From Judith Curry’s Climate Etc.
By Planning Engineer (Russ Schussler)
“Renewables”: some resources support a healthy grid, other challenge it
The first part of this series discussed some of the shortcomings of the renewable/nonrenewable dichotomy. Renewable generation resources are not necessarily sustainable or environmentally sound and non-renewable options can be clean and highly sustainable. For example, you will find many ardent environmentalist groups strongly opposed to “renewable” biomass generation. Similarly, more and more environmentalists are dropping their objections to “nonrenewable” nuclear power. For those who are concerned with the health of the planet as well as those who want to use the earth for human flourishing the renewable/nonrenewable dichotomy is losing relevance. Referring generally to “renewable” and “nonrenewable” resources or structuring policy to favor renewable does more harm than good as we face the complicate challenges ahead in maintain an adequate electric power supply in an environmentally responsible manner.
This posting examines the impacts of various generation alternatives s on the power system and the electric grid. Renewable resources do not have a general impact on the grid; impacts vary by resource type. The various renewable resources alternatives available today differ greatly in how they impact the grid and should not be clustered. Hydro resources with storage for example, work well to support the electric grid. In fact, it may be the best resource available considering the varied needs of the major grids. Demanding loads that stress the system are often best located near hydro resources. Other “renewable” resources to a greater or lesser extent may present challenges to the operation of the grid and grid reliability. In assessing the challenges of changing resources, reports that a particular grid is operating with 80% renewables may be impressive or virtually meaningless. Of course, a grid can function well depending on 80% hydro resources, or 78% hydro and 2% wind and solar. That’s very different and much less challenging than operating a grid with a penetration level of 40% wind and solar. Let’ look at some of the important characteristics of generation resources and how they differ among resource types.
Load Following/Scheduling/Dispatch/Resource Availability
Generation alternatives, especially some renewables, differ greatly in how and when they supply power. Starting out, the first question, “is the provided energy dependable?” The chart below is the daily output taken from A solar array It shows the energy produced on a typical sunny day with clouds rolling by. You can see the unpredictability introduced by random clouds superimposed upon the predictable daily curve made by the suns path. A bigger footprint or aggregating more farms would tend to smooth the output and increase predictability. But even when greatly smoothed, the energy output is following the sun not the system load.
Electric generation in the form of alternating power has to match load on an instantaneous basis. It’s important that the total generation supply be able to match the load as it ramps up or down. Resources that are dependable and can ramp up and ramp down to follow changes in load are very valuable allowing system operators to depend on them. Plants with the best dispatchability include hydro storage facilities, natural gas plants and batteries/storage. In the middle are plants which provide dependable baseload but are more limited in how well they follow load. These plants rang from coal, combined cycle gas plants, biomass and geothermal to nuclear. Wind and solar generally complicate load following as they are not dependable or able to follow load without attached storage. Run of river hydro is rare and to the extent it is unpredictable it can create difficulties. Speaking generally of the dispatchability of “renewable” resources makes little sense.
One manifestation of load following problems is known as the “duck curve”. In 2014 I warned of the emerging duck curve here and discussed in depth issues related to dispatchability for various generation resources. Since then, as expected, it has worsened considerably. The chart shows that as solar kicks in and fades out, the remaining resources have to ramp up and ramp down at a very steep rate that greatly challenges system operation.
While the daily impacts of solar resources ramping in and out present challenges, at least solar is somewhat predictable. Wind in some locations at sometimes is predictable to a degree but in other locations and at other times it can be highly variable. Sometimes wind and solar track load changes and sometimes they work against the variance in load.
This variability presents problems beyond load following. Generating resources that can’t be counted on need back up resources. If resources might become available, dependable generation must back up those resources. As noted above hydro and batteries can work well to balance energy and it can be easy to have them on standby for that purpose. Other resources however mut be committed and running on line at lower generation levels or depending on the timeframe, in standby mode. Also coal and gas generation have start up times which may delay their availability as well as minimum cool down periods during which they cannot be operated.
