[kragen]

If, say, further insulating your house or building a sand battery will pay for itself in 50 years, it's a bad investment, financially speaking, and probably environmentally speaking as well. You can deploy "the same amount" of resources in something else with a higher ROI, like maybe solar panels with a one-year payback, and get a much bigger benefit. This is an important consideration as long as you are constrained by some kind of resource limitation.

So I think ROI is a first-order consideration.

[danielfoster]

I agree with you, but one point I see everyone missing is the fact that this is a first-time installation of a new technology that hasn’t scaled. There needs to be a business plan of course. At the same time, no one would expect to see ROI figures for the first build of a concept car.

[kragen]

That's because concept cars aren't investments. This project is an investment. Investors invest in investments to get a return on their investment (ROI). Car buyers, other than car dealers and outfits like Budget Rent-A-Car, do not buy cars to get ROI. Advertising an investment without publishing any projected ROI figures (the business plan you mention) is like advertising a concept car without publishing any photos, video, or drawings.

And I don't think it's accurate to say, "this is a first-time installation of a new technology that hasn’t scaled". People have been using thermal energy storage for household heating for literally millions of years. https://en.wikipedia.org/wiki/Thermal_mass https://en.wikipedia.org/wiki/Thermal_energy_storage https://en.wikipedia.org/wiki/Storage_heater https://en.wikipedia.org/wiki/Ondol#Advantages_and_disadvant... https://en.wikipedia.org/wiki/Seasonal_thermal_energy_storag... https://en.wikipedia.org/wiki/Masonry_heater https://en.wikipedia.org/wiki/Ground_source_heat_pump https://en.wikipedia.org/wiki/Trombe_wall https://en.wikipedia.org/wiki/Feolite https://en.wikipedia.org/wiki/Drake_Landing_Solar_Community https://en.wikipedia.org/wiki/Kang_bed-stove https://en.wikipedia.org/wiki/Earthship#Thermal_performance https://en.wikipedia.org/wiki/Rocket_mass_heater https://www.helen.fi/en/news/2018/Gigantic-cavern-heat-stora... https://en.wikipedia.org/wiki/Barra_system https://en.wikipedia.org/wiki/Storage_heater https://en.wikipedia.org/wiki/Earth_shelter#Active_and_passi... https://en.wikipedia.org/wiki/Bokpoort_CSP#Energy_storage https://en.wikipedia.org/wiki/Russian_stove#Design https://en.wikipedia.org/wiki/Passive_solar_building_design#... https://en.wikipedia.org/wiki/Aquifer_thermal_energy_storage https://en.wikipedia.org/wiki/Home_energy_storage#Thermal_en... https://en.wikipedia.org/wiki/Qanat#Cooling https://en.wikipedia.org/wiki/Regenerative_heat_exchanger https://en.wikipedia.org/wiki/Rammed_earth#History https://www.mha-net.org/ https://en.wikipedia.org/wiki/Solana_Generating_Station#Ener... https://en.wikipedia.org/wiki/Hot_water_storage_tank

[bryanlarsen]

Finland is the only country in the world where solar isn't the cheapest form of electricity because they get so little sun and they have good alternatives.

[hulium]

Certainly not the only country. Iceland is even more extreme in this regard and unlike Finland it is powered by 100% renewables, hydro and geothermal energy. In Finland the only good renewable alternative is wood/biomass.

[bryanlarsen]

Seems reasonable. I'll have to dig up my source to double check. Maybe they just didn't have Iceland data in their set? It's certainly a surprising result to see other non-sunny places like the UK, Germany, Norway & Sweden have solar as their cheapest energy source.

[kragen]

It's hard to get really solid estimates for solar costs because they've been dropping so precipitously, and because they depend on so many ancillary factors: wiring, inspections, permitting, power electronics, storage, and so on. Getting solid estimates for solar return on investment is even harder, because it depends on the future price of energy.

[bryanlarsen]

Yes, it's certainly possible that Iceland is better for solar than Finland not because of its sunlight, but because of those myriad extra factors.

[hulium]

I think Finland just has a large enough extent from south to north that solar might be starting to become viable in the south but not in the north. While Iceland already produces more electricity per capita than any other country, using only hydro and geothermal, so solar is pretty much non-existent.

Comparison of solar share:

https://ourworldindata.org/grapher/solar-share-energy?tab=li...

Solar potential:

https://en.wikipedia.org/wiki/Energy_in_Iceland#/media/File:...

[ponector]

I'm sure there is no sense in solar energy in Iceland due to strong winds there as well as geothermal energy.

It's sad they are building gas-powered data centers in US instead of powered by renewables in Iceland.

[CRConrad]

Actually, calling geothermal energy "renewable" is a bit of a misnomer, isn't it? At least if the heat energy in the Earth's crust, which is what "geothermal energy" harvests, comes from the inside. The Earth's core may not be cooling down very fast, but we know for sure it's not getting any warmer (not before the Sun in its death throes swells up into a red giant and swallows the inner planets, anyway).

Yeah, I know, super-nitpicky — but, hey, it's the Best Kind Of Correct™. (Unless the crust is actually heated more by the Sun than from below, but I doubt that.)

[kragen]

Most geothermal energy comes from the decay of radioactive elements in the Earth's crust, although heat from Earth's formation is a non-negligible fraction of it. If you check out the web site of Iceland's geothermal energy agency, I believe they do have a calculation there of the sustainable power level that could be extracted (without cooling down the crust), but I don't remember if they're currently above or below it.

If I recall correctly, however, the fossil heat trapped in the crust under Iceland is several billion years of the sustainable extraction rate.

And, on the third hand, even if you only extract energy at the rate that radioactive decay produces it, in only a few tens of billions of years, most of the radioisotopes will have decayed away if you don't replenish them.

You are correct that the crust is heated more from below than by the Sun. That's why the bottom of the crust, where it contacts the mantle, is hotter than the surface.

[fulafel]

You could be forgiven to think that about northern places, but the dark winters are compensated by the long (or even round the clock) daylight in summer. It's still fewer sunlight hours than markedly sunny places like italy or california but not 50% less.

see eg this map where scandinavia is the same color as france or southern uk: https://vividmaps.com/annual-sunshine-hours-of-world/

But of course wind is more stable around the year and produces more in the winter when there's more need for energy. And the sunlight is more direct closer to the equator.

[bryanlarsen]

I didn't just think that, I read it in a news article about a study. My memory of what I read may be faulty, though.

Besides fewer sunlight hours, Finland also has lots of clouds and very steep sun angles which significantly affects production.

[fulafel]

The cloudiness is accounted for in the visualization, otherwise you wouldn't see that much variation on the same latitudes. But yep the sun angle affects things too like I mentioned.