[AnthonyMouse]

I'm consistently hearing two claims here. One is that we'll have energy to do carbon capture because we may need to overbuild renewables by 3-5x to account for intermittency and then most of the time we'll have a lot of surplus power, and the other is that the only solution is for people to drastically reduce energy consumption.

Clearly at least one of these is wrong, because we can't simultaneously have a big surplus and have to reduce consumption, so which one is it?

[strken]

Why can't we have an energy surplus and also need to reduce consumption of carbon-intensive goods? It's not clear to me why they'd be mutually exclusive.

If e.g. smelters still need to use coal, then an energy surplus doesn't help them. If carbon capture is expensive even with virtually free power due to wages and infrastructure, the capture cost was reflected in the price of steel, and demand for steel is elastic, then we'd both capture more carbon and reduce steel consumption.

[AnthonyMouse]

> Why can't we have an energy surplus and also need to reduce consumption of carbon-intensive goods? It's not clear to me why they'd be mutually exclusive.

The vast majority of carbon-intensive goods are related to energy production. Even when people talk about things like transportation and agriculture and construction, a major proportion of their CO2 emissions are from burning fuel.

> If e.g. smelters still need to use coal, then an energy surplus doesn't help them.

Smelters are using coal for heat. Burning it directly on site is more efficient than burning it in a power plant, losing most of the heat to conversion inefficiency, losing some of the electricity to distribution and then turning what's left back into heat.

If you had cheap electricity that didn't come from burning coal they could just use electric heat. At which point there would be no need to reduce steel consumption.

[hakfoo]

Part of it is the time dimension.

Electricity infrastructure used to be defined by the factories that run from (say) 9AM to 5PM. The grid has to be sized mostly for their needs, and baseload power (fossil, atomic, hydro) are sized for it, This is slow and costly to spin up and down. You see this reflected in things like utility "time of use" plans, where they offer you dirt-cheap energy at 2AM if you're willing to pay a penalty at 3PM. They'd love for you to sop up the glut by running a Bitcoin miner or chilling your house to 15C overnight.

Renewables move on a dime by comparison. If we need n GW of power at the peak time of 5PM, depending on the yield factors of local solar/wind/tidal/etc, we may end up with an infrastructure that generates 3n or 5n at other times of day. A lot of thinking has gone to batteries/molten salt/pumped hydro as ways we can store that surplus for later needs, but we can also direct the glut into processes that are energy-intensive and only economically viable in a power-too-cheap-to-meter scenario.

The CO2 scrubbers could be a viable sink for that excess power once we've got enough grid-scale storage.

[AnthonyMouse]

You're just making the "we're going to have an energy surplus" case.

We already have storage technologies that could compete with present-day energy prices if charging them was near-free. They're currently not competitive because it isn't, but in your scenario during off-peak it would be. So why would anybody have to reduce consumption then? Buy a battery, charge it when power is dirt cheap and use as much as you do now for no more than you pay now.