Despite recent explosive growth rates, the wind and solar power industries must overcome key innovation challenges before they can contribute a substantial share of national or global energy supplies, a panel of leading technology experts said today in Washington DC. 
Speaking at the Energy Innovation 2013 Conference organized by the Information Technology and Innovation Foundation and the Breakthrough Institute, Armond Cohen of Clean Air Task Force, Fort Felker of the National Renewable Energy Laboratory (NREL), and Minh Le of the Department of Energy'sSunShot Program each stressed that taking solar and wind to scale starts with taking a "cold, hard look" at the real innovation challenges facing the growing renewable energy industries.
Scale, scale, scale
Wind energy has experienced "explosive growth" in America over the last 15 years, said Felker, who directs NREL's National Wind Technology Center. With double digit annual growth rates, wind has contributed 35 percent of all new generating capacity built in the United States over the last five years, second only to natural gas-fired power plants.
Solar power has experienced even more rapid growth rates in recent years, although it lags behind wind in total installed capacity.
Despite recent growth however, wind power provided only about 3.5 percent of U.S. electricity in 2012, while solar photovoltaic and thermal power technologies contributed just 0.1 percent. The panelists each agreed that these renewable energy technologies must reach orders-of-magnitude larger scale before they can contribute substantially to the national energy supply.
To date, the U.S. has built more than 40,000 wind turbines, for example, but Armond Cohen noted that it would take 300,000 1 megawatt wind turbines to equal the capacity of the current U.S. coal fleet. (The always astute Robert Wilson notes on Twitter that taking differing capacity factors into account, it would take roughly twice that number of turbines to equal the energy output of the U.S. coal fleet).