Enhanced geothermal system
Traditionally, geothermal power systems operated only where naturally occurring heat, water, and rock permeability are sufficient to allow energy extraction.
The injection increases the fluid pressure in the rock, triggering shear events that expand pre-existing cracks and enhance the site's permeability.
Good locations are typically over deep granite covered by a 3–5 kilometres (1.9–3.1 mi) layer of insulating sediments that slow heat loss.
Some EGS projects operate at the edges of hydrothermal sites where drilled wells intersect hot, yet impermeable, reservoir rocks.
The Soultz project explored the connection of multiple stimulated zones and the performance of triplet well configurations (1 injector/2 producers).
[citation needed] The Portuguese government awarded, in December 2008, an exclusive license to Geovita Ltd to prospect and explore geothermal energy in one of the best areas in continental Portugal.
[citation needed] The Pohang EGS project started in December 2010, with the goal of producing 1 MW.
The first EGS effort — then termed Hot Dry Rock — took place at Fenton Hill, New Mexico with a project run by the federal Los Alamos Laboratory.
The results demonstrated that heat could be extracted at reasonable rates from a hydraulically stimulated region of low-permeability hot crystalline rock.
In 2009, The US Department of Energy (USDOE) issued two Funding Opportunity Announcements (FOAs) related to enhanced geothermal systems.
[83] The DOE opened another FOA in 2009 using stimulus funding from the American Reinvestment and Recovery Act for $350 million, including $80 million aimed specifically at EGS projects,[84] Developing EGS in conjunction with a district heating system is a part in Cornell University's Climate Action Plan for their Ithaca campus.
[93] The Infrastructure Investment and Jobs Act authorized $84 million to support EGS development through four demonstration projects.
[99] According to the Australian government, risks associated with "hydrofracturing induced seismicity are low compared to that of natural earthquakes, and can be reduced by careful management and monitoring" and "should not be regarded as an impediment to further development".
