Baseload Power

[bhobba]

Merry Christmas to everyone.

I have a quick question. Recently, in the power debate in Australia, a politician said baseload power is an outdated concept.

My eyes went wide, as did others who heard it. So did an electrical engineer friend who once worked in one of the control centres that stabilises the grid on the East Coast of Australia.

So off to Wikipedia I went, and to my surprise, it said:

'While historically large power grids used unvarying power plants to meet the base load, there is no specific technical requirement for this to be so. The appropriate quantity of intermittent power sources and dispatchable generation can equally meet the base load'. (slight changes from Grammarly)

That was surprising.

Hence, in this post, is baseload power necessary in modern electrical grids? If not, is it an economic thing or historical that power systems (certainly here in Australia, they do) still use it?

I noticed an insights article from Anorlunda that touched on some of these issues. I will have to give it a good read.

Thanks
Bill

 

[russ_watters]

Necessary? As long as the supply curve matches the demand curve, it doesn't matter how you achieve it.

Here's a curve for a particular day I found via google:

And explanation:
https://www.eia.gov/todayinenergy/detail.php?id=830

There's an infinite number of production mixes that can match that curve. But for that particular curve:

1. An all solar grid would need something like 52 GW of capacity and 234 GWh of storage to match it.
2. An all nuclear grid would need around 13 GW of capacity and 36 GWh of storage to match it.
3. A 10 GW nuclear and the rest solar grid would need around 12 GW of solar and 54 GWh of storage to match it.

Both Options 2 and 3, using baseload nuclear, require less storage than an all solar grid. If that curve hasn't changed then I don't see how the utility of baseload power has changed. IMO, saying the concept of baseload is "outdated" is a political statement that ignores the actual shape of the demand curve, hoping to score points for intermittent renewables at the expense of traditional baseload sources like nuclear power.

 

[DaveE]

Hence, in this post, is baseload power necessary in modern electrical grids? If not, is it an economic thing or historical that power systems (certainly here in Australia, they do) still use it?

In the utility world, I don't think you can separate "necessary" from "economic thing" or "historical". It is necessary to provide cheap electricity using what you've already got and what you will build for tomorrow. Plus political, environmental, and sustainability issues.
It's a complicated business that isn't well served with overly broad statements like those you mentioned.

 

[Baluncore]

I think base load has become less significant, since the capacity of solar and wind energy, have encroached on its domain from above. There are times when solar and wind energy can satisfy the total load, without the need for long term, base load contracts.

 

[Rive]

Hence, in this post, is baseload power necessary in modern electrical grids? If not, is it an economic thing or historical that power systems (certainly here in Australia, they do) still use it?

There is a strong hint that part of the reason why Germany dropped nuclear was to make room for the intermittent renewables. In this sense, this indeed works.

The following dependency on Russian gas and continuous delays of coal usage reduction (among other things) may be taken as a hint that even if it works it may not be the brightest idea, regardless of its popularity in some 'green' movements.

 

[russ_watters]

I think base load has become less significant, since the capacity of solar and wind energy, have encroached on its domain from above. There are times when solar and wind energy can satisfy the total load, without the need for long term, base load contracts.

What about the other 90% of the time? I don't think it makes sense to scrap the baseload for an intermittent replacement when the intermittent renewable needs storage either way, and more of it the more you encroach into the baseload region.

 

[Baluncore]

What about the other 90% of the time?

The transition migration continues. Base load will become night load. Storage of solar and wind energy will take over a greater part of what was base load. Energy will be supplied by successful bidders on the spot market.

 

[Lnewqban]

There's an infinite number of production mixes that can match that curve. But for that particular curve:

1. An all solar grid would need something like 60 GW of capacity and 180 GWh of storage to match it.
2. An all nuclear grid would need around 13 GW of capacity and 50 GWh of storage to match it.
3. A 10 GW nuclear and the rest solar grid would need around 20 GW of solar and 60 GWh of storage to match it.

I don’t know the answers to the following two questions:

Would you mind explaining how did you estimate those values?

Also, when we talk about storing huge amounts of energy during low demand periods of time, what is modernly used, other that reversed hydroelectric storage?

 

[russ_watters]

Would you mind explaining how did you estimate those values?

Sure:

• The minimum demand is just over 10 GW, so that's where I drew the line for baseload.
• I estimated the curve above 10 GW to average about 3 GW (13 GW overall average).
• I used a simplistic 25% solar capacity factor (er; 13/.25 = 52, not 60) and an all-or-nothing 6 hours of production. I see a math error, though, in the storage; using percent instead of hours. Using the 13 GW and 18 hours of storage = 234 GWH.
• Similar issue on nuclear storage: if we're charging at 2 GW for 18hrs that's 36 GWH.
• And similar issue on scenario 3. 3 GW average production over 24hrs is 72 GWH, producing it in 6 hrs is 12 GW.

