Will Solar Power Outshine Oil in the Near Future?

[Ken Fabos]

It is actually a bit surprising to me that as much effort has been put into storage as we are seeing - mostly before intermittent renewable penetration reaches levels that require it. Are people saying the storage must be in place first, before it is necessary and that further expansion of RE capacity should be curtailed until it is? If so I disagree; that kind of investment, at large scale, in solutions to intermittency won't happen until and unless the need for it becomes great enough. I don't see the level of foresight and planning - and regulatory interventions - that putting storage in place, before it's needed, requires. The stage where it does become needed is fast approaching but preventing that need from becoming significant will impede that transition. Foresight and planning would still be worthwhile of course.

The growth of solar and wind are, I think, the necessary precursors to the required investments in storage, demand management, distribution and efficiency that will follow. If they don't grow to the point where it strains the system that incentive will be reduced or be absent.

The shift of fossil fuel plant into an intermittent backup roles seems predictable and reasonable - and the more intermittent it gets the more it reduces overall demand for those fossil fuels. At the same time it creates the economic incentives (because running plants intermittently makes them more expensive) to invest in non-fossil fuel solutions.

 

[zoobyshoe]

It is actually a bit surprising to me that as much effort has been put into storage as we are seeing - mostly before intermittent renewable penetration reaches levels that require it. Are people saying the storage must be in place first, before it is necessary and that further expansion of RE capacity should be curtailed until it is? If so I disagree; that kind of investment, at large scale, in solutions to intermittency won't happen until and unless the need for it becomes great enough. I don't see the level of foresight and planning - and regulatory interventions - that putting storage in place, before it's needed, requires. The stage where it does become needed is fast approaching but preventing that need from becoming significant will impede that transition. Foresight and planning would still be worthwhile of course.

The growth of solar and wind are, I think, the necessary precursors to the required investments in storage, demand management, distribution and efficiency that will follow. If they don't grow to the point where it strains the system that incentive will be reduced or be absent.

The shift of fossil fuel plant into an intermittent backup roles seems predictable and reasonable - and the more intermittent it gets the more it reduces overall demand for those fossil fuels. At the same time it creates the economic incentives (because running plants intermittently makes them more expensive) to invest in non-fossil fuel solutions.

I don't know where you are posting from, but here in California I think we're at the point where we need storage:
http://www.pe.com/2017/03/18/heres-how-california-ended-up-with-too-much-solar-power/
I'm not sure what level of strain of the system you think is best, but there is already a strain, at least here.

 

[OmCheeto]

This is surely the main reason for the difference. If I were all electric, the bill would definitely be higher than my combined bill now. Still, I'm surprised by the fish tank consumption.

There are a lot of hours in a month.

731 hrs/mo x 0.0636 kw = 46 kwh/mo

When the last of the guppies die, I can turn off the heater(55 watts), and the load will only be 4 kwh/month. (≈50¢)

I do, but I grew up in New England, lived in Ohio for 5 years, and then in Minnesota for 8 years. I can understand the psychological appeal of a stalwart, imperturbable nuclear plant humming away during a blustery night blizzard. In the middle of winter up there, the idea of solar seems ridiculous: in the day you often can't tell where the sun even is through the overcast. You feel like, if you collected a day's worth of what hits your yard, you'd have about 3 minutes of night electricity. For one lamp.

So, how much would I have paid for 85 kWh's up there?

A dollar more! $19

We have a "base rate" that is tacked on.

SAN rates    $/kwh   
<380 kwh    $0.20837   
≥380 kwh    $0.42970   
       
PDX rates    $/kwh      +Base rate
≤1000 kwh   $0.11122      $10.50
>1000 kwh   $0.11844      $10.50

Yesterday I found out about this pumped hydro plant in Michigan on the banks of the Great Lake there:
https://en.wikipedia.org/wiki/Ludington_Pumped_Storage_Power_Plant
It's head is 363 feet. So your site isn't a lot less.

Unfortunately that's in a protected park.

