New technology could bring geothermal energy back

Geothermal energy heats buildings using the heat of the earth. Thanks to the development of technology and the identification of optimal heat sources, geothermal energy has become more promising.

Geothermal energy, or using a ground-source heat pump to pull energy from a circulating fluid in coiled pipes under the ground, was all the rage in the early 2000s alongside solar and wind energy. What happened? You don’t hear much about geothermal today, but it’s still out there. Is it too expensive? Did the efficiency of solar outpace geothermal as a practical renewable energy source?

What happened to geothermal energy?

Geothermal energy requires drilling into the ground to lay pipes circulating steam that can naturally absorb heat from the ground. That steam is pumped through a circulating system of underfloor heating coils that gently warms a building through radiating heat rather than forced air. The problem with early geothermal projects is that they used old drilling rigs with no automation or software, and they weren’t using directional digging — the idea that looking for pockets of heat could make a project more efficient.

The early idea in geothermal energy technology was to get geothermal pipes in the ground at a depth that stayed above freezing, usually at the depth of 50 to 400 feet. The steady temperatures at those depths guarantee a steady supply of 60-degree Fahrenheit temperatures all year round that can be drawn upon to heat homes and offices. This type of geothermal system is called a ground-source heat pump, and it’s one of the simplest and most practical forms of geothermal renewable energy. 

It’s also possible to drill deeper in areas where the natural heat of the earth provides more energy. For example, near a volcano or deeper into the Earth’s crust where it is hotter because it is slightly closer to the center of the Earth. Drilling depths for this type of geothermal energy range from several hundred to several thousand feet and can be used for bigger applications like neighborhood or municipal heating grids. It’s this type of project that first taught the geothermal industry they should be using technology to look for optimal sources of heat in the ground, just like the oil and gas industry already does for locating oil.

Photo from Canva.com

New technology for next-generation geothermal energy

Fervo Energy is trying to incorporate techniques from the oil and gas industry for finding heat sources into the geothermal industry to create renewable energy that is more efficient. While most ground-source heat pumps are circulating energy from a ground source that is about 60 degrees Fahrenheit, finding better sources of higher heat can mean using a heat source of 100 to 200 degrees Fahrenheit that is much more efficient and provides a lot more energy per project.

This type of ground temperature is often found at depths of thousands to tens of thousands of feet below the surface of the Earth, and that requires better technology to locate and to drill. This deeper geothermal setup uses high-energy-content steam at temperatures of 300 to 700 degrees Fahrenheit, and involves drilling both injection wells and production wells. Cold water is pumped down the injection well and flows through the geothermal reservoir to the production well. The water returns to the surface at a higher temperature, and that energy is captured at the surface and enters an electric generation cycle.

It requires a lot more technology to drill so deeply and produce electricity from these types of geothermal wells, and they are much more expensive. This means that the technology is best applied to larger projects that can provide heat to entire communities or industrial complexes. It’s more challenging and expensive to find heat sources for these types of projects. Fervo Energy uses sourcing technologies from the oil and gas industries to make it possible for geothermal to thrive at a larger scale.

The future of geothermal is technology

Fervo uses a combination of technologies to revive geothermal as an option for 100% clean energy. Horizontal drilling technology and multi-stage well drilling is combined with distributed fiber optic sensing for tracking data on energy available from heat sources.

Once people realize their skills for finding energy sources like oil and gas can be applied to a new type of energy generation and the clean energy revolution, they get excited about it. With technology to make geothermal more efficient and more productive, it is possible to bring energy companies and entire industries into the future producing clean energy instead of polluting oil.

Source: https://inhabitat.com/new-technology