> It's probably still cheaper to avoid emitting the CO2 in the first place, but that does put an upper bound on the cost of reaching net zero.
It seems hard to believe that removing CO2 from the atmosphere could ever be less expensive than not emitting it to begin with. You're working against thermodynamics.
So the whole thing seems like a fraud. An excuse to keep emitting CO2 while claiming that you'll do something about it "tomorrow."
Bear in mind that (a) you're just pulling it from the atmosphere and burying it, not splitting the C from O2 so you can use it as fuel again, and (b) there are applications like long-haul jets and cement production where eliminating emissions isn't that easy.
To put some numbers on (a), David MacKay's book has some numbers[1]:
> The laws of physics say that the energy required must be at least 0.2 kWh per kg of CO2....
> Lackner told me in June 2008 that, in a dry climate, the
concentration cost has been reduced to about 0.18–0.37 kWh of low-grade heat per kg CO2. The compression cost is 0.11 kWh per kg. Thus Lackner’s total cost is 0.48 kWh or less per kg.
Burning a kilogram of coal generates 8 kWh[2] and 2.42 kg CO2[3]. So that's 8 kWh generated, requiring 1.16 kWh to pull 2.42 kg CO2 back out out of the atmosphere.
So about 15% of the energy obtained by putting carbon in the atmosphere is needed to remove it.
Right, which is why mostly the idea is to just bury the CO2.
However, if you do want to make fuel from it, say for airliners, then it's totally possible, you just have to add hydrogen, and more energy than you'll get from burning the fuel. E.g. the Sabatier process to make methane.
Spend much time working with hydrogen as a fuel and you'll mostly be learning just how amazingly convenient sticking your hydrogens on to carbon chains is compared to the alternative.
Carbon is the ideal hydrogen storage system. It raises the critical point by 160K and increase the density achievable at normal temperatures and pressures drastically. Don't discount the energy that needs to go in to pressurizing and cooling hydrogen, it results in significant CO2 production. I'd be very interested in seeing a comparison of the energy requirements for methane production vs. hydrogen storage, I have a feeling that it would favour methane if you accounted for all of the variables.
> there are applications like long-haul jets and cement production where eliminating emissions isn't that easy.
I disagree, there's an easy solution to eliminating those emissions: have zero long-haul jets and zero cement production. Before this gets (inevitably) downvoted, the more interesting question is why do we need either, what alternatives are there, how fundamentally we're willing to question our biases and expectations over what counts as a necessity. If saving our environment is an overriding priority, then the extent of the compromises we have to make can be made clearer.
I would say it's pretty dang tough to not have cement.
What do you use for a house foundation? Many apartments are made of cement and essentially every building uses a cement foundation.
Luckily, cement is not a big part of the total emissions.
Neither is long haul travel, particularly. Short haul flights are about half of all passenger-miles in air travel, can be made fully electric, and long-haul and medium haul flights can be split up into multiple legs for almost every route.
EDIT:I will say there are ways to reduce CO2 emissions from cement. You can make clinker with electric heat just fine. But half the CO2 is from the clinker itself. Over time, cement will absorb the CO2 it emitted as it fully cures, but that can take a century. It’s possible to accelerate that process. It’s also possible to use alternatives, like sulfur cement.
> and long-haul and medium haul flights can be split up into multiple legs for almost every route.
A better solution would be to eventually ban/tax out of existence regular jet fuel, and move to synthetically-produced jet fuel[1] which can be used in today's jet engines, but is carbon neutral. Perhaps eventually all fuels can be 100% synthetic when new jets are designed for it.
Aviation and shipping make up 5-6% of GHG emissions, not a trivial amount. Aviation is projected to expand several-fold by 2050 which, in the context of decarbonisation, means it will take up a progressively larger fraction of global emissions over time. It will be one of the last and greatest challenges - which is exactly why it will require offsets, carbon capture or otherwise. The aviation's offset market, CORSIA, is already one of the most developed in the world.
Your optimism about electrifying aviation is not shared by the industry.
It's not actually easy to ban long-haul travel. It's technologically simple, which is probably the angle you are looking from, but politically very difficult.
We can drastically reduce our usage of jets though. There is no reason why people should be flying between SF and LA, or NYC and Boston. Those are well within comfortable range of high speed rail, which is electric.
Once we’ve shifted all the excess air travel over to rail, that will leave a much smaller set of jet travel to offset.
If you look at a map of all airline flights there are many thousands of short-range flights. Replacing them all with trains would be interesting. Just the right-of-way property transactions would be daunting. Look at California as a lesson in how this can't be easily done.
The other thing is, people move around. Airlines can change flights easily to map to demographic changes; that's a major strength of air travel. Not as easy to rip up tracks and start over.
