PowerGen pros and cons - an honest discussion

OVERKILL

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Some recent back-and-forth's seemed to hint at the idea that we might want to discuss power generation in a bit more depth given the push for electrification and confusion surrounding some of the terminology. I'll preface this with the fact that I'm personally very pro-nuclear and pro-hydro but they each have their own merits and detractors just like any other source.

****If you are incapable of behaving yourself and contributing to a productive conversation, please don't bother posting.****

In terms of actual thermal plant operation, @Shannow has likely forgotten more about this topic than I know, but I don't think we need to get that deep.

First off, before getting into the sources themselves we should clarify some language that is regularly used and that quite often, the media uses incorrectly, swapping MW for MWh and similar.

Nameplate Capacity: Often abbreviated to just "capacity". This is the installed capacity for a specific source, typically in MW. It can apply to a single unit or as a whole, so a wind turbine can be 3MW or wind capacity can be 5,000MW speaking as to all units as a collective on a given grid, farm...etc.

Output: This is the amount of power a facility or generation unit produces, expressed typically in kWh, MWh, GWh, TWh. So, for example, a 1,000MW Nuclear reactor could theoretically produce: 1000x24x365=8,760,000MWh; 8,760GWh; 8.76TWh a year.

Capacity Factor: This is the amount of output, relative to Nameplate Capacity, that a facility or unit actually produces. So, that 1,000MW unit above, US nuclear units have an average CF of 93%, so in terms of Capacity that means 930MW, or in terms of Output 8.15TWh a year.

Each source we are going to discuss has wildly different capacity factors, which in turn means that their Installed Capacity (Nameplate) will not align with their relative contribution. This creates a lot of confusion particularly when we bring in things like Anticipated Capacity, which is essentially just a snapshot of CF for a specific period rather than the whole year.

Getting into the sources themselves now:

1. Nuclear
Pros:
- Very high Capacity Factor (highest of any source)
- Very predictable output
- Excellent baseload generator
- Small footprint
- Very cheap fuel
- Very low fuel consumption (refuelling period is typically every 18-24 months for a US PWR/BWR)
- Very high fuel security (fuel is stored on-site, so not vulnerable to supply disruption issues)
- Hardened and secured facilities are typically less vulnerable to weather related issues

Cons:
- Extremely high CAPEX (expensive to build)
- Relatively high OPEX (nukes have a considerable amount of staff)
- Poor load following capability (nukes can load follow, see: France, but economics are impacted, and fuel cycling becomes more frequent, lowest OPEX is baseload)
- Large unit size means that a single unit trip results in considerable capacity disappearing
- Long-term management of waste/used fuel, despite small footprint, will be required post-decommissioning

2. Hydro
Pros:
- High capacity factor (usually 60-80%)
- Very predictable output
- Excellent baseload generator
- Excellent load-following generator
- Excellent peaking generator
- Zero cost fuel
- Extremely low OPEX
- High fuel security (draughts that impact hydro output are reasonably rare)
- Hardened and secured facilities (dam operation centres are often inside the dam or in robust buildings nearby. The units themselves are contained.)

Cons:
- High CAPEX (expensive to build)
- Geography dependant (cannot be built everywhere)
- Extremely large footprint (reservoir setups)
- Large environmental impact for reservoir setups (run of river is better, but has no reserve capacity)
- Vulnerable to long-term supply shortage, IE, rare draughts that reduce water availability
- Cannot run at 100% constantly due to water flows/reservoir capacity
- Permanent landscape/nature/water disruption even after facility is EOL

3. Coal
Pros:
- High capacity factor (usually next after nuclear)
- Excellent baseload generator
- Decent load-following generator
- Low OPEX
- Low CAPEX
- Good fuel security (coal is stored onsite)
- Relatively self-contained facilities are typically very low in terms vulnerability to extreme weather-related issues

Cons:
- Poor peaking generator (slow ramp)
- Relatively high footprint if significant coal is kept onsite or plant is adjacent to mine
- Very high emissions footprint (highest of any source)
- Extended supply disruptions could impact generation (if coal is shipped or brought in by rail)

4. Gas
Pros:
- High capacity factor (particularly with steam thermal plants and baseload CCGT's)
- Excellent baseload generator
- Excellent load-following generator (GT/CCGT)
- Excellent peaking generator (GT/CCGT)
- Small footprint
- Low OPEX
- Low CAPEX
- Relatively self-contained facilities can be setup to be of low vulnerability to weather events

Cons:
- High emissions footprint (lower than coal, but that's not setting the bar very high)
- JIT delivery of fuel means extremely vulnerable to supply disruptions