I am not trying to go into detail about the intricacies of scheduling and dispatch here, but rather trying to illustrate that generation availability can create challenges that are highly dependent upon the available resource mix and the specific characteristic of the individual resources. All individual renewable and non-renewable resources have their own unique characteristics. When we wonder as to how the grid might responds to renewable, we need to know which renewables are under consideration.
VRE and IRES: The Good and the Bad of these Terms
Some of you may want to remind me that some technical work does break down renewables into a separate Variable Renewable Energy (VRE) group or Intermittent Renewable Energy Source (IRES) group when discussing issues of reliability. Certainly, speaking specifically of the challenges of integrating large amounts of VRE or IRES into the grid is an improvement over discussing the challenges of generic unspecified renewable resources. Referring to VRES and IRES can be seen as somewhat a step in the right direction consistent with the recommendations here for clearer language, but we can do better.
The term renewable in both IRES and VRE is redundant. There are no significant nonrenewable generating options that are variable or intermittent in nature. (There are limited amounts of run of river hydro in some areas.) However, my major concern with this term is that it does not recognize the larger problem currently inherent with most intermittent renewable resources. In the series Academics and the Grid, I argued that it seems like there is a deliberate effort to hide the real challenges of a net zero transition by focusing almost exclusively on the problems associated with intermittency. These names seem to help promote the misconception that variability or intermittency stand as the major challenge. .
Imagine a factory with a problem that workers are showing up late and mostly all of them are intoxicated. Upper management instead of reacting to the very real concerns around inebriated employees, focuses instead on tardiness. They bring in experts to help ensure employees show up on time and provide innovative scheduling so that gaps can be covered with extended hours once the employees show up. To the extent that the measures address the problems of “tardy” employees and that they are able to cover the hours, the more problems associated with intoxication will show up. Maybe the business fears that if the intoxication problem becomes known they will have to slow down, make major changes, maybe lose some contracts. One can imagine that a business might short term want to hide the problem of “intoxication” so that it does not impact near term goals, but for long term success it must be confronted.
The big problem with wind and solar generating resources seems almost hidden in a similar manner. Many do not want to see the march towards “renewables” slowed. It’s obvious there are problems with increasing “ the level of available renewables, but if most of the talk about the smaller problems and the greater public ignores the larger problems, perhaps this is better for the current “momentum” of available renewable options. The focus on intermittency is distracting relevant actors from the bigger looming problems ahead. Far too many policy makers think that batteries or other solutions to the intermittency problem will enable us to march ahead towards net zero with resources that currently are not up to the task.
The Big Looming Problem Associated with Increasing Wind, Solar and Batteries
The major challenges associated with increased penetration of wind and solar generation are not caused by intermittency, but rather from how the energy is injected into the grid. The electric energy produced by wind and solar is transformed by a power converter using inverters in order to synchronize with the oscillating grid. In terms of reliability, resources that spin in synchronism with the grid as electric energy is produced are much better for the grid than those resources which use inverter-based technology to convert direct for grid injection. Resources that spin with the system are called synchronous resources, while inverter-based generation is called asynchronous generation. Note – Although wind turbines spin, they do so at variable speeds, requiring them to produce direct current power which must be then be converted to AC before entering the grid.
Synchronous resources readily provide inertia and essential reliability services which support the grid. In addition to dispatchability, hydro resources are valuable because they spin in synchronism with the grid. They are typically large and among spinning resources they have great grid supporting characteristics. Good spinning resources also include nuclear, coal, geothermal, natural gas, biomass, geothermal and molten salt thermal solar plants. In terms of supporting grid reliability, wind and solar resources which rely on asynchronous inverter-based technologies are at the other extreme.
It’s important that we distinguish between inverter-based technology and spinning machines because there is a strong potential to improve inverter-based technology. To some extent now, with additional features, power converters can roughly emulate some behaviors of rotating machines and help provide important reliability functions to the grid. There is hope that inverter-based generating resources will be better able to approximate spinning generation in future years. The National Renewable Energy Laboratory (NREL) recognizes that:
Managing the stability of electric power systems is based on decades of experience with large, synchronous generators. Today’s electric power systems have increasing numbers of nontraditional sources, such as wind and solar power, as well as energy storage devices, such as batteries. In addition to the variable nature of some renewable generation, many of these resources are connected to the power system through electronic power inverters.
