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There's always the opinion that solar is useless on cloudy days. It's my understanding that on a normal cloudy day they're only 25% as efficient as when sunny, and 10% when it's really cloudy. So, not great, but it's something that is being improved upon all the time.

> In some cases, clouds can actually result in better panel performance than standard sunny weather. A cloud can reflect or sometimes even magnify sunlight, which results in additional power output from your solar panels. [0]

In my country (Oz) we have two states that are into solar: SA has a tesla battery plant (built in <100 days) [1], but more as a 'surge saver', and WA which has recently mentioned it's about to reach serious trouble because solar is now getting in the way of it's existing non-renewable coal (meaning there's an over supply). WA doesn't have battery storage up and running, whereas in SA the tesla plant can ramp up demand almost instantaneously and is saving a bucket load of cash per year (because the coal plants don't need to spin up another turbine to meet demand: something which takes hours to achieve AND is costly)

> "We know that the 100 megawatt capacity of the existing Hornsdale battery has saved South Australian electricity consumers $40 million per year since its inception," he said. [1]

[0] https://news.energysage.com/solar-panels-work-night-cloudy-day/

[1] https://www.abc.net.au/news/2019-11-19/sa-big-battery-set-to-get-even-bigger/11716784

In short, the good thing about solar…

It's tougher than that. They are outdoors and have to stand up to weathering and storms. In the case of dual axis trackers they have an additional degree of freedom.

Finally, an the toughest, in my opinion, is how little net energy budget they have to work with to be economical: they have to require less energy to build, install, and operate than the incremental solar energy they generate over their operation life. They give an approximately 40% production improvement (that's roughly the single/dual axis midpoint. towards the high side), so if you say a 10 yr life with zero maintenance and controlling a single 250w panel you're talking 9 mWh, or $1080 retail electricity value generated. A 40% improvement on that is only $440 worth of energy budget per tracker over a 10 year life.

That glosses over a ton of complexity like if area is amenable to ground vs rooftop, if it's higher latitude, high density panels, stationary panel/tracking mirror, and most importantly having multiple panels per tracker. Zero maintenance/replacement is not realistic, either, since it would cycling dozens of times a day and could be in hurricane/tornado areas.

But given a lower end garage door opener is $150 before installation costs, it gives an idea how tough that would in that price range. Consider that panels are generally engineered to withstand 100+ mph gusts, and this would be a relatively finely tuned machine attached to one or more 18 square foot kites that would be expected to withstand…

Um fusion being close to being viable, which your link is supporting, doesn't mean it's close enough to help us this century with regarding climate change (which is what your link is about), which isn't what I said it would do. I apologize if I worded it a way that you felt implied that.

South Korea I understand is investing heavily here[1]. If I'm not mistaken so is China. Too bad we (Western society) can't work with Iran on this as well.

However, please consider when we talk about changing our sources of energy over, that what will work has to work within costs and regulatory conditions.

If I'm not mistaken it can take around 20 years for an experienced nuclear capable nation to get a reactor up and running from initial phase of saying yes you can build a reactor.

Solar is outpacing that.[2]
Which your link also supports.

"The pattern of power supply is changing. The massive take-up of solar power by households means we have now permanently shifted from the old model of large power stations to one where supply is distributed around the network. "

Fission (by itself) is not solving climate change this century either.

Additionally I think fission powered cargo ships would be a great option to reduce carbon emissions too. Since the U.S. Navy is very experienced with nuclear powered vessels and Russia has that nuclear powered icebreaker, I think it's technology possible.

Unfortunately setting up a regularity system for that is likely completely unrealistic though I'm…

I've just run my own numbers. But looking at your image, something seems seriously seriously off on the solar side. I get roughly similar numbers for nuclear; e.g. 250 thousand metric tonnes concrete / TWh for an AP1000 and 5x that for Sizewell B, using concrete mass numbers from [0]. Averaging these two designs is really close to their 760 number for concrete.

For solar, let's take some average random numbers, 800 pounds for a 6kW array on a roof [1]. So starting just with the panels, a 25% capacity factor over 30 years will generate 394 MWh == 0.000394 TWh. 800 pounds is 0.000363 thousand metric tonnes. So converting to the units of thousand metric tonnes / TWh, we are at 900 thousand metric tonnes/TWh for the panels for solar. Add another 10% for inverters, double that for framing if you're installing in a field rather than on a house, and I don't know where they are coming up with their stuff. 2700 tonnes/GWh for glass alone is ludicrous.

I'm not sure where that report comes from, but it would be worth checking the sources. After a basic sniff test, I'm going to dismiss it. Maybe it's using weights from 1980 solar panels or something.

[0] https://web.archive.org/web/20110722031413/http://www.nuclearinst.com/uploads/Branch%20Presentations/The%20AP1000%20-%20A%20Bull%20-%2016th%20Nov%2010.pdf

[1] https://news.energysage.com/average-solar-panel-size-weight/

Edit: and honestly, both weight / Wh and land / Wh are fairly meaningless numbers for both technologies. What…

Monocrystalline Si solar panels have so many advantages that it's hard to get interested in anything else for home or business construction. Lifetime is measured in decades, not years; efficiency is approaching 25% while prices are dropping (only expensive multi-junction III-V types are better, currently limited to satellite power systems); and for variable surfaces, they can be manufactured as small shingles as well as the standard size panel.

Unfortunately the USA, due to decades of minimal R&D funding, is well behind the technology curve in this area:

> "Some Chinese companies are defying the “more efficient = more expensive” rule in 2022. High efficiency solar panels are entering the market from companies like LonGi, Canadian Solar, and Trina Solar that surpass the 20 percent efficiency rating, but cost less per watt as opposed to SunPower, LG and Panasonic panels. Solar is cheaper than ever without sacrificing efficiency ratings, which begs the question if U.S manufacturers will be able to maintain their pricing premiums."

https://news.energysage.com/what-are-the-most-efficient-solar-panels-on-the-market/

Of course a boom in solar PV installation in the USA would pull the rug out from under natural gas prices, which more-or-less explains government policy in this area.

> If it's the latter, then reduction of 1 kWh delivered should save them the same amount of money.

The "net metering" policy being changed isn't regarding "saving the grid the money by reducing the amount delivered to a customer." If you don't use the power from them, you don't pay for it. But this is about the utility paying the customer the retail rate for excess generation - aka paying retail rate for something that would offset a cost they'd otherwise pay wholesale rate to generate. This is about the current (not the new) system: https://news.energysage.com/net-metering-2-0-in-california-everything-you-need-to-know/

It's not clear to me at all that it makes sense to compel the utility to purchase your excess power at the retail rate, if you're generating more than you can use. It also seems to gives weird incentives to size and spend on your home setup.