In addition to solar energy, there are a variety of other renewable energy sources that can contribute to our future energy needs. The present chapter considers four of the renewable energy sources other than solar that have made the largest contribution to our past energy use and are likely to continue to be the most important in the foreseeable future. These are hydroelectricity, wind, geothermal energy and biofuels. For each of these energy sources the technology for harnessing the energy from nature is considered. The discussion also includes an overview of the geographical distribution of the utilization of each energy source, as well as the growth of the resource over the years.