But Coal Power can't be flexible

[SC Maintenance]

Not really, in comparison to the extensive and intractable environmental problems with coal.

Then we should scrap all EV's. Because 19% of our electricity in USA still comes from Coal.

 

[goingplacesanddoingstuff]

19% of our electricity in USA still comes from Coal.

It’s closer to 16% now.

 

[JimPghPA]

Nuclear is the answer in the longer term, if we can ever get past the opposition to it, but coal works for now and takes advantage of existing generating capacity.

Nuclear plants don't throttle well. They are best used at a continuous rate. Coal, oil, and gas fired plants throttle much easier than nuclear ones. Where both are being used, the nuclear usually is not varied. Its the hydrocarbon fuels plants that vary with load.

 

[4WD]

I'm still trying to understand how anyone could possibly claim that a power source that needs 100% standby backup is in any way "efficient". So not only are you paying to construct 200% nameplate capacity for, at best, about 94-95% uptime, you're also leaving half of the total system completely at the mercy of ALL the elements. Now toss in the loss of prime farmland in many cases, along with killed birds and a brand new desertification source, the solar heat island effect, of large arrays... it's pretty obvious that those pushing these technologies as the "only" solution AND at taxpayer expense, are actually environmental terrorists.

There's a happy, achievable medium to get decarbonization going without setting society back 100 years and causing mass starvation & deaths from exposure. And it can't rely on mandates or subsidies to make it happen if it's going to be socially acceptable.

Well, how many times do you see the same company own multiple means to generate? What’s your favorite table in Vegas?

 

[SubieRubyRoo]

Well, how many times do you see the same company own multiple means to generate? What’s your favorite table in Vegas?

No clue where you’re going with this one… another thing about industrial-scale wind & solar is that not too many public installations are local to where they’re sending power, at least around here. 180+ turbines & 4000+ acres of solar in my tiny county in the middle of nowhere; for all the visual blight, death of wildlife, and loss of prime farmland in the local economy…. Sends the power from Indiana to the NYC metro by design.

If New Yorkers want to be “green”, let New York State (or whoever wants these useless things) destroy their views & ecosystem in order to achieve their utopia. How come nearly every greenie is also a NIMBY? Have the sack to live with your convictions in your own yard… it proves they really are convictions.

 

[SubieRubyRoo]

Hey @OVERKILL or @Shannow quick question for you. Was just perusing the stats for the closest wind farm. It’s got two data points of interest. Annual generation is obviously plenty straightforward, no surprises there.

But right below is: Annual Consumption, “Total fuel consumed based on the most recent 12 months of data available.” There’s no other explanation with this bit of info. Is this intended as an offset number, is this the energy tied up in construction, or is this the amount of excess generation that must be maintained when the wind isn’t blowing?

Because those numbers for the local wind farm are: Annual Generation: 364.3 GWh (1.243M MMbtu, my conversion)

Annual Consumption: 1.3M MMbtu

At my glance, this says this wind farm actually consumes more energy than it ever generates. Am I understanding this correctly?

 

[JimPghPA]

Well, how many times do you see the same company own multiple means to generate? What’s your favorite table in Vegas?

Around Pittsburgh Pennsylvania the major supplier Duquesne Light Electric Co. Owned 2 nuclear reactor generators at Shippingport, and several coal plants scattered around Pittsburgh, and one oil fired plant on Brunot Island. They sold off the nuclear plants, but those continue to supply the grid when up. The oil fuelled plant is very close to the city and the center of their grid, but only used during extreme peak demands like very hot summer days when a lot of AC is being used, because it is the most expensive to run. I'm not even sure the oil fired plant still is operational. It's been years since I worked for them.

Usually grids are vast, and it's not uncommon for nuclear and fossil plants to be on the same grid.

 

[NiwradND]

Of course the modern issue is not so much the NOx and sulphur compounds the scrubbers worked on but simply the CO2.

The sulpher has been cut also, farmers are now adding sulfur as a soil enhancer to get crops to grow better since there is less in the air. The more CO2 in the air is also better, it also is plant food.

 

[thastinger]

The highest grade coal is still used for heating and cooking in some developing countries, especially outside the cities where services are limited. Coal is easy to store, easy to transport.

Present house was built in 1895/6. I bought it 35 years ago, it came with 6 pot belly coal stoves and a 16x32 metal outbuilding that was half full of anthracite coal. They had switched to fuel oil as a heat source but I got rid of that and put central HVAC in.
I gave all of the coal away, I was a 24 year old kid back then and didn't know.

But coal was the main heat source for every house in my neighborhood 80 years ago, just about every house in the neighborhood has 3 chimneys.

 

[OVERKILL]

Nuclear plants don't throttle well. They are best used at a continuous rate. Coal, oil, and gas fired plants throttle much easier than nuclear ones. Where both are being used, the nuclear usually is not varied. Its the hydrocarbon fuels plants that vary with load.

