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Beating climate change absolutely requires new technology
We have what we need to drastically cut emissions — but we're going to need much more
I was thinking of writing about why I disagree with Farhad Manjoo’s column arguing that nuclear power still doesn’t make sense, but I saw some tweets about a failed carbon capture and sequestration (CCS) project and realized that I never replied to an email asking why Slow Boring has paid tens of thousands of dollars for direct air capture (DAC) carbon removal programs.
What makes these topics hard to write about is that they involve complicated technical questions, and the honest truth is that well-qualified technical experts disagree about all of them.
But what links these topics together is that if we want to navigate the climate crisis in a remotely acceptable way, the world is going to need to develop some technologies that are currently unproven.
The opposite view is rarely expressed in explicit terms (because it’s wrong), but it often implicitly backstops skepticism about things like nuclear, CCS, and DAC. People will point out, rightly, that these technologies are pretty uncertain and unproven and currently seem to involve very high costs. Then they point to the fact that solar and wind work just fine, are well understood, and are cheap at the current margin. They’ll say “why not just do that?”
And every once in a while, you see a take like Alejandro de la Garza’s article in Time arguing that “We Have The Technology to Solve Climate Change. What We Need Is Political Will.”
This is true in the trivial sense that we could dramatically reduce CO2 emissions with currently available technology if we were willing to accept a large decline in living standards and world population. But that’s not really a solution to the problem. We should absolutely deploy current technology more aggressively and thereby contribute to solving the problem — but we will also need some new technology in the future, and that means we need to keep an open mind toward investment.
Renewables are great (at the current margin)
There’s a weird internet cult of renewables haters, and also the strange case of the state of Texas, where renewables are the number two source of electricity but politicians pretend they hate them.
This article is about the limits of the all-renewables strategy, but it doesn’t come from a place of hate. The reason Texas — a very conservative state with a locally powerful oil and gas extraction industry — has so much renewable electricity is that large swathes of Texas are very windy, and building wind farms in windy places is a very cost-effective way to make electricity.
And in a place where overall electricity demand is rising, both due to population growth (in Texas) and due to ongoing electrification of vehicles and home heat, renewables buildout does an enormous amount to reduce CO2 emissions and air pollution. Powering electric cars with electricity from gas-fired power plants would have emissions benefits, as I understand it, because natural gas is less polluting than oil and because big power plants are regulated more stringently than car engines or home furnaces. But still, the emissions benefits are much larger if the electricity is partially or wholly generated by renewables.
But the “partially” here is actually really important. An electric car that’s powered 50% by renewables has lower emissions than one powered by 10% renewables and higher emissions than one that’s at 90% — the more renewables in the mix, the lower your emissions. You don’t have to get to 100% renewable power; the key thing is to use “more” renewable power. And when people say (accurately) that renewables are now cheap, they mean that it’s cheap at the current margin to add more renewable power to the mix.
That’s because electricity demand is growing, so a marginal addition of renewable electricity just gets tossed into the mix usefully. But it’s also because Texas (and other states) have all this fixed infrastructure for burning natural gas already. If you get extra wind power you can just burn less gas, and the gas is still there to use if you need it. California, probably the leading-edge state on renewables, actually built a small number of emergency gas generators that they turned on for the first time on September 4 of this year to meet rare peak demand and avoid blackouts.
An all-renewable grid is very challenging
That California experience illustrates two things, I think:
Democratic Party politicians are, in practice, much more pragmatic than unflattering conservative stereotypes of them would suggest.
Democrats who’ve actually had to wrestle with practical problems know that we are further from an all-renewables utopia than environmentalist rhetoric suggests.
Gavin Newsom knows perfectly well he can’t just have a statewide blackout once or twice a year and tell voters that’s a small price to pay for meeting emissions goals. Voters want to see action on climate change, but they have a very limited appetite for enduring personal sacrifice or inconvenience. Using renewables to dramatically reduce emissions while still counting on gas backup when needed? Great. Securing even deeper emissions by accepting that power sometimes doesn’t work? Not great.
Consider this data from my rooftop solar panels.
The first pane says that so far in 2022, the panels have generated 102% of our household electricity use — hooray!
The second pane shows that we generated a huge electricity surplus (blue lines below zero) during the spring when it was sunny and cool, but we are in a small deficit over the summer when it’s even sunnier but our air conditioning use surges.
The third pane shows that in September, whether we are in surplus or deficit on any given day hinges crucially on the weather. It’s going to end up being a deficit month largely because of a big rainy stretch.
So how much does this cost? Well, not very much. Because the key thing about this scenario is that all my kilowatts of electricity get used. When I’m in surplus, that extra electricity goes “to the grid” where it substitutes for other sources of power, and I earn credits that offset my electricity usage during deficit periods. If I had to throw away my surplus kilowatts instead of selling them to the grid, my per-kilowatt cost would soar.
And if everyone had solar power, that’s the problem we would face. Who would we export the extra electricity to during surplus periods? At a small margin, we have the technology for this: instead of exporting power during the day and importing it at night, I could get a home battery and store daytime excess for use at night. That would raise my per-kilowatt cost, but only modestly since batteries aren’t that expensive. And you can add wind as well as solar to your grid so you have some resiliency against seasonal variations in sunlight.
The problem is that without fossil fuels for resilience, the cost per megawatt of renewables soars because redundancy is expensive.
Wasting electricity is costly
Seasonal variation is a big problem here, for example.
