Comment by kulahan
12 hours ago
I don't know why this is downvoted. Solar and wind both essentially suck at anything other than baseline throughput. That doesn't mean they're useless, it just means that solar can't be our only solution unless we have, like... 30 breakthroughs tomorrow. We otherwise need something to handle spikes, which are both common and important, as well as periods when there is extended cloud cover even for typically-dark months.
Even if we handwave all the science needed to build batteries big enough to power cities for days, I don't think it's realistic to handwave the science needed to power a city for weeks. We don't even have enough oil for that.
"Power when it is inconvenient" is pretty much the basis for a modern society.
Solar panels still work just fine when it is cloudy, just with a lower output. And usually when it is cloudy it also tends to be a bit windy, so solar and wind nicely complement each other.
Heavy clouds and zero wind, for weeks? That's a once-a-century freak event. Just build gas peaker plants if you are worried about it. You could even add carbon capture, but constructing it might emit more than it will ever capture...
> Solar panels still work just fine when it is cloudy, just with a lower output.
I assume you never tried measuring the output of a solar panel when it's cloudy. It's 10-15% of a sunny day. Closer to not working than working.
Depends on the cloud. Where I live I routinely get 50% generation on a "cloudy" day.
On a rainy day that drops closer to 20%.
As an aside - cloudy days avoid a problem I have with shade. In winter, at 3:30pm, the sun goes behind a tree and my production plummets to near zero. If there's cloud cover the sunlight is far more dispersed and there's no "shade".
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Worst I've had over a day in the last few months on my home solar is about 25% of my maximum daily generation. It was one day in a very rainy week here in Brisbane Australia.
I did have one rainy day back in the middle of Winter that was 16% but that will end up being literally the worst day of the year.
That's every single winter where I live in the US. We don't have a word for it like the Germans do, though, we just call it January.
The good news is: you're on a national (or semi-national) grid, and conditions like that are more unusual than they are common across the USA.
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Carbon capture makes little sense until fossil fuels have been replaced. I guess there are some Bio char technologies that might change the equation a bit, but watt for watt, you need to replace your carbon emissions first (generally speaking)
A week of low solar and low wind is a yearly or every-couple of years event that you definitely need to solve for a completely renewable grid.
A completely renewable grid is less important than electrifying the low hanging fruit of heating and transport.
Anything below 800g of CO2 (which means basically every current grid) means electrifying is a net win. Even the famously coal heavy South African grid is already past that barrier and even if it wasn't all grids are getting cleaner over time.
A grid that has maxed out wind and solar and then used only coal for 2 weeks would be one of the cleanest grids in the world right now, on par with France or Sweden.
Chasing 100% on a grid to satisfy the complaints of people who are concern trolling isn't smart nor necessary. What you need is bulk cheap electricity to allow you to reduce your heating and transport costs and clean your air at the same time.
Keeping coal plants around is cheap to cover that. Longer term things like producing ammonia during summer and converting it to electricity in fuel cells will allow to remove needs for fossil fuels completely.
I’d keep gas plants around, but anyway, you need to cover that case and can’t just handwave it away.
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Strictly speaking - a battery is stored potential energy
A common battery for grid level storage is pumped hydro - that is, use the peak power during the day(s) to push water from the bottom of an elevation to the top, and hold it there - bonus points if it captures water delivered from other solar processes (evaporation -> rain)
There are about 90 billion battery solutions - none of them are very efficient, cheap to manufacture, easy to manufacture/acquire materials for, and long-lasting all at the same time.
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Typical non-informed incorrect opinion.
The overwhelming majority of generation and storage is best deployed at the point of use.
Grid scale anything, is a massive inefficiency.
The only reason grid and city scale is so prevalent in public discourse is because this is the only electricity the utility is paid for, and they are very actively impeding any other solution.
In the US, there is a very large inventory of flat roof industrial buildings, in the industrial parks that are using huge amounts of electricity. Covering all of those roofs with solar (especially here in the west US) would prevent a tremendous amount of grid scale generation, and implementing storage there would eliminate a large part of the transmission line upgrades the utilities are calling for.
The biggest problem in the US isn't technical, it's the governments desire to primarily support the solutions that are best at serving utility shareholder returns, instead of the technically superior solutions.
How common is it that these industrial/commercial buildings have roof-top solar? If not common, what stops it?
It's quite common in Australia for commercial and residential.