The operation of future power systems must be based on the physical properties and control responses of traditional large, synchronous turbine generators as well as inverter-based resources. But there is no established body of experience for operating hybrid power systems with significant inverter-based resources at the scale of today’s large interconnections. To operate such systems, the assumptions that underlie generation design and control must be reexamined and modified—or even redefined—to take account of the challenges and opportunities presented by inverter-based generation.
Most inverter controllers today are grid-following and built on the assumption that system voltage and frequency are regulated by inertial sources. Such control approaches cannot guarantee system stability in low-inertia setting and are unlikely to sustain an inverter-dominated infrastructure. This limitation has inspired an investigation into grid-forming control methods for power electronic inverters, which provide functionalities that are traditionally provided by synchronous machinery.
Certainly, progress can be made. However, the Eastern Interconnection in the United States in the largest, most complicated machine in the history of the world. The challenge of adding significant amounts of asynchronous inverter-based generation increases the complexity tremendously. I have written extensively on the challenges of increasing the levels of penetration from asynchronous generation sources here, here, here, here and here. I believe that running any large complex grid without support from large rotation machines in very close to impossible within planning time frames. I see the challenge of allowing high penetration levels of asynchronous inverter-based resource as tougher than rocket science or brain surgery. Such an achievement would go beyond the moon landing, the sequencing of the human genome, the atomic bomb or a cure for the common cold.
Many entities, including the National Renewables Energy Laboratory, FERC, and NERC, are working hard to improve the functionality of asynchronous inverter based technology. They may well meet their goals to allow better grid support from these resources within the next five to ten years. Better support is possible. But that will still be a long way from eliminating the grids reliance on rotating machines.
Those who are more optimistic about the development of such technologies may end up being right. I hope so. It may be that we may have functional large grids driven by wind, solar and batteries within the lifetimes of some of our readers. But to get there, we have to recognize and acknowledge the difficulties inherent in such a transformation. Those who assume or pretend that there is no problem are either woefully ignorant or ignoring the looming problem in favor of short-term goals. Unfortunately, the challenges of asynchronous inverter based generation will not be adequately addressed of ever fixed if they are hidden.
Conclusion
Generically speaking about the impact of renewables on the grid, or what renewables can accomplish generates more confusion than clarity. Power system engineers know that it is easier to add wind, solar and batteries where there are existing supportive large hydro resources. It is harder to add wind, solar and batteries where the other resources are not that strong. Comparing the penetration levels of renewable generation for different areas with vastly differing amounts of hydro can be misleading, especially when hydro is included in the renewable category. Failing to distinguish between the capabilities of hydro, and wind and solar can lead to unrealistic selections for low hydro areas. Misconceptions on capabilities are especially a concern as existing hydro resources are increasingly challenged.
Large grids certainly can operate reliability without fossil fuel generation. Large grids can operate on 100% “renewable” energy. Reliability is not a function of the source of the energy input to the grid, but rather how that energy is injected into the grid. If solar powers spin a generator in synchronism with the grid (perhaps through the use of molten salt) that better supports reliability. If wind turbines could be made to spin only in synchronism with the grid, that would aid reliability. If the energy from hydro flows were captured with variable dc motors and injected to the grid with inverters, reliability concerns would increase. As the grid changes and we address reliability, is so much easier, direct and honest to speak of synchronous generation and inverter-based generation. The impact of “renewables” on reliability is too vague to be meaningful. Although this is the case, you frequently see references to renewable percentages which do not distinguish among the resources employed. These figures are quoted by those who want to push a perspective and they impact policy makers.
We do not face a challenge in integrating large amounts of renewable generating resources into the grid. We face operational challenges from intermittent resources. We face large reliability challenges from integrating large amounts of asynchronous inverter-based generation into the grid. The better the problem is understood, the better the problem can be addressed. We many disagree on the scope and magnitude of problems caused by intermittency as well as by asynchronous inverter-based generation. But be assured addressing the emerging problems will be go smoother, the more precisely the problems and successes are identified and defined.
“The better the problem is understood, the better the problem can be addressed.”