I've updated the numbers.

Also, when we talk about storing huge amounts of energy during low demand periods of time, what is modernly used, other that reversed hydroelectric storage?

Batteries.

 

[gmax137]

I always thought "baseload" and "minimum demand" were the same thing. That is, "baseload" is a characteristic of the demand, not a characteristic of the generation source(s). Maybe I have always been wrong, or maybe the definition is evolving.

 

[Baluncore]

That is, "baseload" is a characteristic of the demand, not a characteristic of the generation source(s).

That is correct. Baseload is best described as the minimum demand.

There was a simpler and less diverse time, when a long-term, low-cost contract to satisfy baseload could be written. Now that the intermittent renewables, are sometimes exceeding the baseload, such a contract is less advantageous. The concept of a baseload contract has now lost its importance, as the marketplace has largely been replaced by an online bidding process.

 

[Carrock]

Also, when we talk about storing huge amounts of energy during low demand periods of time, what is modernly used, other that reversed hydroelectric storage?

There's also rail-based gravity storage, with at least one facility in Nevada being built, with an 'artist's impression' suggesting it stores about 0.5GWh, with plans for 16–24GWh capacity. It can ramp up power output faster than gas, but slower than hydroelectric.
A pilot project using an 800-foot track is in operation now. A commercial-scale project is to be built with the Valley Electric Association. (Nevada or California.)

It uses mostly old, cheap, low environmental impact technology, but most of what I could find out was from ares' adverts....

 

[gmax137]

There's also rail-based gravity storage, with at least one facility in Nevada being built, with an 'artist's impression' suggesting it stores about 0.5GWh, with plans for 16–24GWh capacity.

source / link ?

 

[Carrock]

source / link ?

https://www.ediweekly.com/energy-storage-uses-rail-cars-gravity-to-mimic-benefits-of-hydro/

https://aresnorthamerica.com/gravityline/

https://aresnorthamerica.com/las-ve...da-builds-energy-storage-facility-in-pahrump/

 

[gmax137]

I'm curious as to the elevation difference from bottom to top of the tracks. The third link mentions 16 to 24 GW-hr. "Just" one GW-hr is 2.65 trillion ft-lbf. If the elevation is 500 ft, each GW-hr would need a mass of 2.65 million tons. I get the appeal of the idea - it is pretty low tech compared to a power plant. But at the GW-hr scale it's going to be a huge facility. I also wonder about the motor-generators. I bet they don't come cheap.

 

[Carrock]

I'm curious as to the elevation difference from bottom to top of the tracks.

From https://aresnorthamerica.com/gravityline/

"GravityLineTM systems can be sited in a wide variety of locations due to an ability to operate effectively on elevation differentials as low as 200 feet."

Possibly the facility I mentioned in my first post was actually 1 GWh, but it is still big - about 20 acres according to https://aresnorthamerica.com/las-ve...da-builds-energy-storage-facility-in-pahrump/

I hope the motor-generators, while expensive, wouldn't cost prohibitively more than the turbines in a hydroelectric pumped storage facility and would be easier to maintain.

The lack of specific information is irritating but not surprising. For PR reasons, the size of a really large facility is probably something the company wants to keep quiet about.

There is likely to be a widespread misperception about the ecological impact of hundreds of acres of railway cars going up and down a hill vs a new pumped storage facility; I think flooding a suitable valley for pumped storage would cause more harm. Stock the new lake with fish and build a marina and most people won't be concerned about the ecological damage to a valley they've never seen.

 

[Baluncore]

There are too many clever ideas out there. I have no confidence that, the rail based demonstrator systems, or the towers with weights on cables, will be useful in the future. They will not scale like pumped hydro, and the maintenance cost will be excessive. Pumped hydro simply has too many big advantages over small mechanical systems.
It is essential to study the scaling of the project, then extrapolate towards its place in the economics of the future grid.

If you want an honest and realistic appraisal of the energy transition pathway, subscribe to:
https://www.youtube.com/@EngineeringwithRosie
Where you will find analysis like this.
"Is Engineering the Easy Part of the Energy Transition? "


This overview is from a "Cleaning Up Podcast".
"The Climate Challenge is an Engineering Challenge" - Ep171: Dr Rosemary Barnes

 

[Carrock]

There are too many clever ideas out there. I have no confidence that, the rail based demonstrator systems, or the towers with weights on cables, will be useful in the future. They will not scale like pumped hydro, and the maintenance cost will be excessive. Pumped hydro simply has too many big advantages over small mechanical systems.
It is essential to study the scaling of the project, then extrapolate towards its place in the economics of the future grid.

