Basics of Geo Thermal Energy

Geothermal literally means heat from the earth. Typically geothermal energy is defined as the energy or power derived from the different sources of heat present inside the earth. Sources include radioactive decay of minerals, magma, and solar energy itself, which is absorbed at the surface. Geo thermal energy is eco friendly, reliable and cost effective and is widely used all over the planet for space heating and water heating. 

Initially, the use of this form of energy was geographically limited but technology has turned things around:

Geothermal Electricity – The oldest of the geothermal power plants is the Dry Steam Plant followed by Flash Steam Plants. Due to geothermal fluids being low in temperature, the thermal efficiency of a geothermal electric plant is also low. Thus, until recently, these electric plants were exclusively built at the edges of tectonic plates where high temperature thermal energy resources are available closer to the surface.

With the development of binary cycle power plants and improvement in methods of drilling and extraction, the scope of building such plants over a wider geographical range has increased. Total geothermal power generation has increased from by more than 7 GW in last for 4 years, due to a steady rise in the number of plants and their capacity factor.

Geothermal Heating – This involves the direct use of geothermal energy for heating purposes. A lot of countries today use geothermal heating commercially. Until 2007, plants capable of producing around 30 GW of geothermal power were functioning all over the world. More than half of this power is used for space heating and a major chunk is used to heat pools.

Power generated from geothermal resources is being used successfully in commercial sectors, both industrial and agricultural. Interestingly, a few cites of the world located in freezing locations use hot water derived from geothermal plants for melting snow on roads and pavements.

Effects On Environment – Extraction of geothermal energy may have adverse effects on environment. Geothermal fluids include a deadly mixture of gases like carbon dioxide and hydrogen sulfide, which when released in the atmosphere aid the process of global warming and may make acid rains more frequent. Geothermal fluids also contain toxic elements like mercury and arsenic, which if filtered and disposed off carelessly into rivers may make their water unusable for ingestion.

Luckily, most plants are installed with emission-check systems and their emission intensity is just a fraction of what other fossil fuel plants produce.

Plant Requirement and Resources

Geothermal power doesn’t require any fuel but the plant’s capital costs tend to run high. The cost of exploration for appropriate resources and drilling alone comes out to about 60% of the sum total. The rest is for plant construction purposes. A large geothermal plant can power an entire city and a smaller one can easily power a village.

It is said that the heat content of the earth is enough to satisfy the power demand of the global economy over the next 10 billion years but the heat emitted form the earth toward the surface is in a very diffused form. Thus the heat needs to be brought to the surface through boring deep inside the earths crust for geothermal fluids. Solar energy reserve from shallow ground can be easily extracted using a heat pump to serve the purpose of simple home heating.

Geothermal energy is a renewable resource but still has a long way to go before it becomes, somewhat eco-friendly.