9 ms·

AFAIK it's not at all clear that solar and wind are really cheaper when making up a substantial part of a large-scale power grid that meets our current expectat

by ufmace 2y ago

AFAIK it's not at all clear that solar and wind are really cheaper when making up a substantial part of a large-scale power grid that meets our current expectations of 100% consistent and reliable power everywhere, no matter what. The unreliability of solar and wind requires either hot (constantly running and spinning) non-renewable backups or grid-scale power storage (has never been done so ? on cost to build and upkeep) to guarantee reliable voltage and AC frequency. The cost of that should be factored into determine the true cost of these power sources. The stability of the grid is dependent on the collective physical inertia of the many tens of thousands of huge and heavy spinning turbine-generator sets that make up the majority of the current generating capacity. Most current solar power sources rely on grid-following inverters, which are not stable without a grid stabilized by a preponderance of large spinning turbines. There has been some work on grid-forming inverters that are less impacted by this, but AFAIK there aren't currently any that can replicate the grid stability provided by that physical inertia. I'm less certain about wind turbines, but I think they have this problem too. I don't think they're controllable enough to be mechanically synced to the grid frequency. I'd love to be wrong about this, please prove me so if you can! But I don't often hear these points addressed, and we're not helping anything by ignoring the complexity of the real world.

fungi 2y ago
Battery backed renewable energy with grid upgrades is cheaper today and getting cheaper. https://www.csiro.au/en/research/technology-space/energy/GenCost https://www.csiro.au/en/research/technology-space/energy/Gen...
zer00eyz 2y ago
> grid... grid-scale power storage... stability of the grid ... grid-following inverter ... grid stabilized by ... The problem isnt solar, or wind, or storage ... the problem is the grid. Were running on a system that was never designed to do what were asking of it, and yes its going to be a number of problems to solve. All of those are jobs, economic action and improvements to reliability and quality across the board. > I don't think they're controllable enough to be mechanically synced to the grid frequency. Google, there are a number of ways this gets addressed. > There has been some work on grid-forming inverters Yes, we know how, and the race to build them is on... this isnt a hard problem it's just a problem. > grid-scale power storage (has never been done so ? Already deployed in a few places with battery systems (hati, Australia both have them. Possibly Hawaii too). We're doing quite a bit of this. Again a quick google will give you a sea of sources.
epistasis 2y ago
Inverters can easily replace physical inertia, it just requires technology developed within the past 30 years, and most grid folks haven't thought about new technology for far longer than that. As more and more intermittent renewables get pushed onto grids, they become more reliable. Most outages are from single points of failure from large generators or transmission. Dealing with highly distributed renewables means that grid ops get used to acting fast, and there's greater redundancy instead of so many SPOF. Kind of how cloud services got reliable by expecting there to be failure and designing it into the system. Storage is advancing super quickly, is super fast to deploy, and can replace a lot of more expensive things like transmission upgrades. We have all the tech to replace fossil fuels on the grid with the above. The only question is the final cost. It's likely to be far far lower than using existing "hard" energy, because by the time we can deploy 50 TWhs of storage, it will have gotten so cheap. We don't know when costs will stabilize, but they have a loooong distance to fall. And we have all sorts of other technologies that will make all this far cheaper: enhanced geothermal, enhanced geothermal with temporal storage based on injection pressure and release, iron air batteries, flow batteries, thermal storage for industrial process heat, etc. etc. etc. For every area of the energy economy, there are two to three solutions that look promising. Fusion and fission look promising for none. That's not to say that they can't have some serious innovation and start dropping their costs, but nobody currently operating in the field has demonstrated a path. Yet.
- katbyte 2y ago
  What new technology changes things to not require spinning turbines?
  - sanderjd 2y ago
    Massive improvements to battery technology.
    - katbyte 2y ago
      That’s a non answer - what improvement
actionfromafar 2y ago
I think the solution will come from storage but also from a massive grid-wide ability to shed non-critical loads on-demand. The current grid is built on early 20th century principles, before we had real-time digital communications. As a though experiment - imagine a 19th century world suddenly getting all of our current digital tech and wind farms and solar power - there would be no point in trying to create a "static" grid where producers and consumers weren't communicating with each other. Every consumer would negotiate power availabity based on momentary price.
