> These days, the cost of generating electricity from such sources (wind/solar) is roughly on par with that of fossil fuels.
I've never seen a cost analysis that takes into account the unreliability of sources that rely on sun or wind. I don't know exactly how a proper model would account for these factors, but surely ignoring the unreliability isn't the right answer.
One of the reasons that solar projects are so easy to finance is because of their predictability and the fact they can be accurately predicted to correlate with peak demand periods years in the future.
You only hit problems when you are no longer burning fossil fuels and so have no more to turn off. And that's a good problem to have.
I'm referring to the fact that the wind is not reliable or even predictable. The sun is more predictable, but weather can greatly affect solar power generation.
It is nice that the sun is up during part of daily peak demand and is strongest during the season when AC is heavily used. But IIRC peak demand happens several hours after solar panels are generating peak energy.
> You only hit problems when you are no longer burning fossil fuels and so have no more to turn off. And that's a good problem to have.
The point is that if you are looking at the cost of building a solar or wind farm you have to account for the fact that you cannot shut down another power source one-for-one.
If you have to pay for the new source and keep the old source online then the new source is by definition not the same price as the old source.
> But IIRC peak demand happens several hours after solar panels are generating peak energy.
No, peak 'net demand' happens later, because solar has reduced the actual demand peak. This is like saying "eating food just made my hunger peak later"
> If you have to pay for the new source and keep the old source online then the new source is by definition not the same price as the old source.
Yes, but the old source likely has high fuel costs, so when you stop burning the fuel, you not only save carbon and pollution, you save money.
Your first claim seems plausible, but apparently is wrong. Peak demand appears to be after noon all over. In some places it's several hours after. [1]
Your second point doesn't make any sense because the cost of fuel is already factored into the original analysis that supposedly equates the cost of renewable and non-renewable energy generation. If you want to mention that cost again, then I would mention again that supply crunches raise the cost of construction of solar and wind farms. All of these costs were already accounted for so it doesn't make sense to bring them up again.
The grid reported peak doesn't include home rooftop or other behind-the-meter solar, that's why the California grid demand peak has shifted later over the last few years, as well as (but not as much as) the net peak that doesn't count the utility scale solar.
You can also choose when you want the peak to occur to some degree, by positioning your panels in both location and direction. Semi-random alignment combined with solar noon happening over a hour for a timezone means the 'peak' is often rounded and flattened, and shifted in the direction of the solar compared with the load.
e.g. if you have a coastal area with demand on the coast and utility solar mostly inland, then you get a different timeshift between load and supply depending on where the coast is positioned in a West-East direction.
I'm not sure what you're trying to argue regarding price, but since renewables are cheaper than even running existing fossil fuel plants, I'm not sure it matters.
Imagine a salesman comes to your door selling residential cellular internet. He says it will cost the same as your existing wired internet, and will offer the same speeds.
The benefit is that it will have a lower carbon footprint because the ISP's power is provided exclusively by wind and solar. The downside is that it will only run when there is wind power or solar power available.
We dont need weird analogies, We're rolling out renewables across the world, at an astounding pace because its cheaper and better, and continues to get cheaper and better.
They are reliable only on average and on long time scales. On one particularly abnormal weather day, do you just say: "sorry, we only have 50% power today".
PV is so cheap that if it was only 50%, one would just install twice as much.
I think the actual number may be 90% (daytime; obviously more like 100% at night, for which you have some storage).
But at this scale you want multiple types of power anyway just to avoid correlated failures, cf. “all of our coal plants have had to shut down at the same time because the coal miners organised a national strike”.
Question then is: is the cheapest solution to this already green, and if not, what do we need to invent such that the cheapest solution is also green?
From what I’ve seen, batteries at this scale are currently on par with nuclear for cost, but that’s the easiest hurdle to pass given how expensive nuclear is. Global grid is theoretically fine, and the purchase cost isn’t ridiculous, but I don’t know anything about geopolitical issues so it could be anything from “a way to bring the world together” to “laughably naive”, and I don’t know anything about ongoing maintenance costs. Hydrogen is cheap, I don’t know the metallurgy issues. Hydro is great, but has its own issues.
This is only an issue once we stop having electricity sources that can be turned on reasonably quickly when wind or sun is under producing (such as natural gas and, to some extent, hydro electric).
Since wind/solar is still a small part of the overall contribution, there is no need to model unreliability.
The people who lost power and couldn't cool themselves down in 100 degree weather might not agree with your congratulations from afar. They might also not like that their energy costs are dramatically higher than even in neighboring states.
But if it makes you feel better, I guess that makes it all good, right?
I was being sarcastic. California gets 17% of their electricity from solar and 8% wind, but their current issues are during a sunny heat wave so solar should be going like gangbusters.
As noted elsewhere, solar peak is at noon and usage peak is hours later. Wind power happens whenever the wind blows.
The problem is that they have taken other more reliable sources offline. If the 25% you reference were more reliable they wouldn't have to warn people about power usage just in case it got cloudy or wasn't breezy enough. I read that they had to turn off a desalination plant because of the power crunch. That makes their drought even worse. Doesn't sound like winning to me.
Turning off desalination plant if it is easy to turn on-and-off seems like one of the smart use cases. Just need to have it to have overprovisioned size so that it can stock pile water when power is available at reasonable rates. And that really isn't a complex thing, we have been doing it for millenia now.
Do you demand with downtime for coal, for fixing the shoot? The scrubber? The ash removal?
Or for hydro? With dam work? Generator replacement (explosion at Hoover dam this year)
Or nuclear, for fuel rod changeouts?
While solar has more nightly downtime at non-peak demand, both wind and solar are often configured in volumes and geo distributions that reduce maintenance outage (a function of lower output per unit)
All of these examples sound like they can be scheduled. You cannot schedule the sun and wind. You can predict the sun of course and it's nice that it sometimes lines up with peak usage.
I've never seen a cost analysis that takes into account the unreliability of sources that rely on sun or wind. I don't know exactly how a proper model would account for these factors, but surely ignoring the unreliability isn't the right answer.