How Does Geothermal Energy Work to Power a Household?

Homeowners can take advantage of the renewable energy resource provided by geothermal energy with ground source heat pumps. Similar in operation to a refrigerator, these pumps can supply a home with hot water while significantly decreasing the amount of energy needed to heat water.

“Closed loop” geothermal pump systems circulate antifreeze or water through pipes laid underground. During cold weather, this fluid absorbs geothermal heat and transports it through the pipes and into the home. Warmer weather results in the system reverting to a cooling system by extracting excess heat from the home and sending it back into the ground. Alternately, an “open loop” pump system operates in the same way that a closed loop system but can be complemented with an open discharge to accommodate a large supply of water.

Benefits of using non-polluting and renewable geothermal energy include reduced energy costs (as much as 50 percent), provisions for both cooling and heating of a home and low maintenance, since equipment involved in a geothermal system is protected by underground installation technology. In addition, homeowners investing in geothermal energy do not have to worry about inhaling toxic carbon monoxide or gas fumes resulting from faulty conventional heating/cooling devices.

How Does Geothermal Energy Work?

Deep underneath the Earth’s crust lies a vast warehouse of geothermal energy produced by tons of magma, or molten rock. Created by decaying potassium, uranium and other radioactive materials, geothermal energy is constantly being generated due to the volatility of inner Earth, a condition that has existed for billions of years.

The difference between the temperature of the Earth’s surface and its nuclear reactor-like core is called the geothermal gradient. This gradient generates the perpetual transmission of thermal energy that comes from heat radiating in a core to surface manner. Geologists estimate that the Earth’s core thermal reading consistently maintains a temperature of around 10,000 degrees Fahrenheit.

Areas that exhibit extremely high temperatures underground usually contain young, active volcanoes and are known as “hot spots”. Generally, these hot spots occur around plate boundaries and places where the Earth’s crust is attenuated enough to allow heat to escape. Well-known hot spots known to be seismically active include the Pacific Rim (Oregon, Alaska and California)and northern Nevada. Additionally, violent movement of magma coupled with consistent earthquake activity ruptures rock and allows boiling water to circulate, causing geysers and hot springs to emerge from the geothermal energy produced by the Earth’s inner core.

Apart from these vigorous hotspots, geothermal energy is also found at a milder level in our own backyards. Energy that can be harnessed to heat homes or perform other energy-reliant activity can be found between ten and 200 hundred feet below the ground anywhere on Earth. Moreover, vast reserves of heat energy also radiate from deeply embedded, dry rock structures existing about five to ten miles below the surface.

How Does Geothermal Energy Work in Enhanced Geothermal Systems?

A new kind of technology called Enhanced Geothermal Systems, or EGS, is offering to take conventional geothermal energy technology to a new level. Until the development of EGS, geothermal energy relied primarily on naturally occurring resources that produced sufficient amounts of energy to facilitate the viable extraction of hydrothermal power. With Enhanced Geothermal Systems technology, the ability to create geothermal energy utilizing only dry, hot rock is established through hydraulic stimulation.

To improve the permeability of underground areas that do not permit acceptable flow rates of water, EGS technology pumps cold water at an extremely high pressure down into a rock injection well. This high-pressure blast of water increases tension in fractured rock, rallying shear activity that boosts the permeability of the system. Called “hydro-shearing”, this process forces water to travel through rock fractures while also absorbing the heat emanating from the mobilized rock. This hydro-heat is then converted to electricity by employing a binary energy system or steam turbine. After the water has cooled, it is then returned into the ground by injection and heated again to be reused in a closed-loop entity.