The problem is that all these efforts to decarbonize are having negative effect on reliability of our energy systems but no effect on co2 levels. Perhaps adaptation is a better route than mitigation.
We’ve adapted to a reliable grid. The problem is we expect there to be electricity when we flip a switch.
The fact is also that the grid operates better that way. If one had a system to serve only himself, this might be less of an issue, but the grid serves many many millions.
“all these efforts to decarbonize are having negative effect on reliability of our energy systems”
That isn’t the problem. That’s the intent.
No, really. No. The intent was to utilise an emotional narrative (Mann made climate change) to rape and pillage the plebs for their money.
The fact that it would destroy civilisation, was simply not something they considered.
No ‘perhaps’ about it. Especially if as most here suspect, the change in climate has very little to do with human activity and is mostly beneficial…..
The only things “renewable” about wind & solar generated power are those 2 predictable times when they don’t produce anything –
I’ve wondered if it would help to have inverter generation and battery charging to adjust generation or draw in response to short term fluctuations in line frequency. That is generation would be cut back and charging increased when the line frequency increases as one side of the coin with the other side having generation increasing and charging power decreasing when line frequency drops.
I would also wonder if a inverter/converter connecting the AC line on one side and a bank of super/ultra capacitors could provide the equivalent of inertia. Providing the voltage regulating effect of a synchronous machine (alternator, synchronous motor or synchronous condenser) could be more of a challenge.
FWIW, I did take a couple of power systems courses at Cal along with a couple of power systems labs. It was very impressive to watch the generators respond to simulated line faults.
Grid inertia providing supercap voltage stabilizers up to about 4MW have been commercial for over a decade. Above that capacity a big synchronous condenser is more economic.
A big synchronous condenser should also take a lot more abuse than a semiconductor converter based grid stabilizer. One thing where semiconductor based solutions could work better than synchronous machines is providing damping of the swings following a system disturbance. One needs to experience the sound of a large generating station during a disturbance to truly appreciate the forces involved.
Is it not the case that is some places the spinning part of the system has been preserved when the coal, etc. part was destroyed so that it can be used to stabilize the moment to moment fluctuations in voltage and frequency caused by wind and solar variations? Of course this use is a power consumer, not a power provider.
Not in South Australia. The philistines dynamited all the coal fired power stations.
Yes. Steam generators can be repurposed as big.static compensators. Just cut off the turbine and add extra oiled bearings.
Er, Eric, that is precisely what the batteries are for. They cannot do long term storage. They replace the energy in the spinning mass of conventional turbines and generators to stabilise grid frequency.
Leo, this is more like “smart grid” technology, but using line frequency as the trigger for adjustments in load or generation in order to avert a blackout. Preventative measures in place or the last 50 years include load shedding, where some load may be dropped when frequency gets to 59.75Hz, more loads dropped at 59.5Hz an rolling blackouts at 59.25Hz. The flip side is a rapid rise in line frequency due to loss of load, where you would want rooftop solar installations to stop sending power, and encourage loads coming very quickly to absorb the now excess generation.
The common feature to rapid frequency excursions is the possibility o loss of synchronism leading to a grid failure.
Russ and I wrote several related joint posts for Judith a few years ago. Covered wind, solar, and storage. In ‘true cost of wind’ we deconstructed EIA’s LCOE parity falsehoods using ERCOT for backup and transmission at then 10% wind penetration. Bottom line ‘correct’ LCOE result: CCGT $58/MWh, Texas wind $146/MWh. And that at only 10% penetration.
Renewables screwing up the grid at great extra cost to solve a climate non-problem is something only libtards (like AOC and Biden) could imagine.
That about sums it up.
Rud,
Do you actually believe that Zhao Bai Den has a functioning imagination? Hunh!
If wind/solar are a major part of the system…..the design and thus cost of the system will depend on the design parameter of when major absences-es of solar /wind occur…..like 6 or 7 days of little or no wind….and 6 or 7 days of little or no sun. An area may have a record of no sun for a week happening on average every 8 years….or no wind for a week every 10 years on average. Just forget this sol/wind stuff and go to Thorium Liquid Salts Cooled Reactors.
