Technologies available today, and those expected to become competitive over the next decade, will permit a rapid decarbonization of the global energy economy. New renewable energy technologies, combined with a broad suite of energy-efficiency advances, will allow global energy needs to be met without fossil fuels and by adding only minimally to the cost of energy services.The world is now in the early stages of an energy revolution that over the next few decades could be as momentous as the emergence of oiland electricity-based economies a century ago. Double-digit market growth, annual capital flows of more than $100 billion, sharp declines in technology costs, and rapid progress in the sophistication and effectiveness of government policies all herald a promising new energy era.Improved technology and high energy prices have created an extraordinarily favorable market for new energy systems over the past few years. But reaching a true economic tipping point will require innovative public policies and strong political leadership.