deff 2y ago
Regarding stability, this physical inertia is also present in rotating wind turbines. But I guess exploiting this at a meaningful scale would recquire a level of interconnectivity which boils down to the same issue of cost. I am however optimistic about grid-scale storage. There is a long term trend of rapidly dropping battery prices, and with recent developments in sodium ion batteries there is no fundamental reason this won´t continue. Another enabler could be advancements in lifespan. This could allow storage being installed inside or near wind and PV, cutting down on space and installation costs. Even then however, grid improvements would be needed. Some problems still need to be solved indeed, but in my (mostly uneducated) opinion, they seem easier than achieving economically viable fusion. But they do still require large investments in R&D and manufacturing capability.
- XorNot 2y ago
  Wind turbines do not provide grid inertia. They do not spin at 50/60hz, they are deployed with frequency converters to match optimum generation to the grid and spin at whatever speed they can achieve. They're essentially another type of solar plant.
- j16sdiz 2y ago
  Wind turbines don't get the same feedback like traditional generator turbines do. Wind turbines are designed to run on unstable wind speed -- this meant it have to somehow decouple from the main grid
cyberax 2y ago
> Most current solar power sources rely on grid-following inverters There are now inverters that simulate the rotational inertia. They simlpy shift the phase of the generated waveform just a bit if the frequency starts dropping. And it doesn't require any expensive additional hardware.
sanderjd 2y ago
> grid-scale power storage (has never been done so ? on cost to build and upkeep) This is out of date. Grid scale battery storage has recently become economic in lots of cases and is ramping up quickly.
- JumpCrisscross 2y ago
  > Grid scale battery storage has recently become economic in lots of cases and is ramping up quickly Being economic and being cheapest are worlds apart. Solar or wind + utility-scale storage come in at 46 to 102 and 42 to 114 $/MWh, respectively, in terms of LCOE [1]. That does not include grid firming costs [2], which could raise the upper end of those figures to $120 or more, and is based on current storage prices; if everyone tries to build at once, it rises. (On the other hand, there are further economies of scale to be realised.) Fission clocks in around 141 to 221 $/MWh, which is why we aren’t building it, but $31 at the margin, which is why closing working plants is stupid. SMR focus on lowering capital costs through economies of scale. Fusion by reducing compliance costs. In all likelihood, the solution is fusion SMRs baseloading solar, wind and geothermal energy with peaker industrial processes running during the day. (Hydro can come too.) [1] https://www.lazard.com/media/2ozoovyg/lazards-lcoeplus-april-2023.pdf https://www.lazard.com/media/2ozoovyg/lazards-lcoeplus-april... slide 2 [2] https://www.gevernova.com/gas-power/applications/grid-firming https://www.gevernova.com/gas-power/applications/grid-firmin...
  - fsh 2y ago
    SMRs are based on the wishful thinking that, for the first time in history, making an industrial facility smaller increases economic efficiency. It's just not going to happen.
    - sanderjd 2y ago
      I'm pretty skeptical of the SMR thesis, but I think there are plenty of examples of modularization and miniaturization being economically advantageous. For instance, I just the other day came across an article about how in the first wave of electrifying the textile industry, they replaced big centralized steam engines with big centralized motors. But then they realized that motors made it possible to mass produce small machines and put one at each station, and they turned out to be an advantage. I think there are a number of specific reasons to be skeptical of SMRs, but I don't think the entire concept is per se flawed.
ak217 2y ago
Solar and wind are not "unreliable" any more so than any other power source we've used in the past. Just like transformers have been replaced by power electronics in many applications, the reliance on flywheels for frequency stability will be replaced by grid-forming power electronics. There isn't anything magical about this technology.
sudosysgen 2y ago
Another thing that's easy to miss is that, unfortunately, renewables tend to be correlated. An event that reduces insolation over a large area, for example, will affect solar and wind over a large area. So simply over-building is a lot more expensive than it seems when you need to be able to handle tail risks.
gibolt 2y ago
Batteries can mimic inertia better than physical spinning objects. An operator in Australia has seen massive success and profits over the past few years using batteries to out-compete other grid stabilization. IIRC, they have already made enough to pay off the upfront costs. Even better, Australian government was super against the change, but now most places are positive on them because of the obvious success.

