Solar and wind currently use fossil fuels to fill in gaps, but they don't require that. It's just that while we're still burning fossil fuels without CO2 charges, using them for gap filling is the cheapest thing that will do it.

It does until we achieve many times cheaper storage technology. Existing storage solutions don't provide nearly enough capacity to scale (especially since Li is very scarce, and is also required for cars and other modes of transport).

Hydrogen (or Methane) are an existing storage solution that scales very easily. The truth is that currently we have so little renewable generation capacity that we save more CO2 by building more wind turbines and PV per dollar than by building storage.

No, hydrogen and methane storage do not scale easily. Almost all hydrogen production is done through steam reformation, which emits carbon dioxide. Electrolysis has continued to be difficult to do at scale, due to inefficiency and difficulty in getting reliable electrolysis sytems. Then there's the issue of storing and transporting that hydrogen, which is mostly handwaved by assuming there's a salt cavern handy wherever people need to store hydrogen.

Synthetic methane requires hydrogen as an input, so all of the above applies to it, too. It also requires as source of carbon dioxide. Extracting carbon dioxide from the atmosphere is not viable, which leaves either scavenging CO2 byproducts from industrial processes and biofuels. Both of those are not in sufficient availability to produce synthetic methane at grid scale.

We already have excess renewable generation in several energy markets. And it's been the case for years, but the promised energy storage revolution has not come to pass.

Electrolysis can easily be done at scale. A couple of megawatts of electrolysis equipment is about the size of a shipping container. Many such systems are in operations right now and have been for a decade. The technology is fairly mature and reaches efficiencies of 70-80%. You also don't need salt caverns to store the hydrogen. You can store it underground without a salt cavern. Sure, there are losses, but they're not unmanageable.

We're also not going to run out of industrial processes that produce large amounts of carbon dioxide, at least as long as we still build things out of concrete, so if for some reason hydrogen is too hard to transport or store, we can pay the extra price of turning it into methane and use all the infrastructure that we already have for natural gas. We can even recapture most of the carbon when we burn the methane again.

This really doesn't scale to the level of a whole country, or continent, having to contend with low power output for months, as recently happened with wind in Europe. And even if it can in principle scale, it's unproven and requires much more complex ops than a nuclear plant, which has been a well understood solution for decades.

Not to mention, this requires huge over-production, which is a problem in areas with already high land usage, such as Europe. It is probably much less of a problem in the USA, so maybe there the calculations are different.

Nothing can ever happen for the first time. If something hasn't been done now, it can't ever happen.

I just love reactionary conservative nuclear logic.

I'd you're going to be the future of the planet on something, getting on a solution that has worked for over half a century is a lot safer than something that has never been done outside of prototypes.

"Let's just use fusion for all our energy needs. We don't need fission, nor do we need wind and solar. Just because it hasn't been done now, doesn't mean it'll never happen. If you don't support this you're just an anti-fusion conservative reactionary!"

But you see, going with renewables is not betting the future of the planet. We absolutely know that renewables can do it. The technologies all exist now. All that we're doing is quibbling over how much it would cost.

The worst case for renewables would be that costs stop declining. Stack the deck just right and nuclear might end up a bit cheaper. But this is just a financial risk, not a risk of the planet. And if one is looking at financial risks, one must also look at the risk of cost overruns in nuclear. Unlike with renewables, which typically come in within 10% of the contracted cost, nuclear plants are famously subject to enormous cost overruns. Factors of 2, 3, or even more.

Pretending that the promises of nuclear will absolutely come true, but that renewables haven't absolutely demonstrated their cost declines will continue, is a blatant double standard and not how one does proper analysis. That's why utilities and financiers have walked away from new nuclear, especially in markets where they're not allowed to foist overruns off on the ratepayers.

> But you see, going with renewables is not betting the future of the planet. We absolutely know that renewables can do it. The technologies all exist now. All that we're doing is quibbling over how much it would cost.

We have lots of experience with hydroelectricity. So we can just build more dams, it's all just a question of cost right? With more money we can just build more dams until we reach 100% hydroelectric generation right? This is the kind of logic you're using.