That's so high up it snows there in the winter.​

My idea was to pump seawater from sea level up about 361 feet to Telcolote Canyon in Linda Vista. As you can see, it's all twisted up, but there's probably 10 miles of it straightened out:
https://www.sandiego.gov/sites/default/files/legacy/park-and-recreation/pdf/tecolotetrailmap.pdf
Unfortunately, that's also a protected park.

The Ludington_Pumped_Storage_Power_Plant article mentions they had to seal the reservoir because it wasn't bedrock:

I think the same might be true of any big water containment they might build here. I came upon a big sandstone outcropping once in Tecolote Canyon, which might mean it's mostly sandstone all around here under the topsoil. I don't know. It's very gravelly.

Just browsing with Google Earth, it looks like you have scores of potential spots.
The Salton Sea looks like a convenient location. 4000 ft tall mountains within 10 miles.

http://www.pe.com/2017/03/18/heres-how-california-ended-up-with-too-much-solar-power/
I'm not sure what level of strain of the system you think is best, but there is already a strain, at least here.

There is some serious goofiness going on.

From your article;

"The grid system, which excludes Los Angeles, Sacramento, and Imperial Valley area utilities...​

You can't sell rooftop solar, yet half of LA's power is shipped in from 850 miles away?

[ref: wiki re Pacific DC Intertie; "The line capacity is 3,100 megawatts, which is enough to serve two to three million Los Angeles households and represents almost half (48.7%) of the Los Angeles Department of Water and Power (LADWP) electrical system's peak capacity."]

 

[zoobyshoe]

When the last of the guppies die, I can turn off the heater(55 watts), and the load will only be 4 kwh/month. (≈50¢)

Oh, I missed the fact there was a heater involved.

A dollar more! $19

We have a "base rate" that is tacked on.

SAN rates    $/kwh  
<380 kwh    $0.20837  
≥380 kwh    $0.42970  
      
PDX rates    $/kwh      +Base rate
≤1000 kwh   $0.11122      $10.50
>1000 kwh   $0.11844      $10.50

It looks like each West Coast utility has it's own way of charging you the same as every other one.

Just browsing with Google Earth, it looks like you have scores of potential spots.
The Salton Sea looks like a convenient location. 4000 ft tall mountains within 10 miles.

I think that's just about perfect. They have been trying to figure out what to do with the Salton Sea for decades. The water is very polluted from agricultural runoff and industrial effluents, it's not like you're going to wreck the water quality. The "sea" itself, is actually 226 feet below (real) sea level. I wonder if there are any places in those mountains that could be dammed up without doing anything too radical to the mountains.

There is some serious goofiness going on.

From your article;

"The grid system, which excludes Los Angeles, Sacramento, and Imperial Valley area utilities...​

You can't sell rooftop solar, yet half of LA's power is shipped in from 850 miles away?

[ref: wiki re Pacific DC Intertie; "The line capacity is 3,100 megawatts, which is enough to serve two to three million Los Angeles households and represents almost half (48.7%) of the Los Angeles Department of Water and Power (LADWP) electrical system's peak capacity."]

Passing strange! I had no idea. High voltage DC from Oregon!

 

[OmCheeto]

Oh, I missed the fact there was a heater involved.

As a general rule, I turn my heat on the 1st of November, and it doesn't get turned off until the 1st of May.
So the fish tank heater doesn't really cost extra until summer.

It looks like each West Coast utility has it's own way of charging you the same as every other one.

Not sure if you did the maths, but you would have paid a rate twice what I pay, due to that base fee.

Spring 2017

Zoob using 85 kwh in PDX: 22.7¢/kwh
Om using 1084 kwh in PDX: 12.1¢/kwh
​

I think that's just about perfect. They have been trying to figure out what to do with the Salton Sea for decades. The water is very polluted from agricultural runoff and industrial effluents, it's not like you're going to wreck the water quality. The "sea" itself, is actually 226 feet below (real) sea level. I wonder if there are any places in those mountains that could be dammed up without doing anything too radical to the mountains.

Passing strange! I had no idea. High voltage DC from Oregon!

