It's not that nuclear reactors can't be built to vary their output. It's that nuclear power is almost all fixed cost. If the average power level over a year is 50%, the power cost doubles. Geothermal has similar economics.
The cost of enhanced geothermal is roughly the exact same cost as nuclear today (if you exclude the very high cost of failed build attempts for nuclear), and it shares similar economics of a very very low OpEx to CapEx ratio. However the economics differ massively in that enhanced geothermal is getting cheaper as we build more, but nuclear tends to get more expensive as we build more. Geothermal is a technology, nuclear is a monument.
It can’t be both not quire and the same.
All else being equal, a five billion dollar geothermal plant running at 50% has the same problem as a five billion dollar nuclear plant running at 50%: where’s my profit?
Sure, load following is trivial with geothermal, but nuclear generally isn’t trying to compete in that space, so we can discount the difference there.
For nuclear, adding thermal storage for time shifting would be the most equivalent to what's happening with geothermal storage, but with geothermal there's no additional capex or engineering needed.
I don’t understand how you think capex works?
You outlay x on capital expenses to get the plant running, that’s all the plant and equipment. You run the plant at 50% it takes you twice as long to recoup your capex.
Always happy to be corrected.
Reducing the draw from the well at time X, leaves more available at time Y. In this way, the capital cost is reasonably preserved and your correction is offered.
--It's not exactly the same thing as flux ---I haven't verified the relative losses here of delaying utilizing the available heat, but rather am assuming the OP is correct about what I believe to be their point*
If the geothermal plant isn’t ran at or near capacity all the time, the capex takes longer to recoup.
You can’t just, say, run it at 50% for a while, and then at 150% later, because a) ya typically can’t run plant at 150%, and for power generators ya can only run them at whatever you’re contracted to supply, so you’d typically want to run geothermal at capacity all the time.
This is true of anything that requires capital expenditure.
> They just let pressure build up higher than normal for 6-8 hours and then the turbine generates more power than normal until the pressure falls back to normal levels again.
So they can run at more than 100%.
The expensive bit is drilling and that gives you roughly X heat per month. You can use that at a constant rate or all in one week.
Of course we can build something less efficient to allow "pressure build up", but that's another trade off.
Isn't this logic flawed?
> Sure, Metric A is better with Option A, but Option B is so bad in that space they are avoiding it, therefore we can discount the difference there.
Fervo/Google got dogged for announcing their plant in UT because they avoided disclosures about the capacity [0]. It's more of a very small scale pilot of a couple MWs, but they buried key facts about the project assumedly on purpose due to lack of significance.
[0] https://blog.google/outreach-initiatives/sustainability/goog...
I don't agree with the above comment:
> Fervo isn't just trying, they are succeeding
Or they simply ran into headwinds on a speculative project. I'll "take the under" when your PR is cagey about basic project attributes.
It will be interesting to see the results of the Cape project once they do multi-well laterals from a single pad power plant with larger diameter wells. That is really more a demonstration of power plant economics beyond the technical feasibility of creating a horizontally fracked reservoir that can be operated for a year.
Cape Station does look much more significant. [0] 400MW of power plant capacity with 2028 COD and mostly contracted with SoCal Edison? Good job.
[0] https://www.utilitydive.com/news/cape-station-enhanced-geoth...
Granted you then have to built of of those power-using-things and only run it when grid demand drops.
That's done a lot in France, but there's a limited amount of pumped hydro available in the end.
Until recently, countries with lots of available nuclear energy didn't really need to produce fresh water, and non-gas-produced hydrogen is still a WIP.
If you find a cheap solution to power storage, you can make a lot of money. This is the key enabler for a 100% renewable grid.
Although presumably if you set up one of these facilities you need it running 24/7 to be profitable not just when there is a lull in demand elsewhere.
Major footnote here that I'm wayyyy out of my wheelhouse on this stuff, so there may be reasons that this doesn't work. I invite correction if that's the case so we can all learn some stuff :)
David Roberts
Yeah, we have a lot of hills. And that's it. So, other than that, you could plop one of these down almost anywhere.
Erik Steimle
That's correct, yeah. You need some proximity, obviously, to transmission and load.
I'm pro nuclear, but I don't think using hypotheticals and futures is how to convince people nuclear is good, it's good because it works and it doesn't poison the planet (Yes there have been accidents and they have been dramatised but count deaths and it becomes as irrational as being afraid of flying)
Though due to the xenon poisoning, they apparently use the reactors which at the moment have the freshest fuel for the load following, as they have more excess reactivity available to overpower the xenon. They can ramp at something around 5% of rated capacity per minute between around 30-100% of full power.
Most other countries with nuclear power plants have a much lower share of nuclear in their grids, so they haven't needed to do it, as due to the economics of nuclear it makes the best sense to run flat out as much as possible in order to recoup capital costs.
https://www.oecd-nea.org/upload/docs/application/pdf/2021-12...
There were a lot more factors at play in the chain, but the burnoff of the xenon wasn't itself the proximal cause of the explosion.
Doesn't the ground itself act as an energy reservoir for geothermal? I haven't looked this one up, but it definitely seems like geothermal should be very dispatchable.
They don't because I fuel costs are so low that the power is essentially free when compared to idling.