by ufmace 2y ago

fungi 2y ago

Battery backed renewable energy with grid upgrades is cheaper today and getting cheaper. https://www.csiro.au/en/research/technology-space/energy/GenCost https://www.csiro.au/en/research/technology-space/energy/Gen...

zer00eyz 2y ago

> grid... grid-scale power storage... stability of the grid ... grid-following inverter ... grid stabilized by ... The problem isnt solar, or wind, or storage ... the problem is the grid. Were running on a system that was never designed to do what were asking of it, and yes its going to be a number of problems to solve. All of those are jobs, economic action and improvements to reliability and quality across the board. > I don't think they're controllable enough to be mechanically synced to the grid frequency. Google, there are a number of ways this gets addressed. > There has been some work on grid-forming inverters Yes, we know how, and the race to build them is on... this isnt a hard problem it's just a problem. > grid-scale power storage (has never been done so ? Already deployed in a few places with battery systems (hati, Australia both have them. Possibly Hawaii too). We're doing quite a bit of this. Again a quick google will give you a sea of sources.

epistasis 2y ago

Inverters can easily replace physical inertia, it just requires technology developed within the past 30 years, and most grid folks haven't thought about new technology for far longer than that. As more and more intermittent renewables get pushed onto grids, they become more reliable. Most outages are from single points of failure from large generators or transmission. Dealing with highly distributed renewables means that grid ops get used to acting fast, and there's greater redundancy instead of so many SPOF. Kind of how cloud services got reliable by expecting there to be failure and designing it into the system. Storage is advancing super quickly, is super fast to deploy, and can replace a lot of more expensive things like transmission upgrades. We have all the tech to replace fossil fuels on the grid with the above. The only question is the final cost. It's likely to be far far lower than using existing "hard" energy, because by the time we can deploy 50 TWhs of storage, it will have gotten so cheap. We don't know when costs will stabilize, but they have a loooong distance to fall. And we have all sorts of other technologies that will make all this far cheaper: enhanced geothermal, enhanced geothermal with temporal storage based on injection pressure and release, iron air batteries, flow batteries, thermal storage for industrial process heat, etc. etc. etc. For every area of the energy economy, there are two to three solutions that look promising. Fusion and fission look promising for none. That's not to say that they can't have some serious innovation and start dropping their costs, but nobody currently operating in the field has demonstrated a path. Yet.

katbyte 2y ago
What new technology changes things to not require spinning turbines?
- sanderjd 2y ago
  Massive improvements to battery technology.
  - katbyte 2y ago
    That’s a non answer - what improvement

actionfromafar 2y ago

I think the solution will come from storage but also from a massive grid-wide ability to shed non-critical loads on-demand. The current grid is built on early 20th century principles, before we had real-time digital communications. As a though experiment - imagine a 19th century world suddenly getting all of our current digital tech and wind farms and solar power - there would be no point in trying to create a "static" grid where producers and consumers weren't communicating with each other. Every consumer would negotiate power availabity based on momentary price.

deff 2y ago

Regarding stability, this physical inertia is also present in rotating wind turbines. But I guess exploiting this at a meaningful scale would recquire a level of interconnectivity which boils down to the same issue of cost. I am however optimistic about grid-scale storage. There is a long term trend of rapidly dropping battery prices, and with recent developments in sodium ion batteries there is no fundamental reason this won´t continue. Another enabler could be advancements in lifespan. This could allow storage being installed inside or near wind and PV, cutting down on space and installation costs. Even then however, grid improvements would be needed. Some problems still need to be solved indeed, but in my (mostly uneducated) opinion, they seem easier than achieving economically viable fusion. But they do still require large investments in R&D and manufacturing capability.