You don’t need the thorium/uranium nuclear cycle to start MSR. A uranium/plutonium MSR can recycle all the spent conventional nuclear fuel rods (bereft of their zirconium cladding) first at much lower cost (cause the spent fuel pellets are ‘free’) . There was a very good about 40 page technical discussion of the remaining engineering issues at MIT spinout TransAtomic a while back. I archived it for reference.
Bottom line, you need a way to periodically extract some of the molten salt (easy) to remove a small volume of radioactive decay byproducts (hard but chemically feasible). There were on paper several possibilities, but none yet pilot tested.
With fracked natgas, the US has several decades to get MSR research and pilot scale testing done. Why we are wasting money on EVs and ‘green H2’ instead is beyond comprehension—except for Biden’s obvious cognitive impairment.
Biden’s condition is just a convenience for the program, not the cause of it.
First, invent useable Thorium Liquid Salts Cooled Reactors.
Sorry, I am going to upvote this. No one denies that thorium has a great part to play in the future of nuclear power, but te fact remains that a supply chain, tried and tested technology and fuel disposal methodologies exist for uranium reactors that are here, now, economically viable and can be built in a few years.
The first priority – if we are going to preserve a civilisation that runs on electricity, which is by no means a given, is rapid deployment of something that already works. And that means as little innovation as possible.
Advanced PWR, BWR and SMR all work now, as does the CANDU style reactor. First let’ build more of those.
Then, crisis averted, we can slowly develop thorium technology. Without having to get government funding
Leo, a thorium breeder reactor has been invented, tested and proven workable many years ago. The Light Water Breeder Reactor designed and built by the Naval Nuclear Propulsion Program produced a U233-Thorium-U233 breeder reactor core in the early 1970’s and operated it in the Shippingport Atomic Power Station for a few years. Selected portions of the core were reprocessed afterwards and found to contain about 1.3% more U233 fuel than initially included in its construction. President Carter’s banning of reprocessing killed the whole idea. But all the design specifics and details are in DOE archives, unclassified as I recall. Liquid salt cooled reactors, otherwise known as homogeneous reactors, have very significant operational and maintenance difficulties that might not be fixable.
I’m not sure where the images for the past few articles, including this one, are coming from, but I find them very visually disturbing and hope you will not be using more like them. Thanks.
I find the climate emergency disturbing since it’s a lie. Perhaps disturbing “art” is relevant.
Did they remind you of that day at the beach with the missus?
I’d like to see more cute fluffy animals.
Ribs for dinner. What could be better?
They are all AI generated images as was announced last December. Faster to create and publish with no copyright cease and desist issues.
Fair use was a great plan for everyone except lawyers and woke liberals.
“I find them very visually disturbing and hope you will not be using more like them.”
“you will find many ardent environmentalist groups strongly opposed to “renewable” biomass generation”
and very stupidly, in fact- that is, woody biomass when done right- regarding the agricultural kind, I know nothing about
On my beloved for over 40 years now Uplands Wisconsin dairy farm, we have two kinds of ‘woody biomass’.
The corn stover and such not baled for dairy bedding is fall plowed into the row crop field soil for carbon replenishment. Also then spring manured for natural fertilizer.
The crowns of about every 15 year selective logged woodlot trees (too steep to farm or pasture, about 150 acres in three sections) become our winter firewood. A pain to harvest, a joy to burn in the double wall firebox plus blowersupplementing our propane furnace.
The small residual logged crown ‘brush’ becomes piled havens for many of the forest animals that also live in our farm woods. Ruffed grouse, raccoon, grey and red squirrel, red fox, coyote… Wild turkeys roost in the winter trees. White tailed deer shelter under big invasive laurel or medium pines, always away from the snow blow.
When you finally learn how to walk the prairie savanna (now mostly farmland) and remanent woods like native Americans did, everything is obvious. Wild animals are very ‘human’ smart. Else they would not survive.
Some reading I did, long ago, when wood burning was a possibility for the house we had, detailed how many cords of firewood/acre could be harvested per year without ever decreasing the amount of wood in growing trees. That does, of course, depend mainly on rainfall amounts.
