[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.