Large scale applications have been in use for electricity production and direct heat for more than 45 years, demonstrating long-term sustainable potential. However although deep geothermal is mature, research efforts are still needed to reduce operational costs, devise strategies to avoid or mitigate
adverse environmental effects, better understand reinjection and resource use, improve efficiency of energy extraction, develop more efficient binary and organic Rankine cycles, and improve sustainable utilization strategies.
Further RD&D efforts could make the use of geothermal more attractive in more regions located away from tectonic plate boundaries. During the last 20 years capital costs /MW installed of geothermal projects have decreased by about 50% as the easier problems have been resolved. As a result of RD&D investment, refinements in exploration techniques continue to improve the success rate of drilling, and reduce development risk and costs. Refinements in treatment processes of waste waters and gases continue to provide cost-effective options that are environmentally preferable. For example full reinjection of waste fluids is becoming more widespread, and even an obligation in some countries.
General RD&D priorities for geothermal include life-cycle analysis of direct heat use systems, sustainable production from geothermal resources and the use of shallow geothermal resources for small-scale individual users. More specific research tasks are the development of better exploration, resource confirmation and management tools, the development of deep (> 3000 m) geothermal resources and cogeneration of heat and power. Costs for geothermal well drilling, logging and completion also need to be reduced. Also relevant is research on local geothermal resources used for space and district heating as well as multi-purpose heat “cascading”.
Methodologies and tools to better determine a geothermal resource without drilling and to better assess its financial viability need to be developed. Expertise in geothermal exploration and equipment installation is lacking in many countries and capacity building is required. This can be achieved in part through co-operation, exchange of information and joint workshops with experienced countries such as Italy, Iceland and New Zealand.