Energy security issues, climate change, fossil fuel depletion, new technologies, and environmentally conscious consumers are powerful forces shaping the renewable energy sector. The future of renewable energy depends upon how powerful these forces are and which combination of forces prevails. This paper defines and analyzes four different scenarios, business as usual (2010-2030), focus on climate change (2010-2060), focus on energy security (2010-2030), and a clean and secure energy future (2010-2100) for the future of renewable energy. A clean and secure energy future, where renewable energy accounts for between 50% and 80% of total energy demand, is the most favorable scenario for the future of renewable energy but also the scenario that takes the greatest amount of commitment, in terms of time and money from businesses, individuals, governments, and policy makers. (C) 2011 Elsevier Ltd. All rights reserved.