If you want an honest and realistic appraisal of the energy transition pathway, subscribe to:
https://www.youtube.com/@EngineeringwithRosie
Where you will find analysis like this.
"Is Engineering the Easy Part of the Energy Transition? "


This overview is from a "Cleaning Up Podcast".
"The Climate Challenge is an Engineering Challenge" - Ep171: Dr Rosemary Barnes

A quick edit as my browser crashed during my first attempt.....

You need to justify claiming that an apparently cost effective solution will not be useful in the future.

From https://www.vox.com/2016/4/28/11524958/energy-storage-rail
"And rail storage is faster, with lower capital costs, than its main rival in grid-scale storage, pumped hydro (which pushes water up and downhill just like ARES pushes slabs). It’s also more scalable than pumped hydro — you can do it incrementally all the way from 20 MW to 3 GW — and can be located in more places. All it needs is some open land and a slope. Notably, it doesn’t need water, which allows it to operate in the arid American West."

From https://www.utilitydive.com/news/fi...project-targets-role-in-caiso-ancilla/417817/
"But the fair comparison is not with batteries, [CEO James] Kelly said, but with pumped storage, and there also he said rail storage has advantages, namely, a smaller footprint, less environmental damage, higher reliability, faster ramp rates and lower capital and operation costs."


I don't see how pumped hydro can be scaled, since water volume is normally limited by geology or local population centres.

Recent references are a bit thin on the ground, but the company is still around in 2024 and https://greenenergymaterial.com/advanced-rail-energy-storage-benefits-and-future-prospective/
has some useful looking oldish references I haven't checked.

I don't know if this concept will be successful but I certainly don't see any serious engineering issues in scaling it up.

 

[russ_watters]

The scale-ability problem with rail storage vs hydro seems pretty self evident to me. The number/mass of railcars needs to be huge and it doesn't have a smaller footprint for the same output unless they use a purposely twisted definition of footprint.

 

[gmax137]

Possibly the facility I mentioned in my first post was actually 1 GWh, but it is still big - about 20 acres

20 acres is tiny. The 2.65 million tons I came up with is over 40,000 standard freight cars (wiki says 130,000 pounds each, loaded).

This scheme doesn't pass the giggle test at gigawatt hour scale.

 

[Baluncore]

You need to justify claiming that an apparently cost effective solution will not be useful in the future.

No, my experience gives me an uneasy feeling about such a one-sided analysis as they present. When there are no disadvantages mentioned, I can't trust the source to be fair and balanced.

All it needs is some open land and a slope. Notably, it doesn’t need water, which allows it to operate in the arid American West."

Storage should be dispersed across the wider grid. There will be a better place than an arid desert. I suspect, from your marketing, that you are selling shares in the concern. Pumped hydro storage could be on a hill, atop the arid sea cliffs on the coastline.

I don't see how pumped hydro can be scaled, since water volume is normally limited by geology or local population centres.

Being scaled is a different thing to geographical location. Baseload assumes a distributed grid with sources and sinks. Storage can be optimally located, anywhere within reach of that grid.

I don't know if this concept will be successful but I certainly don't see any serious engineering issues in scaling it up.

To me, you demonstrate an irrational confidence. I now suspect you are trying to sell your own shares in the project. There are simply too many things that could go wrong with an expansion of that project.

 

[Tom.G]

There are simply too many things that could go wrong with an expansion of that project.

Could you enlighten this poor reader?

 

[Baluncore]

Could you enlighten this poor reader?

In pumped hydro, the pump/turbines are few, and fixed in position. The water is efficiently recycled and has zero complexity. To double the energy storage, double the volume of the high reservoir. A lake, or the sea, can form the lower reservoir. To double the power capacity, duplicate the pump/turbines.

ARES cars have great complexity, and must be manufactured and maintained. To double the energy storage capacity, double the number of cars and double the area of the car storage sidings, at both the top and bottom.

Rails and wheels wear. Friction is lost when the rail is contaminated by ice or organic debris. The friction coefficient of a wheel on a rail, determines the load that can be moved by the traction motors. That sets the maximum grade of the track to the friction coefficient.

If each mass car had a dedicated motor/generator, they would be expensive, and underutilised while waiting in the storage yards. If a few tugs are used to move many mass cars, the tug will need to get under, and carry the mass car it is moving, or it would have insufficient traction. A more complex arrangement would be to couple all the axles of the mass car to the tug, for traction. The cost of building and maintaining mass cars is greater than the cost of water.

Engineers may make a prototype and get it to work, but will it work reliably every time without engineers on the site.

 

[Rive]

Pumped hydro simply has too many big advantages

I too see many advantages in pumped hydro, but apparently the market seems somewhat reluctant to scale up things.

 

[Baluncore]

I too see many advantages in pumped hydro, but apparently the market seems somewhat reluctant to scale up things.

Hydro is changing its mode of operation, as the energy supply world around it changes.

