Geothermal Energy: Tapping into the Earth's Natural Source of Heat

by Brooke Spencer

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Here at Hollyhock, we place great importance on ecologically sound practices and are interested in ways that we can harness sustainable energy and share what we learn with all of you.

Our  lodge on Cortes Island uses solar panels to preheat water in the hot tubs and cottages, and we have various methods and tools to conserve water in our campus.

On our quest to stay up-to-date with energy efficiency news, this article on The National Geographic Magazine about geothermal energy caught our attention.

Geothermal energy has been used for cooking and heating purposes, tapping into the world’s internal heat source. Beneath the Earth’s crust, rock and liquids are home to thermal energy which can be found close to the Earth’s surface or several miles down.

This type of energy can be used to heat individual homes as well as larger buildings and offices, greenhouses and even pipes on streets to melt snow on the roads.

Underground, areas of steam and hot water can be used to create electricity that can heat or cool surrounding buildings.

To harness geothermal energy, they use what is called a heat pump system . This allows the Earth’s internal heat to warm houses in the winter and transfer heat from the house back into the ground in the summer, making the house cooler without the need for air conditioning.

There are three different kinds of geothermal power plants: binary, flash and dry steam. Dry steam is accessed through cracks in the ground which draw up steam which is used to power turbines. Flash plants pump high pressure water out of the ground and turn it into cooler, low pressure water. The steam that appears, is used to move the turbines. Inside binary plants, hot water passes through another liquid with a lower boiling point than the water. This causes the secondary liquid to vaporize, which again, turns the turbine. Binary plants are said to to be the most popular in the future.

Like anything, nothing is perfect and it does have some downsides. While it isn’t necessary to burn fossil fuels, a particular gas is released that smells of rotten eggs called hydrogen sulfide. Also, the disposal of some geothermal liquids may contain low traces of toxic material. The energy can be used for decades but eventually the heat source will deplete.

With this being said, the biggest advantages of using geothermal energy relate to the cost, extraction process, the lack of fossil fuels and its accessibility. Geothermal energy has little cost and can be extracted without the use of burning fossil fuels like coal, gas or oil. It costs less to use than burning fossil fuels. The fields only produce one sixth of the carbon dioxide that natural gas plants produce. The binary plants produce little to no toxic emissions. Geothermal energy has little limitations to its accessibility, it can be used 365 days a year.

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Please find the original article in the National Geographic.