[sir_bearington]

No, it's not "worst case we spent a bit more". Total global lithium ion battery production amounts to less than one hour of storage for the United States alone. Things like pulleys and synthetic methane remain in the prototyping stage.

By this logic why not just use fusion? It's possible. We don't know which exact approach we'll use (lasers, magnets, etc.). We don't know how cheap it'll be, but hey it'll happen eventually right? No.

It's not "worst case we spend more money". It's "worse case we never solve climate change". And that's a pretty bad worst case.

We're already at the point where markets are starting to see saturation with renewables. But this unfounded aversion to nuclear power is hampering actual progress to decarbonization. The cost of waiting around and hoping for storage to become viable is not just the cost of building those storage systems, but also the continued release of fossil fuels as we wait for that to happen - and who knows when that will happen, if ever.

[pfdietz]

No, it is "worst case we spend a bit more". We absolutely know that storage is possible. Pumped thermal electricity storage, for example, uses only well understood technologies.

We solve climate change by raising CO2 costs high enough. Again, this is not a go-no go thing, it is just haggling over the price.

> We're already at the point where markets are starting to see saturation with renewables.

This just means CO2 taxes aren't high enough. BTW, they'd have to be $300-400/ton for new nuclear to compete with gas in the US.

[sir_bearington]

No, pumped storage is not feasible. It's both geographically limited, and it's not available at the appropriate scale. Estimates for how much storage would be necessary for renewables to work range from 12 hours to weeks of storage depending on the solar and wind mix. The US has ~25GWh of hydroelectric storage. There are no active hydroelectric storage projects at the moment, only proposals [1]. This is why proposals to decarbonize through intermittent sources always assume a nearly-free mechanism of energy storage.

It's easy to make renewables look cheap if you assume some wundertech makes storage free. Will thermal storage, synthetic methane, or who knows what else fulfill this need? Who knows, but they don't yet. Thus renewables only present a solution coupled with an engineering breakthrough. It's like assuming moore's law held true and developed an app that assumed it'd run on a 1THz single-core processor presumably developed a decade in the future. Seems reasonable in 1995, but that's have been a very bad bet.

1. https://en.m.wikipedia.org/wiki/Pumped-storage_hydroelectric...

[pfdietz]

Pumped THERMAL storage. This is not pumped hydro. Rather, it involves a heat pump, for example compressing argon near-adiabatically, transferring the heat to a hot store (cooling the argon in the process), then expanding the argon back to the starting pressure. The argon is now around at mildly cryogenic temperature, and the cold is transferred to a cold store (liquid hexane, perhaps).

To recover energy, this is reversed, with the temperature difference driving the cycle in the other direction. Detailed calculations with inefficiencies show an overall round trip efficiency of 60% or better could be achieved. All the temperatures are below the creep limit of ordinary steel, so this system would require no exotic materials whatsoever.

It's also possible to design a thermal storage system without the cold store, using the ambient environment as a heat sink when running the generator. In that case, adding a backup heater (burning hydrogen, say) would make the store double as a backup generator at extremely low extra capital cost.

[sir_bearington]

Right and who can I call to install 1 GWh of thermal storage? I can't, because this technology only exists in prototypes. The only actual use of thermal storage is in solar thermal energy, which hasn't experienced the massive drop in price that photovoltaic solar has.

[strken]

You or I could go out today and buy off the counter parts, build a scale model of a pulley system, and use it to store power. We could have done that a century ago.

To the best of my knowledge, fusion only demonstrated net-positive energy production this decade, and hasn't yet reached ignition in a man-made device.

They're not the same.

[sir_bearington]

Yeah you and I could built a simple pulley system and store gravitational potential energy. Physics works, I know I'm not surprised. But we couldn't use it to store moderately enough energy to be useable to decarbonize our energy footprint. And building them at scale is a gamble on unprecedented application of technology.

It's like trying to be carbon neutral through burning biomass. Yeah, it works as a general principle. But the energy density just isn't there. The US consumes about much energy each year as we'd get from clear-cutting the entire country over the span of a single year. And the plants take longer than that to grow. Sure, we could try more exotic things like dumping iron into the ocean and harvesting algae blooms. But as a general principle, biomass energy source doesn't scale well.

Same with energy storage. Nuclear isotopes are a great store of energy. The best we know how to tap into in term of energy density, that's why we use it on submarines. Chemical energy like methane is good, but the sabatier process isn't that feasible and it needs a pre-existing source of carbon dioxide. Electrochemical storage like batteries is great for systems that need to store a relatively small amount of energy, like cars and electronics. But it isn't available at nearly the required scale. Hydroelectricity storage is better for scale, but still not good enough. And I'm sure you can name other proposed systems like pulleys, hydrogen, compressed air, an d more. But the point is that until they've demonstrated commercial viability let alone beaten competitive solutions it's a big assumption to factor these into solutions to climate change.

Are people accepting contracts to store X GWh of electricity in pulleys, or or compressed air and operating those projects successfully? Until then, these do not represent presently available solutions to climate change. I'd be happy to be proven wrong, but until then saying we have a realistic plan to provision enough energy storage to decarbonize through renewables is counterfactual - at least save for places like Norway or Iceland that have dispatchable sources of renewable energy nearby in the form of geographically dependent hydro and geothermal power.

[pfdietz]

Biomass has low energy density, but that has nothing to do with non-biomass renewable sources, or with storage. The implication that the low density of biomass carries over is a deception.

The argument that nothing that hasn't been commercialized can be considered is a double standard. Nuclear on the scale needed to replace fossil fuels is also currently impossible. The infrastructure to build it isn't there, and the breeder reactors that would be needed to fuel it aren't commercially available either.

[sir_bearington]

> Biomass has low energy density, but that has nothing to do with non-biomass renewable sources, or with storage. The implication that the low density of biomass carries over is a deception.

No, it's not deception. Both solar and wind suffer from low energy density, especially as compared to nuclear. 200 Watts per square meter isn't all that good energy density.

> Nuclear on the scale needed to replace fossil fuels is also currently impossible.

Again, France just mysteriously doesn't exist in the alternate reality that hardcore renewable supporters live in. Globally, nuclear generates more than solar and wind combined.