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Comment by coryrc | Hacker News Reader

If we're using renewables, we need seasonal shifting, so cycle life doesn't matter at one cycle per year.

You could build nuclear to supply your winter power, but then you're overbuilt for summer and don't need any renewable. Or you could store heat directly in the ground like that Alberta pilot project, heat collectors on the roofs all summer drive the heat underground, pump it back out all winter.

Or our current plan, pretend to be "green" by spending money on solar while increasing coal usage and no feasible plan to replace space heating.

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We don't need seasonal storage. The sun still shines in the winter, unless you're in the Arctic circle. We can use over building, production diversity, interconnection and short term storage instead. Or just use natgas peakers for the last 1% and call a 99% solution good enough.

If we had reasonably priced seasonal storage we'd use it, but we don't need it.

In winter cloudy conditions solar PV produces 10-15% power. Assuming some hydro storage, that's 4x overbuild. Not cost effective.

Europe all gets winter at the same time. If you've got a cold snap for three weeks with low wind, the only plan is reliance on massive fossil fuel backup. The cost of keeping that capacity for only using a week a year isn't priced into solar either.

The CO2-intensity of electricity generation in France stood at around 57 CO2/kWh in 2020 (source: Statista). In Germany, the electricity mix at the same time had a CO2-intensity of 366g CO2/kWh, which was more than six times higher

But yeah Germany's approach is really working!

> In winter cloudy conditions solar PV produces 10-15% power

Depends on the latitude and these numbers seem to be for very high ones close to the polar circles.

> Not cost effective.

Are we pricing in the societal collapse due to climate change? I’d suspect a 4x overbuild would be quite cheap against that.

OTOH, keeping some natgas capacity for when a freakish cold snap with no wind hits seems kind of OK.

> Depends on the latitude and these numbers seem to be for very high ones close to the polar circles.

No, those values are far from polar circle. I'm guessing closer to central Europe, since for example in Finland the PV produces 0% during the winter months.

10-15% would be insane to get here, but there simply isn't any energy in the sun (and closer to the polar circle you get - there's no sun at all during winter) and the panels are often covered in snow in any case. And I'm not even talking about cloudy days now, but "sunny" ones.

March/October are already approaching those 10-15% levels. Nov-Feb is closer to 0% in most of the Finland.

Finland (the south of it anyway) has about a gigawatt of HVDC lines connecting it to other countries, about 200W/capita.

GP is clearly talking about cost-effectiveness compared to other solutions, such as France's approach and seasonal storage.

> The cost of keeping that capacity for only using a week a year isn't priced into solar either.

Keeping gas power plants around for backup power isn’t all that expensive since fuel accounts for two thirds of their cost of generation.

Offshore wind is far more expensive than onshore wind and solar but even so costs about a third of new nuclear power, with strike prices in the UK of £37/MWh vs £106/MWh for Hinckley Point C. Maybe keeping gas backup adds another £15/MWh to that but it still works out at half the cost of nuclear.

By building more France will probably get nuclear costs down some, but even so will struggle to be competitive with renewables and backup.

> But yeah Germany's approach is really working!

Germany’s approach of keeping coal plants around while closing existing nuclear is extremely dumb.

> Or just use natgas peakers for the last 1% and call a 99% solution good enough.

Sadly, no. Given how long the CO2 stays in the air, anything less than 99.9% over all emissions from all nations — and that also includes cement and iron chemistry leading directly to CO2, cattle biochemistry leading directly to methane, etc. — then we're not pushing hard enough.

Natural gas is great as a way to buy time, but we can't let it be more than a rounding error in the ultimate ensemble… well, not unless there's corresponding CO2 capture.

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