Possibility and feasibility are two different things. Lithium ion batteries exist, but we'll never deploy a day's worth of battery storage. The scale just isn't there. No amount of money thrown at the problem is going to make it possible.

Sure things like hydroelectricity and electrolysis exist, but they have significant barriers to feasibility. The likely path for an attempt at solar and wind grid is to build a bunch of solar and wind, try to build storage, fail, and keep using fossil fuels. Nobody, and I mean nobody has ever built grid scale storage for more than an hour's worth of electricity use (let alone total energy use). Energy storage remains an unsolved problem, and it's not just a question of cost. There's no telling if it can be done even with unlimited financial resources.

By comparison we just need to build 4 nuclear plants for every existing one in the US. No massive 10,000x increase in storage capacity required. No reliance on technology that's never been deployed at scale.

No continent currently runs on nuclear power, not even a single country currently runs on nuclear power. Nuclear power is hence unproven at scale by your logic.

France generates over 70% of it's power from nuclear energy. At it's peak it was over 80%, with the remainder fulfilled by preexisting hydroelectricity.

France gets 70% ef its electricity from nuclear. It only gets about a third of its primary power from nuclear. Clearly, the technology can't handle the task if the country can't even run its electric grid on 100% nuclear. /s

By comparison, the largest share of wind and solar in any country is only 43% in Denmark. Germany comes in second only 33%. https://en.wikipedia.org/wiki/List_of_countries_by_renewable...

So if 70% is insufficient to demonstrate feasibility, then solar and wind are even worse off.

In this thread I'm making fun of the assertion that proven technology can't scale. I guess I should've added more sarcasm markers.

Does not scale, I hear that a lot about everything that isn't nuclear. Maybe people said that to the semiconductor industry before the explosion in person computers or smart phones.

Nuclear has got to have the worse scalability story of any hyped technology ever. Very monolithic system with tight integration between components. Hazardous materials. Complex science and engineering that needs lots of different highly trained people. Exotic materials. High temperatures. Enabling works with quantities in the millions of square metres. Processes that are difficult to model. Endless secrecy for national security. Very strong buildings. Harsh design margins. Sites in remote areas with absolutely no night life.

We should be optimistic about nuclear. But also apply optimism to other technologies and industries. If the petro-chemical industry want to make hydrogen work they will succeed. So will the battery industry and solar. If nuclear can scale than so can they.

And yet for all the complaints about nuclear, France powers over 75% of it's grid with nuclear. Several other countries have it at around 40-50%. Nuclear continues to produce more electricity than wind and solar combined.

And yet for all the scepticism about renewables it has almost caught up with nuclear in a much shorter time.

But my wider point is that we need to be more consistent in how we apply scepticism and optimism to different technologies. In some dimensions that gives a benefit to nuclear and in others the benefit is with renewables or storage.

That hydrogen is currently produced by SMR is irrelevant. Electrolysis is of course trivial to scale, you just build more electrolyzers. There is nothing that prevents arbitrary numbers of them from being operated in parallel.

Would this cost money? Yes. But it would likely cost less than a grid based on nuclear power plants. The key insight is that hydrogen can feed combined cycle power plants, which cost a factor of 10 less than a nuclear power plant of the same power output. So, one could (if necessary) back up the entire grid with CC plants at a fraction of the cost of powering the same grid with nukes. If desired, one could use simple cycle power plants, which (while less efficient) are even cheaper by another factor of about 2, or 20x cheaper than the nukes.

What? How on earth is it irrelevant that almost all of our hydrogen comes from steam reformation? We have very little experience with large scale electrolysis, and its proven to be difficult and expensive to do at scale.

Those gas plants may be cheaper build, but if the electrolyzed hydrogen is expensive the total operating cost is higher since the fuel is too expensive. If you're using single cycle gas plants you'll need even more of this hydrogen, and thus driving up costs. Are you really just comparing cost of construction and ignoring the cost of electrolyzed hydrogen fuel? And remember this is on top of the solar and wind that needs to power this electeolysis in the first place.

