Geothermal Energy Resources of Saudi Arabia: Country Update

Abstract

Saudi Arabia consumes 240 terawatt hours of electricity to date from oil and gas and the projections are that the country's demand will reach 736 terawatt hours by 2020 (IEA, 2012, WB 2009). 80% of the electricity is being used for cooling purpose. The current per capita emission of CO2 has increased to 0.016 Gg from 0.012 Gg in 2000. The country has now focusing on developing renewable resources that were not utilized due the availability of huge oil and gas resources. Large potential of unutilized geothermal resources are encountered in Saudi Arabia, mainly of three categories. Low enthalpy resources represented by deep-seated aquifers that can be accessed only by deep oil wells, medium enthalpy resources (hot springs) encountered along the western and southwestern coastal parts and high enthalpy resources (Harrats) that are represented mainly by lava fields of approximately 80,000 km², with fumarole activity (Harrat Khaybar). The issuing surface temperatures of the thermal springs in these provinces vary from 31 to 96 ºC / with a flow rate of 5 to 20 L/m. Preliminary assessment was made on the geothermal potential of the hot springs encountered at Al-Lith and Jizan sites (Ain Al Harrah, Al Khouba, Al-Ardah and Bani Malik) using integrated geological, geochemical and geophysical techniques. Wide ranges of reservoir temperature (130-220ºC) and heat flow (120-210 µW/m2) are estimated from geothermometers. The geophysical investigations have indicated that geothermal feed zones are titled and controlled by a number of NW-SE, NE-SW and E-W oriented fault systems. Based on the reservoir characteristics, surface area of the volcanic flows, flow rates, heat flow and geothermal gradients of the geothermal provinces, it is estimated that the wet geothermal systems can generate about 23 x 109 kWh. Moreover, the western Saudi Arabian shield encloses a large number of pre and post orogenic high radioactive granites with very high generating capacity from 15 to 134 µW/m3. It is estimated that this granite can generate about 160 x 1012 kWh of electricity.