Hacker News Reader

Comment by pstuart | Hacker News Reader

On a related note: why not seriously tap these geothermal hot spots for energy? Doesn't stop at night or when the wind dies down.

View on HN

We do, where it makes sense, like Iceland:

https://ourworldindata.org/energy/country/iceland#energy-mix

But, as it being listed as 'other renewable' hints, it doesn't make as much sense elsewhere, where generally you can just install more solar and wind and save more carbon/money that way, and leave worrying about windless nights till you've picked the low hanging fruit.

For example, the current US plan is that after getting to 95% carbon free energy, to switch the focus to electrifying more things that currently burn fuel directly, rather than worry about that awkward last 5% before they need to.

At least in the US, environmental activism has contributed to lack of geothermal development. While the US has large regions with high geothermal potential, such as the Great Basin area of the mountain West, much of this land is undeveloped and under Federal control. This allows activists anywhere in the country to make getting permission difficult and expensive, the effect of which has been to limit the practical size of the power plants to ~25 MW.

Large-scale geothermal installations are not pretty and they cover large areas of land. The individual bore holes must be widely separated from each other, so if you are aggregating the energy of many bores, you are building giant pipe networks. It looks a bit like a large oil field. This gets attacked by environmental activists as despoiling the natural habitat/beauty etc of the formerly undeveloped land. In places like Nevada, which has a lot of geothermal power, there is nothing attractive or unique about this land, it is essentially volcanic badlands of the boring variety, but the campaigns against them use deceptive pictures from other parts of the country suggesting that they are paving over national parks and similar.

This propaganda against geothermal power generation makes it impractical at scale. Instead, the geothermal power plants that are practical to build in this regulatory environment are all solutions with small land footprints. The largest geothermal power plant in Nevada is <100 MW and most don't even do 20 MW.

Of course, there are similar challenges when trying to install solar power at scale in the same kinds of places. Too much of our "green energy" policy is dictated by activists that don't want to build any kind of power generation anywhere.

There is plenty of geothermal power generation going on in the US, but it is not increasing.

That is not a triumph of ecoterror, but of economics: solar and wind are already substantically cheaper, and continue getting much cheaper, where geothermal, like nukes, stays just as expensive to build and operate as ever. So, pace baseload, a dollar spent today is overwhelmingly better spent on a solar panel or wind turbine, or, soon, storage for solar and wind, or production of H2 as feedstock for industrial processes and hydrocarbon synthesis from captured CO2.

There is never any need to install new solar or wind in wilderness. Both coexist productively and synergistically with current agricultural land use. A farm or pasture with solar is more agriculturally productive than the same without, and also generates clean power. In effect, the power output subsidizes construction of the shading infrastructure that reduces heat stress and evaporation.

A wind turbine displaces minimal ground area, and thus may be in the middle of a solar farm, both situated in current, productive cropland. Output may be used locally to produce ammonia when spot prices bottom out, useful on-site for both fertilizer and fuel.

Iceland generates 25% of their energy geothermically https://nea.is/geothermal/

There is plenty of geothermal. Where there’s not, it’s usually because another local form of generation is more attractive (e.g., hydro for volcanos near the sea) or the volcanic system is environmentally or culturally protected.

It's not a very efficient process. Firstly, you need to drill very very far down, unless you are near an active volcano. If it isn't very near the surface, most heat is lost traveling up the bore hole. Remember that you never drill INTO the magma chamber, because that would collapse/plug the hole, so companies drill adjacent to the magma chamber and allow radiant heat to rise.

It's also unstable and inconsistent. Ground water changes, magma movement, hole collapses, all make it an unreliable source of power.

It's a great idea and they do it, particularly in Iceland and Hawaii, iirc.

My recollection is that the big issue with geothermal is the minerals leaching out of the drilled rocks and fairly rapidly fouling the near/above-round equipment or depositing on the tubes/pipes closing them down. I understand that progress had been made; if anyone has more details handy, could you post links?

Here's a good "state of the art of geothermal drilling" article - https://austinvernon.site/blog/drillingplan.html

It's hard to drill in to hot things, bits melt.

You don't have to go all the way in to be able to obtain energy. Hawaii and Iceland both have geothermal power generation facilities; it's very doable.

Maintenance costs overrun any efficiency gains by using geothermal even under optimal conditions, so unless there's other reasons to use it, ideological or economic, most companies will stick to the local grid.

There are some really cool innovations with graphene coatings generating power as hot saltwater flows over it, simplifying power generation by basically creating giant linear convection flows(, as well as graphene coatings on bits to increase durability.) The technology has a ways to go to compete with solar or coal or gas if grid proximity isn't a problem.

Reply on news.ycombinator.com