5. Wind
Pros:
- Extremely low OPEX
- Extremely low CAPEX
- Small footprint (per unit)
- Low lifecycle emissions (similar to nuclear)

Cons:
- Tends to produce out of phase with demand
- Variability means it must be backed 1:1 relative to nameplate, typically with gas
- Susceptible to extreme weather (extreme heat w/no wind, extreme wind: turbines shut down, extreme cold w/no wind...etc)
- Medium-low capacity factor (~30-40% depending on location)
- Susceptible to seasonal variance not reflected in overall CF (summer CF can be quite low depending on geography, in the order of 12-15%)
- Short lifespan (~20 years)
- Diffuse (multiple generators must be installed over a large area to prevent shadowing and achieve significant installed capacity)
- Significant transmission requirements due to the above

6. Solar
Pros:
- Relatively low CAPEX
- Extremely low OPEX
- Reasonably low lifecycle emissions (about double that of hydro)
- Output tends to align with a large portion of daytime peaking requirements during the summer months
- Can be roof-mounted

Cons:
- Low density
- Large footprint (commercial, 10MW nameplate can take up almost 200 acres)
- Extremely low capacity factor (12-24% depending on latitude)
- Even lower winter capacity factor
- Short lifespan (~20-25 years)
- Susceptible to extreme weather (hail damage for example)
- Variability in output means it must be backed with either storage to cover the morning/evening ramps or 1:1 capacity in the form of gas


I'm sure there are some I've forgotten.

So, let's say we want to replace 5,000MW of baseload coal with wind.
- We would not install 5,000MW of wind, because on average, at say 33% CF, that 5,000MW of wind would produce 1,650MW.
- We'd install significantly more nameplate wind capacity than the coal capacity we want to replace to give us our average of ~5,000MW, on the order of about 15,000MW, which would provide similar annual output to the coal plant.
- We'd firm it with fast-ramp GT gas capacity of ~5,000MW nameplate that would fill for when it isn't windy. We'd also be able to export wind when output was higher than planned capacity, or curtail it if nobody needs it, at low cost.

The above is how you get into a situation where in terms of installed capacity, wind is one of the largest generators, but in terms of actual sources of electricity, may be quite a ways down the list. I'll use Ontario as an example, from this page:

You can see that wind, at 12% of installed capacity accounts for 8% of power generated (most wind is exported, not reflected in these diagrams) yet nuclear at only 34% of installed capacity produced 60%, and that's despite being down two units for refurbishment last year. Nuclear output in Ontario can approach 100TWh with all units online.

Screen Shot 2021-02-19 at 6.59.29 PM.jpg
Screen Shot 2021-02-19 at 6.59.50 PM.jpg


Gas capacity, which is primarily used for load following above the capability of hydro and peaking is the least utilized.

So in a very gas/wind heavy grid, gas being displaced by wind will result in a similar situation where the wind share of total output is lower than installed capacity might suggest but gas nameplate is higher than its output might suggest, because of that displacement.

Nukes are typically, as the Ontario data shows, on the other end of the spectrum, run typically in 100% baseload and satisfying a larger share of the annual demand than one might think.


Please discuss! (nicely!) and if you have questions on any of the above, I'll try and answer to the best of my ability. These are generalized so there are of course certain statements that exceptions may apply to. I've also not included more niche generators or ones that are going out of popularity like oil, geothermal...etc for the sake of keeping this brief, nor have I included massive pumped storage projects, as they mostly fall under the hydro category, but in a more limited capacity.
 

OVERKILL

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Great post! Typical @OVERKILL.

My vote goes for ROI.

ROI is another great metric but it unfortunately has the potential to wade into politics because of how different systems are regulated. But trying to keep my comments away from that, I'll say that ROI improves on big thermals once the CAPEX is recouped. The longer you run them past that point, the better the ROI, even given things like refurbishments, generator replacements...etc. This can be a pretty long period for more recent plants.

On wind the payback will be quicker, particularly due to the extremely low OPEX, but lifespan is significantly shorter too, so there's some relativity.

Hydro probably has the absolute best ROI. We have a local dam that's 150 years old, that kind of staying power is untouchable for basically any other source. It's had one generator/turbine replacement as far as I know, and that increased its output.

There's also whether a plant is recognized, and compensated, for its ability to pretty much always meet demand (capacity value) which in some systems generators are. Here in Ontario pretty much everything is paid on a fixed-rate compensation scheme, but that ultimately over-pays generators with low capacity value so a mixed scenario where the staple generators are paid a fixed rate and the intermittents are paid a variable tied to market would yield the best value for ratepayers IMHO. This yields the best ROI for the folks who own the baseload sources (the people of Ontario) and forces competition for sources with lower capacity value, reducing the risk of for-loss exports and paid curtailment.
 
