Researchers map where solar energy delivers the biggest climate payoff
rutgers.edu
rutgers.edu
Whoa, that's really cool.
You can see the paper along with figures & regional breakdowns here: https://openpaper.ai/paper/share/1d0c6956-4820-4ee2-ac1e-12c...
The savings is minuscule. But important nonetheless. It just goes on to show how much more solar is required.
If you replace 0.5% of things that emit carbon with non-carbon sources it reduces carbon emissions by 0.5%.
Put another way, if I could grease the right palms to shave commensurate minuscule savings off of the budget of ICE, it'd pay off my mortgage. Twentyfold.
Back to greenhouse gases, I'm no climatologist, but isn't it plausible the difference could, for instance, make or break one catastrophic wildfire across the western seaboard of North America?
Beware of statistic thinking in a stochastic world.
We need vastly less total primary energy to run a 90-95% efficient BEV compared to a 20-30% efficient ICE.
That is excluding the entire very inefficient supply chain to refine and transport the fuel to the ICE.
While true, that requires actually transitioning to BEVs, which in turn requires having enough batteries to transition to BEVs.
Doing that in the USA is (~290M vehicles, say 60kWh each, ~= 17.4TWh) more than enough to provide the entire USA with several days worth of backup storage, even if the place somehow got a continent-wide version of a Dunkelflaute that wasn't merely "20% normal output" but "actually no output".
I am hopeful this will happen, but last I checked, it was further away than the PV itself is, what with the batteries needing replacement every few thousand cycles but the PV mostly lasting 25-35 years no problem.
The global battery manufacturing capacity reached 3 TWh in 2024.
With say an average lifetime of 15 years getting a bit over 1 TWh of new batteries per year for the car fleet seems easily feasible.
Then please give us a source for regarding your continental dunkelflate doomsday scenario so we can make sure is a plausible scenario, and not made up scary numbers.
Of course ignoring that you assume that we need to charge every single car to 100% every day.
OK, that's better than I thought, I was led to believe it was 1 TWh in 2024.
> With say an average lifetime of 15 years getting a bit over 1 TWh of new batteries per year for the car fleet seems easily feasible.
I think that's optimistic; none of my (non-car) batteries have maintained significant capacity for that long. I think grid use will look more like phone or laptop use than like car use, with daily full cycles?
> Then please give us a source for regarding your continental dunkelflate doomsday scenario so we can make sure is a plausible scenario, and not made up scary numbers.
I think you're misunderstanding me on this. I'm saying it's good enough even for a very weird and unusual condition far in excess of the normal talking points.
> Of course ignoring that you assume that we need to charge every single car to 100% every day.
No? I'm saying I expect an average car to get a 60kWh battery pack, and that there are 290 million vehicles in the USA, and that this makes a combined manufacturing requirement of sustaining a capacity of multiply-those-numbers-together storage. This says nothing about how often that storage will normally get charged, and instead I was saying how long this could power the USA for if discharged in a very weird condition.
Actual power consumption of those vehicles is tiny, something like 80% of mean consumption (in places where shaded parking isn't the norm) could be supplied by requiring their surfaces to be covered in PV.
First, the US isn't northern Europe (where solar energy is very popular regardless). Especially the southern half is more comparable to southern Europe or even North Africa. Places like Berlin are at 52 degrees latitude. You have to go deep into Canada to find cities at a similar latitude. Most of the US is below 49 degrees and gets decent amounts of sun. It's more than fine most of the year. If you regularly need to wear your sun glasses in January, you live in a place that can have solar power.
But sure, the Sun doesn't always shine and it gets grey and cloudy sometimes. Even in San Diego. But there are also wind, and batteries. And people always forget that you can use cables to move energy around as well. And a lot of cables aren't at their maximum capacities all of the time. So, they can be used to move energy around when it isn't needed and be used to charge batteries close to where it is needed later. San Diego is basically at the same latitude as places in Northern Africa that might end up supplying power via HVDC cables to Europe. The US can mix off shore wind on both coasts, solar across the south and its deserts with hydro in mountainous regions and lots of batteries. At this point very doable already and long term only getting more obvious to do as cost and efficiencies continue to improve.
