Magazine / April, 2013 9
HEAT RESERVOIR
Where it is used.
Geothermal energy can power homes, pools, and spas. The natural heat melts snow on sidewalks in the winter and dehydration plants are powered to dry onions and garlic. 5,600 megawatts of geothermal energy creates 100,000 jobs.
Geothermal reservoirs use the steam and hot water beneath the earth’s surface. This energy produces over 3,000 megawatts of energy and 200 geothermal projects has a total capacity of 78,000 megawatts. These reservoirs however, may have negative impacts on the environment and threat local groundwater and increase tremors from drilling.
How it works.
Hot magma from beneath the earth’s crust moves close to the surface, heats underground water and traps it in cracks and porous rocks, creating reservoirs of very hot water and steam. Deep wells can tap the high energy content of this water and steam. This can drive energy services for electricity, heating, industrial processes and melt snow. Geothermal wells involve hydraulic fracturing of underground formations, fracking, similar to oil collection. However, protection over drinking water piping systems needs to be ensured in case of contamination and chemical additives. Drilling and fracturing activities need management of toxic wastes and high levels of environmental protection. Geothermal heat pumps take the temperature difference between the earth’s surface and air and allow the heat from the ground to be pumped into the building. This allows for winter and summer to stay at moderate temperatures because the hot air from the building is pulled to the ground as well. Excess energy can heat water.
Geothermal energy costs.
Initial costs of drilling and installing geothermal power plants are high, but operation and maintenance costs are low and there are no fuel costs. Currently the power is 3 cents per kilowatt-hour.
Advantages.
o Clean, green, renewable resource
o Earth continues to emit heat from the core and has no signs of depletion
o Sustainable source however some underground aquifers may be affected by lack of precipitation
o Geothermal plants can re-inject fluids underground to replenish reservoirs
o Produce next to no pollution emission and unlike other sources, geothermal energy is readily available around the clock
Future of geothermal.
o Produce energy from hard to reach areas and those with less water in harder beds of rock
o Hybridization which pairs geothermal with solar technologies to increase energy capture and electricity generation