A northern US hardwood forest should grow about .5 to 1 cd. of wood per acre per year. When to cut and how much to cut and which trees to cut is complicated- almost as complicated as climate science- that’s why to get the real story about forests one needs to talk to a “professional forester”- not tree hugging wackos, like we have too many of here in Wokeachusetts who think they can save the planet by not cutting trees.
The Gang Green only learned to love hated-hydro when they grudgingly saw that renewables simply did not work without despatchable back-up gas, coal nuke or hydro, they chose hydro because at least they could go on heating FF and claim hydro at least was renewable.
Those that know of the pitched battle waged against hydro by their predecessor greens may regret now that they succeeded in getting some ops dismantled and others prevented. Today, New England would not be able to have the option to ruin their economy and impoverish their citizenry if they weren’t connected to the world’s largest and cheapest source, Quebec Hydro.
They can make “renewable” nuclear reactors by making breeder reactors that make more nuclear fuel.
Yes, nuclear fuel reprocessing can be, and is being done (for example, in England). However, after the US signed the Nuclear Nonproliferation Treaty, such reprocessing in the US was prohibited by a Presidential EO.
Lol!
Wind and solar seem okay for the rural areas in developing countries where they don’t have a grid.
As long as one ignores all the research on long term damage to living tissues of humans and other animals exposed to the extremely energetic infrasound pulses of conventional wind turbines. There are designs that don’t produce those but they don’t seem to be making any headway in the market.
This appears to be a gratuitous statement devoid of any evidence. Are there any reliable grids currently running w/o any hydrocarbon generation?
I asked the various ChatGPT engines out there, and if any AI search engine is capable of discovering such a large grid, the biased systems would reveal it; but alas, every answer was aspirational and identified a couple countries that are foolishly pledging not to add any additional coal-fired power generation some time in the future.
Perhaps for the kinds of society that cook when power is available and store dried food for when it isn’t, and otherwise enjoy year around mild weather.
He explains what he means quite clearly in the sentences which follow your quotation:
Reliability is not a function of the source of the energy input to the grid, but rather how that energy is injected into the grid. If solar powers spin a generator in synchronism with the grid (perhaps through the use of molten salt) that better supports reliability. If wind turbines could be made to spin only in synchronism with the grid, that would aid reliability. If the energy from hydro flows were captured with variable dc motors and injected to the grid with inverters, reliability concerns would increase. As the grid changes and we address reliability, is so much easier, direct and honest to speak of synchronous generation and inverter-based generation. The impact of “renewables” on reliability is too vague to be meaningful. Although this is the case, you frequently see references to renewable percentages which do not distinguish among the resources employed. These figures are quoted by those who want to push a perspective and they impact policy makers.
We do not face a challenge in integrating large amounts of renewable generating resources into the grid. We face operational challenges from intermittent resources. We face large reliability challenges from integrating large amounts of asynchronous inverter-based generation into the grid.
His point is, you could have a reliable grid based on 100% renewables as long as you have synchronous generation from those renewables. Its not whether they are renewables that counts, its whether their inputs are synchronous.
His other point is that intermittency is an operational problem, but its not the key one that has to be solved in delivering reliable supply from wind and solar. If you could address intermittency you still have not necessarily succeeded in delivering a reliable supply. If your solution delivers asynchronous generation, he is saying, you might have resolved the intermittency problem, but you will still not have succeeded in providing reliable supply.
Its a very interesting point, and it goes along with his remark that the concept of ‘renewable’ is not useful, because it lumps together both synchronous and asynchronous generation sources which are totally different in their implications for reliability.
A point I have never seen addressed by the renewables advocates here or elsewhere. Put it very simply: ‘renewable’ is a positively dysfunctional concept in power generation planning and should be dispensed with, because it veils the fact that some renewables present completely different problems than others. We should stop calling two completely different things by the same name.
