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Finnish City Inaugurates 1 MW/100 MWh Sand Battery

cleantechnica.com

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Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#181

Post by flowerthoughts »

grues-dinner wrote: post #123
flowerthoughts wrote: post #104

Earlier quoted context omitted.

W and J are the SI units for power and energy. Those units make the most sense to use in Europe, regardless of the type of energy. Wh is an abomination that has come about because professionals think consumer brains would expose if they ever saw the unit watt-seconds (J). No consumer had any preconceived notion of either Wh or J, so had we used J from the start, it wouldn't have been a problem... (Yes, same with Ah v…

I dunno, 1kWh seems quite natural as a unit of building-scale energy usage when you know a kettle or space heater is about 3kW. We think about energy usage much more in terms of kW and hours than in watts and seconds. And even in small devices like an LED bulb, 5W is more obviously 0.005kW than, say, 2 hours is 7200 seconds. And in this context it's much more obvious that it can notionally deliver energy at a peak ra…

This still falls under the "but we're used to it" argument. That notion that it feels natural, I argue, is a result of you having seen both W and Wh in enough contexts that you start building intuition for them. Had we had W and J, you would have been able to build the same intuition.

> If you said 1MW/360GJ, I don't think that would be nearly as clear.

Wouldn't have been using the hour as the mental reference. As you say, it's impractical. We would have probably rounded the 86,400 seconds in a day to 100,000 and used that as the reference for comparisons. There's nothing noteworthy about the hour in this context.

> A battery that provides 1 amp (at 12V, but that's already given in a system) for 50 hours. Makes immediate practical sense, especially when equipment is often labelled in current draw and you can measure amps with an ammeter. 2.16MJ far less so.

I argued Ah could have used the SI base unit C, not that we'd use J. Whether you count As or Ah is still just a matter of building intuition.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#182

Post by hulium »

bryanlarsen wrote: post #153
kragen wrote: post #150

Earlier quoted context omitted.

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.

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.

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:...

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#183

Post by kragen »

ta1243 wrote: post #173
zahlman wrote: post #115

Earlier quoted context omitted.

The long term average is a bit over 10%, but there are definitely 30-year periods that have fared worse than that.

Which specific 30 year period?

If we restrict our attention to the cherry-picked-with-hindsight US stock market, the worst 30-year period would probably be 01929 to 01959, although 01903 to 01933 isn't that great either. The S&P 500 only goes back to 01957, but https://www.econstats.com/eqty/eq_d_na_4.csv shows the DJIA at US$382.01 on 01929-09-05. 30 years later, on 01959-09-04, it had reached US$653.91. That's 1.8% return per year, which is lower than 10%.

But wait! Those are nominal numbers, not inflation-adjusted numbers. And the dollar had lost nearly half its value over those 30 years! According to https://data.bls.gov/cgi-bin/cpicalc.pl?cost1=382.01&year1=1..., US$382.01 in September 01929 would be worth US$646.99 in September 01959. So the inflation-adjusted return was 0.035% per year. At least it's not negative! And that doesn't even include the dividends!

Nowhere close to competitive with insulating your house or bulk-buying food, though.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#184

Post by kragen »

kragen wrote: post #180
ponector wrote: post #178

Earlier quoted context omitted.

Difference is massive, but price of land should be also accounted for. Solar uses 5 times more land per MW. The solution is to develop everything, all kinds of renewables.

Even the EIA-commissioned study I linked doesn't include that, but it is a potentially significant cost. If we take the median price of US$4702 per Texas "acre" from https://texasfarmcredit.com/resources/texas-land-pricing-gui... it works out to US$1.16/m². At 30° latitude your panels provide about 0.86 square meters of panel per square meter of land, or more like 0.3 with trackers, so the land price is on the order…

Sorry, that's Texas farmland "acres". An "acre" is a medieval unit of measure defined as one "chain" by one "furlong", the area a single man can plow in a day with a team of oxen. Although people have been plowing with horses since the 12th century, the "acre" is still in use in Texas, where it is roughly equivalent to 0.405 hectares (4050m² in SI units). In Texas, latitude ≈30°, it amounts to roughly a megawatt of solar energy (3 megawatts peak) before accounting for panel inefficiency.