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ROI is another great metric but it unfortunately has the potential to wade into politics because of how different systems are regulated. But trying to keep my comments away from that, I'll say that ROI improves on big thermals once the CAPEX is recouped. The longer you run them past that point, the better the ROI, even given things like refurbishments, generator replacements...etc. This can be a pretty long period for more recent plants.

On wind the payback will be quicker, particularly due to the extremely low OPEX, but lifespan is significantly shorter too, so there's some relativity.

Hydro probably has the absolute best ROI. We have a local dam that's 150 years old, that kind of staying power is untouchable for basically any other source. It's had one generator/turbine replacement as far as I know, and that increased its output.

There's also whether a plant is rewarded for its ability to meet demand (capacity value) which in some systems generators are. Here in Ontario pretty much everything is paid on a fixed-rate compensation scheme, but that ultimately over-pays generators with low capacity value so a mixed scenario where the staple generators are paid a fixed rate and the intermittents are paid a variable tied to market would yield the best value for ratepayers IMHO. This yields the best ROI for the folks who own the baseload sources (the people of Ontario) and forces competition for sources with lower capacity value, reducing the risk of for-loss exports and paid curtailment.
Exactly. Bring us back to the other thread. Regulations are like a box of chocolates!

In general, I agree with you - and feel the same way about Hydro and Nuclear - but nonetheless, you will never have a better metric of costs/profits than a lightly or non-regulated market. And I mean profits for all, consumers included.

The picture, or "meme" I posted before was intentional - better a wood fire pit than freezing your derriere off in Dallas now.
 

OVERKILL

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Exactly. Bring us back to the other thread. Regulations are like a box of chocolates!

In general, I agree with you - and feel the same way about Hydro and Nuclear - but nonetheless, you will never have a better metric of costs/profits than a lightly or non-regulated market. And I mean profits for all, consumers included.

The picture, or "meme" I posted before was intentional - better a wood fire pit than freezing your derriere off in Dallas now.

It's funny you mention that. Electricity in Ontario used to be almost entirely vertically integrated. Ontario Hydro owned almost all the generating assets (save the local stuff) and they set the rates, sold the exports...etc. Exports were actually a for-profit exercise under that system, as they were comprised primarily of excess hydro.

Unfortunately, fear of ratepayer backlash by way of electoral results meant that rates were not sufficient to properly recoup CAPEX for large projects that had been constructed and grid infrastructure was also suffering from this same phenomenon.

When Ontario Hydro was broken up, operation of the world's largest operating nuke plant was privatized (the province still owns the plant) on a fixed-rate compensation scheme, the first of its kind here. We then began participating in what's been described as a "hybrid market" system. It's not a true market, as pretty much all our sources are, as I noted earlier, on fixed-rate compensation schemes. The only slight deviation from that are the wholly public generators that get reimbursed for whatever their OPEX is, so their rate is fixed for a given period, but fluctuates relative to OPEX.

So Ontario buys/sells power on the market to the northern US states as well as its neighbouring provinces like Manitoba and Quebec, but its generating costs are in no way tied to that activity.

An artifact of this phenomenon has been the decline in HOEP (Hourly Ontario Energy Price) as sources of low capacity value (primarily wind) have come on the grid. When Ontario Hydro was first broken up and the market system was setup, it was structured based on two metrics:
- HOEP - The value of electricity
- Global Adjustment - The difference between HOEP and the actual cost of generation

Initially, HOEP, with the sources all being thermal and hydro, was quite high and it came very close to covering the cost of generation, so the Global Adjustment was extremely low. As more wind capacity was added, exports skyrocketed. The issue is that those exports typically are opposite to demand, which makes them very low value, which in turn drives down market price. So as these exports increased the average HOEP decreased and so the Global Adjustment was naturally increased to compensate. At this point in time the Global Adjustment basically IS the cost of generation, with HOEP being only around $0.014/kWh while the average wind contract price is $0.148/kWh and the average price for Nuclear being around $0.08/kWh.

Now, there's nothing inherently wrong with a low HOEP, it's that the ratepayer needs to make up the difference between the $0.014/kWh market rate and the $0.148/kWh contract cost that's the issue. If sources of low capacity value were paid market, it really wouldn't matter what that price was, but they aren't. Hence my earlier comments along these lines.