Lots of strange to go around everywhere. We have similar geography here in the Columbia river gorge, which could be dammed up and used for pumped storage, as our wind farms are also dumping energy when there is too much.
But what do we use the hillsides for? Garbage. You may recall that Seattle ships their garbage there, 260 miles, by the trainload. [ref: PF Oct 2015]

Utility; "We'd like to dam up a ravine on Otay Mt, and use the water from lake Otay for a pumped storage project."
Public; "No! Turtles and Flowers and things!"
Utility; "Ok. How about a dump. If we don't dig a pit, it means you'll have to separate your glass from your trash."
Public; "Um. Go ahead and scorch the earth. Ain't nobody got time for recycling."​

This is why I hate humans.

 

[mheslep]

...

I never considered France to be "advanced" with respect to engineering; but holy snap they got it going on.

Snap:

 

[mheslep]

Are people saying the storage must be in place first,

Utility scale energy storage is not like warehouse space that one can simply run out and rent when the basement gets full. The technology for the scale of economicly suitable storage required must be invented first; it does not exist. There is cause for solar and wind advocates to waive away this problem, since if the technology of large scale storage became available, it's cost is almost certain to be large relative to the existing cost of power, and that cost would become prominent. Then comes an end to throw away lines about the low cost of solar, as the high cost of solar plus storage becomes new starting point.

As it is, solar and wind seem to the best thing going for fossil fuel power, as where there is someof the former there is a lot of the latter, and for a long time. An alternative scenario of 80% nuclear would demolish fossil fuel power, as it did in France, Sweden, Switzerland, putting real fear in our fossil fuel interests.

 

[mheslep]

4000 ft tall mountains within 10 miles.

Lopping the top off such a mountain in CA would yield 10 hrs or so of power at a couple GW. Intermittent power needs 10 days of storage, with power sufficient to run the CA load that's not covered by hydro.

Of course, attempting to lop off a mountain in CA would first have Jerry Brown or the Sierra Club lopping off the head of the storage developer. Apropos, it was Jerry Brown that either stopped or closed enough nuclear power to make California 3/4 clean power today.

 

[zoobyshoe]

Reprocessing of spent fuel is prohibited in the US. MOX is a fuel type heavy with plutonium, but the plutonium can come from sources such as retired Soviet nuclear weapons or reprocessing.
First, the outright bans on reprocessing by Presidents Ford and Carter (politicians) crushed the private efforts underway at the time, meaning that any restart of the technology will understandably require government funding to reboot. The lift of the ban by Reagan provided no such finance.
Second, reprocessing that recovers plutonium (which is a product of current fission reactors) is once again prohibited by US policy, both by act of Congress and President Clinton:

OK. I find what you are saying confusing with respect to the particular plant the wiki talks about:

In March 1999, the U.S. Department of Energy (DOE) reversed its policy and signed a contract with a consortium of Duke Energy, COGEMA, and Stone & Webster (DCS) to design and operate a mixed oxide (MOX) fuel fabrication facility. Site preparation at the Savannah River Site (South Carolina) began in October 2005.[13] In 2011 the New York Times reported "...11 years after the government awarded a construction contract, the cost of the project has soared to nearly $5 billion. The vast concrete and steel structure is a half-finished hulk, and the government has yet to find a single customer, despite offers of lucrative subsidies." TVA (currently the most likely customer) said in April 2011 that it would delay a decision until it could see how MOX fuel performed in the nuclear accident at Fukushima Daiichi.[14]

First, did someone not notice there wasn't enough money to complete this project without a government reboot? What's your understanding of why it was ever started when there was no money for it? The quote claims the government was offering lucrative subsidies for customers, at any rate. Which indicates the government had cash in hand waiting to give it out somewhere.

Second: I'm not following whether MOX recovers plutonium or not. If it does, why wasn't this project quashed from the get go? The site preparation began in 2005, long after Clinton had prohibited this, apparently.

 

[mheslep]

MOX reactor fuel and reprocessing of spent reactor fuel are two different things. MOX requires plutonium as a source, which can come from various sources, retired military nuclear weapons, overseas recovered plutonium. At one point a majority of US reactors were burning, in part, the plutonium from Soviet weapons. For years.