Also when I said "US$0.10/Wp" I was wrong. I'm in the lazy habit of rounding US$1 = €1, but that's a significant error now. The correct price of €0.100/Wp for mainstream solar modules is more accurately US$0.117/Wp.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#185

Post by ta1243 »

kragen wrote: post #149
ta1243 wrote: post #109

Earlier quoted context omitted.

> There are 10% opportunities in most people's lives Average S&P total return (reinvesting dividends) is well over 10% over any appreciable timeframe (say 30 years), even during really low times (say buying at the peaks in 1999 or 1972)

That's cherry-picking a single country's stock market with the benefit of hindsight, though. Over the time frame you're talking about, that country became the world's sole superpower and also underwent an unprecedented redistribution of income from workers to investors. Neither of those things can happen again in the US, they aren't very likely to happen anywhere else, and if you had invested at those points in time,…

> Romania in the 01930s

You've lost me.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#186

Post by kragen »

ta1243 wrote: post #185
kragen wrote: post #149

Earlier quoted context omitted.

That's cherry-picking a single country's stock market with the benefit of hindsight, though. Over the time frame you're talking about, that country became the world's sole superpower and also underwent an unprecedented redistribution of income from workers to investors. Neither of those things can happen again in the US, they aren't very likely to happen anywhere else, and if you had invested at those points in time,…

> Romania in the 01930s You've lost me.

Great! Recognizing you're lost is the first step to getting found.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#187

Post by CRConrad »

hulium wrote: post #126
bryanlarsen wrote: post #114

Earlier quoted context omitted.

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.

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.

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.)

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#188

Post by kragen »

CRConrad wrote: post #187
hulium wrote: post #126

Earlier quoted context omitted.

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.

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…

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.

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#189

Post by CRConrad »

kragen wrote: post #184
kragen wrote: post #180

Earlier quoted context omitted.

Even the EIA-commissioned study I linked doesn't include that, but it is a potentially significant cost. If we take the median price of US$4702 per Texas "acre" from https://texasfarmcredit.com/resources/texas-land-pricing-gui... it works out to US$1.16/m². At 30° latitude your panels provide about 0.86 square meters of panel per square meter of land, or more like 0.3 with trackers, so the land price is on the order…

Sorry, that's Texas farmland "acres". An "acre" is a medieval unit of measure defined as one "chain" by one "furlong", the area a single man can plow in a day with a team of oxen. Although people have been plowing with horses since the 12th century, the "acre" is still in use in Texas, where it is roughly equivalent to 0.405 hectares (4050m² in SI units). In Texas, latitude ≈30°, it amounts to roughly a megawatt of s…

> An "acre" is a medieval unit of measure defined as one "chain" by one "furlong", the area a single man can plow in a day with a team of oxen. Although people have been plowing with horses since the 12th century, the "acre" is still in use in Texas...

1) People plowed with oxen well into the 20th century. Most places, only fancy people could afford horses at least into the 17th-18th century. So not so totally-medieval.

2) The acre is used in all kinds of backwards (Anglophone) places, not only Texas. All of the USA for starters, probably Australia, maybe the UK... Heck, I remember my elders using the (roughly) corresponding "tunnland" in daily conversation in Sweden as late as the 1970s. (But yeah, they were really rather elderly.)

3) Aren't you the guy who should call that "the 0012th century"? (Sorry if I'm getting you mixed up with someone else.)

Re: Finnish City Inaugurates 1 MW/100 MWh Sand Battery

#190

Post by kragen »

CRConrad wrote: post #189
kragen wrote: post #184

Earlier quoted context omitted.

Sorry, that's Texas farmland "acres". An "acre" is a medieval unit of measure defined as one "chain" by one "furlong", the area a single man can plow in a day with a team of oxen. Although people have been plowing with horses since the 12th century, the "acre" is still in use in Texas, where it is roughly equivalent to 0.405 hectares (4050m² in SI units). In Texas, latitude ≈30°, it amounts to roughly a megawatt of s…

> An "acre" is a medieval unit of measure defined as one "chain" by one "furlong", the area a single man can plow in a day with a team of oxen. Although people have been plowing with horses since the 12th century, the "acre" is still in use in Texas... 1) People plowed with oxen well into the 20th century. Most places, only fancy people could afford horses at least into the 17th-18th century. So not so totally-mediev…

Agreed on all points! (Except "should".)
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