Finally, modern batteries already last quite long. LFP and sodium ion are basically getting lifespans of 5000 or more cycles at this point. That's basically decades with normal usage and over a decade even with full daily cycling (which would be intensive usage).
Sodium ion means lots of dirt cheap batteries for storage and (small) vehicles. Basically it uses no rare materials and lasts a long time. It has the potential to decimate the cost of batteries from close to 100$/kwh to more like 10$/kwh by some estimates. At 10$/kwh, most house holds would be able to afford to have a mwh battery - enough to power an inefficient US household for a month. And a more efficient household throughout even the longest imaginable type of dunkelflaute. You can't quite get those yet of course but at this point we have some reason to be optimistic about this being possible mid to long term at least.
Add nuclear, hydro and geothermal to the mix and you have a lot of clean ways to generate and move around clean energy. That kind of system takes time to build but there really aren't a whole lot excuses not to.
This transition period has a lot of people looking in the rear view mirror being blind to the huge stuff that is clearly visible ahead at this point. There are a few wild cards that are interesting but not that essential. Like small reactors, fusion, etc. Nice but not really that essential.
The dunkelflaute is an interesting technical and infrastructure challenge that requires some out of the box thinking. But it's very solvable and it doesn't require any major new technology breakthroughs. We just need to do more of what we're already doing and preferably a bit cheaper. All very doable and within reach. And we have time to do it as our old infrastructure isn't magically about to disappear. Most of this stuff will be cost and economics driven.
Lots of countries that are ahead of the curve might be importing progressively less oil in the decades ahead. That means their trade balances shift and they start having economic growth and a competitive advantage.
IMHO countries that are lagging here will first fall behind, suffer the economic consequences for a while, and then fix it by compensating with massive investments. The US seems to be doing all the wrong things to set itself up for exactly that right now. Which is why I'm quite optimistic it will figure it out eventually.
The tech is great. I'm usually the one defending it, even. But you do actually have to build the factories. Which we (humanity, I'm not American) are, as fast as we can, but that's the trend-line to look at, not what the tech can ultimately do.
I mean, to one of your points, I'm one of the few people here who keeps saying that if China wanted to make it a strategic goal, they have the manufacturing capacity to put in a genuinely global power grid with 1Ω electrical resistance for a fairly low material cost (few hundred billion), what a shame about the geopolitical realities getting in the way of this…
This seems like questionable reasoning to me. If California has 100 MW of solar power for every 10 MW in Indiana, a 10% increase in solar will show up as 10x more CO2 savings for California just because it has a larger installed base.
To me the relevant question is the relative dirtiness of the nonrenewables being replaced, and the relative cost and effectiveness of solar. IMHO the data ought to be normalized to a per-MW-installed-rating basis.
I wish the study went like this (all the following numbers are completely made up, based on nothing more than the fertile imagination of an HN commentator mildly annoyed by the study's questionable numeracy):
- In California, clouds / latitude / etc. mean a panel's only usable 10/24 hours on average per day
- In Indiana, the geography's less ideal, so clouds / latitude / etc. make it usable 8/24 hours on an average day
- In California, it would be replacing a super-clean natural gas plant installed in 2008 that has expensive high-tech emissions control devices required by the super-strict California environmental regulations and emits 0.4 tons of CO2 per MWH.
- In Indiana, there was no money or political will for modern power plants or strict environmental regulations, so the solar panel would be replacing a smoke belching coal plant from the previous millenium that emits 1.2 tons of CO2 per MWH.
- In California, labor for >1 MW solar installations costs $0.20 / W, costs are inflated by high CoL / taxes and business unfriendly regulations but there are lots of firms with experience who can install quickly.
