Harnessing Geothermal Energy: One of the most abundant sources of renewable energy is the heat deep in the earth. This geothermal energy could provide clean heat and energy to whole cities, and in some parts of the world, such as Iceland, it does. But accessing this resource can be difficult. Dr. Woskov is developing a way to convert abandoned coal and gas mines – which are drilled very deep– into geothermal wells. He discusses the abundance of geothermal energy, the challenges of accessing it, and the geothermal project using a microwave-emitting mechanism called a gyrotron.