It's much easier, IMHO, to switch over these short haul flights to electric aircraft than to High Speed Rail in the US. By the time even one major new HSR route will be finished, we'll have certified and be flying electric passenger aircraft with just as much speed and just as long of a route (500 miles) BUT with ability to go anywhere in the country by hopping.
I kinda doubt it will go that quickly. See how many problems Boeing had with their lithium batteries in the 787. And those were just auxiliary power. This will take a hundred times that many batteries with the scale bringing many engineering challenges. And then the totally different engines.. I think it'll take a long time to have a battery powered airliner built, in mass production and as reliable and safe as current airliners. There's a lot of stuff to be built from scratch without half a century of trial and error to learn from.
I think biofuels might be a better option for aviation until the tech has time to catch up.
I'd love for that to be true, but I am quite dubious. Flight technology tends to be very weight sensitive, and our battery densities are just nowhere close to the density that flight needs.
Current batteries have an energy density of 90-190 Wh/kg, depending on the specific chemistry. Jet fuel on the other hand has an energy density around 12,000 Wh/kg. Obviously some amount of that will be made back up with the relative light weight and high efficiency of electric motors, but that is a very step energy difference to overcome.
A quick bit of Googling says that turbofan engines are about 40% efficient, while triple phase electric motors are roughly 85% efficient. Given the 3,000 nautical mile range of a 737NG, some back of the envelope math says that an EV equivalent would have a range of about 100 miles at best[0]. Forget LAX -> SFO, this isn't even enough to get you from LA to Bakersfield. And even 100 is optimistic, given that the FAA requires that all planes have extra fuel for diversions, weather, holding, etc.
At this point, I suspect it might be easier to refine kerosene out of capture CO2 using excess renewable energy than it would be to make an EV 737 replacement.
0 - I'm obviously not accounting for weight and aerodynamic differences, which are beyond my capability to estimate, but I doubt that would make a significant difference. I'm also assuming that we're using Li-Ion Cobalt batteries, which have the highest density. The more common Phosphate chemistry makes these numbers even more bleak.
The best lithium ion batteries have 300-400Wh/kg (some cells do up to 650Wh/kg with sulfur), electric motors can have up to 95% efficiency. Long range jets can fly 20,000 km with passengers. Easily enough to do 500 miles. But if you improve aerodynamics, can go much further.
Source on 400-650Wh/kg? That’s significantly higher than what’s even reported in Tesla EVs, and I’m curious if that’s lab or production figures. Even going up to 400Wh/kg and 95% efficiency only yields 237 miles for a 737 equivalent, which isn’t enough.
The top spec 777 would give you 677 miles on batteries, assuming 400Wh/kg. Enough to serve the LAX to SFO route, but a fairly limited vehicle all things considered, especially for the price and size.
> Long range jets can fly 20,000 km with passengers.
Sure, but economics begins to dominate here. There’s a reason I chose the 737 as a reference benchmark; it’s the gold standard of short to medium range airliner, and absolutely the vehicle that we should be aiming to minimize. If you have to pull out a 777 sized aircraft to service LAX -> SFO, then the price of tickets is going to begin rising significantly to cover the higher vehicle cost. I’m also genuinely quite doubtful that many airports can handle 100% of their jets switching over to wide body aircraft, which this would require, without significant improvements to the terminals and other facilities. If governments are forced to upgrade airports to save money on rail, I’d argue that that’s penny wise and pound foolish.
All of this can be done, of course, but it really begins to erode all of the supposed cost savings over HSR.
> If you look at a map of all airline flights there are many thousands of short-range flights. Replacing them all with trains would be interesting.
Replacing “them all” is to set the bar unnecessarily high. I suspect there’s an 80/20 rule in effect here, and we should aim to replace the most popular short haul routes, not all of them. That’s why I specifically called out SF->LA. Major population centers within a few hundred miles of each other are prime HSR targets, and in countries with HSR we see a lot of passengers preferring rail for these exact types of trips.
There’s no reasonable world where every single small town gets a high speed rail running to it, but we shouldn’t set that as our goal. Don’t let the perfect be the enemy of the good. In particular there are nice stretches of good density along the coasts of the US that seem like prime targets for high speed rail, that would make travel more ecologically sound and comfortable for a large chunk of the population.
> Just the right-of-way property transactions would be daunting. Look at California as a lesson in how this can't be easily done.
And yet right of way transactions regularly pass for highway and highway expansions. Not without difficulty, but they get done. Letting rail projects grind to a halt while forcing road ones through is a political choice, not a law of nature.
> The other thing is, people move around. Airlines can change flights easily to map to demographic changes; that's a major strength of air travel. Not as easy to rip up tracks and start over.
This is only kind of true. Changing routes is easy only to a point. Expanding and refitting airports to handle increased traffic can be incredibly expensive and slow. LA is going to spend a huge amount of time and money trying to fix not just their airport, but also the transit to their airport which is currently overwhelmed.
