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Comment by philipkglass | Hacker News Reader

15% capacity factor is reasonable for rooftop, but utility scale PV in the United States was at 27% last year: https://www.eia.gov/electricity/monthly/epm_table_grapher.ph...

Emissions are pretty obviously not going to peak by 2020, unless there's some sort of civilization-smashing catastrophe in the next few years. Large scale active carbon dioxide removal measures will be needed later, or natural processes will eventually restore the pre-industrial equilibrium over ~100,000 years. We're not going to stay in the "safe" zone below 2 degrees. Reducing future emissions is necessary but not sufficient. I say this as someone who fully wishes that humans had cut emissions quickly enough to render active CDR measures unnecessary, but recognizes that we did not act in time.

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27% is better, though from a quick look it applies only to the US, and in Europe it looks closer to 15%. I need to take time tomorrow to find good sources on this.

I'm not convinced by carbon storage, though I don't know enough about it to be sure. It is my understanding that it is either energy-hungry (so useless because we don't and likely won't have enough carbon-neutral energy surplus) or pretty slow (also useless). And completely unproven at large or even moderate scales, too.

Germany has the most PV installed of any European country. Utility scale PV facilities in Germany may reach only 10% capacity factor. But most of the world's present and future electricity demand centers are significantly closer to the equator than Germany is.

"Carbon storage" would normally refer to physically sequestering purified carbon dioxide or other carbon bearing compounds. I agree that storage of that type is not practical.

Enhanced silicate weathering is IMO the process with the best prospects for large scale atmospheric carbon dioxide removal. It is relatively slow but the thermodynamics are favorable and the kinetics are still orders of magnitude faster than waiting for unaided nature to restore the pre-industrial equilibrium. Enhanced weathering CDR just accelerates the kinetics of the natural chemical reaction that turns alkaline silicate rocks and CO2 into silica and alkaline carbonates. Doing it on a scale large enough to make a difference would be a gargantuan undertaking, of course, because the scale of the problem is also gargantuan.

That's interesting, thanks for the information, I'll probably spend a good portion of tomorrow reading up on this. Geoengineering is scary.

Honestly, I am extremely pessimistic about mankind's ability to work on such a scale. Too many people seem to assume global warming is still a far-off problem, and that for some reason humanity is destined to "progress" forever, even though we know of many civilizations that have collapsed before ours.

I'd just like more people to grasp the dire reality of the situation, and stop assuming that somehow technology and/or progress will save us no matter what.

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