 

[OmCheeto]

Lopping the top off such a mountain in CA would yield 10 hrs or so of power at a couple GW. Intermittent power needs 10 days of storage, with power sufficient to run the CA load that's not covered by hydro.
...

I thought I posted something that refutes that?
hmmm...
I think I have several conversations going on in my head at the moment.

Anyways, my analysis of "Otay" gave me a number that says it could supply all of Zoobytown for 2+ weeks.
Of course, my numbers might be wrong.
And it assumes all 'Diegans consume at a Zoob rate.
Which might be difficult, as even I can't do that.
(pats Zoob on the back)

 

[mheslep]

Bath County PHS is the world's largest by power, with 45 million m^3 upper reservoir. At max flow, empties in 14 hrs. Even in Zoob land the municipal water pumps, the hospitals, the grocery stores, the farms and factories and street lights and police stations and movie theaters all use more than a few dozen kWh per month.

https://en.m.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station

 

[OmCheeto]

Bath County PHS is the world's largest by power, with 45 million m^3 upper reservoir. At max flow, empties in 14 hrs. Even in Zoob land the municipal water pumps, the hospitals, the grocery stores, the farms and factories and street lights and police stations and movie theaters all use more than a few dozen kWh per month.

https://en.m.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station

Sounds like some hospitals, grocery stores, et al, had better get up to green-speed.

 

[zoobyshoe]

MOX reactor fuel and reprocessing of spent reactor fuel are two different things. MOX requires plutonium as a source, which can come from various sources, retired military nuclear weapons, overseas recovered plutonium. At one point a majority of US reactors were burning, in part, the plutonium from Soviet weapons. For years.

Thanks. That clears it up.

 

[mheslep]

Why? Those are the things that allow a civilization to make people relatively healthy, safe, prosperous and, well, not Haiti. Pumped water is not private jet travel, and requires a certain amount of energy.

There's always a shack in the woods for those compelled to go 18th century peasant.

 

[zoobyshoe]

Utility scale energy storage is not like warehouse space that one can simply run out and rent when the basement gets full. The technology for the scale of economicly suitable storage required must be invented first; it does not exist. There is cause for solar and wind advocates to waive away this problem, since if the technology of large scale storage became available, it's cost is almost certain to be large relative to the existing cost of power, and that cost would become prominent. Then comes an end to throw away lines about the low cost of solar, as the high cost of solar plus storage becomes new starting point.

Exactly.

But, it should be pointed out that some few utilities have already incurred that "high cost" in pumped storage (pumped hydro) for the purpose of simply not wasting the fossil energy they have to make at the "wrong" time. The mismatch between time of generation and time of demand already exists in the fossil grid, and solutions have been 'pioneered,' at least, but probably better than pioneered. I think 'invention from scratch' is not quite the situation. No one has ever piped hydrogen around the country, but we have piped oil and gas and water. Some meaningful percentage of that know-how will carry over into solving the new problem.

Solar and wind people have to start thinking of large scale storage in terms of much longer periods of time. 24 hours of storage is a joke. You have to start thinking about months. Smaller storage units have to feed into a strategy of larger storage, rather than end up interfering with it later.

As it is, solar and wind seem to the best thing going for fossil fuel power, as where there is someof the former there is a lot of the latter, and for a long time. An alternative scenario of 80% nuclear would demolish fossil fuel power, as it did in France, Sweden, Switzerland, putting real fear in our fossil fuel interests.

This site:https://www.nei.org/Knowledge-Center/Nuclear-Statistics/World-Statistics says 11% of the world's electricity is now generated by nuclear. A figure given in various places for how many years we have left of nuclear fuel at current rate of usage is 230 years. So, if electricity were now 22% nuclear, we'd have 115 years of fuel left, If it were 44%, then 57.5 years left, if it were 88%, 28.75 years left. The more nuclear plants you add, obviously, the faster you consume your remaining fuel. That's just electricity, not all energy needs. And that's today's electricity needs: I assume we'll be consuming more and more per annum as time goes by, rather than less. No breeder reactors = no nuclear utopia. The longer you go without breeder reactors, the faster you use up the best fuel.