My city is probably well on its way to its airport being incapable of handling the recent population growth. Expanding that airport and improving transit to it will be massively expensive, and require the eminent domain of a lot of property.
Secondly, while people do move around, it’s not like they’re throwing darts at the map and moving there. The places Americans are moving to are easily predictable; they’re moving to cities. You’re not going to wake up one day to discover that America has moved to the middle of nowhere Kansas.
Generally the cities that would make the best HSR targets are also the least likely to totally collapse in population too. NYC isn’t going anywhere, neither is Boston or Philadelphia. One would be forgiven not predicting the rise of say, Denver, but that doesn’t mean we shouldn’t at least be aiming for HSR to the obvious targets.
And thirdly, transit availability and where people move is a two way process. People like and care about access to transit options, and the quality of the local airport (and cost of flights) is already one thing that people consider when they move to a new location. There’s no reason to believe that access to HSR wouldn’t be the same. Especially since it’s possible to put HSR stations in far more convenient locations, given the lack of turbine noise to piss off the neighbors.
This would be a lot more insightful if we hadn't already spent decades and billions of dollars looking for greener alternatives only to find that they don't exist.
Upvoted, because I think it's a legitimate question. I don't think you're actually saying let's stop all long-haul flights and cement production. You're saying that if we actually believed something was an existential risk to civilization, we'd put almost any option on the table for mitigating it, even if only to rule it out. I assume there is a list of sacred things we wouldn't even consider doing without, no matter the cost in human lives. But is jet travel and cheap construction on that list or not? Maybe, maybe not.
Concrete and jet travel are not existential. They're a few percent of the total. 3% for cement and 2% for aviation. Less than 1% for long haul aviation.
Long haul aviation makes immigration feasible without dangerous long ship trips, which are worse emissions than long haul aviation. So we should keep them around in some form, but we can improve the efficiency and even electrify them.
Thermodynamics is about entropy AND enthalpy. A stationary algae bloom using otherwise unused sunlight can be a lot cheaper than trying to fly a heavy battery along with 300 passengers. Earth is also full of natural alkaline minerals that can be used as cements or for soil enrichment while naturally absorbing acidic carbon dioxide. Direct consumption of electricity for carbon capture is not necessarily the main solution, but fine for when renewable or nuclear energy would be otherwise wasted.
> A stationary algae bloom using otherwise unused sunlight can be a lot cheaper than trying to fly a heavy battery along with 300 passengers.
The alternative isn't just trying to fit a heavy battery into a plane, it's to scoop the algae up and use it to make carbon-neutral biofuels to run the plane.
> Earth is also full of natural alkaline minerals that can be used as cements or for soil enrichment while naturally absorbing acidic carbon dioxide.
Then you're trading the thermodynamic problem for an economic one. You have to mine all of that stuff up, do chemistry on it, lose the economic value of the minerals in their existing form and end up with an incredible volume of industrial waste you have to pay to dispose of.
It doesn't violate the laws of physics for that to be cheaper, but it's still pretty unlikely. Remember that the alternative doesn't have to cover the full cost of generating electricity from non-carbon sources, only the difference in cost between that and burning coal. That's pretty close to zero, if not negative, as it is, and that's without a carbon tax.
It's easier than that, simply make carbon neutral transit cheap and carbon intensive transit expensive then the market will innovate. It's just no country wants to take a hit on their economy to force the transition to happen.
» It's easier than that, simply make carbon neutral transit cheap and carbon intensive transit expensive then the market will innovate. It's just no country wants to take a hit on their economy to force the transition to happen.
I am completely with you. We aren't even able/willing to remove all existing subsidies/tax breaks for coal. We know what we need to do. We can't wait for developing nations to freeze/starve to death before we cut subsidies on our own coal and gas industry.
Even people at Brookings (which I'd call right wing) can't support subsidies and tax breaks for coal and gas:
» To lead global subsidy reforms, the United States will have to strengthen these commitments by actively dismantling its own substantial production subsidies. The Environmental and Energy Study Institute reported that direct subsidies to the fossil fuel industry totaled
$20 billion per year, with 80% going toward oil and gas. In addition, from 2019 to 2023, tax subsidies are expected to reduce federal revenue by around $11.5 billion. Considering that production subsidies
grew 28% between 2017 and 2019, the United States will be under a lot of scrutiny from other countries wanting to see evidence of reform before making their own commitments.
» This is a challenging task for the United States because production subsidies are embedded in the tax code and promote fossil fuels in a variety of ways. For example, producers can deduct a fixed percentage of gross revenue instead of their actual costs as capital expenses, deduct exploration and development costs, amortize geological and geophysical expenditures, and benefit from accelerated depreciation of natural gas infrastructure. Oil and gas companies are also permitted to use the Last In, First Out (LIFO) accounting method to sell their most recent and expensive reserves first, thereby reducing the value of their inventory. Other incentives include foreign tax credits and energy production credits.
