Global Status, Development and Prospects of Shallow and Deep Geothermal Energy

Abstract

Geothermal heat pump systems (GHP), producing from shallow resources, are the spearhead of geothermal achievement and development. Global heat delivery grew exponentially to 600 PJ in 2020. GHP is the fastest growing segment in geothermal technology and one of the fastest growing application of renewable energy technologies worldwide. Other, various direct-use applications like space heating, bathing and swimming/wellness, industrial, agricultural (especially greenhouses) and aquacultural applications are based on deep, hydrothermal resources. These varieties produced worldwide 420 PJ heat in 2020; the average linear growth was, from 1995 on, about 10 % per year. It can be expected that this trend continues. Power generation, also from deep, hydrothermal resources, develops slowly but steadily, with an average growth-rate of 5 % per year, producing 95.0 TWh in 2020 in 30 countries. When comparing with other renewable power plant technologies (hydro, biomass, solar PV, wind), geothermal falls far behind – both in installed capacity (GWe) and in production (TWh). Only the annual availability of geothermal electricity is the highest among the renewables (60 %). Low geothermal productivity and growth-rate is due to extensive investments for solar PV and wind, which are by orders of magnitude higher than for geothermal power. The technology of Enhanced Geothermal Systems (EGS), based on deep, petrothermal resources, could be a game-changer. Requirements, problems and research goals to find solutions are presented.