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Comment by Qwertious | Hacker News Reader

Focusing on batteries is thinking too long-term IMO. If you have 50% renewables or less in the grid, you basically don't need batteries yet, and our deadline isn't time here but greenhouse gases emitted - getting to 50% renewables will give us more time to tackle the rest of our emissions. I expect nuclear to easily beat solar/wind+batteries for the last 10% of the grid, but frankly the last 10% of the grid almost doesn't matter - if we've reduce our emissions by 90%, then we have 10x the time to tackle the rest.

Of course, I've been wildly conflating electricity with all emissions, but I think the low-hanging fruit argument still applies.

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But you can't run the grid on 50% renewables without solving storage. It's just not possible: the grid has to run. Peak usage isn't in the middle of the day, it's around 6-8pm when people are home. In winter that's pitch black, in summer depending where you are there's still very little solar output, so you better hope the wind is blowing. And it is...mostly, but not on demand.

Germany's power grid has started to struggle because they're at 30+% solar capacity, but not reliability - the grid can't sustain losing large swathes of generation capacity suddenly because a cloud passed overhead, or if a region is overcast that day then you've got to make up that shortfall - which you can do so long as you have basically the same installed capacity of gas, coal and oil on standby where they can just turn on an extra-turbine or boiler on demand.

But if you want to actually decarbonize, then you need to solve that problem. Otherwise you end up with the perverse situation that increased renewable investment necessitates new fossil fuel power plants, because you still need to backstop the intermittent sources.

The NSW Australian power grid has this problem right now: the reality is that no one wants to invest in fossil fuel power plants. Great! You'd say. But the grid actually does need a new reliable generator and power price pressure is a big political issue. Getting reliable watt-hours onto the grid - not more intermittents - needs to happen. The catch-22 is people rightly don't want to subsidize more fossil fuels, but the available renewable options are being installed anyway - but they won't solve the actual availability problem we have (and in a country with bush fires it's a big one - 3 months of summer with overcast skies along the east coast from smoke means no one's solar panels were working well, and grid-interconnects have limited capacity).

> But you can't run the grid on 50% renewables without solving storage.

Counter-example: Brazil's national grid routinely runs on over 85% renewables with essentially zero storage (there might be a couple of experimental battery storage units, but if any they're much less than 1%; and all it has of pumped hydro storage is one partial preliminary study of possible locations).

65% of Brazil's energy is coming from hydropower, which is extremely reliable, but geography dependent. When people make that statement, they're usually referring to wind + solar, which are intermittent.

This right here is an example of a lie of omission: over what time frame? With what renewable?

Oh right - hydroelectricity. Providing 65% of it's total electricity.[1] Wind is 11% and solar is 2.5%.

And they're also building a new nuclear reactor at their existing plant.[2]

[1] https://en.m.wikipedia.org/wiki/Renewable_energy_in_Brazil

[2] https://en.m.wikipedia.org/wiki/Angra_Nuclear_Power_Plant

> This right here is an example of a lie of omission: over what time frame?

Sorry about that. It's the average over a whole week (I looked at the weekly bulletin of a random week from last month, but they're all similar).

> With what renewable?

Around 62% hydro, 22% wind, and 1% solar (we're in winter right now, so we have less solar and more wind; on summer we'd have more solar and less wind).

> And they're also building a new nuclear reactor at their existing plant.

And that reactor is the main reason I'm very skeptical of nuclear power: it's been under construction for nearly 40 years, and it's still not near done. All the parts have already been bought and have been stored on site for a long time; just the upkeep to make sure none of these parts degrades while under storage is already a high cost.

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