Geothermal Energy

by Joanne Miller

The earth offers various steady sources of energy waiting to be tapped. There is solar energy, wind energy and wave energy that most of us are familiar with. However, natural energy sources are not limited to these alone. Geothermal is yet another form with tremendous potential to cater to household energy requirements.


Underground temperatures are quite stable, varying between 5.56 degree Celsius and 26.67 degree Celsius. The fact that these temperatures remain steady all year round is quite advantageous. This is energy (heat) trapped just a few feet underground and can be tapped to heat/cool structures above the ground.

Cheaper Alternative

Energy providers are now using ground-breaking technologies to tap geothermal energy; such as the innovative heat exchange systems that utilize heat pumps for exploiting underground heat wells. There has been an increase in numbers of businesses and sustainable homes that now bank on this novel method for their energy needs. Apart from being environmental friendly this method brings down energy costs substantially.

The advantage is that the geo-exchange system works as a heating system in the colder months and cools the environment when temperatures are soaring. With this system in place you do away with the need of installing air conditioners and/or heaters that work on gas, LPG or oil and guzzle power, require maintenance regularly and work out costly.

On the other hand, maintenance cost of geothermal units is way low and the life span is more than 15 years. The pipes laid underground come with a warranty of 50 years and stay good over generations. This is one factor that significantly augments the resale value of any sustainable property.

Effectiveness Of Geothermal Coolers

The mechanism of the geothermal heating system is quite simple and can be reversed to either cool buildings in hot dry weather conditions or heat them in winter months. During summer a cycle of transferring warm air from inside a building to the underground, where it is cooler comes into effect. The air is cooled and transferred into the building through air ducts. When the weather turns cold the process is reversed and now the warmer underground temperatures are used to heat buildings on the surface.

The Working Of The Geothermal System

The first step is to spread a network of underground pipes close to the structure that needs heating/cooling. Next water or a combination of water and anti-freeze is pumped into this network. This liquid transfers the heat from the ground to the heat pump and back. The air that is now either cooled or heated is circulated through air ducts or other radiant heating methods.

Greenhouse Heating

Permaculturists recommend geothermal systems for greenhouses as a simple and effective method for heating. The area outside the greenhouse with the pipe network, acts as an oversized battery that can maintain favourable temperatures inside, all year round.

Cost Involved

The cost of setting up a geothermal system can vary depending on location. In fact, a number of factors decide the cost – soil composition at the site, ease with which pipes can be laid, elevation of building and depth at which heat wells are located etc., but you should always check with your local council about eco-subventions.
Photo credit: Mercury Refrigeration