Ultimately, fixed-rate contracts were signed to incentivize rapid procurement of sources that at the time, were not cost-effective, regardless of the cost to the ratepayer. This was motivated by ideology, not logic. This has created hurdles and even stonewalled more sensible projects as ratepayer tolerance hit a boiling point.
 
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In general, wind and solar complement hydroelectric nicely, with the dams acting as hydraulic "batteries" (i.e. storing water in the reservoir for when it's needed).

However, both have significant drawbacks for places with cold winters.

Solar
Here in Manitoba, our peak electrical load typically occurs around the winter solstice, due to cold temperatures (requiring more electric heat, for space heaters and automotive block heaters), very short days (so more artificial lighting being used), and Christmas light displays. But when is the least solar energy generated? Around the winter solstice, when it's needed most.

Wind
It would be very good to get something positive out of our harsh prevailing winter winds. Unfortunately, I believe the first two wind farms established here used turbines that could not function below -26°C. So, the turbines are out of service when their power is most needed. Worse, they still need power for heat and controls - so now, instead of contributing, they're imposing additional load on the grid.

They would be a better complement to hydroelectric in a more temperate climate.

I believe thermal generation (coal- and NG-fired turbines) is much harder to ramp up and down than hydroelectric is, so wind and solar are not as good a fit.

Small-scale solar intrigues me - I could see dumping the variable electrical output from a small solar array into an electric water heater, or preheating cold air before the air is drawn into the furnace's air intake. No battery or inverter required.
 
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Thank you Overkill for writing about energy. I find it fascinating and appreciate the time and effort you put into your write-up.

I don't pretend to understand why there have been problems with electric power in Texas recently. Politics seems to muddy the technical reasons why there are such problems taking place there. I am sure it is not as simple as wind generators getting knocked off line by ice on the blades, etc.

It does seem as though environmental concerns prevent the U.S. from being able to build the infrastructure to withstand sudden changes in demand caused by weather events. Grid management and the electric market are complicated.

I am having a hard time with the signal to noise ratio of media coverage of the recent electric problems in Texas.

I would be interested in your take on what's happening in Texas over the last couple few days. Kind of a "Gods eye view" perspective.

My question is not intended to cause controversy or promote bad behavior on BITOG.
 
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NJ
How do you know so much about electricity production?

I can see the future where most homeowners and small business are generating their own electricity through solar and battery storage as opposed to today's model. The current model is confusing as to the regulations and lack of options in who delivers the electricity to my house.

What is the incentive for the power companies to storm proof of upgrade the power grid. Many people would rather get off the grid.

The large nuclear or hydro plants are cost effective but create huge impact if they go offline. I don't know what that probability is. I don't think there's a best answer right now. Personally I'd burn the coal while we improve the decentralized green energy sources.

Overall I really like electricity but the current oligopoly of power companies is not good for consumers.
 
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5,047
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Pittsburgh,PA U.S.A.
I lived very close to three mile island for a year and a half and left there one year before the big meltdown. And at the time I had read the book "We Almost Lost Detroit" and I was aware that the larger the reactor the faster things can go wrong. And also aware that Westinghouse made the safer systems with a heat-exchanger between the reactor loop and the turbine steam side. And that the reactors at three mile island were large Babcock & Wilcox units that were not as safe as Westinghouse units. I felt very uncomfortable living on the Penn State Harrisburg campus that was a short distance from Three Mile Island. And was very glad that I was in Pittsburgh when the meltdown happened. And also thought of the fact that there had to be other college students living on that campus when the reactor melted down and there was a release for a longer than should of been time with the wind blowing the release towards the campus, and its housing, where I had lived the year before.

I know that reactor design has come a long way over the years, and the Westinghouse AP1000 is a very safe unit. And also there are some other designs from other countries that are very safe.

But unfortunately often the contract goes to the lowest bidder. And the safest nuclear plants seldom are the ones with the lowest bid.

Also the red tape and antinuke crowd make nuclear a difficult option. Maybe the only good thing about them is that in some ways there nit-picking may make the safer designs a lower over all cost option because there may be less opposition to those designs.

I would not have any worries if the local Beaver Valley plants were replace with Westinghouse AP1000 units. But if they ever are replaced again the lowest bidder will most likely win the contract.

It is a shame that with all the money Westinghouse spent on the development of the AP1000 resulting in a safe design there are not a lot of them being built in the United States.
 
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5,541
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NJ
Thank you Overkill for writing about energy. I find it fascinating and appreciate the time and effort you put into your write-up.

I don't pretend to understand why there have been problems with electric power in Texas recently. Politics seems to muddy the technical reasons why there are such problems taking place there. I am sure it is not as simple as wind generators getting knocked off line by ice on the blades, etc.

