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==Geothermal Energy==

Enhanced Geothermal System

An enhanced geothermal system(EGS) is a geothermal energy system that can make electrical energy without naturally occurring underground water. For a long time, geothermal energy production was only used when hot rocks, underground water, and cracks in rocks were available. Now, new ways of getting this never ending power source are being created. Areas with possible energy potential need to be altered by humans in order to get the energy. These areas can lack either underground water and/or cracks, or fracture network, in rocks. Enhanced geothermal systems also allow for geothermal energy to be harnessed outside of the typical geothermal areas, like active plate boundaries to areas like western U.S.A.

In order to first get the hot rocks, holes must be carefully dug 1000’s of meters below the surface of the earth, not within 40 meters of each other (to ensure no heat stealing between wells) (Bu et al 2012). Water is then poured down the holes at controlled, scientifically determined rate for both fracture network creation and use in the energy cycle. Cracks or fractures are created due to induced seismicity, or the forced reopening of cracks due to water pressure causing small seismic events rarely felt on the surface (US DOE 2012). Once a good enough crack system is created, the heated water can then be pumped out from a production well and into the power plant to be using in the chosen energy extraction process and circulated through again. In order to increase the likeliness that the water will flow in the direction of the production well, microholes arrays can be drilled to allow for a higher probability that fractures will connect in the right pathway for energy production (US DOE 2012). These holes are less than 4 inches in diameter and reach outward from water injection wells and water extraction wells.

Geothermal systems can also be enhanced by recycling old oil and gas wells for geothermal use (Bu et al 2012). It is cheaper to change these wills for heat mining than to drill brand new holes. These wells do not allow for physical contact between the water and the heat source. These wells are made out of two [cylinders]: a bigger one and a smaller one. The smaller one fits inside the bigger one and is where the heated water is pumped out from. Water in inserted between the lining of the inner pipe and the outer one (Bu at al 2012). Due to the lack in direct contact with the hot rocks as well as some heat loss from lack of a good insulating material, the energy output is not as high as in ordinary geothermal systems.

Some say that this form of energy is one of the “greenest” alternative energies out there. Studies have shown that two of the three techniques of geothermal energy flash-steam and dry-steam give off less than 7% of the green house gasses that fossil fuels give off. The third method, known as a closed binary-cycle system, gives off nearly zero green house gasses (Bayer et al 2013). The most emission heavy part of EGS is the drilling when the drills are powered by diesel fuel. Research on EGS Life Cycle Analysis has shown that a good correction for this would be to hook the drill up to the power grid decreasing the already minimal impact GEP power plants has on human health, climate change, and ecosystem quality (Blanc et al 2013). Supporters also claim that because geothermal energy systems don’t rely on the changing weather, it is a more reliable energy with a constant energy output.

US Involvement The US has the largest potential geothermal energy reserve in the world yet only 4% of its total energy consumption (15 billion kWh) is from GEP. California has the highest number of geothermal heat pumps out of a total of the nine states that use geothermal energy. Hawaii gets 20% of its power form geothermal power plants. Knowledge about geothermal energy is not well known. This makes getting money for research and development very difficult. Developers have also been known to have trouble getting permits to drill on public land and get funding from both the federal government and outside investors (Scott et al 2011). There are however two projects that were commissioned by the Senate to help get EGS out of the pilot stage.

In 1990, legislation took to creating incentives to develop the industry. It was attempted with the Energy Act of 2005 and Energy Independence and Security Act of 2007 with issued tax credits and the creation of Senate supported research and development programs (Apergis et al 2011). Despite these small steps, more must be done on the political front to make it easier to start up production and help boost GEP if geothermal power is to make its mark in the future energy markets.

Future Projections

Purkus et al. (2011) identifies four environments related to the future of geothermal power production: electricity market, policy, society, and technology. These four focus shape the three major scenarios they predict as a possible future of the energy industry.

1. The first scenario says that environmental awareness continues to grows, nuclear power and lignite-fire practices become unacceptable, and countries continue to decentralize energy and sanction more GEP research and development.
2. The next scenario states that fear of economic instability and society’s indifferent attitude towards climate change creates a short-term satisfaction mentality causing research to focus on more efficient fossil fuels.
3. Scenario three says that fear of climate change stunts fossil fuel production, but economic worries push people towards nuclear power. The final discussion of all three scenarios foreshadows the future somewhere in the middle of all three (Purkus et al 2011).