2011 saw huge advances in solar, wind and other renewable energy sources, and these advancements will continue into 2012. In fact 2012 could be the year that renewable energy sources start to seriously compete with traditional fossil fuels, at least that is the hope in the battle to reduce carbon emissions and our dependence on dwindling oil stocks. However a major problem with renewable energy sources is that they can rarely provide consistent power levels, due to a myriad of factors outside of human control. Eric Wesoff, an industry analyst with Greentech Media, explains that, "A wind farm only works when the blades are spinning. It might have a nameplate capacity of 100 megawatts, but it never puts out that much. Sometimes it's 70; sometimes it's nothing. To a grid operator, that kind of resource is a headache rather than an aspirin." To overcome these fluctuations energy storage systems can be used to store excess power at peak generating times and release it when needed to provide a more constant level. "So now that 100-MW wind farm can say, 'We're a 40-MW, steady-state, 24/7 energy source'-more like a coal plant. That's more valuable to society."