Michel, I understand what you are saying but don’t think it is helpful in the real world. Most people, greens and especially politicians see unreliables as wind and solar and call them ‘a good thing’ that will help us get to net zero.They will never admit what the IEA itself said back in 2020 –
“the system value of variable renewables such as wind and solar decreases as their share in the power supply increases” (IEA ‘Projected Costs of Generating Electricity’ 2020 p13)
High shares of intermittent unreliable energy leads to instability and potential collapse of the grid which in turn requires significant investment in back up capacity, firming of the grid and storage solutions. All these costs are disregarded by those promoting unreliables as the cheapest form of power.
Take your point about communication. His point however is about the underlying problem. He is saying that as a matter of fact intermittency is, however serious, not the most serious problem.
Yes, its a very serious practical matter. But even if you manage to solve that somehow, the most serious problem remains, and that is, wind and solar both deliver a product which will destabilize the grid. Because synchronicity.
I haven’t read the IEA report, but it sounds like he is saying the same thing, giving synchronicity as the reason.
Agreed it will be a very difficult point to get across. But if he is correct its very important, because it undercuts all current policy efforts to move to renewables and somehow fudge intermittency. Even if you could do that, if you don’t also correct the synchronicity problem you are not going to have a stable grid, and the higher the proportion of even intermittency compensated renewables, the worse it will get.
I have never come across anywhere this is taken account of. The Royal Society report for instance proposes extraordinary measures to remove intermittency – this is by storing quantities of hydrogen in caverns and burning it in time of calm. But this will do nothing to solve the synchronicity problem for the times, must well the majority of the time, when wind and solar are used in raw form, without relying on the storage.
I think you say what I say, but better.
Michel did a nice summary. I will add that I have made references to Iceland earlier in the post. They do quite well with hydro and georthermal and likely can continue do so so for a long while. They have aluminum smelters and no doubt can accomadate the most demanding account. This ight help make that point that the term “renewable” is misleading in dicussions of power and grid issues and therefore should be retired!
This is kind of nit picking, not terribly relevant to the main point, but in two places run-of-river hydro systems are depicted as minor in number. This article
https://www.energy.gov/eere/water/articles/integration-run-river-hydropower-energy-storage-creates-additional-grid-value
says “Nearly half of the U.S. hydropower fleet operates as run-of-river”
I suspect the difference between the two articles via a vis run-of-river is that while there are many of them, run-of-river generation is relative small compared to many hydro dam facilities. Is this the case?
Further, is the claimed grid-following nature of wind applicable to the types of “storage” the article describes for run-of-river generators? That is, does it assume the spinning generators will supply the necessary stable voltage and frequency?
Sod all energy in run of the river stuff. A typical small river as was used for watermills is at best a couple of horsepower.
Basically there is no head, and the extractable energy is flow rate times head.
Fair enough. I should have been more careful. There may be way more run of river in parts of the country I am not as familiar with. I meant to say it’s not a big deal usually. I’m not sure in the quote about at “half or the fleet” means. I doubt it means half of the MWH’s produced come from run of river (but I could be wrong). It suspect it means half of the “installations”. Run of river probably are smaller and stored damns are usually larger. Bonneville has both I know, and there storage capaibilty coupled with their base demands probablby means any challenges with accomaditing the run of river part are trivial.
I’m going to take up myself. I looked at the biggest “run of river” plant in the US and did a little digging. Big Ben is classisfied as run of river and it doesn’t have extensive storage capability but it can do “pondage”. They do daily and weekly pondage operations so they can use the power when they need it llkely to follow load to some extent. I wouldn’t call it intermittent in the same was that wind solar or some small run of rive hydro facitilies operate. I expect to find similar for other large “run of river plants. https://apps.dtic.mil/sti/tr/pdf/ADA581200.pdf
“The Big Bend Project is located in central South Dakota. The project is basically a run-of-the-river power development with regulation of flows limited almost entirely to daily and weekly power pondage operations.” Note the word “almost” means they can even go a little past daily and weekly. No duck curve type problems and the ability to compbat such. I think neith planners or operators loose sleep over resources like this.
I suspect the planners count it as it as available during peak periods and the operators consider it as an available dispatchable resource on most days..
Another question that isn’t relevant to the main topic but then how many articles would it fit with? At least hydro dams are mentioned a number of times here.
