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article imageGeothermal energy — An under-exploited energy source (Part 1)

By Karen Graham     Jan 23, 2017 in Technology
In our search for clean, cost-effective sources of renewable energy to mitigate the effects of climate change, one source of that energy has been right under our feet all along — Geothermal energy is not only clean and sustainable, but it is eco-friendl
In 2016, the International Energy Agency (IEA) reported that renewable energy has become the world's second largest source of electrical production. Today, solar and wind power are right behind Hydro, and solid biofuels as being sources of clean energy.
The report also mentions geothermal energy and its steady, but slow, growth rate of 3.1 percent annually, noting that this source is underutilized.
An example of a geothermal station in Iceland
The Krafla Geothermal Station in Iceland
by scudsone
But the statistics on geothermal energy may be changing as technological advances have expanded the range and size of viable sources of geothermal energy. Over the weekend, Digital Journal ran an excellent story on geothermal energy production in Iceland, a world leader in the use of geothermal energy.
What is geothermal energy?
Basically, geothermal energy is heat energy stored in the Earth. It has been there all along, and we can see it in the form of volcanoes, hot springs and geysers. Early humans could surmise the center of the Earth was hot after seeing thermal phenomena.
But it wasn't until between the 16th and 17th centuries when the first mines were excavated a few hundred meters below the surface that we were able to "feel" the Earth's heat. It was during this period that thermometers were used to measure just how hot it was in a mine.
The Earth s crust  mantle  and core. Top right: a section through the crust and the uppermost mantle...
The Earth's crust, mantle, and core. Top right: a section through the crust and the uppermost mantle.
International Geothermal Association
And while we understood the physical properties of the heat the Earth generated, it wasn't until the 20th century that we began to understand the role played by radiogenic heat and the "heat balance" continually generated by the decay of the long-lived radioactive isotopes at the Earth's core.
Early uses of geothermal heat
Humans have been using hot springs to bathe in since Paleolithic times. The oldest known pool is located on China's Lisan mountain built during the Qin Dynasty in the 3rd century BCE.
The oldest known pool fed by a hot spring  built in the Qin dynasty in the 3rd century BCE.
The oldest known pool fed by a hot spring, built in the Qin dynasty in the 3rd century BCE.
Ytrottier
Later, in the First century AD, it was the Romans that first exploited geothermal power by charging a fee for users of the public baths in what is now Bath, England. There, the hot springs not only fed the baths but were also used for underfloor heating.
Believe it or not, we have been taking advantage of the planet's geothermal heat for hundreds of years, using the natural steam for its mechanical energy. In the early part of the 19th century, A chemical industry was set up in what is now known as Larderello, Italy.
Boric acid was extracted from the boric acid hot waters or from specially drilled boreholes. The boric acid was evaporated out of the hot waters in iron boilers using logs from nearby forests as fuel for the fires. But in 1827 Francesco Larderel, founder of this industry figured out a way to utilize the heat of the boric fluids in the evaporation process, thereby stopping the depletion of forest resources.
Geothermal steam is one of many ways scientists propose to power the earth. However one team at MIT ...
Geothermal steam is one of many ways scientists propose to power the earth. However one team at MIT has found a new way to turn sunlight into steam.
Ævar Guðmundsson
Between 1910 and 1940 the low-pressure steam in this region of Italy was being used to heat industrial and residential buildings and greenhouses. It was during this time that other countries began utilizing geothermal energy on an industrial scale, including the city of Boise, Idaho, in the United States, with the nation's first geothermal district heating system.
While Iceland started out using geysers to heat greenhouses about the same time that Italy began using this steam to heat buildings, it wasn't until 1943 that Iceland began using steam and hot water to heat homes. But with technological advances, Iceland has become the world's leader in the use of geothermal energy.
Steam rises from the Wayang Windu geothermal power station on West Java
Steam rises from the Wayang Windu geothermal power station on West Java
Bay Ismoyo, AFP
Today, geothermal energy use is growing as science and technology collaborate in finding better, more efficient ways of using this renewable energy source. From the world's very first commercial geothermal power plant, built in Larderello, Italy in 1911, to the geothermal power plants in operation across the world, we have learned to better utilize this renewable source of clean energy.
In Part 2, we will examine the different methods used to extract geothermal energy, as well as the question of whether fracking for enhanced geothermal systems should be scrutinized with the same parameters as fracking for natural gas.
More about geothermal energy, Fossil fuels, Hot springs, cost effective, underexploited