A study from the Department of Energy's National Renewable Energy Laboratory (NREL) has found that today's renewable energy technologies could supply up to 80 percent of US electricity by the year 2050. The NREL's study explored various scenarios, concluding that onshore wind power will have the most significant impact while offshore wind power continues to grow. Solar power and biomass were also projected to play an important role, with geothermal and hydropower contributing significantly less due to resource and cost limitations.
Reaching the projected 80 percent would obviously require significant amounts of funding and political will. The bright side is that the DOE claims most of the other barriers could be resolved, saying "no insurmountable long-term constraints to renewable electricity technology manufacturing capacity, materials supply, or labor availability were identified." Also, the study fails to take into account the potential environmental effects of these technologies.