What is Geothermal Energy and how can we use it?
Simply put, Geothermal energy is naturally stored heat, usually within molten rock, inside the Earth. In nature, we see this heat released as hot water or steam through geysers, hot springs, vents, and mud pots. This energy has been used for many centuries to warm up homes and businesses. It was discovered, long ago, that hot water could be pumped up from the depths of the Earth at temperatures of up to 400 degrees Fahrenheit!
Today, this thermal energy also generates power that can be harvested by drilling wells. The British Geological Survey describes geothermal energy as a “carbon-free, renewable and sustainable form of energy that provides a continuous, uninterrupted thermal supply that can be used to heat homes and office buildings and generate electricity.”
Geothermal energy sources are often found in “fields”. California has the largest “field” area which spans over 45 square miles and contains 22 power plants, with an estimated power capacity of over 1.5 GW, enough to power a half-million homes. The USA considers itself a ‘pioneer’ of geothermal power, producing 25% of its energy from 5 geothermal power plants. Recently, there have been huge efforts to tap into this renewable energy resource for electricity production in developing nations.
How does Geothermal energy work for buildings?
One way in which large buildings and campuses are able to utilize geothermal energy is by using a ground source heat pump connected to a loop of underground pipes. About ten feet below the Earth’s surface, the temperature remains at an almost constant 54 degrees. During the winter months, the warmer temperatures below the surface can be used to heat a water-based solution that is pumped through these pipes by the heat pump thus greatly reducing the energy needed to warm the ambient air inside. Conversely in the summertime, the temperature below the surface is much cooler than the above-ground temperature, so the heat pump sends the warmer solution down into the ground for cooling and it resurfaces as a cooler liquid. This is then converted into air cooling by the geo-exchange system. The network of pipes below the surface can either be laid horizontally, if there is a large surface area of land available, such as a car park, or if there isn’t much space available, then the pipes can run vertically to achieve the same energy savings.
Is Geothermal energy a sustainable resource?
There are certainly environmental advantages to using Geothermal technologies over conventional power generation.
In order to extract power from geothermal energy, wells are dug deep underground to access the steam and hot water which can be used to drive turbines connected to electricity generators. There are three types of geothermal power plants: dry steam, flash, and binary. The binary geothermal power plant technology has no air or liquid emissions, only dry steam, making it the most favorable option of the three.
Geothermal energy is considered to be safe and sustainable because of the low carbon footprint and the vast amount of available heat generated and stored by the Earth’s core.
Why you should consider Geothermal energy
Geothermal heat pump systems use 25% to 50% less electricity as compared to conventional heating or cooling and require less space for plant equipment.
Geothermal heat pumps have relatively few moving parts, so their life span is relatively long. The heat pump pipes can have warranties of up to 50 years, while the pumps typically last for 20 years or more.
Geothermal energy is becoming an increasingly popular option for large buildings and campuses because it is eco-friendly, provides reliable and readily accessible heat, and generates lower operating costs for many years to come.