stanford and Mark A. Delucchi of the Institute of Transportation Studies at the University of California, worldwide demand for energy in 2030 will be 16.9 trillion watts (TW), 4.4 TW more than today. (By comparison, a typical house uses about 10,000 million watts per year.) Today, the world generates only 0.02 TW of energy by wind and 0.008 TW through solar energy. This amount compares to a total available wind energy of 40-85 TW and 580 TW for solar. The footprint for the required wind turbines would be about 50 square miles and with the required spacing occupy less than 1% of the earth's land surface. 13,000 new coal plants, by the way, would be required to produce the additional 4.4 TW of the expected demand by 2030. The authors expect the cost of this renewable energy to be competitive with today's energy cost of about 7cents/kWh by 2020, with wind energy already cost competitive. They estimate construction costs at about $100 trillion dollars over 20 years, not including transmission, as compared to $10 trillion for the required coal plants. Of course this cost comparison does not factor in the health and environmental costs (e.g., global warming) of building 13,000 new coal plants. Among the additional hurdles the authors identify in this plan are materials shortages, as both wind turbines and solar power systems today require a number of rare-earth materials, such as neodymium used in turbine gear boxes and tellurium used in thin solar cells. The authors did not consider nuclear power, coal with carbon capture or ethanol, considering them poorer options for overall environmental impact.

See Mark Z. Jacobson and Mark A. Delucchi, A Path to Sustainable Energy by 2030, 301 Scientific American 58 (November 2009).