Comment by modeless | Hacker News Reader

Comment by modeless | Hacker News Reader

I recently heard (on HN, maybe you did too) about a form of energy that sounds pretty utopian to me. Ultra deep bore geothermal.

Geothermal has been around for a long time and has problems like causing earthquakes and needing very specific geological formations that only exist in certain places. But these limitations are mostly due to the fact that we can't bore that deep.

Geothermal energy exists under every point on Earth, in quantities far greater than we could ever use, in the form of heat which can be used to run steam turbines that existing power plants already have.

The problem is that this energy lies deeper than we have ever dug. If we could dig deeper, we might be able to replace the fuel burning part of most existing fossil fuel power plants with geothermal steam. Deep boring is a hard problem to be sure, but is it harder than fusion? Seems unlikely!

Anyway, this startup https://www.quaise.energy/ was on HN a while ago, and while I have no idea if their specific technology works, it seems like we ought to be allocating at least a medium size fraction of the fusion research budget to deep bore geothermal research instead.

Ah… Moria. The dwarves delved too greedily and too deep…

Fervo (https://www.fervoenergy.com) is another deep bore geothermal startup.

Sounds too good to be true! Is geothermal truly renewable? Or is it just abundant enough that it would last us for thousands of years? I wonder if there are other long term side effects of releasing heat from the core.

Read here: https://en.wikipedia.org/wiki/Geothermal_energy#Renewability...

It should probably last until the sun becomes a red giant. (And earth will have lost its atmosphere long before that.)

Most geothermal heat is produced by nuclear decay in subsurface radioisotopes vs gravitational/frictional source or residual heat of planetary formation, so it's effectively renewable at any kind of level of extraction that we might feasibly be able to make use of.

"About 2,900 kilometers (1,800 miles) below the Earth’s crust, or surface, is the hottest part of our planet: the core. A small portion of the core’s heat comes from the friction and gravitational pull formed when Earth was created more than 4 billion years ago. However, the vast majority of Earth’s heat is constantly generated by the decay of radioactive isotopes, such as potassium-40 and thorium-232."[0]

[0] https://education.nationalgeographic.org/resource/geothermal...

Interesting! This might be my favorite type of energy now :D

Ultra deep bore geothermal is a science project right now.

So is fusion.

Absolutely. Fission on the other hand, proven and ready to go.

It's a shame it's an economic loser of a technology, even after generations of government pump priming.

But it can do something that wind/solar can't ... it can actually power a modern economy. So fission is a loser, what does that make wind/solar?

Wind/solar can power a modern economy, and probably more cheaply than nuclear can.

There is no country on Earth that is powered by wind/solar or replaced fossil fuels with wind/solar.

Ah yes. If something hasn't happened yet, it's impossible. This is an excellent future-oriented mindset you have there.

Obviously that's not true, but it is a data point you have to explain. For all the lip-service paid to wind and solar, nobody is actually acting like wind/solar are the future.

Look, all that the lack of domination of solar/wind shows at this time is that solar and wind are not yet cheap enough to displace already installed, capital-cost-sunk fossil-fuel-using plants which are not being charged CO2 fees. Be able to achieve that would be remarkable.

However, in most of the world, most new generating capacity is renewable, even without CO2 charges. Renewables have crashed in cost so quickly that there's still a large installed base of fossil fuel capacity that just hasn't reached end of life yet. The persistence of this zombie technology doesn't mean renewables can't power the world, it just means zombies are hard to kill.

>Look, all that the lack of domination of solar/wind shows at this time is that solar and wind are not yet cheap enough to displace already installed, capital-cost-sunk fossil-fuel-using plants which are not being charged CO2 fees.

Even if solar/wind were free, they still can't displace fossil-fuels(i.e. they need coal or natural gas to serve as base load). That's the problem.

Of course it could, in any number of ways. No, you don't need coal or natural gas to serve as baseload. One could, for example, make hydrogen, store that underground, then burn that when renewables are not directly available. If renewables are very cheap, one could simply heat some large thermal mass (rocks, sand) by resistive heating, then use that later to drive a thermal cycle.

Babcock and Wilcox is commercializing a system like that second right now, using sand heated to 1200 C to store energy for 100 hours or more, with a round trip efficiency > 50% and a storage cost of maybe $0.05/kWh.

Those are science projects that may not see widespread use for decades (if ever). Right now there are no alternatives for fossil fuel baseload.

This is what I was talking about when I dissed you for saying anything that wasn't existing yet couldn't exist. You need to censor your prejudices about renewable energy, your irrational dislike for it is leading you astray.

These are engineering projects, not science projects. They are becoming practical not because of huge advances in science fictional novelties, but because the economic context (where fossil fuels are going to be gone, one way or the other) is making approaches using largely off-the-shelf things competitive. Thermal storage, for example, is almost steampunk.

The big question with renewables is not whether it can do the job -- it clearly can -- it's which of the many subsidiary technologies will win.

>This is what I was talking about when I dissed

Ha. Dissed? Is this high school?

>These are engineering projects, not science projects. They are becoming practical not because of huge advances in science fictional novelties,

You equivocate between things that are ready and proven NOW versus things that may be ready in the future. This is a common method of argument with proponents of wind and solar.

How about this: There are around a thousand cities in the world with a population of 750,000 or more. When you show me one of those cities powered by wind/solar/choose-favorite-storage (not even to 100%, but maybe to 90%), then maybe we can say that wind/solar can do the job.

Right now that number is 0 (and there are no near to mid-term plans to change that) so I think you have to have a little bit of humility with respect to wind/solar viability.

What's happening is that the environment in which these technologies have to work is changing. When fossil fuels were cheap and CO2 untaxed, it's really hard for renewables and storage to win.

But that's not going to be the world going forward. Fossil fuels have to be phased out, which means raising CO2 taxes as high as needed to make that happen. In that environment, it's suddenly highly profitable to push these technologies, and they will go from nothing to dominant in very little time.

The supposed advantage of nuclear, that it has already been demonstrated, means very little. Nuclear had its change to get better, and it got worse. It's already demonstrated it's a loser.

The market is already making the judgment on how this will turn out, whether you like it or not. Money is flowing into renewables and storage; very little is going into nuclear. Nuclear is old, tired, and slowly dying.

A science project that could indeed be worth it.

Yeah - put R&D and money in it, and maybe it'll work in a couple decades. But don't bank on it just yet as a solution to climate change.

And we should absolutely pursue it. In the meantime let’s do more natural gas, solar, wind, and nuclear.

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