The economic environment now favours investment with a quick return, from renewables generation to replace the fossil fuel plants being retired. That huge investment in wind and solar has redirected funding that would have gone to nation-scaled hydro schemes. We must wait a little longer before storage becomes critical, when the contenders to provide storage will submit tenders for the privilege.

Pumped hydro works best where there is already hydro, but it is not actually needed there, since a hydro scheme can store energy, without the pumping, simply by delaying the flow of water through the turbine. That can be done because hydro requires very much larger storage to survive the dry season, than pumped hydro does, to fill in overnight.

A thermal system is cheap to build, but then it must buy the fuel as required, that it converts into electricity and CO₂. A hydroelectric scheme starts expensive, because it invests significantly more capital up front, but then it never has to pay for fuel. Investment in hydro requires economic stability, with low interest rates, or funding from the national government.

Previously, the construction of a hydro system required a baseload contract to secure the investment. Now, in the gig economy, hydro fills in for the intermittent sources when they are not available.

 

[Carrock]

I suspect, from your marketing, that you are selling shares in the concern.

I now suspect you are trying to sell your own shares in the project.

I am impressed by your logic and skill in this devastating refutation of everything I said. I shall of course recuse myself from this thread. Congratulations on your win.

 

[gmax137]

I shall of course recuse myself from this thread.

Sorry to hear that...

 

[Rive]

We must wait a little longer

It's a bit problematic that we still need to wait longer, even for to see the planning for constructions to start while the issues caused by the intermittent renewables are already here.

Kind of feels like ... fusion? ...

 

[Baluncore]

It's a bit problematic that we still need to wait longer, even for to see the planning for constructions to start while the issues caused by the intermittent renewables are already here.

Yes, but challenges are expected with any transition.

The intermittent renewables need to more than replace the old order before there will be excess energy, sufficient to always recharge storage. At the moment, the old order is able to provide what future storage must eventually provide. That is why we are in an era of battery and energy storage evaluation.

There are many startups trying their hand, some will succeed, some will fail. Picking a winner is unnecessary, they will pick themselves as the market selects from the available candidates.

The delay of energy storage implementation will increase the available choice, and improve the efficiency of those systems implemented. That delay comes at the cost of extending the life of inefficient thermal generators.

I expect any critical shortage of supply, will be filled by systems like distributed gas powered generators, that need to be available to handle transmission or storage emergencies.

I had not expected clean energy to be lower in cost than the old fossil order, so I am pleasantly surprised at how well the market appears to be doing, at navigating the transition through dynamic variable pricing.

 

[russ_watters]

The intermittent renewables need to more than replace the old order before there will be excess energy, sufficient to always recharge storage. At the moment, the old order is able to provide what future storage must eventually provide. That is why we are in an era of battery and energy storage evaluation.

But curtailment of solar/wind is already happening:

https://www.eia.gov/todayinenergy/detail.php?id=60822

20,000 MWH per day on a typical summer day in the US. Are you saying there needs to be excess solar even in winter before storage gets adopted at proper scale? That's a lot of waste.

 

[Baluncore]

Are you saying there needs to be excess solar even in winter before storage gets adopted at proper scale? That's a lot of waste.

Yes, to an extent. Once there is curtailment, there is an economic advantage in energy storage. To justify installing storage, that curtailment needs to be significant, and to be spread over much of the year. A little waste is justified, as it increases availability during adverse conditions.

Where the curtailment is due to transmission limitations, there is an economic advantage in upgrading the transmission lines, or diversifying the location of new solar farms. Energy storage, located at solar farms, could delay the energy transmission until dusk. In Spain, there are a few big solar farms with molten salt energy storage.

There needs to be some use for excess solar or wind energy.
I am now paid so little for my excess solar energy, that I could get a better return mining cryptocurrency.

 

[Devils]

When you have few sources of power, base load may be a meaningful concept. In Australia this sued to be coal & gas. There are continuous consumers of power eg hospitals, some industrial processes, steel & aluminum smelting.

Now what we see in Australia are millions of producers. Australia has the large rooftop solar power production and some is exported to the grid. In 2024 there was a time when 72% of Australian electricity production was renewables. Matching production and consumption is the problem. The four main alumumium smelters in Australia want to operate 24 hours a day, whereas the Jones family use most of their electricity from 7am-7pm.

The way to match production with consumption, while relying on renewables, is the issue Australia faces. You need storage whether it be home batteries, grid-scale batteries, pumped hydro, or hydrogen-based solutions. You also need the Eastern-state electricity interconnects which are only about 1GW each at the moment.

Getting to 90% renewables in Australia is achievable with current technology. The issue is the 1% of the time when its cloudy and not windy - this is why 1-2 days of electricity storage is needed, maybe 500GWh, and that is hideously expensive. That's where the baseload idea comes in, you need to supply 14GW minimum at all times.