The Death Of Fossil Fuels

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bjn
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Re: The Death Of Fossil Fuels

Post by bjn » Fri Mar 24, 2023 8:42 pm

dyqik wrote:
Fri Mar 24, 2023 8:29 pm
The incentive is the money you make in non-maximum production times, when electricity generation pays more.

For solar, that's every day, in the morning and evening, even on sunny days. And on cloudy days.
That's a very small number of hours over the lifetime of your asset to make all you money back, especially when everyone else is doing it as well. I'd need to build a model to play with it, but gut tells me its not huge. Also, with mixed generation, your solar and wind can be under cutting each other in those periods too. On a windy day, your profitable evening/morning solar generation windows will be worth diddly squat.

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Re: The Death Of Fossil Fuels

Post by lpm » Fri Mar 24, 2023 10:11 pm

For the next 7 years you are knocking out gas power stations.

For the 10 years after that you are adding capacity and knocking out petrol and gas heating.

For the 10 years after that you are avoiding expensive storage solutions.

You keep going to the point where solar costs balance storage costs. It can't stop before this point because capitalism arbitrages the more expensive solution out of the mix. It is inevitable that in 2050 there is massive oversupply and lower storage, assuming solar PV doesn't get cut undercut by some really cheap storage method.
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Re: The Death Of Fossil Fuels

Post by lpm » Fri Mar 24, 2023 10:48 pm

The glut/drought mix is the same as the farmer problem. In a great year you get a huge wheat harvest. But so does every other farmer. You get a low price. Revenue is P x Q.

In a drought year you get a poor harvest. So does everyone else. High price, revenue is unchanged, still P x Q but flipped around.

For a farmer the big cost is buying land upfront. This is equivalent to a solar farm upfront install cost. The farmer's operating costs are low, with little extra for planting another acre, and this is like the even lower operating cost p.a. for generating solar PV. It works whatever the P and Q dynamic, because the extra Q in good years costs almost zero. It's not like manufacturing where extra Q automatically requires extra cost.

When we get our Ripple turbine we will be delighted when it generates loads of kWh in autumn winds even if we sell each kWh for a penny, because to produce loads costs us no more than to generate a little. We are equally happy when it generates a little in lulls because we sell each kWh for a lot of pennies.

It all simplifies to a single variable: initial build cost. So long as build cost out competes storage, we keep installing.

We are so used to static energy prices, which we've had all our lives, that it's hard to grasp how full dynamic pricing in 2050 works.
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Re: The Death Of Fossil Fuels

Post by jimbob » Fri Mar 24, 2023 11:26 pm

lpm wrote:
Fri Mar 24, 2023 10:48 pm
The glut/drought mix is the same as the farmer problem. In a great year you get a huge wheat harvest. But so does every other farmer. You get a low price. Revenue is P x Q.

In a drought year you get a poor harvest. So does everyone else. High price, revenue is unchanged, still P x Q but flipped around.

For a farmer the big cost is buying land upfront. This is equivalent to a solar farm upfront install cost. The farmer's operating costs are low, with little extra for planting another acre, and this is like the even lower operating cost p.a. for generating solar PV. It works whatever the P and Q dynamic, because the extra Q in good years costs almost zero. It's not like manufacturing where extra Q automatically requires extra cost.

When we get our Ripple turbine we will be delighted when it generates loads of kWh in autumn winds even if we sell each kWh for a penny, because to produce loads costs us no more than to generate a little. We are equally happy when it generates a little in lulls because we sell each kWh for a lot of pennies.

It all simplifies to a single variable: initial build cost. So long as build cost out competes storage, we keep installing.

We are so used to static energy prices, which we've had all our lives, that it's hard to grasp how full dynamic pricing in 2050 works.
When I started working in the semiconductor industry, I told my parents about the drivers of the economic cycle.

Dad said, "ah that's the same as the pig cycle"

And indeed it is. My brother's father in law subsequently told me that bankers were traditionally leery of lending to pig farmers for this reason. You get gluts and shortages with consequent falls and rises in the price of pork and with the fixed length affected by the time to service the sows, and raise the consequent litters.

It might be somewhat relevant to this discussion.