It does seem as though environmental concerns prevent the U.S. from being able to build the infrastructure to withstand sudden changes in demand caused by weather events. Grid management and the electric market are complicated.

I am having a hard time with the signal to noise ratio of media coverage of the recent electric problems in Texas.

I would be interested in your take on what's happening in Texas over the last couple few days. Kind of a "Gods eye view" perspective.

My question is not intended to cause controversy or promote bad behavior on BITOG.
I concur. Regarding Texas, I've read different reasons for the grid failure. From stupid windmills that froze to the robber barrons that own the grid convincing Texas to isolate their grid to avoid federal regulations that would have made them winterize the grid.
 
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New Hampshire
I grew up in the Imperial Valley of Southern California. Most of our electricity was from geothermal. My house was about 5 miles away from the geothermal plant. I remember the sulfuric smell when driving past the electric plant. I knew some folks that worked at the local utility and would like to visit the plant next time I go to the area. I like the technical and machinery side of things. My next door neighbor was a steam well driller in the area who had moved out from Oklahoma after the oil business slowed down. I always enjoyed talking to him..

I remember the electric rates being relatively inexpensive and stable for SOCAL, according to my parents.
 
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Overkill, what are your thoughts on small scale nuclear? I can't remember the story, but I read something years ago about safe, small scale nuclear being designed by Toshiba or?
 
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5,047
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Pittsburgh,PA U.S.A.
The Pittsburgh Pennsylvania area has not had anywhere near the problem of not enough generation ability and in a way has been blessed with an excess of generation ability over the last 30 years because with the unfortunate reduction in the number of steel mills because of jobs going over-seas, and the reduction in companies that made the equipment those mills used such as for example Mesta Machine that made and maintained the equipment for the rolling mills, and the reduction in companies that processed that steel, there has been an excess of power generation ability that previously was used by those industries, and that really was a lot of power. Some of those plants used so much power that they had there own very high voltage towers and lines leading all the way from the generation plats to there own sub-station near or on there sites. Add to that the reduction in demand from housing because of the switch from incandescent bulbs to compact fluorescent, and now LED bulbs, and the Pittsburgh area really has had plenty of excess generation ability in recent years.

Though besides Beaver Valley, all the other generation plants, and there are many of them, were coal fired. But they can and many are easily and quickly changed be ran on natural gas which now with fracking widely going on is abundant and low cost.

Getting into the current state of the two nuclear units at Beaver Valley, a couple of years ago they were scheduled for final shut-down in May and October of 2021. Now with green-house-gas regulations, those shut-downs have been rescinded.

With all the excess generation ability from the previously coal fired now most likely ( I do not have hard data on the number of plants that have made the switch from coal to gas ) natural gas fired power plants that are located in all directions around Pittsburgh, our local utilities could very likely produce all the power needed, without nuclear plants, if we had to, or if they wanted to.

I think that the power companies have even had to retire some of those power plants because when not in use for too long a time they cost too much to keep in good usable shape.
 
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OVERKILL

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In general, wind and solar complement hydroelectric nicely, with the dams acting as hydraulic "batteries" (i.e. storing water in the reservoir for when it's needed).

However, both have significant drawbacks for places with cold winters.

Solar
Here in Manitoba, our peak electrical load typically occurs around the winter solstice, due to cold temperatures (requiring more electric heat, for space heaters and automotive block heaters), very short days (so more artificial lighting being used), and Christmas light displays. But when is the least solar energy generated? Around the winter solstice, when it's needed most.

Wind
It would be very good to get something positive out of our harsh prevailing winter winds. Unfortunately, I believe the first two wind farms established here used turbines that could not function below -26°C. So, the turbines are out of service when their power is most needed. Worse, they still need power for heat and controls - so now, instead of contributing, they're imposing additional load on the grid.

They would be a better complement to hydroelectric in a more temperate climate.

I believe thermal generation (coal- and NG-fired turbines) is much harder to ramp up and down than hydroelectric is, so wind and solar are not as good a fit.

Small-scale solar intrigues me - I could see dumping the variable electrical output from a small solar array into an electric water heater, or preheating cold air before the air is drawn into the furnace's air intake. No battery or inverter required.

Yes, you've brought up an excellent point. I'm a bit jaded on wind due to the gong show in Ontario, but it does seem to work well as a compliment to reservoir hydro like what Quebec operates (most in Ontario is run-of-river, so does not work the same way) so IF you have access to the generous hydro resources of a place like Quebec, then wind power may integrate well with very few drawbacks and not require the gas backup that it does in other grid structures.
 
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