The opprtunities for geothermal power to play a much larger role in overall energy production in the future require technical innovation, reduced startup costs, public education, and a level economic and regulatory playing field with other energy technologies.
North American output could rise to 11,700 MW with existing technology and 25,390 MW with enhanced technology under development by joint government-industry programs.
Most of the easily located geothermal systems, those with hot springs, fumaroles, and geysers at the surface, are already known and many have been developed. In order to locate and characterize hidden geothermal systems that do not reach the surface, new approaches to exploration are needed.
The high economic risk of drilling has limited geothermal exploration in recent years. Significant growth in geothermal generating capacity during the next decade will rely on the discovery and production of several new water-dominated geo-thermal fields as well as drilling techniques for reaching them.
Researchers believe that the economic risk of exploratory drilling will be reduced through the development of new core hole evaluation technologies. Core drilling provides a set of rock samples and fine temperature-gradient information. It will be necessary to develop the methodology and equipment to conduct reservoir testing and evaluation during core drilling in order to take full advantage of the lower cost of core drilling.
Steam and hot water reservoirs are just a small part of the geothermal resource. The Earth’s magma and hot dry rock will provide cheap, clean, and almost unlimited energy once technology can tap into them. One future promising new geothermal technology known as Hot Dry Rock (HDR) geothermal is designed to be able to tap into much deeper geothermal resources than current technologies permit, thus allowing geothermal energy to be used for low cost, renewable electricity generation anywhere in the world.
However, the technology to drill deep enough boreholes (approximately 4 to 10 miles into the earth’s surface) does not yet exist at a low enough cost, and is a subject of current research and development.
The economics of geothermal power can be further improved through co-production of goods and services from high-temperature geothermal brine. Examples of this include zinc and silica, which can be recovered from geothermal brine in conjunction with electrical generation stations.
Large quantities of distilled water, which is currently costly to produce, is also a convenient byproduct of the generation of geothermal power. Geothermal power production can also be co-located with pollution remediation equipment in the context of cleaning sub-surface spills or other contaminations.