Geothermal energy systems are finally warming up

Geothermal activity has shaped the Earth since its inception, creating the very earth on which we reside. Today, technology harnesses heat from underground to power a new wave of green energy production. The main source of heat for the earth will play a major role in our future. The last report from the International Energy Agency shows that technology, developed over 150 years ago, is finally gaining a foothold in the 21st century.

The first geothermal heating system was installed in Boise, Idaho in 1892. Today, there are 23 geothermal heating districts in the United States, supplying 1.7 million units. About 40 percent of these facilities are residential, while 60 percent are commercial or institutional. The United States is the world leader in geothermal capacity, producing about 3.6 gigawatts in 2020, or nearly 25% of total global capacity. Yet geothermal energy contributes less than 1 percent of overall energy production in the United States. Thanks to new innovations and a push towards green energy, the latest geothermal report from the IEA predicts that the capacity of geothermal energy will be multiplied by 26 by 2050. Geothermal energy is not the ultimate solution, requiring geothermal activity means for many parts of the country it is It is not possible to exploit it, but it can play a major role in achieving climate goals.

“I am proud of what geothermal energy is and excited about the future. Sharing the geothermal story with new stakeholders is essential as we embark on a new geothermal chapter, and the content of the IEA reports is at the heart of this story, ”said Dr Susan Hamm, director of the IEA offices. geothermal technologies from the Ministry of Energy.

Geothermal heating requires a certain level of underground geothermal activity. That’s why about 90 percent of current geothermal energy capacity is found in California and Nevada, where mountain building and volcanic activity has occurred recently, at least in geological terms. The GTO GeoVision, a report on the future of geothermal energy, shows the potential of 17,500 districts nationwide capable of supporting 28 million geothermal heat pumps producing 60 GWe by 2050, or more than 8% of the national energy capacity. Evaluating the feasibility of geothermal heating is an important first step in adoption.

In New York State, Westchester County is partnering with the New York State Energy Research and Development Authority (NYSERDA) on a new tool it calls “Westchester GeoPossibilities” providing residents with information and assistance on the geothermal potential, highlighting energy efficiency and clean heating solutions that reduce carbon emissions. The website also helps building owners explore the financial and environmental savings potential of their buildings.

“New York State now has one of the toughest climate change laws in the world. To meet this ambitious challenge, stakeholders will need to be proactive, and our businesses and owners will need tools and incentives to help them adapt. GeoPossibilities is just the latest of many programs NYSERDA offers to help us move towards a stronger, more sustainable future, ”said Michael Romita, President and CEO of the Westchester County Association.

Explore the details

Geothermal energy is harnessed by heat pumps, a relatively simple technology. The first heat pump was theorized by Lord Kelvin in a scientific journal of 1852. His thought process was not complicated. If you could harness the heat from a fire or an engine with a draft, you could use it to heat buildings more efficiently. Kelvin’s idea was originally aimed at making coal fires more efficient. Almost 150 years ago, CVC still operates on the same basic principles. Modern geothermal heat pumps are misnamed because they do more than heat, they can also cool.

A ground source heat pump starts with drilling a well under the structure, the key is to have a ground temperature that stays around 50 degrees all year round. A loop is installed, vertically or horizontally, filled with groundwater or antifreeze, which is pumped to the structure. From there, the basic refrigeration cycle involved in every refrigerator, air conditioning unit, or radiator begins. In winter, heat from the underground fluid is transferred to a closed loop of liquid refrigerant which is compressed by electricity, turning it into gas, making it hot in the process. A fan blows over the coils, heating the space with hot air. The fan cools the liquid, restarts the process and powers the cycle. In summer, this process is reversed by pumping the refrigerant in the opposite direction.

Absorption pumps are common in commercial and industrial environments. The main difference between traditional heat pumps is that absorption pumps use an ammonia-water absorption cycle, requiring less pumping power. A heat source, such as geothermal hot water or solar energy, is used to boil the ammonia in the water, recover the heat, and start the cycle again. Natural gas is the most common fuel source for absorption pumps, which leads to the devices being commonly referred to as gas pumps, but renewable sources of heat production are possible. Absorption pumps using ground source heat have the potential to make ground source heat pumps even more efficient.

