When considering renewable energy, most reviews focus mainly on two areas: wind and solar. Both sources are growing rapidly. All these sources are gradually becoming cheaper. In recent years, both sources have seen their cost per megawatt hour drop below that of coal, helping to entice utilities to switch to renewables and reduce the need for fossil fuels. Then, now it’s cheaper to generate new solar or wind power rather than just keeping an old coal plant running.
Hydro power is often mentioned, but because it plays such an important role in current electricity, there are few options for expansion. Although wind and solar are increasing, hydropower generation is down.
And then there is geothermal energy. In 2000, geothermal generated twice as much electricity as wind. In 2023, wind will produce 25 times more electricity than geothermal. Geothermal constraints limited this to a few areas while thousands of wind turbines spread across the country. But a new discovery may have greatly increased the growth of geothermal energy. And what it takes is … fracking.
The Department of Energy they have nothing but glowing things to say about geothermal energy. Geothermal plants are smaller than traditional fossil fuel plants and much smaller than solar power farms. They can work continuously, without worrying about the weather (or the problem that the sun hides for half a day). They have a smaller environmental role in their lives than the role of wind turbines. This makes it easy to understand why the DOE plans to generate 60 gigawatts of electricity from 17,000 small geothermal power plants by 2050.
But right now, the United States generates only 3.7 gigawatts of electricity from the ground. This is very much in the world, but it was not much. The reason is simple. Existing soil plants need two things: a heat source that is not too deep to make drilling worthwhile, and rocks that can allow water to cut through. Cold water goes down, hot water rises, and the result is energy that comes from the Earth.
However, not all places have the right conditions. In many areas, drilling deep enough to find the right temperature means encountering rock formations that are too dense and impermeable to water. The power is down there, but getting it out is a challenge.
Like Bloomberg Reports, Houston-based startup Fervo Energy has completed demonstrations of its geothermal power generation system. The demonstration site, located in Utah, produced approximately 3.5 megawatts of electricity (enough for approximately 2,500 homes) for 30 days, and did so in an area previously considered unsuitable for geothermal energy.
How Fervo did this will be familiar to anyone who has followed the oil and gas industry over the past two decades: They did it through fracking.
Fervo’s system is called “strengthening the global warming system,” also known as EGS. Three drones have been built in the past decade, but Fervo is the first to create what appears to be a commercially viable solution. The pilot station, dubbed “Project Red,” will join the group later this year and is said to provide power to Google’s server farm as part of a major partnership between Fervo and Google’s parent company, Alphabet.
Fervo plans to expand energy production at a test site in Utah with other wells and generators. It currently plans to generate 400 megawatts at this site by 2028. It is currently planning and permitting six additional sites in the western US.
Although the technology used to open deep cracks and allow water to flow through is very similar to that used in oil and gas production, it must have a much lower environmental impact. For one thing, there are many fewer wells being drilled to support a single Fervo plant, even a larger plant, than are used for even one gas field. Also, the depth drilled to generate geothermal energy is very large, often several kilometers below the surface. If the wells leading to the “hot spots” are adequately sealed, it should be possible to use these plants without the risk of pollution or damage to the water tables in the area.
There are other things to consider. The return on water injected into the system is not 100%, so after a while Fervo will need water to feed the bottom of the well. And there have been problems in other areas related to fracking small earthquakes connected to fluid injection. The establishment of early fractures and the long-term feeding of water through the system can lead to similar events.
Even with these considerations, the potential to expand geothermal energy is exciting. Many people, even strong supporters of renewable energy, have been concerned about the size of the areas needed to produce enough solar and wind power, and that both systems need similar energy storage if they are to act as a “base load” to meet energy needs.
Geothermal can work as a primary source. In addition, Fervo insists that their plants are also flexible enough to act as “surge plants” to respond to spikes in energy demand. In paper written together with researchers from the University of Princeton, representatives of Fervo insist that the flexibility of this structure represents another reason why their model can greatly increase the performance of geothermal energy in an unaltered mixture.
EGS, hydraulic stimulation is used to create ice storage where there was none before. Deep EGS resources lie beneath much of the western United States, and successful development of this technology could unlock hundreds to thousands of gigawatts of potential geothermal resources across the country.
The “thousands of gigawatts” is obviously more than the 60 gigawatts the DOE indicated from this technology.
The Fervo plant is a one-stop shop, and it’s only for 30 days. But it’s hard not to enjoy the opportunity.