 

[acidmatic]

when one resource runs out, another will takes its place. solar maybe, power densities per area are increasing (aka efficiency). surface area for solar are a key constraint.

a skyscraper that powers itself?? but only until the sun goes down, then the whole building becomes dark and cold :(

the flip side, oil hoarders love solar, why? because solar can offset the massive use of oil thus slowing down the pumping of oil, so instead of $20 billion a month for the next 150 yrs, they have $5billion a month for the next ~400yrs.

oil will be around for a long time even with the introduction of newer/better technologies in large salt water batteries, solar, wind, nuke, coal, plant fuels, etc.

Completely agree... It's similar to the current situation with cars... Hybrids. Most of them run on electricity + petrol. Technology is developing gradually just like anything else in our Universe.

 

[OmCheeto]

...
There's always a shack in the woods for those compelled to go 18th century peasant.

I call those people "worm eaters".

Can't cut down trees. Can't eat meat. Can't do this. Can't do that.

I always think to myself;
"Where do tree huggers live, and what do they eat?
Ah ha! They live in their parent's crawl spaces, and eat worms."

As far as your laundry list of "other" users goes:

municipal water pumps
hospitals
grocery stores
farms
factories
street lights
police stations
movie theaters​

Umm... As I've said before; "I ain't god, and I ain't got time to micro-analyze and come up with a solution to every stinkin' little problem."

ps. I believe Russ said "street lights" were a prime candidate for solar. I'm pretty sure the solar panels I inherited from my dad were from oceanic bouys. Kind of the same thing. Still pumping out plenty of trons, even after 20+ years.

 

[zoobyshoe]

And it assumes all 'Diegans consume at a Zoob rate.
Which might be difficult, as even I can't do that.
(pats Zoob on the back)

Thanks!
But for humans you should figure in AC in the summer and an all-electric household, the goal being to replace our dual gas/electric system entirely.

I have to tell you that most people I know in San Diego do not even bother turning on any heat in the winter! 60 ºF feels pleasantly cool to them, so they might throw on a sweater at most. I start shivering and my teeth chatter at 72 ºF. On the other hand, I find AC has an unpleasant clammy quality that gives me a headache if I sit in it for over 30 minutes, so I cool with fans in the summer. Desert heat is dry heat, and feels 20 degrees cooler than eastern humid heat.

 

[mfb]

A figure given in various places for how many years we have left of nuclear fuel at current rate of usage is 230 years.

At the current price and current way to use it. Breeding would increase that number massively. Thorium would increase it again.
The current uranium reserves with the current way to use it don't last long simply because there is no need to save uranium. The reactors can use the uranium that is the most readily availabe, in the most wasteful way - because there is no shortage of uranium.
This has been mentioned multiple times already.

The mismatch between time of generation and time of demand already exists in the fossil grid

At a much smaller scale, and you can plan ahead to reduce the mismatch.
Hydro can be a nice storage method, but the number of places where it is cheap is very limited. You can't store a significant fraction of the daily or weekly electricity consumption there in most countries.

 

[OmCheeto]

Thanks!
But for humans you should figure in AC in the summer and an all-electric household, the goal being to replace our dual gas/electric system entirely.

I have to tell you that most people I know in San Diego do not even bother turning on any heat in the winter! 60 ºF feels pleasantly cool to them, so they might throw on a sweater at most. I start shivering and my teeth chatter at 72 ºF. On the other hand, I find AC has an unpleasant clammy quality that gives me a headache if I sit in it for over 30 minutes, so I cool with fans in the summer. Desert heat is dry heat, and feels 20 degrees cooler than eastern humid heat.