Marginal farmland does historically go into and out of cultivation,
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Re: The Death Of Fossil Fuels

Post by dyqik » Sat Mar 25, 2023 12:43 am

bjn wrote:
Fri Mar 24, 2023 8:42 pm
dyqik wrote:
Fri Mar 24, 2023 8:29 pm
The incentive is the money you make in non-maximum production times, when electricity generation pays more.

For solar, that's every day, in the morning and evening, even on sunny days. And on cloudy days.
That's a very small number of hours over the lifetime of your asset to make all you money back, especially when everyone else is doing it as well. I'd need to build a model to play with it, but gut tells me its not huge. Also, with mixed generation, your solar and wind can be under cutting each other in those periods too. On a windy day, your profitable evening/morning solar generation windows will be worth diddly squat.
Solar panels are so cheap that you only need to make money a few hours a day on them.

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Re: The Death Of Fossil Fuels

Post by Woodchopper » Sun Mar 26, 2023 9:45 pm

Thanks for some interesting points lpm.

Just one thing. The costs of new solar cells are just part of the cost of generating new solar energy.

There’s labour, connecting a solar farm to the grid, and buying or renting the land. So graph of the cost of installing solar panels isn’t going to go vertically downward. It’ll level off when the solar cell’s price is trivial compared to the other costs.

Land will be most difficult. Of course setting up solar panels on the roofs of industrial buildings is easy. But as we’ve seen with wind, expect active opposition to any development that doesn’t look like someone’s fantasy of a rural idyll.

If the U.K. is to produce four times its current energy output from solar, how much land would that need?

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Re: The Death Of Fossil Fuels

Post by lpm » Sun Mar 26, 2023 10:02 pm

We'll have something like 50x current solar, rather than 4x. And something like 10x wind.

Retrofit on roofs is a different cost profile to 25 years of new buildings. Once panels are cheap even marginal slopes get the same treatment.
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Re: The Death Of Fossil Fuels

Post by bjn » Sun Mar 26, 2023 10:36 pm

Domestic behind the meter installs are a no brainer as you avoid all the distribution costs as well as generation costs. You just have to look at Australia where domestic installs are now generating a significant proportion of leccy. My friends and family there are now going one step further and installing batteries to capture the full value of their self generation. That last one is still economically iffy in lots of locations world wide, but expect that to expand as prices drop.

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Re: The Death Of Fossil Fuels

Post by Grumble » Sun Mar 26, 2023 10:44 pm

bjn wrote:
Sun Mar 26, 2023 10:36 pm
Domestic behind the meter installs are a no brainer as you avoid all the distribution costs as well as generation costs. You just have to look at Australia where domestic installs are now generating a significant proportion of leccy. My friends and family there are now going one step further and installing batteries to capture the full value of their self generation. That last one is still economically iffy in lots of locations world wide, but expect that to expand as prices drop.
Battery prices have stopped dropping currently but probably only because of supply chain issues which are hopefully temporary. But they are following a similar albeit slower learning curve to solar and wind. The magic figure of $100/kWh for price parity of BEV with ICE is not far away now. I’ve not seen a magic figure for static storage but at $100/kWh the iffiness you describe probably goes away as well.
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Re: The Death Of Fossil Fuels

Post by bjn » Sun Mar 26, 2023 10:47 pm

Most everything got more expensive because of inflation due to supply chain and energy prices. I don’t see that being much more than a blip.

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Re: The Death Of Fossil Fuels

Post by lpm » Tue Mar 28, 2023 9:18 am

IvanV wrote:
Fri Mar 24, 2023 9:53 am
lpm wrote:
Thu Mar 23, 2023 7:57 pm
One thing not mentioned on the slides is winter storage as non-water heat.
There have been various non-water heat storage trials, and they all seem disappointing to me. Technical feasibility is demonstrated for numerous technologies. But they all seem to get stuck at a cost level which looks too high, and very little sign of how it might get over a cost barrier to make it look usable. So there's a bunch of prototypes of various technologies around, and no sign of any of them going anywhere. Rather like wave energy, which never managed to achieve its breakthrough to a sufficiently cheap and reliable technology deployable at scale, despite something like 50 years of research.
This topic a few days ago got buried. To resurrect, here's a timely tweet thing from https://twitter.com/drvolts
Although electricity gets most of the attention in clean-energy world, half of the final energy humans consume is in the form of HEAT. And of that, half -- roughly a quarter of all human energy consumption -- comes in the form of high-temperature industrial processes.