One complaint about hydro that I’ve run across many times is that the dams fill up with silt and eventually become useless. Moving material from the mountains to the ocean has long been a function of rivers but there are potential solutions to the dam filling problem. I don’t know if any are very practical.
Dredging is an art long practiced by humans and could be used to remove the material collecting behind a dam. It seems like some very valuable uses could be found for the removed material in agriculture, landscaping, and construction.
If that isn’t actually feasible or profitable, it could be fairly simple to have a continuous process sucking up material from behind the dam and injecting it into water leaving the dam. On a more or less continual basis the rate could, at least in many instances, be slow enough not to damage the downstream lands or clog the stream below the dam, at least any more than no dam present would be doing.
I took a tour of Hoover Dam in the summer of 1974 and asked the guide how long it would be before the area behind the dam silted up.
His answer was 800 to a 1000 years before silt reaches the inlets of the intake towers.
He went on to say that well before the silt gets that high, the area behind the dam near the intake towers will be dredged.
His opinion as a technician who was employed at the dam prior to his retirement was that there is no fundamental reason why Hoover Dam couldn’t be producing electricity a thousand years from now.
I concur with that. Silt is far more a function of slower flow rates downstream towards estuaries. But best power is gained up mountains where there is very little erosion that hasn’t already happened.
In a saner world inverter-base wind and solar wouldn’t be allowed to weaken the national grid until they had demonstrated 24/7 reliability and dispatchability! To accomplish that they would need to have their own backup, whether batteries or CCGT!
In the world in which we currently live, the billionaire class gets to maximize their looting and plundering of the tax revenues and economy, while the politicians clap and bark like circus seals!
Energy can only be used once – it cannotbe renewed.
It’s the usual problem of the ArtStudent™ mind coming up with an emotive qualitative and cuddly Boolean term for a situation which needs careful, nuanced and quantitative analysis. And then big corporations bending government ears and filling government pockets to get their technology mandated.
Renewable Obligation, my arse.
As usual the human race is beset by ignorant incompetent government, which is scarcely better than no government at all, staggering on from one crisis to the next, grabbing as much personal wealth as it can, until it becomes so blindingly obvious what the correct course of action is, that you don’t even need a government to make it happen.
Our biggest problem is that we have been brainwashed into thinking that this is not the case and ought not to be the case.
Eventually people will hit on the right solution (nuclear), after every other alternative has been fully explored and found wanting. (Rain, wind, sun, tides, waves, biofuel, batteries, hydrogen…I attended a conference for investors back in the early noughties where we looked at everything: The conclusion. Not one of them that wasn’t already being exploited was commercially viable without government intervention.)
It’s no good saying as an engineer or as a person who can do cost accounting ‘none of that shit is going to work’
In today’s woke anti-science anti-expert (except climate expert/scientist) world, that is merely your opinion.
One can but sit back, like Cassandra and watch the lemming like March of the Morons towards climate science induced catastrophe…
It will be interesting to see how AI can improve grid management. It has been used with remarkable success to not only stabilize, but stably manipulate the plasma in Tokamaks. After extensive training on Tokamak plasma control system simulators, it has demonstrated the ability to identify and head off the onset of plasma instabilities 30 msec ahead of time in real Tokamaks. That’s no small feat.
Of course, a more remarkable successful application of AI was to monitor the entire internet around 2020, and spot and suppress every tiny expression of “disinformation” on social media, e.g. thoughts that mail-in ballots were a bad idea, climate change was not a real problem, the Wuhan Red Death resulted from a lab leak, unproven vaccines were not really a good idea, etc. It successfully brought civilization to the brink of destruction in four short years, and may finish it off in November. It would be interesting to see whether the powers that be would be willing to try using AI in a positive application – a stable grid with high “renewable” penetration – or not. My money is on “or not.”
I think the term ‘renewable energy’ is an apt one.
Because all the inputs of these energy sources need to be constantly renewed – at great cost to consumers and the environment.
The term ‘sustainable energy’ is the one I take issue with.
An energy source entirely dependent on *rare earth* minerals could hardly be described as sustainable.
I’ve taken to calling it fickle energy now and nobody asks you to explain what you’re talking about. They all get it and it only rankles the odd religious nutter.