Geothermal energy is derived from heat stored beneath the surface of the earth. This natural source of energy was used even in the Paleolithic era. To extract the heat from the earth, pressurized water is forced through the rocks deep inside the earth. When water comes in contact with the hot areas of the earth, it heats up. When it’s taken out, the water is hot enough to be utilized for various purposes in homes and industries. Since ancient times, the Chinese and Romans have been known to use hot mineral springs for cooking, bathing, and therapy. Geothermal power is generated using three types of power plants, namely, flash steam, dry steam, and binary cycle.
- Geothermal Technologies Program: A History of Geothermal Energy
- History of Geothermal Power – Earthworm Tunneling
How is it used?
Geothermal energy is used in a number of applications. It’s used in heating pumps in some homes in the United States and Sweden. Heat pumps are used to provide warmth and heat in the house. Countries such as Iceland and Turkey use it for the purpose of district heating. Countries such as China and Japan even use it for bathing. New Zealand has been using geothermal energy for agricultural applications, commercial purposes, water heating, and desalination. Electricity has been produced using geothermal energy for the past several decades. With the production of electricity, it’s utilized not just for heating but also for cooling as well as other purposes.
- Uses of Geothermal Energy
- Geothermal Heat Pumps
- Geothermal Resources in Iceland
- Geothermal Energy Revealed
Pros and Cons
There are several advantages of geothermal energy. It is renewable, reliable, flexible, sustainable, and clean. This implies that there is no pollution unlike other sources such as coal. The overall cost of having a heating or a cooling system in homes turns out to be $30 to $50 a month. A disadvantage of such systems is that the initial cost related to the installation and design is high. Another disadvantage is that the piping system required for the complete set up is very large and may not be suitable for smaller places. In spite of this drawback, the positives would outweigh the negatives in the long run. Use of geothermal energy saves a whole lot of energy wastage. It’s at least 6 times more efficient than conventional sources of energy.
How does it run?
There are open and closed loop heat pumps. In an open loop system, water from a lake or a pond is pumped into the geo-thermal loop, which is a set of pipes. It is then directed back to its source after heat is exchanged between the heat pump and the geo-thermal loop. In a closed loop system, heat exchange occurs directly from the copper pipes. The cost of a heat pump with one ton capacity is about $2500, where an average home requires three such units. Geothermal pumps are quite durable and do not require much maintenance. There are fewer components in a geothermal system compared to other systems. The piping system usually comes with a guarantee of 25-50 years. In this sense, replacement is not required unless there are manufacturing defects in the unit installed.
- Geothermal Heat Pumps
- Geothermal Heat Pumps – National Renewable Energy Lab
- Diagram of a Geothermal System
More information on Green Homes check out:
- Kids Korner: Geothermal Energy
- Geothermal: Energy and kids
- EIA Energy Kids: Geothermal
- Geothermal Energy Lesson Plan
- Geothermal Energy Basics