Recent surges in gasoline prices and deepening instability in the Middle East are reminders that the world's heavy dependence on fossil fuels carries an array of hidden costs, including energy insecurity and damage to human health and the natural environment. Fortunately, more and more nations are recognizing that they can address these problems by investing in renewable energy. Solar and wind power are the world's fastest growing energy sources, and investors are pouring billions of dollars into these industries every year. Around the world, a growing number of nations have recognized the economic, social, and environmental benefits of renewable energy, and are enacting tax incentives and other policy measures favorable to renewable technologies. In Germany, Japan, Spain, and a handful of other countries, clear government commitments to renewable energy and strong, effective policies have overcome barriers and created demand for these technologies, leading to dramatic growth in renewables industries and driving down costs. If these countries stay the course and others continue to join the renewables bandwagon, they will end up not only with cleaner and more efficient energy systems, but will also reap economic rewards in the form of new industries and jobs.