Those processes range widely, in the temperature they require & how they need the heat delivered. Most of it, on the lower-temp end, is steam, 600C or less. Some processes (think concrete & steel) require temps up to 1000C or even 1500C, usually via special furnaces.

Conventionally, these industrial processes were viewed as "difficult to decarbonize." Use electricity instead? Too expensive. Biofuels? Hydrogen? Too expensive. These are often low-margin industries that could be rendered uncompetitive if energy costs bump way up...

... And that's what we're seeing: a whole bunch of startups creating *thermal storage batteries*. There are varieties but a bunch are clustering around the "box of rocks" concept. Rondo (whose CEO I interviewed) basically uses the electricity to heat up ... bricks.

Other companies are using graphite, sand, or various other materials. Now here's the cool part: electrochemical electricity storage (the familiar lithium-ion batteries) have a round-trip efficiency of ~70, 75%. Hydrogen as electricity storage is more like 30%. Pumped hydro: 80%.

But when you convert electricity to heat, store it as heat, and then *use* it as heat (no conversion back to electricity), the round-trip efficiency is on the order of 95%! Rondo has gotten up to 98%!

https://twitter.com/drvolts/status/1640060077527924737
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Re: The Death Of Fossil Fuels

Post by bjn » Tue Mar 28, 2023 9:23 am

Volts is indeed a very good podcast.

That podcast also pointed out that heat storage is currently quite short term, on the order of days. You can make it last longer, but it gets more expensive as you add more insulation.

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Re: The Death Of Fossil Fuels

Post by IvanV » Tue Mar 28, 2023 9:52 am

lpm wrote:
Tue Mar 28, 2023 9:18 am
... here's a timely tweet thing from https://twitter.com/drvolts
Although electricity gets most of the attention in clean-energy world, half of the final energy humans consume is in the form of HEAT. And of that, half -- roughly a quarter of all human energy consumption -- comes in the form of high-temperature industrial processes.

Those processes range widely, in the temperature they require & how they need the heat delivered. Most of it, on the lower-temp end, is steam, 600C or less. Some processes (think concrete & steel) require temps up to 1000C or even 1500C, usually via special furnaces.

Conventionally, these industrial processes were viewed as "difficult to decarbonize." Use electricity instead? Too expensive. Biofuels? Hydrogen? Too expensive. These are often low-margin industries that could be rendered uncompetitive if energy costs bump way up...

... And that's what we're seeing: a whole bunch of startups creating *thermal storage batteries*. There are varieties but a bunch are clustering around the "box of rocks" concept. Rondo (whose CEO I interviewed) basically uses the electricity to heat up ... bricks.

Other companies are using graphite, sand, or various other materials. Now here's the cool part: electrochemical electricity storage (the familiar lithium-ion batteries) have a round-trip efficiency of ~70, 75%. Hydrogen as electricity storage is more like 30%. Pumped hydro: 80%.

But when you convert electricity to heat, store it as heat, and then *use* it as heat (no conversion back to electricity), the round-trip efficiency is on the order of 95%! Rondo has gotten up to 98%!

https://twitter.com/drvolts/status/1640060077527924737
Yes, it is all these hot rocks type stores that seem to be crap. Clearly a lot of them focus on conversion back to electricity, as you can sell electricity at a unit price much higher than heat. So if your round turn efficiency is 70%, then that's very good compared to a round turn efficiency of 98% on heat, if you can sell the energy output at 3 times the price.

This heat is not going to be useful to industrial processes, because it always degrades and ends up as lower grade heat. And it will be difficult to use more than a small portion of that in a high temperature process. You can use a heatpump to upgrade it, but that will take your efficiency down well below 98%.

So what we end up with, is storing heat for heating buildings, and that will be sold at 1/3 the price (at most) of electricity. So, there seems to be a fundamental problem with making this a large scale heat store.

So, to be economically useful, the point of these hot rock type stores must be to be much cheaper to make/build than well-studied compact stores like lithium batteries, with their expensive chemicals.

The main problem they seem to have is that they are seriously huge for the quantity of energy that they store. So the civil construction of them is large, and they would take up a lot of land if you did it on the kind of scale you might want to. They fail in the basic aim of being a lot cheaper than lithium batteries.