I wouldn't say they don't throttle well; don't load follow well, it's that, unlike with gas/oil/coal, the fuel for a nuke is almost free, the largest cost is staff, so you have effectively fixed OPEX, so the lowest cost mode of operation is 100% wide-open all the time, churning out the highest number of kWh, which results in the cheapest kWh possible from that facility. With fossil plants, the main cost is the fuel, so the less fuel you burn, to a point, as long as you are running the plant enough to cover its fixed costs, the lower the cost to run that facility will be.

Most, if not all, US nuclear plants aren't permitted to load follow from what I recall. In Canada, our regulator doesn't love the idea of varying reactor power to chase load, so we can do it in "chunks" using steam bypass, which permits ~2,400MW of flexible output at Bruce. Because this has economic impacts, Bruce is the last in the stack to curtail, we curtail hydro and wind first.

France does a fair bit of load following with their fleet, Germany used to with theirs. There are several papers on load following with nuclear plants, but as I noted, it's generally not economically in the operator's best interest, so it's mostly avoided in grids where that's possible.

 

[JimPghPA]

I thought nuclear generation was not used to load follow because once up and running stable with everything in the physics of generating stable, its easier on the equiptment and less prone to problems if it is just continously doing the same thing. No variations of flows, temperatures, pressures, and fiddling with trying to adjust to new operating. If everything is happy and not causing problems, don't rock the boat.

I know the reactors at Shippingport were designed with cooling pumps larger that actually required, and those cooling pumps don't throttle well. And probably the entire plant is less prone to any problems if just left to operate at a steady output.

I did not even think of the optimization of financing with the fixed overhead of staffing. Good point.

 

[OVERKILL]

I thought nuclear generation was not used to load follow because once up and running stable with everything in the physics of generating stable, its easier on the equiptment and less prone to problems if it is just continously doing the same thing. No variations of flows, temperatures, pressures, and fiddling with trying to adjust to new operating. If everything is happy and not causing problems, don't rock the boat.

It's definitely easier on the equipment (that goes for any thermal plant) but if the conditions are present to warrant it (France, Germany, Sweden...etc) then it is done. It's not a matter of technical ability, but rather economics and grid design. If it makes financial sense to operate the plants in a load following mode, and regulation permits, then they are

I know the reactors at Shippingport were designed with cooling pumps larger that actually required, and those cooling pumps don't throttle well. And probably the entire plant is less prone to any problems if just left to operate at a steady output.

I did not even think of the optimization of financing with the fixed overhead of staffing. Good point.

Bruce here in Ontario was designed to be able to grid island and run on steam bypass indefinitely. This was a decision made during the early stages because of the high probably of partial or full load rejection by the grid, due to somewhat sketchy transmission conditions to the site. What this involves is stepping back the reactor to around 60% power, dumping most of the potential generation into the lake as heat and then stabilizing at an output level, rejecting into the lake as necessary, that sustains the plants and any other loads it still has, such as maybe Kincardine or other nearby municipalities that are fed directly from the site.

And, this of course happened during the early years. They called the guys that ran the plant "cowboys" because they'd be riding these grid disturbances and rejections and keeping the units up. Darlington, being an evolution of the Bruce design, is capable of the same, but isn't operated like Bruce is.

There's an article by a former Ontario Hydro electrical engineer that talks about how by using steam bypass and reactor power adjustments, the Bruce and Darlington units can actually respond faster than CCGT gas units:
https://atomicinsights.com/ontarios-candus-can-be-more-flexible-than-natural-gas-and-hydro/

But, due to the economic impact of doing this, we don't. Instead, we use gas to peak and curtail hydro and wind as necessary, only doing power output changes at Bruce if required. You can see a few of those in this graph from 2019 where, even though wind crapped the bed for pretty much the entire period, overnight, demand was low enough and there wasn't sufficient export demand available, that we reduced generation at Bruce:

 

[Yourhomiematt]

Around Pittsburgh Pennsylvania the major supplier Duquesne Light Electric Co. Owned 2 nuclear reactor generators at Shippingport, and several coal plants scattered around Pittsburgh, and one oil fired plant on Brunot Island. They sold off the nuclear plants, but those continue to supply the grid when up. The oil fuelled plant is very close to the city and the center of their grid, but only used during extreme peak demands like very hot summer days when a lot of AC is being used, because it is the most expensive to run. I'm not even sure the oil fired plant still is operational. It's been years since I worked for them.

Usually grids are vast, and it's not uncommon for nuclear and fossil plants to be on the same grid.

Duquense Light was pretty prominent in the coal game at one time as well. The power company had its own captive mines and all. They are actually kinda a big deal in the area cause they were the only mining company to ever use the longwall method in the Sewickley coal seam (5 foot coal). The big player out here is the Pittsburgh 9 foot seam.