Both processes still operate according to the principles of each HVAC system, but much more efficiently. The key is in the constant temperature of the soil. Systems don’t have to work as hard when the temperature difference isn’t as great. When it’s 10 degrees outside, a traditional heating system based on outside air should adjust the temperature by almost 60 degrees compared to just 20 degrees for a geothermal system using the latent ground temperature of 50 degrees. The system saves energy by transferring heating or cooling between the structure and the ground. Although they are more expensive to install because they require drilling, ground source heat pumps reduce energy use by 30-60% and help control humidity more than air pumps.

The process still requires electricity to run the pump, and much of the electricity in the US power grid is still powered by fossil fuels. Increasing the efficiency of heating and cooling reduces the demand on the grid, which saves electricity. Centralizing the production of renewable energy in the country’s few thousand power plants and distributing that energy through electrification is an easier problem to solve than tackling the furnaces and fossil fuel energy sources in millions. of structures.

FORGING new possibilities

Drilling is the biggest obstacle to the widespread adoption of geothermal energy. Drilling accounts for about 50 percent of the cost of geothermal development, according to the IEA. The Frontier Observatory for Research in Geothermal Energy (FORGE) led by the University of Utah is working with researchers at Texas A&M on Efficient Drilling for Geothermal Energy (EDGE). Drilling is very time consuming and burns through expensive drill bits. The Aggies team was able to design workflows averaging 40 feet per hour with a bit life exceeding 700 feet per pass. The work is just one of seven projects funded by the GTO to advance geothermal drilling developments. The GTO is also developing Direct Deep Use (DDU) systems that can harness geothermal resources at lower temperatures, expanding the geothermal potential to more areas.

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A large-scale DDU system has yet to be tested, but the potential is immense. DDU technology “can potentially be used to replace conventional district heating and cooling systems in military installations, hospital complexes, office buildings, hotels and other high-energy end-uses, by developing geothermal energy by as renewable thermal energy in large parts of the United States, “according to the IEA. Cornell University is testing DDU for its energy needs, drawing from the Appalachian Basin below the campus.

Innovation will struggle to overcome logistical problems. Any thug can tell you, drilling is a loud and messy affair. You cannot drill into existing structures. Geothermal energy is perhaps best suited for developments from the ground where intensive drilling can be done freely. Although the technology is over a century old, the commercial geothermal energy industry is still in its infancy. High upfront costs have limited applications, used in luxury custom homes or installations large enough to benefit from efficiency. Technological improvements for installation and storage will help change that.

Dandelion Energy, a spin-off from Google’s X Lab, is working to bring geothermal power to homes at lower costs through commercialization. The company’s proprietary drilling techniques, heat pumps and smart remote monitoring have reduced the cost of installing geothermal systems by more than 60%, according to Dandelion. Bill Gates’ Breakthrough Energy Ventures was part of a Series B funding that raised over $ 30 million. Dandelion is currently focused on the residential market, but the innovation the company is leading is likely to have larger commercial applications. Dandelion’s system uses smaller drilling equipment, penetrating where conventional rigs cannot. The platforms are also less disruptive and cleaner than conventional systems. Costs for an average 2,000 square foot home range from $ 18,000 to $ 25,000. An installation of a traditional furnace and central air conditioning will cost approximately $ 12,000. The difference can be saved over a few years by eliminating fuel costs, which the US Energy Information Administration estimates can average between $ 600 and $ 1,200 per year.

The green economy is only part of the renewable energy conversation. Geothermal energy is one of the most efficient ways to reduce carbon emissions. Dandelion estimates that the company has already eliminated 100,000 tonnes of carbon emissions. Geothermal energy resources already offset 4.1 million tonnes of carbon per year, according to the Department of Energy. The best part about geothermal energy is that it isn’t intermittent. Unlike solar and wind power, geothermal energy is available 24/7/365. Geothermal power plants have an average availability of 90% or more, compared to around 75% for traditional coal-fired plants.

The potential of geothermal energy is immense. Like sunlight, it is almost impossible to exhaust the heat of the earth’s core. Geothermal energy production has continued unabated at the sites for decades. The Lardarello field in Italy has been in operation since 1913. Geothermal energy is not a panacea, it is an essential part of a variety of renewable energy solutions needed to transition production to sustainability. Sometimes, to grasp the future, we have to learn from the past.

About Leah Albert

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