There's a whole bunch of other energy storing methods too - chemical stores - "flow batteries" that use much cheaper chemicals than lithium pumping back and forth in tanks, pressurised or liquified gases, flywheels, lifting heavy weights up and down towers or wells, etc, etc. One of the more promising I heard of was being tested in the Netherlands - storing energy as lumps of iron, which you then burn back to iron oxide. The advantage is that the iron can be stored as heap moved by digger.

But they are currently all ultimately failing in that test of being a lot cheaper than lithium batteries, which is why I see them as so much crap.

If there are a lot of start-ups around, I'm afraid this terrible thought occurs to me. There's this nice "scam" where you get investment money and run a loss-making business while paying yourself nice wages, and then go bust. There's already been a bunch of start-ups in this area that went bust, what are the new lot offering that is genuinely cheaper? These "scams" work because they often aren't even illegal, and you can market it to investors and customers if it looks like the good thing we've all been looking for and would make a lot of money when you get it working properly. We've seen it often enough with "zero-point energy" generators, and other perpetual motion machines. Another popular one was devices to let your car run on much less fuel (one of two of them actually did produce some modest fuel savings, but wrecked your engine.) But so much better to do it with a technology that actually works and is consistent with the laws of physics. The only problem is that it costs too much, but we'll get it cheaper or the value of the output will go up. Unfortunately most of these things are not the kind of thing that can be made an awful lot cheaper. No Moore's Law will apply to constructs that are mainly old-fashioned civil or chemical engineering. The same thought occurred to me, rather sadly, as I was reading in the Economist just the other day that there are now around 40 privately funded fusion companies around the world aiming to build a first-of-class prototype power station, typically 25% to 70% of full size, usually claiming that they hope to do so by around 2030. A huge benefit to mankind if they can be got to work, and doubtless that brings in the investors. But I see no sign of anyone getting anywhere near enough to a practical working power station.

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Re: The Death Of Fossil Fuels

Post by dyqik » Tue Mar 28, 2023 10:06 am

The storing heat as liquid cryogenic gases option is being scaled to commercial sizes (by a UK company) in Vermont.

That system has the advantage that while it takes energy input to maintain the store, recovering the energy does not take external energy inputs, and can use well known turbine systems to turn pressure back into electricity.

Cost wise, it has the advantage that it is using mostly off the shelf tanks, pumps, etc. Liquid nitrogen is a big enough business for other industrial processes that pretty much all the components are well known at scale, and easy to price. The main sort of novel technology is the low temperature turbine.

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Re: The Death Of Fossil Fuels

Post by lpm » Tue Mar 28, 2023 10:13 am

IvanV wrote:
Tue Mar 28, 2023 9:52 am
lpm wrote:
Tue Mar 28, 2023 9:18 am
... here's a timely tweet thing from https://twitter.com/drvolts
Although electricity gets most of the attention in clean-energy world, half of the final energy humans consume is in the form of HEAT. And of that, half -- roughly a quarter of all human energy consumption -- comes in the form of high-temperature industrial processes.

Those processes range widely, in the temperature they require & how they need the heat delivered. Most of it, on the lower-temp end, is steam, 600C or less. Some processes (think concrete & steel) require temps up to 1000C or even 1500C, usually via special furnaces.

Conventionally, these industrial processes were viewed as "difficult to decarbonize." Use electricity instead? Too expensive. Biofuels? Hydrogen? Too expensive. These are often low-margin industries that could be rendered uncompetitive if energy costs bump way up...

... And that's what we're seeing: a whole bunch of startups creating *thermal storage batteries*. There are varieties but a bunch are clustering around the "box of rocks" concept. Rondo (whose CEO I interviewed) basically uses the electricity to heat up ... bricks.

Other companies are using graphite, sand, or various other materials. Now here's the cool part: electrochemical electricity storage (the familiar lithium-ion batteries) have a round-trip efficiency of ~70, 75%. Hydrogen as electricity storage is more like 30%. Pumped hydro: 80%.

But when you convert electricity to heat, store it as heat, and then *use* it as heat (no conversion back to electricity), the round-trip efficiency is on the order of 95%! Rondo has gotten up to 98%!

https://twitter.com/drvolts/status/1640060077527924737
Yes, it is all these hot rocks type stores that seem to be crap. Clearly a lot of them focus on conversion back to electricity, as you can sell electricity at a unit price much higher than heat. So if your round turn efficiency is 70%, then that's very good compared to a round turn efficiency of 98% on heat, if you can sell the energy output at 3 times the price.