Although Wolram started the thread out with "spray on" solar "PV" technology, my experiments in solar "thermal" indicate that you could probably heat your dwelling very inexpensively with such a unit. As you may have seen, my San Diego sister talked me into building one a couple of years ago. I told her it was just an idea, and I hadn't worked out all the details, but she insisted; "Stop thinking about it, and build one!". So I did. Fortunately, it was only $100 for all of the components, and would probably have generated quite a lot of energy. Unfortunately, solar energy in the winter here is a bit scarce so I've never used it. I haven't even bothered testing it, as I haven't even bothered finishing it. From Oct 1st of last year through May 1st of this year, it rained an average of 4 out of 5 days. (I'm guessing this is why we have lower electrical rates. It acts as an anti-depressant for all this flirpin' cloudy weather...)

But anyways, from my somewhat simple equations, my sister could heat her house with two of my units.
She used 941 kwh worth of natural gas therms for heating in February of this year, and one of my units has a theoretical output of 600 kwh per average month. In San Diego of course.
Theoretical output in Portland is zero!

Total DIY cost: ≈$300.
Cost of her heating and hot water (1345 kwh of natural gas) from SDG&E: $20.28 (again, Feb 2017)
Good grief! ≈1.5¢/kwh natural gas

It's no wonder I'm broke, and everyone says I'm stoopid...

ps. It looks as though she would require a third unit to heat her water in February.

pps. Obligatory graph:

 

[OmCheeto]

Of course, if my heating costs had only been 10% of their historical values, I'd never have calculated that $4000 worth of insulation would have saved me $700 per year. (Payback time: ≈6 years)
(I thought I was going to be a "house flipper" 28 years ago, and opted just to only install the minimum.)

And scratching my head about why Zoob's e-bill is so comparatively low, prompted me to google, and find out that buying a brandy new refrigerator, rather than keeping my 2nd hand refrigerator, would have a payback time of 3.4 years.

current Omic fridge: 1350 kwh/yr
$400 new fridge: 300 kwh/yr [ref]

@ PDX rates, of course.

ps. @wolram , thank you for this thread.

 

[zoobyshoe]

one of my units has a theoretical output of 600 kwh per average month. In San Diego of course.

I don't recall this project. Link me, please.

$4000 worth of insulation would have saved me $700 per year. (Payback time: ≈6 years)

When I lived in Minnesota, I observed this to be a common problem: people did not have adequate insulation on their (decades old) homes. And that caused unnecessarily high heating bills.

current Omic fridge: 1350 kwh/yr
$400 new fridge: 300 kwh/yr

Yes, my fridge is only about 4 years old. It replaced an older energy hog. A kWh saved is a kWh earned.

Which brings me to the question of why it ends up being easier to engineer and build a pumped hydro plant in Michigan (or anywhere they've built one) than it seems to be to engineer and build an electricity generation system that you can 'turn down' when demand is low. What are the obstacles to that?

 

[OmCheeto]

I don't recall this project. Link me, please.

No wonder. It's a bit old.

Is now a good time to invest in solar? [ref: PF]

Om
Aug 25, 2010, 08:09 AM
...

I did an experiment last summer using 1/2 inch 100' long black irrigation hose and a $22 bilge pump. The system collected ~2.3 kwh of thermal energy in about 3.5 hours.
...
Some numbers:
flow: 1.6 gpm (~ 24 watts pump)
area of hose: 0.27 m^2
system fluid capacity: 32 gallons
max delta T / hr: 11 'F
To = 61.7'F
Tf = 90.9'F

Eek! Late for work. BBL.​

Basically, it just proved that you get ≈1 kilowatt of "thermal" power from 1 square meter of black stuff.

When I lived in Minnesota, I observed this to be a common problem: people did not have adequate insulation on their (decades old) homes. And that caused unnecessarily high heating bills.

Yes, my fridge is only about 4 years old. It replaced an older energy hog. A kWh saved is a kWh earned.

Which brings me to the question of why it ends up being easier to engineer and build a pumped hydro plant in Michigan (or anywhere they've built one) than it seems to be to engineer and build an electricity generation system that you can 'turn down' when demand is low. What are the obstacles to that?

I would answer, but I have not a clue.

