This three-volume set introduces researchers to issues surrounding both current energy sources and alternative energy options. While there is significant discussion of the non-renewable resources now used to meet the majority of the world's energy needs (oil, coal and natural gas), the primary focus of the set is on newer options to meet the ever-growing demand. These options include wind and solar energy, fuel cells, hydropower, geothermal power and biomass energy. In addition, more theoretical sources are also explored, including cold fusion, zero point energy and universal forces. Entries discuss the science behind the energy source, notable scientists and scientific discoveries, current examples of use, and the issues, challenges and obstacles to large-scale use. Arranged alphabetically by entry name.