This heat is not going to be useful to industrial processes, because it always degrades and ends up as lower grade heat. And it will be difficult to use more than a small portion of that in a high temperature process. You can use a heatpump to upgrade it, but that will take your efficiency down well below 98%.

So what we end up with, is storing heat for heating buildings, and that will be sold at 1/3 the price (at most) of electricity. So, there seems to be a fundamental problem with making this a large scale heat store.

So, to be economically useful, the point of these hot rock type stores must be to be much cheaper to make/build than well-studied compact stores like lithium batteries, with their expensive chemicals.

The main problem they seem to have is that they are seriously huge for the quantity of energy that they store. So the civil construction of them is large, and they would take up a lot of land if you did it on the kind of scale you might want to. They fail in the basic aim of being a lot cheaper than lithium batteries.

There's a whole bunch of other energy storing methods too - chemical stores - "flow batteries" that use much cheaper chemicals than lithium pumping back and forth in tanks, pressurised or liquified gases, flywheels, lifting heavy weights up and down towers or wells, etc, etc. One of the more promising I heard of was being tested in the Netherlands - storing energy as lumps of iron, which you then burn back to iron oxide. The advantage is that the iron can be stored as heap moved by digger.

But they are currently all ultimately failing in that test of being a lot cheaper than lithium batteries, which is why I see them as so much crap.

If there are a lot of start-ups around, I'm afraid this terrible thought occurs to me. There's this nice "scam" where you get investment money and run a loss-making business while paying yourself nice wages, and then go bust. There's already been a bunch of start-ups in this area that went bust, what are the new lot offering that is genuinely cheaper? These "scams" work because they often aren't even illegal, and you can market it to investors and customers if it looks like the good thing we've all been looking for and would make a lot of money when you get it working properly. We've seen it often enough with "zero-point energy" generators, and other perpetual motion machines. Another popular one was devices to let your car run on much less fuel (one of two of them actually did produce some modest fuel savings, but wrecked your engine.) But so much better to do it with a technology that actually works and is consistent with the laws of physics. The only problem is that it costs too much, but we'll get it cheaper or the value of the output will go up. Unfortunately most of these things are not the kind of thing that can be made an awful lot cheaper. No Moore's Law will apply to constructs that are mainly old-fashioned civil or chemical engineering. The same thought occurred to me, rather sadly, as I was reading in the Economist just the other day that there are now around 40 privately funded fusion companies around the world aiming to build a first-of-class prototype power station, typically 25% to 70% of full size, usually claiming that they hope to do so by around 2030. A huge benefit to mankind if they can be got to work, and doubtless that brings in the investors. But I see no sign of anyone getting anywhere near enough to a practical working power station.
Did you type all that but miss the point that the user wants heat, not electricity? They're not dumb enough to store electricity as heat, turn heat to electricity and then use that electricity to heat.
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Re: The Death Of Fossil Fuels

Post by shpalman » Tue Mar 28, 2023 10:20 am

You can't use heat as heat unless the heat you need is the same or less hot as the heat you have, otherwise you need extra energy to make the cooler heat into hotter heat. That extra energy needs to either be heat which is hotter than the hotness of the heat you eventually need (in which case just use that in the first place) or it needs to be a non-thermal (i.e. low entropy) source.
having that swing is a necessary but not sufficient condition for it meaning a thing
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Re: The Death Of Fossil Fuels

Post by lpm » Tue Mar 28, 2023 10:27 am

But I'll just use 1,200 hot when I need 1,000 hoticity. 700 hot when I need 600. Where's the problem?
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Re: The Death Of Fossil Fuels

Post by dyqik » Tue Mar 28, 2023 10:30 am

The "obvious" store for (ETA: energy for) high grade heat is as cryogenic liquid hydrogen and oxygen. You can burn them to produce pretty much any temperature you want on demand.

And any spare can be used for lower grade heat or fuel cells.
Last edited by dyqik on Tue Mar 28, 2023 10:37 am, edited 2 times in total.

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Re: The Death Of Fossil Fuels

Post by dyqik » Tue Mar 28, 2023 10:33 am

lpm wrote:
Tue Mar 28, 2023 10:27 am
But I'll just use 1,200 hot when I need 1,000 hoticity. 700 hot when I need 600. Where's the problem?
The problem is in turning 700 units of 1200°C into 600 units of 1400°C, for a process that only works above 1350°C.