- In Indiana, labor for >1 MW solar installations is $0.15 / W, they pay a lot less and don't have as much red tape, which slightly outweighs the fact installers don't have much experience and bumble around being slow and making expensive mistakes.
- Your per-watt cost is $0.20 / (10/24) = $0.48 in California but $0.15 / (8/24) = $0.45 in Indiana (which is also your per-MW cost in millions).
- Your daily emissions reduction is 0.4 x 10 = 4.0 tons for California and 1.2 x 8 = 9.6 tons emissions reduction for Indiana.
- Therefore every $1M spent in California buys 4.0 / $0.48 = 8.3 tons / day of emissions reduction and every $1M spent in Indiana buys 9.6 / .45 = 21.3 tons / day of emissions reduction.
If you care about efficiently spending money to reduce emissions, in this example (using made-up numbers) Indiana is the low-hanging fruit, investments there are better by a factor of 21.3 / 8.3 ~ 2.6.
But the way the study's written, if we assume solar is currently 2000 MW for California and 200 MW for Indiana, its calculations would suggest a 10% increase in California (200 MW) would save 200 x 4.0 = 800 tons and a 10% increase in Indiana would save 20 x 9.6 = 192 tons.
This is very misleading.
If you don't think about the units and just look at the numbers, you might be tempted to conclude the study's telling you that California's emissions reduction rating is 800 and Indiana's rating is 192, so if you care about CO2 reduction every dollar of investment is a factor of 4 as effective in California -- when in reality, with these numbers every dollar is actually a factor of 2.6 more effective in Indiana.
The question I'm asking (and that I think the study was trying to ask) is "If we have limited resources to apply, how should we try to minimize CO2 emissions?"
The point I was trying to make (and that I think the study was trying to make) is that replacing the plants that emit the most tons of CO2 per MWH is a decent place to start, especially when you know you don't have the money and political will to replace them all.
(But you probably ought to put other factors into the math, like that you need X MW of solar to replace 1 MW of fossil fuels, to account for the fact the sun doesn't shine at night -- and the exact value of X differs due to local conditions like latitude and weather.)
Saying "I wish we had the money and political will to replace all fossil fuel plants" or "We have a moral imperative to replace all fossil fuel plants" is...not productive. Your wishes or moral views don't change the fact that we don't actually have that much money and political will.
There will be some bureaucrat or politician or somebody somewhere who at some point says "Okay, we know how much money and political will we have for this CO2 emissions reduction thing. Where should we spend it? Let's see if anyone's made a study."
And when that decision maker goes off searching the literature, we really want them to find a study that gives an honest, non-misleading analysis -- with the example numbers I gave, that would mean closing the coal plant in Indiana is the optimal play, even though that state's climate and weather is less ideal than south or west.
If the study uses misleading math and the resources get applied in a sub-optimal place -- if we could have gotten rid of X tons of emissions with the money and political will available, but because of the bad math we applied it in the wrong place and got rid of Y tons instead, for some Y < X -- that just seems like unnecessary societal inefficiency and stupidity.
local CO2 emissions. This has not affected pumping of oil, and since we aren't even able to store much oil, that means it's getting burned. That makes it clear the global effect must be very close to zero. And for CO2, only global matters.
For example, there are oil fields that are unexploited because they would not be profitable. If demand rose, prices would rise and new wells would be opened. The reverse is also true.
But using it to make a subtle jab agains CAHSR isn't really fair -- they're two very different projects (for one of them, it's genuinely a stretch to call it "HSR") in two very different regions.
Yes, it's harder to get big projects through the red tape in California than it is in West / Panhandle Texas or Central Florida. Go take a drive through those regions and you'll quickly see some reasons why, besides just NIMBYism, Californians are a bit more protective of their landscapes. If a massive wind project were proposed across large swaths of the Texas Hillcountry, you'd see a lot more push-back.
