Geothermal Power

Abstract

IntroductionFuture deployment projections of geothermal energy resources have been published by the International Energy Agency (IEA) in a "Roadmap" document [1]. In volcanic and plate boundary settings, high-temperature geothermal energy is often the least expensive renewable energy option, especially in terms of long-run marginal cost (LRMC). For example, in New Zealand, the LRMC for new geothermal projects is US$ 50-67 MWh -1 (NZ$ 60-80) for the next 10 TWh, or 1.2 GW of installed capacity (Figure 18.1). The result is a projected replacement of coal (and gas) by geothermal (and wind) generation, reaching a target 90% renewable by 2020 ( Figure 18.2).Geothermal energy also has the added benefits of being a source of base-load power, in addition to efficiently providing on-demand heating and cooling for buildings, or for industrial and agricultural direct process heat applications. In order to assist decision-makers with future policy development and investment decisions, the IEA-GIA (Geothermal Implementing Agreement) has assisted in generating geothermal deployment projections and technology "roadmaps" through multi-party collaboration. This includes participation in the geothermal chapter of the Intergovernmental Panel on Climate Change (IPCC) special report on renewable energy [2]. The outcome of the deployment projections is location specific, but by 2050 geothermal energy could potentially contribute up to 30% of demand in volcanic countries (such as New Zealand, Philippines, and Japan) and 2-4% of electricity and heat demand for nonvolcanic countries through the development of hot sedimentary aquifer (HSA) and enhanced geothermal system (EGS) technologies (such as in Australia, Korea, China, India, and most of Europe).In some countries, rapid geothermal deployment over the past 5-10 years is already displacing coal-fired power generation (Figure 18.2). With a concerted collaboration effort, experienced countries can help out those that are relatively inexperienced in geothermal development, especially in East Africa, South America (Chile, Peru, etc.) and the South Pacific (e.g., Papua New Guinea), and by assisting nations (such Transition to Renewable Energy Systems, 1st Edition. Edited by Detlef Stolten and Viktor Scherer.