 

[mfb]

Which brings me to the question of why it ends up being easier to engineer and build a pumped hydro plant in Michigan (or anywhere they've built one) than it seems to be to engineer and build an electricity generation system that you can 'turn down' when demand is low. What are the obstacles to that?

Thermal cycles are bad for the materials in big power plants.
Even if you can build a power plant that doesn't have that issue, it is still wasteful. Plant construction and fixed operation cost is the dominant cost of nuclear power and still the largest part for coal. The marginal cost of running the plants is small.

 

[zoobyshoe]

Thermal cycles are bad for the materials in big power plants.

This is something that would never have occurred to me. Why worse for materials in big power plants, as opposed to, say, the common car engine?

Even if you can build a power plant that doesn't have that issue, it is still wasteful. Plant construction and fixed operation cost is the dominant cost of nuclear power and still the largest part for coal. The marginal cost of running the plants is small.

What about natural gas? I found out that the "peaker" plants that serve my local utility are natural gas and use gas turbines. I googled gas turbines and it said:

Another significant advantage is their ability to be turned on and off within minutes, supplying power during peak, or unscheduled, demand. Since single cycle (gas turbine only) power plants are less efficient than combined cycle plants, they are usually used as peaking power plants, which operate anywhere from several hours per day to a few dozen hours per year—depending on the electricity demand and the generating capacity of the region. In areas with a shortage of base-load andload following power plant capacity or with low fuel costs, a gas turbine powerplant may regularly operate most hours of the day. A large single-cycle gas turbine typically produces 100 to 400 megawatts of electric power and has 35–40% thermal efficiency.[36]

So, our "peaker" plants can only be turned off and on because they are single cycle gas turbines: Hence, only 35-40% efficient because they don't recover the waste heat.

So, this makes me wonder what other ways of recovering the waste heat could be developed that also can be turned on and off quickly. Of course the first thing that comes to mind is a stirling engine:
https://en.wikipedia.org/wiki/Stirling_engine

The claim is made in that article: "Stirling engines have a high efficiency compared to steam engines,[4] being able to reach 50% efficiency." The heat recovery steam generator mentioned in the article achieved a 62.22% efficiency rate, so the Stirling is not miserably far behind.

Which sounds good enough to start mentally exploring scenarios. A combined cycle gas turbine/stirling engine would have that quick on-off capability. The cost of the fuel wasted may be small, but there is its finite nature to consider.

 

[mfb]

This is something that would never have occurred to me. Why worse for materials in big power plants, as opposed to, say, the common car engine?

In a car engine you cannot avoid it, you make it more robust and tolerate a lower efficiency and a higher price (compared to a car that would break down after a month).

Gas turbines are more expensive to operate and have a lower efficiency. They are a bit like cars in that aspect.

The cost of the fuel wasted may be small, but there is its finite nature to consider.

And the CO2 emissions. Both are relevant for fossil fuels only. As discussed, there is more than enough uranium.

Stirling engines are difficult to scale up to gigawatts of power.

 

[mheslep]

The mismatch between time of generation and time of demand already exists in the fossil grid, and solutions have been 'pioneered,

Yes, dispatchable power, i.e. [power with an on/off switch that works any time, night/day, winter/summer. Intermittent power like solar is so named because it has no such switch.

 

[rootone]

Depending on how 'green' you want your power supply infrastructure to be,
I'm sure that a large diverse nation as the US could set up a reliable 2O% or so from a variety of solar,wind, hydro, and tidal.

 

[mheslep]

Depending on how 'green' you want your power supply infrastructure to be,
I'm sure that a large diverse nation as the US could set up a reliable 2O% or so from a variety of solar,wind, hydro, and tidal.

Solar and wind could hit 20% in the US, at substantial cost, because it means for the most part leaving the fossil fleet in place and running it a bit less, but not replacing it. And to what end? Cutting *global* GHG emissions means adopting an affordable clean energy plan that can ~80% of emissions, and one that the developing world can use, in India, Vietnam, Philippines, etc. There's only one technology available that can make it happen, close fossil fuel plants. Its not solar/
&wind.