Let’s say you have enough solar panels to cover 100 percent of your electricity needs on an average December day. That means you’re going to have way more panels than you need on an average June day when the sun is shining for a much longer period of time. On a pure engineering basis, that’s fine — there are just some panels that in practice are only generating power for a few days per year in the dead of winter. But the cost per megawatt of those panels is going to be astronomical because a solar panel is almost 100 percent fixed costs.
The same is true of random fluctuations in weather. If you’re like Texas and rely on a mix of gas and wind, then wind is cheap — you add some turbines and that means you burn less gas. If there’s some freak day when there’s very little wind, then you burn an unusually large amount of gas. As long as you’re using almost all the wind power you generate, the cost per megawatt of your turbines is low. But if you try to build enough turbines to keep the lights on during low-wind days, you’re wasting wind on high-wind days. This means your cost per megawatt rises.
Because massively overbuilding renewables would not only cost a lot of money but wastefully consume vast tracts of land, it seems like a better idea would be to use long-term batteries. If you had really big batteries that stored electricity for a long time, you could simply store surplus power in the high season and unleash it in the low season.
In fact, if you are lucky enough to have large hydroelectric dams at your disposal, you can probably use them as a seasonal storage vehicle. You can let the water pile up when renewables are at maximum capacity and then run it through the dam when you need it. Not coincidentally, politicians from the Pacific Northwest — where there’s tons of hydro — tend to be huge climate hawks.
But for the rest of us, it’s Hypothetical Storage Technology to the rescue.
I’m not saying anything here that renewables proponents aren’t aware of. They write articles about seasonal electricity storage all the time. There are plenty of ideas here that could work, ranging from ideas on the technological cutting edge to brute force engineering concepts like using pumps to create extra hydro capacity. Another idea is that maybe you could replace a lot of current fossil fuel use with burning hydrogen, and then you could manufacture hydrogen using renewable electricity while accepting seasonal variation in the level of hydrogen output. It might work!
The known unknowns
Speaking of hypothetical hydrogen applications, it’s also worth saying that while electricity, cars, and home heat together constitute a very large share of global emissions, they are not the whole picture.
You can build an electric airplane with current technology, but we absolutely do not have a zero-carbon replacement for conventional passenger airplanes at hand. Nor do we currently have the ability to manufacture steel, concrete, or various chemicals in a cost-effective way without setting fossil fuels on fire. These aren’t necessarily unsolvable problems, but they have not, in fact, been solved. It isn’t a lack of “political will” that has denied us the ability to do zero-carbon maritime shipping. Right now, the only proven way to power a large ship without CO2 emissions is to use one of the nuclear reactors from an aircraft carrier. But this is both illegal and insanely expensive. You could maybe do something with hydrogen here, or else it is possible that if the Nuclear Regulatory Commission ever decides to follow the law and establish a clear licensing pathway for small civilian nuclear reactors, the companies who think they can mass produce these things in a cost-effective way will be proven right.
And if they are, that would not only solve the container shipping problem but would make decarbonizing electricity much easier. And that’s true even if the microreactors never become as cheap as today’s marginal renewable electricity because we ultimately need to move beyond these margins. The same is true for geothermal power. Even if the most optimistic scenarios here don’t pan out and geothermal remains relatively expensive, a new source of baseline zero-carbon electricity would solve a lot of problems for a mostly-renewable grid.
By the same token, CCS doesn’t ever need to be cheap enough to use at a massive scale to be incredibly useful. Even a very expensive gas + CCS system could be a cost-effective way to backstop renewables rather than engaging in massive overbuilding.
With Direct Air Capture — sucking carbon out of the air with essentially artificial trees — not only would the west pay de factor climate reparations (see Olúfẹ́mi Táíwò’s writing and interviews about this from last year), but we could also achieve net zero without actually solving every technical problem along the way. You could make airlines (and private jets) pay an emissions tax and use the money to capture the CO2. Of course, with all these capture schemes there’s the question of what you actually do with the carbon once it’s captured. One idea is that the CO2 removed from the air could be used to manufacture jet fuel. Airlines would then burn it again and put it back out into the atmosphere, but this process would be a closed loop that wouldn’t add net new greenhouse gases.
The case for agnosticism
People on the internet love to cheerlead for and fight about their favorite technologies.
But everyone should try to focus on what the real tradeoffs are. When towns in Maine ban new solar farms to protect the trees, that is a genuine tradeoff with the development of renewable electricity. When California votes to keep Diablo Canyon open, by contrast, that does absolutely nothing to slow renewable buildout. And the idea that investments in hypothetical carbon capture technologies are preventing the deployment of already existing decarbonization technologies in the present day is just wrong.
The basic reality is that some new innovations are needed to achieve net zero, especially in the context of a world that we hope will keep getting richer.
These innovation paths require us, essentially, to keep something of an open mind. As a matter of really abstract physics, “use renewables to make hydrogen, use hydrogen for energy storage and heat” makes a lot of sense. As a matter of actual commercially viable technologies, though, it’s stacking two different unproven ideas on top of each other. Insisting that all work on cutting-edge industrial hydrogen projects be conducted with expensive green hydrogen throws sand in the gears of difficult and potentially very important work. And when you tell the world that all the problems have been solved except for political will, you unreasonably bias young people who worry about climate toward either paralysis or low-efficacy advocacy work. What we need instead is for more young people who are worried about climate to find ways to contribute on the technical side to actually solving these important problems.