So many think that the world of geothermal energy is a new, high-tech way to heat or cool a home’s air or water. But, this industry in the United States alone is over 40-years-old. Well before that, humans were putting geothermal energy into use in multiple ways. While the technology does continue to advance, making the move to geothermal even more sensible, the use of this renewable energy source is not a new concept.
Let’s take a look through time to understand the uses of geothermal energy, and how we got to the space we are now (and where we’re likely headed in the future, too).
The First Uses of Geothermal Energy
The age of planet earth is estimated to be about 4.54 billion years old. That’s a whole lot of birthday candles! Scientifically speaking, if estimates are correct, that makes geothermal energy about 4.54 billion years old. After all, geothermal energy is simply using the temperatures within the earth to convert into energy.
Since, no matter the weather above ground, most of the United State’s ground, even just about 20 to 30 feet deep, remains around 50 to 60 degrees, this temperature difference is used to heat and cool homes. If it is wintertime at your home, the ground is warmer than the air. If it is summertime, the ground is cooler than the air. Utilizing these factors, geothermal energy systems for homes focus on altering your home’s air to comfortable living temperatures, no matter what Mother Nature is doing around it.
But, we’re skipping way too far ahead. Humans weren’t around much at that start of the earth, 4.54 billion years ago. But, once they were, they used geothermal energy. Did they have extensive ground-loop systems warming their caves? No. But, harnessing this factor is nothing new.
Geothermal for Heating Baths and Cooking
Have you ever wondered how we even arrived at the term “geothermal?” The word is a combination of root terms, with “geo-” coming from the Greek word for “earth,” and “thermal” deriving from the Greek word “therme” for heat.
It may then come as no surprise that the Greeks and Romans were some of the first to use geothermal energy regularly. But, they weren’t likely the very first. Archeological evidence shows that some Native American tribes used both hot springs and even elements of the earth’s temperature to cook! It is clear that, as far back as 10,000 years ago, the Paleo-Indians settled around naturally-occurring hot springs.
To get very technical, humans were not even likely the first to “discover” this science. It is said that macaque monkeys used geothermal energy, via heated hot springs, in order to expand their living space into northern Japan. Due to freezing temperatures, the habitat would not be survivable without them. But, thanks to the warm waters, heated by the earth’s crust, the primates were able to move to colder portions of the country.
The Homeric era of ancient Greece featured heated baths thanks to geothermal warmth back in 1,000 B.C.E. Both Greek and Roman ancient civilizations used baths for hygiene, but also for therapeutic treatments. Minerals often found in natural hot springs can provide a sense of calm, muscle relaxation, and are often thought to heal the body.
Geothermal for Home Heating
The use of geothermal energy for priorities beyond bathing and cooking likely began in the city of Pompeii when ancient Romans used natural springs and steam emitting from the earth to heat living spaces.
These ancient uses, of course, were limited in location. Domiciles (or baths) were created around sources known to be producing warmth or steam. Still, they would be the primary uses for the energy source until the 14th century, when “the world’s first district heating system was installed at Chaudes-Aigues, France.”
By 1892, the United States caught onto the possibilities of this natural wonder. A single street, known as Warm Springs Avenue in Boise, Idaho, “wins” the title of the first homes to be heated by geothermal heat in the country. By 1970, most of the city was heated by geothermal sources.
However it is Reykjavik, Iceland that claims the title of the “largest and most-famous geothermal district heating system.” There, 99 percent of the city received geothermal water for space heating starting in the 1930s!
Expansion into Industrial Use
What’s good for the home is good for industry, too, right? It wasn’t long before the world of business began to harness the energy source. The first direct-use applications started in Larderello, Italy, as the city created direct-use applications extracting borate compounds from geothermal fluids in the early 19th century.
Larderello must have liked the progress, as it was also home to the first geothermal electric power generation plant, an experimental plan the town launched in 1904. By 1913, the plant produced a whopping 250 kilowatts (kW). [For comparison, the seven states with geothermal power plants in the United States, as of 2022, were able to produce 17 billion kilowatt hours of power.]
Geothermal power plants soon followed in both New Zealand in 1958 and then along the geysers of northern California in 1960. As of 2015, 80 countries have harnessed power of geothermal energy in one form or another, with leaders noted as:
- United States
‘Going Green’ Gains Momentum
It was not until the 1960s and 70s that the “Going Green” movement began, “driven by popular and scientific concerns about local and global degradation of the physical environment.” Popularity of the geothermal energy potential grew as its clear abilities to be both a renewable and clean energy source were realized.
Geothermal heating and cooling can reduce a home’s greenhouse gas emissions by as much as 75 percent. Growth of the resource continues across the country. Estimates project that the electricity generated from geothermal energy plants will grow from 2022’s “17 billion kWh to 37.2 billion kWh in 2050.” This steady rate of 3% growth is expected to continue.
Ground-Source Heat Pumps
The ground-source heat pumps we know today were created for home use far later than the industrial plant projects. In-home use of geothermal ground source heat pumps was said to have started with Robert C. Webber, who claims to have made the first direct exchange ground source heat pump in the late 1940s.
Historians disagree over “firsts” in this case, as by 1948 the first successful commercial project was installed in the Commonwealth Building of Portland, Oregon. The building has since been designated as a National Historic Mechanical Engineering Landmark by the American Society of Mechanical Engineers (ASME).
It is Ohio State University Professor Carl Nielsen that is credited with the first residential open-loop version of a ground-source heat pump in a home. That, too, happened in 1948.
By the 1970s, the oil crisis drove engineers to seek out alternative sources to heat their homes. According to the International Ground Source Heat Pump Association (IGSHPA)’s own historical page, that is “when Dr. James Bose, professor at Oklahoma State University, came across the heat pump concept in an old engineering text.”
IGSHPA says that Bose was inspired to seek a solution as a homeowner’s heat pump was dumping scalding water into his pool
“Bose fashioned the heat pump to circulate the water through the pipes instead of dumping the water into the pool,” says the IGSHPA site. “This was the beginning of the new era in geothermal systems.”
Bose continued to work on the concept, thus creating Oklahoma as “the center of ground source heat pump research and development.” IGSHPA itself was formed in Oklahoma, and was based on the campus of Oklahoma State University, where Bose served as executive director until his retirement in November of 2013.
Today’s Uses of Geothermal Energy
IGSHPA says there are approximately 50,000 geothermal heat pumps installed in the United States each year. Today’s reports show that the growth of ground-source heat pumps being installed into homes at an “3.8% annual rate with 1.685 million units (12 kW size) in operation” as of 2019.