Nearly every country in the world today concedes that the age of sourcing energy from fossil fuels — chiefly crude oil and coal — is waning. Not only is there a finite amount of fossil fuel reserves in the Earth, but the environmental (and even political) cost of using these reserves is higher than most countries are willing to bear. As a result, the search for energy derived from alternative sources — including geothermal, nuclear, solar, wind, and hydroelectric technologies — has taken on enormous importance in political and scientific circles. Some countries have made significant strides toward converting their energy bases from fossil fuels to renewable energies; for example, Denmark which supplied more than 95% of its national energy from fossil fuels in the early 1970s, now supplies more than 30% from wind and other renewable sources. Many other nations, including the United States and China, are still largely fossil-fuel based, but are awakening to the need to make national-level investments in alternative energy innovations that could transform their economies in the near future. The next twenty years may well bring a massive reinvention of the world's approach to energy.

There are many questions that must be answered and hundreds of paths that can be followed in the quest to move beyond fossil fuels. Should the world's governments emphasize energy efficiency strategies that reduce the demand for fossil fuels by reducing energy consumption? One example of this approach is the use of "smart grids" that more effectively regulate the flow of energy from utility companies to homes and businesses. Or should governments emphasize the cultivation of new energy sources such as wind or geothermal power? Or a combination of the two? Should the cars of the future run on fuel cells, electricity, plant-based fuels . . . or fossil fuels? In the alternative energy debate, there are no simple answers. Forming a rich understanding of the many points of view in this dialogue is essential to developing a thoughtful, balanced position.

In this Spotlight, we provide a guided tour through the quest for alternative energies. What are the various kinds of energies being explored, and what are their pros and cons? How are traditional energy companies — including oil and gas companies and utilities — reacting to the challenge? How can cultivation of alternative energies spur economic growth? We hope your exploration of the resources we've gathered here to answer these questions will only be the beginning of a lifelong engagement with one of the most important issues of our time.

Image: NASA.