Also again, to convert hydrogen to methane you need a large source of carbon dioxide.

A summary of this comment is, "it's cheaper if we just ignore all the technical challenges of synthetic methane."

It is irrelevant because the proposition is to use hydrogen to store surplus electricity, not to use hydrogen made from natural gas.

This is exactly the point I'm making: storing hydrogen for electricity storage has to be done through electrolysis, because steam reformation emits carbon dioxide. But we don't currently use electrolysis for our hydrogen production, because it's not cost competitive with steam reformation. It's not cost competitive with existing energy storage either.

Dude, we use natural gas because that is cheap. Why is it cheap? Because we externalize the costs of climate change. By that argument we should ditch nuclear and burn lignite. It's a lot cheaper and proven technology.

Nobody claimed electrolysis is cheaper than using natural gas. Nobody even claimed that electrolysis is cheaper than batteries at small scales. The claim is that electrolysis is proven technology that is a lot simpler to scale that lithium batteries.

I agree we should include the cost of climate change. That's why nuclear is cheaper than solar and wind: because solar and wind require either energy storage or fossil fuels. And since energy storage at grid scale does not exist, solar and wind contains the cost of climate change.

> The claim is that electrolysis is proven technology that is a lot simpler to scale that lithium batteries.

And my point is that this is false. Electrolysis is not proven technology at scale, almost all hydrogen is produced through steam reformation. No, it does not scale better than lithium ion batteries. If we try to build it at scale it'll make solar and wind more expensive than nuclear power.

You provide zero supporting arguments for your point. Megawatt electrolyzers exist today. They existed ten years ago. They don't use anything in large quantities of which supply is limited. You give no reason why we can't just build more of them.

A megawatt is basically nothing. Average load for electricity in the US is 500 GW. How much did that megawatt electrolyzed cost? Does it also include the cost of converting that hydrogen back into electricity? And remember this cost is on top of the cost of generating the stored energy in the first place.

You still didn't explain how "build more" is not an option, which is, you know, the original claim that we're debating in this comment chain.

But is it cheaper to build more electeolysis storage, and lots of overproduction in renewables? Well, until someone actually offers hydrogen storage commerically, there's no price. If it were cheap, we wouldn't be using steam reformation.

So at least now you accept that it does scale and it's just a matter of cost. Glad we could reach an agreement.

Maybe? So far titanium electrodes are the most promising solution, but titanium is a rather precious resource.

Oh good grief. Titanium ore is literally dirt cheap. Titanium has been pricey because of how it's made from the ore, not because the ore is scarce. Titanium is the 9th most abundant element in the Earth's crust.

The fact that it's scarce because it's so difficult and expensive to perform the chemical processes to isolate titanium doesn't chance the fact that it's scarce. Unless you have some novel way to drive down the cost titanium, building huge public projects using large amounts of titanium will remain infeasible.

Yes, because we can rely on fossil, nuclear, or hydro to give us reliability and pick up the slack when renewables falter. Just look at Germany, which just approved new coal plants because it needs more energy, and they are stuck to their demented plan of decommissioning nuclear plants.

It's also worth noting that France is producing less than half the greenhouse gases of Germany, despite having significantly less renewables, because it has a serious nuclear infrastructure.

It is also worth noting that a sizeable fraction of France's reactors are currently offline and France is dependent on imports to cover the gaps.

They will continue to require fossil fuels until energy storage comes along and we have no idea when that will occur. So far, all of our storage systems have proven inadequate.

You can't adequately model energy with a single price per MWh. There is more to it than that and that is true of all energy types. But the low cost of renewables is still a feature that grids can exploit. It will make storage viable when it otherwise wouldn't have been.

No source of energy is a silver bullet for climate change. Wind and solar aren't. And neither is the nuclear industry. There just isn't a serious plan for scaling up quickly enough. The supply chain and expertise just doesn't exist and will take years. And moaning about mistakes in the past is irrelevant to the present.