XorNot 2y ago
Wind turbines do not provide grid inertia. They do not spin at 50/60hz, they are deployed with frequency converters to match optimum generation to the grid and spin at whatever speed they can achieve. They're essentially another type of solar plant.
j16sdiz 2y ago
Wind turbines don't get the same feedback like traditional generator turbines do. Wind turbines are designed to run on unstable wind speed -- this meant it have to somehow decouple from the main grid

cyberax 2y ago

> Most current solar power sources rely on grid-following inverters There are now inverters that simulate the rotational inertia. They simlpy shift the phase of the generated waveform just a bit if the frequency starts dropping. And it doesn't require any expensive additional hardware.

sanderjd 2y ago

> grid-scale power storage (has never been done so ? on cost to build and upkeep) This is out of date. Grid scale battery storage has recently become economic in lots of cases and is ramping up quickly.

JumpCrisscross 2y ago
> Grid scale battery storage has recently become economic in lots of cases and is ramping up quickly Being economic and being cheapest are worlds apart. Solar or wind + utility-scale storage come in at 46 to 102 and 42 to 114 $/MWh, respectively, in terms of LCOE [1]. That does not include grid firming costs [2], which could raise the upper end of those figures to $120 or more, and is based on current storage prices; if everyone tries to build at once, it rises. (On the other hand, there are further economies of scale to be realised.) Fission clocks in around 141 to 221 $/MWh, which is why we aren’t building it, but $31 at the margin, which is why closing working plants is stupid. SMR focus on lowering capital costs through economies of scale. Fusion by reducing compliance costs. In all likelihood, the solution is fusion SMRs baseloading solar, wind and geothermal energy with peaker industrial processes running during the day. (Hydro can come too.) [1] https://www.lazard.com/media/2ozoovyg/lazards-lcoeplus-april-2023.pdf https://www.lazard.com/media/2ozoovyg/lazards-lcoeplus-april... slide 2 [2] https://www.gevernova.com/gas-power/applications/grid-firming https://www.gevernova.com/gas-power/applications/grid-firmin...
- fsh 2y ago
  SMRs are based on the wishful thinking that, for the first time in history, making an industrial facility smaller increases economic efficiency. It's just not going to happen.
  - sanderjd 2y ago
    I'm pretty skeptical of the SMR thesis, but I think there are plenty of examples of modularization and miniaturization being economically advantageous. For instance, I just the other day came across an article about how in the first wave of electrifying the textile industry, they replaced big centralized steam engines with big centralized motors. But then they realized that motors made it possible to mass produce small machines and put one at each station, and they turned out to be an advantage. I think there are a number of specific reasons to be skeptical of SMRs, but I don't think the entire concept is per se flawed.

ak217 2y ago

Solar and wind are not "unreliable" any more so than any other power source we've used in the past. Just like transformers have been replaced by power electronics in many applications, the reliance on flywheels for frequency stability will be replaced by grid-forming power electronics. There isn't anything magical about this technology.

sudosysgen 2y ago

Another thing that's easy to miss is that, unfortunately, renewables tend to be correlated. An event that reduces insolation over a large area, for example, will affect solar and wind over a large area. So simply over-building is a lot more expensive than it seems when you need to be able to handle tail risks.

gibolt 2y ago

Batteries can mimic inertia better than physical spinning objects. An operator in Australia has seen massive success and profits over the past few years using batteries to out-compete other grid stabilization. IIRC, they have already made enough to pay off the upfront costs. Even better, Australian government was super against the change, but now most places are positive on them because of the obvious success.