Here, two energy professionals introduce low enthalpy geothermal energy as a ubiquitous alternative to less reliable renewable energy sources such as solar and wind power. They outline the working principles, attainable efficiency, and the carbon footprint of tapping into geothermal energy sources, including novel technologies such as using carbon dioxide as an underground heat carrier. Numerous cases studies from different countries and regions illustrate the state of the art in geothermal systems, as well as current environmental and economic challenges associated with this technology. A critical discussion of the potential of geothermal energy, taking into account its economics and societal impact, is included.