Well, CA HSR doesn't exist. It's missing the R part of the HSR. So that must be the one it's a stretch to call "HSR".
How fast is California's HSR?
That's both sarcasm and an actual question. It doesn't go anywhere now but I keep hearing it's speed get downgraded as they encounter the real world. Plus, the goal of LA-SF is practically abandoned and now it takes you from a place you don't want to be to a place you don't want to go.
You really can't compare the two because one exists only as a goal and the other is an accomplishment.
https://www.fitchratings.com/research/infrastructure-project...
https://www.bloomberg.com/news/articles/2025-07-11/florida-s... | https://archive.today/LEyBC
"It doesn't deliver enough net benefit" is a bit of a silly thing to say: when speaking of net benefit, anything is better than nothing.
Rather, become one of the people who's improving things – or, if somehow your only skill is attacking, attack the people who are making things worse.
By the by, "net zero" is not enough. The vast majority of offsetting schemes are little more than accountability laundering and on-paper games, not translating to any concrete offsetting in the real world. We need gross zero.
That's a good framework to think about things. Going all-in on renewables implies keeping fossil fuels around, because storage tech is several breakthrough behind. Renewable proponents like to point out that every kWh not produced with CO2 emission is still a win.
Yet deploying renewables means they flood the market with cheap electricity when the weather is good, hurting the profit, thus viability, of (i.e. precluding) stable low-carbon sources (in other words I'm butt hurt about nuclear).
> The vast majority of offsetting schemes are little more than accountability laundering and on-paper games, not translating to any concrete offsetting in the real world.
A case I heard is that they count the carbon captured by planting trees, yet ignore it when the carbon is released back to the atmosphere in a wildfire.
>EIA publishes hourly operational data across the United States electricity grid, including demand, net generation of electricity from various sources (such as coal, natural gas, solar), CO2 emissions, import/export to other regions, and many more. The complete details of the EIA-930 data is available here: https://www.eia.gov/electricity/gridmonitor/about. Furthermore, we obtained the solar capacities of each year and each region from EIA (https://www.eia.gov/electricity/data/state/) and had stored the information in the file solar_capacity_factor.csv. (2023-07-01)
€0.3943 / kWh
That's about US$0.46 or AU$0.71 per kWh
That largely explains the surge in popularity of patio solar in Germany.
You'll typically get ~30 these days with minimal comparison.
Still expensive but a full quarter less.
There's an argument to be made that in a democracy the people could vote themselves lower taxes, but if that were the cast why haven't they already.
Subsidies are paid for by tax payers anyway, so, ya know, TANSTAAFL - There Ain't No Such Thing As A Free Lunch. And there's no guarantee subsidies survive the next election.
[0] https://ec.europa.eu/eurostat/statistics-explained/index.php...
We've got one. As per the law, limited to 800 W. €350 (of which €50 was delivery), including the inverter and the stands. As it happens, the stands weren't too useful for us (didn't fit our balcony so the panels are now on the driveway) and we could've reduced that to €250 if we'd gone for a model without stands and had been able to pick the kit up in person rather than getting delivered.
But even at €350, assuming 10% capacity factor, €350/(800W*24h*10%*€0.3/kWh*365) = 1.665 years = 1y8m.
Even if electricity was a third of the price, even with the €350 we spent, these things would still be no-brainers because they would still pay for themselves five to seven times over in their expected lifespans. As is, 15-21 times over.
The focus on CO2 is for climate purposes. If one is genuinely concerned about the environment then one would look at all power generation technologies, not only solar. If one did this then solar would not be a focus of concern for power generation. Articles like this one suggest that solar is an answer to climate change, when, at best, it is a distraction.
I actually would say the solutions to climate change from a grid perspective are pretty straightforward but tough to implement. New generation: Large nuclear hubs, smrs, solar and battery. hydro and wind as is.