Regarding "repurposing". You have it backwards. Hydraulic fracturing for geothermal -- then known as Hot Dry Rock, but now called EGS -- has been around in practice since (at least) the 1970s [1]. It's basically the creation of permeable pathways for water to flow through in order to mine the heat.
"Fracking" for natural gas took off in 2000's. The essence of the process is the same -- creation of permeable pathways. But many of the more controversial practices (high volume flow, slickwater, heavy use of biocides) are avoided by EGS projects specifically for environmental reasons.
No- fracking became a known cause du jour in the 2000s, and it benefited from higher oil prices plus multiple advances in the various technologies and geology/ geophysical mapping.
The important point is that a lot of current infrastructure and expertise is in fracking, which can be repurposed for EGS, irrespective of which technology was technically first.
But, until the practice became the mainstay of new shale gas production hydraulic fracturing was about as uncontroversial as drilling itself. (Yes, there are deliberate ironies in that statement.)
Geologically speaking (roughly), a gas or oil "play" involves source rocks (which are the locations where the hydrocarbons were deposited and matured) and traps (which are locations where the oil and gas migrated to in economically recoverable quantities). Oil and gas, being less dense than water, migrate upwards as buoyant fluids in the overlying rocks until they are trapped by impermeable layers. There are other styles of trap, but that gives you the gist of it.
Old style oil and gas plays exploited the traps. Fracking plays now exploit the (mostly shale) source rocks.
In my opinion, what caused the recent controversies are the sheer numbers of wells being drilled for fracking. In addition to the new locations where development takes place -- at least in recent memory in places like Pennsylvania -- there were also a larger number of accidents per unit time. Perhaps there was an element of less-experienced operators drilling and fracking wells that also increased the rate of accidents.
EGS geothermal plays fracture rocks, yes. (Heck, so do quarries for things like road metal.) But the resource value proposition is so weak compared to hydrocarbons that geothermal people realize they MUST do things right or they will be shut down. Hence, better casing designs -- leading to far fewer leaks -- and a reluctance to use nasty chemicals.
Everything is a tradeoff. Geothermal is not a fossil fuel. But it is not a panacea either.
The Geysers is one of the handful of places in the US that has all the ingredients—the heat, the water, and the right amount of fractures. Forge is trying to figure out how to enhance geothermal systems so you can have viable geothermal in areas without the favorable subsurface rick features.
"Our flagship effort over the next five years is the Frontier Observatory for Research in Geothermal Energy (FORGE) initiative — the first dedicated field site of its kind for testing targeted enhanced geothermal systems (EGS) R&D."
"EGS are engineered reservoirs, created beneath the surface, where there is hot rock but limited pathways through which fluid can flow. During EGS development, the injection of fluid into the hot rock enhances the size and connectivity of fluid pathways by re-opening fractures. Once completed, EGS function just as natural geothermal systems do: fluids circulating through the hot rock carry energy to the surface through wells, driving turbines and generating electricity. EGS could provide up to 100+ GWe of economically viable capacity in the United States. This potential could supply green electricity to over 100,000,000 American homes, and represents a domestic energy source that is clean, reliable, flexible and renewable."
I can see the headlines from 40 years in the future: Geofracking Responsible for Devastation of the State of Tennessee as Record Breaking Earthquake Shakes the Eastern Seaboard”
Also how exactly is extracting heat from underground renewable? What exactly renews the constantly cooling core of our planet?
The core of the earth is essentially a fission reactor with quite a lot of fuel available. While this heat source is technically finite, so is the sun, and the universe itself. If you somehow live to see the heat death of the universe, you’re probably SOL.
But for humans living on earth today, and in timescales we care about (millions of years), the Earth’s core won’t run out of heat.
Not the core, which is made of stable elements like iron, but the crust. You'd think that uranium and thorium would settle to the core because they're heavy, but they're not siderophilic, so most of them stays in the crust. About two thirds of the geothermal heat flux is from fission in the crust: https://en.wikipedia.org/wiki/Geothermal_gradient
Non-sustainable heat extraction is much more likely, because the sustainable resource is only about 44 TW, while world marketed energy consumption is already 18 TW (https://en.wikipedia.org/wiki/World_energy_supply_and_consum...). By contrast, there are about 100 000 TW of solar energy available. There are billions of years of fossil heat locked up in the crust, amounting to conservatively many millions of times the total oil supply, and by extracting it faster than it was produced you can get much higher power.
Like (above-ground) nuclear energy, this is not currently an economically competitive source of exergy because of the cost of the heat engines required, except in unusual cases. It was until only a few years ago, but PV has gotten much cheaper since then. It probably won't be again until a revolution in manufacturing technology.
As others have pointed out, nothing is renewable on long enough timelines. The earth will burn out, the sun will burn out, eventually the universe will burn out.
There's no such thing as infinite energy in this universe. There's enough deuterium in the oceans to power humanity at our current pace until well after the sun expands and makes earth uninhabitable, but that is still a limit where we'd run out.
Centralized deep-well heat pumps could maximize the electricity generated by EGS to utilize the latent heat at around 200-300 feet below the surface, and achieve energy COP in excess of 4.0.
"The intent is to use this collaborative site for transformative science that will create a commercial pathway for large-scale, economically viable EGS."
So, public funding for commercial interests. Cool cool.
I don't disagree with the approach in general. I just think there's too much selective memory when it comes time for those industries to pay taxes, or be regulated in any way. Then suddenly it's all about the virtues of the mythical free market.
There should also be a general policy requirement that the government gets say 20% of the equity of any venture based on govt-funded R&D. Currently the govt gets all the downside and no (direct) upside to these things.
It is not meant to be profitable but it is meant (we hope at least) to provide infrastructure for a society in domains that are not profitable for businesses while trying not to extract too much wealth from taxpayers. Maybe it would be a good thing as it would make the state less dependent on being able to get credit at a good rate and thus less dependent on financial institutions. Do you not agree ?
Current geothermal technology requires very favorable geological conditions which significantly limits where it can be deployed. If EGS turns out to be both safe and viable it will mean that geothermal power plants can be widely deployed across the globe. I believe this research is also in the public interest as we want clean highly-reliable power, and EGS is one of the few technologies that can potentially provide that.
Yes, it is cool. It's not like they're singling out an existing commercial entity and just showering tax dollars on them. They're getting the tech to the point where private companies can run with it.
You could chalk up a lot of what NASA had done over the past 50 years as "public funding for commercial interests". Are you against NASA too?
Probably better than fracking for fossil fuels, for multiple reasons, but still a mildly ironic repurposing of the tech.