As the 1973 Oil Embargo demonstrated how dependent the United States is on foreign energy sources, it is necessary for the United States to advance alternative energy sources, and the growth of renewable energy technologies is contributing to a diverse and sustainable energy portfolio in the United States. According to DOE/EIA, the contribution of renewable energy was 9% of total energy use in 2011. Taking into account existing federal tax credits and state renewable portfolio standards (RPS), the contribution from renewable energy is projected to reach 13% by 2040. The growth of renewable energy is also encouraging the establishment of a clear and long-term energy policy. President Obama’s energy plan contains an ambitious goal of generating 80 percent of the United States’ electricity from “a diverse set of clean energy sources, including renewable energy sources, nuclear power, efficient natural gas, and clean coal.” Renewable energy also contributes to electricity infrastructure modernization, as increased penetration of renewable energy is not possible with an electric infrastructure that still relies on traditional power generation. Integrating renewable energy into the United States’ current grid system is driving the move towards updating electric infrastructures, including interconnection standards and procedures, grid flexibility and storage, transmission and distribution infrastructure expansion, and flexible conventional generation and mix diversity. Finally, the growth of renewable energy fosters research, development, and innovation. Such technical innovations significantly impact the scenarios for renewable energy penetration, and high penetration of renewable energy is also driving technological improvement and innovation in other energy technologies, including storage technologies, load-following nuclear power plants, and CCS coal plants.
