Describing how geothermal heating and cooling systems work can make it sound like science fiction. After all, you’d think that some kind of futuristic technology would be required to harness renewable thermal energy underground to heat and cool homes at anywhere from 300-600% efficiency.
Humans have been using the principles behind geothermal for centuries and the basic technology that powers geothermal heating and cooling systems, or ground source heat pumps, has existed since the late 1940s.
Western European and Nordic countries have been converting homes to geothermal since the 1970s. In 1980, Germany installed nearly 25,000 systems, and today one in five Swedish homes use ground source heat pumps.For the US, a Department of Energy study found that 28 million homeowners could save significantly by switching to geothermal.
So if geothermal is the most efficient and often the most cost-effective way to heat homes and the technology has been used for decades, why isn’t it more common?
To really understand why, you’d need to look at the whole history of heat pumps, but the short answer is cost. Installing a geothermal system is a major investment, and while it can save most homeowners thousands of dollars in the long run, it has traditionally come with a steep price tag upfront. Fortunately, Dandelion’s innovative technology, business model, and financing tools are “disrupting the geothermal energy space,” making it more affordable and accessible for homeowners than ever before. To find out how Dandelion has shifted the status quo, let’s zoom out and take a look at the historical context of geothermal home heating and cooling.
From Cavemen to Lord Kelvin
Archeological evidence shows that humans were harnessing thermal energy over 10,000 years ago. Early humans must have understood the fact that the earth holds a steady temperature year-round because, as the name “cavemen” suggests, they used underground caverns to keep cool in warm weather and stay warm in cold climates. Archeologists have noted that cave-dwelling persisted past pre-history and into the ancient world as people in places as disparate as ancient New Mexico and Turkey developed large ‘cave cities’ to keep comfortable and store food at a consistent temperature.
In more recent history, Bavaria’s beer gardens kept kegs cool with underground ice cellars. Even after refrigeration, brewers relied on deep cellars to maintain steady temperatures. Nearly 200 years ago, Yuengling in Pennsylvania hired coal miners to dig “beer caves” that kept beer at about fifty degrees year-round.Those “beer caves” are still in use to this day!
The first theoretical application of geothermal as we’d know it today came about at the height of the Scientific Revolution. In the mid-18th century, Scottish physician William Cullen used a pump to demonstrate the possibility of artificial refrigeration. A century later, British engineer Lord Kelvin used that innovation to theorize that the refrigeration process could work in reverse and laid down the concept of the modern heat pump. A few years later, in 1857, the Austrian Peter von Rittinger developed the first working heat pump and in 1912, Mexican-Swiss engineer Heinrich Zoelly filed the first patent for a geothermal, or ground source heat pump in Switzerland.
From Theory to Home Heating
The earliest “geothermal” heating systems could more accurately be called “hydrothermal” because they used river water as a heat source. In the 1930s, Zurich’s town hall building harnessed thermal energy from water flowing in the Limmat River to provide heating and cooling. Given that river water temperature fluctuates, and can even freeze over, the limitations of the technology are quite evident. It wasn’t until the 1940s that American scientist Carl Nielsen of Ohio State University developed the very first true ground source heat pump for use in his own home.
Nielsen’s ground source heat pump still used water, but his system harvested thermal energy from groundwater where temperatures are consistent. BBy tapping steady underground heat, Nielsen’s system kept his home comfortable year-round. Researchers soon built on this progress, and in 1946 Oregon installed the first commercial geothermal system to heat and cool a 14-story building in downtown Portland. Like Nielsen’s home heating system, Portland’s geothermal system utilized ground water as a heat source. Today, we’d call that an “open loop” geothermal system, we’ll talk a bit more about ground loops a little later.
In the most favorable circumstances, Zurich’s 1930s “hydrothermal” experiment provided space heating and cooling at over 200% efficiency. Not bad for a technology that was introduced at a time when people were still burning coal and sawdust to keep warm. Better yet, the American geothermal systems of the 1940s boasted an operating efficiency of over 400%. While the core principles of geothermal technology haven’t changed much since then, further innovations in installation would make ground source heat pumps even more efficient, affordable, and accessible to everyday homeowners.
From Oil Crisis to Decarbonization
America’s post-war boom was powered by cheap fossil fuel. In 1964, you could fill up your family’s Ford Galaxie with gas that cost just $0.30 a gallon. The same principle applied to home heating: coal and sawdust had given way to fuel oil. This process was cheaper than ever, while more and more homes were outfitted with cleaner, more efficient, natural gas hook-ups. That changed in the 1970s, when oil-producing countries cut global fuel supplies after the Yom Kippur War, triggering the 1973 and 1979 “oil shocks.” Overnight, the price of fossil fuels skyrocketed, sending the American and European economies into a deep recession. One of the consequences of the oil crises of the 1970s was a reexamining of technologies that could free homeowners from the wild ups and downs of the fossil fuel market.
At Oklahoma State University, researchers developed the first truly successful “closed-loop” geothermal systems. Closed-loop systems install piping underground that circulates a water-based solution that absorbs the ground’s thermal energy. Unlike the “open-loop” systems of the 1940s, closed-loop systems don’t rely on groundwater and can last up to 50 years without maintenance. Early versions used horizontal loops that required lots of land, but most systems today use closed loops, with ongoing innovations making them even more accessible.
Europe Leads Early Geothermal Innovation
Meanwhile in Europe, countries like Austria, France, Germany, Sweden, and Switzerland invested heavily in home geothermal to cut fossil fuel use. In 1980, Germany added 25,000 systems, and by 1982 more than 50,000 French homes upgraded with heat pumps. That same year, a Swiss firm introduced the first vertical ground loop, which needed far less space than horizontal systems. This innovation would open up geothermal technology to homeowners who don’t have Oklahoma-sized properties to work with.
Today, the oil shocks of the 1970s pale in comparison to the challenges posed by climate change. According to Green Tech Media, geothermal will be “a key technology for decarbonizing the roughly one-third of global energy consumption that goes toward heating buildings.” Governments understand this too, and in recent years local, state, and federal governments have scrambled to incentivize homeowners to upgrade to geothermal. Currently, homeowners can claim a 26% federal tax credit to install a geothermal system. Further, New York State offers generous utility rebates, while Connecticut homeowners can claim thousands in incentives.
The Dandelion Difference
Geothermal has been the most efficient way to heat and cool homes since the 1940s. Despite the oil crises of the 70s ramped up commercial production of ground source heat pumps, the cost of installing a geothermal system has often been prohibitive. That’s where Dandelion comes in. Originally conceived at X, Alphabet’s innovation lab, Dandelion’s mission is to make geothermal heating and cooling affordable and accessible for homeowners.
Dandelion is “driving down the cost of installing geothermal systems” through a groundbreaking business model and innovative technology. Dandelion designs custom geothermal systems with smart software and a proprietary heat pump built for efficiency and low maintenance. By specializing in vertical ground loops, the company installs at scale while keeping costs down. (TechCrunch)
Since 2017, Dandelion has emerged as one of the largest geothermal providers in the country. Across New York and Connecticut, Dandelion has helped hundreds of homeowners go green, save money, and live more comfortably. The company’s goal is to install up to 10,000 homes a year. Last year investors like Bill Gates’ Breakthrough Energy Ventures put $30 million towards making that happen. Yahoo! Finance declared that Dandelion’s innovations are “disrupting the geothermal energy space.” With Dandelion’s financing options, you can install a geothermal system for no money down and pay as little as $150 a month. It’s no wonder so many homeowners are making the switch.
Simply put: there’s never been a better time to upgrade your home to geothermal.
