How Do We Actually Use Geothermal Energy?
Large landscape companies buy from farms where huge greenhouses are used to grow bedding plants and shrubs for sale to the public. Geothermal energy is used to heat the large open spaces in acres of greenhouse structures.
Geothermal energy has been used for hundreds of years in Europe to heat greenhouses and soil in order to grow vegetables during cold seasons. For farmers, how geothermal energy can be used is an interesting topic.
Once the heat source has been accessed in the ground, producing the heat in an ongoing way for agriculture is quite inexpensive compared to other forms of generated power. Geothermal energy is a good generator of electricity but there are so many other valid uses as well for this natural heat source.
Business
Industries often utilize geothermal energy for drying fruits and vegetables, curing wood, or dying fabrics. Thermal energy can also be used to extract silver and cold from mined ore. Small town public works departments use geothermal energy to warm the sidewalks and streets. The warmth under the sidewalk or road surface keeps ice from forming on top the walk or road during cold winter months.
Fish farms use geothermal energy to maintain water temperature in the growing ponds. In the southern states, the water used for growing shrimp, trout and other fish sold in food markets remains warm enough naturally throughout the year. In states like Idaho, Oregon and Washington, geothermal energy is used to provide water at temperature for maximum growth on fish farms.
There are resort areas where tourists flock to pay entrance fees and bathe in natural geothermal pools. In most of these resorts the thermally heated water is natural but is piped into a manmade pool or pond from the geothermal source.
Many thermal fields exist but are located away from major population areas so tapping into the heated water beneath the earth's surface and pumping it through a pipe system to a pool makes sense from a business point of view. It the water is cycle in from the thermal field and then pumped back into the geothermal area it becomes a resource that is sustainable.
Even though the ground may feel very cold in winter, in fact the ground retains heat below the surface. Ten feet below the surface of your property the ground has a consistent temperature in moderate climates.
That temperature is significantly warmer than air temperature in winter months. Heat pumps commonly used on home heat and air conditioning systems extract the heat from the ground to help boost the heating for your home. This saves on electricity bills as you don't pull as much electric power when using a heat pump as part of your home's HVAC system.
Generate Electricity
There are four methods used to generate electrical power from a geothermal energy source. Geothermal fields are excellent electricity generators and more reliable than other alternative energy methods like wind or solar power.
Wind energy depends on the volume and speed of the prevailing winds while solar power can require backup power on cloudy days. Geothermal energy is produced at a constant level in the earth.
Flash steam plants use hot water pumped from the earth to flash boil and release stem to turn turbines. The turbines act to generate electricity. Dry steam plants use the steam released directly from a geothermal field's underground reservoir and that steam directly powers the turbine and generator.
Binary power plants use hot geothermal water to heat a secondary liquid. That second, man-made, liquid then is turned to steam and powers the turbines. The second liquid is reusable as it is vaporized to steam and then cooled back to liquid form only to be vaporized again.
This form of geothermal electricity production increases turbine life as the turbine is not exposed to the high mineral content of the water coming directly from the thermal field. There are also hybrid plants where flash methods are combined with binary power and used for high efficiency electricity production.
Summary
Heating homes (heat pumps) and businesses is the most common method for producing geothermal energy. Using thermal fields for heat commercially can be traced back to the 1800s in the U.S. In France, geothermal heating was common 500 years ago.
Surprisingly, few people realize the term "heat pump" has anything to do with how we use geothermal energy.