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Re: The Death Of Fossil Fuels

Post by shpalman » Tue Mar 28, 2023 10:35 am

dyqik wrote:
Tue Mar 28, 2023 10:30 am
The obvious store for high grade heat is as cryogenic liquid hydrogen and oxygen. You can burn them to produce pretty much any temperature you want on demand.
In what way is that a store of heat rather than a store of energy? (I mean, how do you make hydrogen and oxygen and then liquify them just using heat rather than some low-entropy source of energy? Is there an Einstein–Szilard fridge which could work from room temperature down to 20 K?)
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Re: The Death Of Fossil Fuels

Post by dyqik » Tue Mar 28, 2023 10:35 am

shpalman wrote:
Tue Mar 28, 2023 10:35 am
dyqik wrote:
Tue Mar 28, 2023 10:30 am
The obvious store for high grade heat is as cryogenic liquid hydrogen and oxygen. You can burn them to produce pretty much any temperature you want on demand.
In what way is that a store of heat rather than a store of energy? (I mean, how do you make hydrogen and oxygen and then liquify them just using heat rather than some low-entropy source of energy? Is there an Einstein–Szilard fridge which could work from room temperature down to 20 K?)
You use spare electricity to generate them. High temperature processes aren't that common in terms of total energy usage.

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Re: The Death Of Fossil Fuels

Post by lpm » Tue Mar 28, 2023 10:39 am

dyqik wrote:
Tue Mar 28, 2023 10:33 am
lpm wrote:
Tue Mar 28, 2023 10:27 am
But I'll just use 1,200 hot when I need 1,000 hoticity. 700 hot when I need 600. Where's the problem?
The problem is in turning 700 units of 1200°C into 600 units of 1400°C, for a process that only works above 1350°C.
Well don't do that then. Nobody's expecting to do that.
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Re: The Death Of Fossil Fuels

Post by dyqik » Tue Mar 28, 2023 10:40 am

lpm wrote:
Tue Mar 28, 2023 10:39 am
dyqik wrote:
Tue Mar 28, 2023 10:33 am
lpm wrote:
Tue Mar 28, 2023 10:27 am
But I'll just use 1,200 hot when I need 1,000 hoticity. 700 hot when I need 600. Where's the problem?
The problem is in turning 700 units of 1200°C into 600 units of 1400°C, for a process that only works above 1350°C.
Well don't do that then. Nobody's expecting to do that.
It's precisely that that's needed for high temperature industrial processes. But as I said above, that's not a huge portion of the global energy to heat consumption.

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Re: The Death Of Fossil Fuels

Post by lpm » Tue Mar 28, 2023 10:49 am

So what has Dr Volts, if that is indeed his real name, got wrong then?

We already have those solar power stations that melt salt at 600 C or whatever. OK, they use that heat to spin turbines at the moment. But why can't we use 600 C salt for a 500 process? Why can't they heat graphite or something to 800 and use it for a 700? Or get to 800, wait a day and use the degraded heat for a 500? Why can't we keep stepping up over the decades till we're heating unobtainium to 2,000 and using it for 1,350?
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Re: The Death Of Fossil Fuels

Post by dyqik » Tue Mar 28, 2023 10:55 am

lpm wrote:
Tue Mar 28, 2023 10:49 am
So what has Dr Volts, if that is indeed his real name, got wrong then?

We already have those solar power stations that melt salt at 600 C or whatever. OK, they use that heat to spin turbines at the moment. But why can't we use 600 C salt for a 500 process? Why can't they heat graphite or something to 800 and use it for a 700? Or get to 800, wait a day and use the degraded heat for a 500? Why can't we keep stepping up over the decades till we're heating unobtainium to 2,000 and using it for 1,350?
The maximum temperature you can heat something to with sunlight with no losses is less than 6000K (temperature of the sun, adjusted down for the bits of the EM spectrum that don't reach the ground). The power will reduce significantly as you approach that temperature.

So it's in principal possible for a thousand K or more.

But, the storage and transport losses go up rapidly with working temperature. Unless you are doing your process right at the solar boiler, it's not very efficient. Pretty soon it's more efficient to convert the heat from the solar plant to electricity for transport and storage.

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