If we can't even remove direct subsidies and tax breaks (including accounting hijinks) from our domestic coal and gas industry, what moral authority do we have to ask other (less affluent) countries to reduce their subsidies?
Here are some options:
- Provide relocation subsidies to areas with public transit
- Increase public transit
- Treat bike lanes as first class infrastructure
- Provide direct gas assistance and carbon tax rebates for low income earners
This tracks for cities and looks good, but also looks like just a start.
What about rural areas? They have higher logistical costs, so cost of goods would go up. Things being sold to rural businesses also require someone to traffic their way out there. Point of reference: https://www.nytimes.com/2018/12/06/world/europe/france-fuel-...
There's no silver bullet to solve this problem. If there were, we would have already done it by now. The government will need to weigh the cost of subsidizing rural residences with that of other policies. The outlook for rural doesn't look great either way, many rural areas will not be able to afford the costs of climate change.
Sounds like a policy that won't pass muster then. Making things work for marginalized groups and rural areas is pretty top priority, unless significant and warranted backlash is to be expected.
The US isn't France and a set of transfers is a real solution. But I have no doubt that politicians will ignore the gravity of the situation to pander to their voter base. The huge cost of climate capture (likely 50% of our gdp) is probably a policy that won't pass the muster either. The fact is that it is far cheaper to reduce emissions today than try to capture emissions tomorrow.
This is totally true, awesome, and under appreciated. Check out project vesta. Basically there's an infinite amount of magnesium silicate minerals, and they weather to absorb co2 and release magnesium. You get some iron for free, but no heavies or toxics.. You can put it in the soil too, which is great because fe and esp mg are being depleted in soils. You can dump it in the ocean and raise PH while also mobilizing calcium. It's a win win win win win win.
In some sense it's just using the entire atmosphere as a battery. Burn fossile fuels where it's the only reasonable option (currently), such as for planes, then spend energy to pull CO2 out of the atmosphere elsewhere.
In a very literal sense, we have been using the atmosphere as half of a battery since forever-- combustion on earth uses atmospheric oxygen as as an electron acceptor.
It's also hard to believe that insurance against theft could ever be less expensive than nobody stealing anything, but that doesn't imply insurance is a fraud to allow people to carry on stealing. We live in a world where theft and carbon emissions are going to happen with or without the blessing of the US government, so if they want to spend some money seeing how far they can mitigate the damage then good.
I'd rather pin my hopes on technological progress than political magic.
Suppose it costs $1 to avoid emitting CO2 (e.g. replace gas car with electric car) and $10 to extract the CO2 after the fact. If you get the latter down to $3, you're still upside down. So where does the $3 come from? Presumably a government, but it doesn't even matter. Anyone would still be better off spending that money to subsidize electric cars or solar panels or something.
Which number do you think is larger, the cost for the US to dictate industrialisation policy for the rest of the world or the cost for the US (and possibly other governments more interested in reducing global warming, if the tech is there) to offset some of their emissions?
The problem isn't getting wealthy Californians to swap their SUV for a Tesla, it's getting poor Cubans to give up the only car their government will allow them to afford, cryptoenthusiasts to give up on Bitcoin, Saudi Arabia to decide it doesn't want to exploit its only resource and China to retire its recently constructed coal power plants. That doesn't just require lots of money, it requires magic
> Which number do you think is larger, the cost for the US to dictate industrialisation policy for the rest of the world or the cost for the US (and possibly other governments more interested in reducing global warming, if the tech is there) to offset some of their emissions?
You only have to dictate policy to them if you're trying to get them to pay for it. If you're going to pay for it yourself, there is nothing at all stopping you from paying people in Africa or South America to buy electric cars. The main thing preventing this is that you would have to convince your taxpayers to pay to offset emissions in some other country. But that's the same problem with carbon capture, except worse, because you would need more dollars to offset the same amount of CO2.
> you would have to convince your taxpayers to pay to offset emissions in some other country
I strangely think the rich world would be more comfortable building carbon capture infrastructure at home than clean energy offshore. The jobs are domestic. And you aren’t handing a productive asset to another country.
Hell, find it with an import tax on polluting countries and we don’t even have to pay for most of it.
Don't think it's even a strange thought; the US has been always much happier with industrial policy than welfare. "NASA, but for your climate" is a much easier political sell than "let's give foreigners [almost] free luxury goods".
And if you don't want people in the developing world to simply sell the brand new Teslas you've swapped for their 30 year old bangers, you're also going to have to build out a charging infrastructure, ensure that new power stations built to handle the increased electricity demand are renewable, and shut down people's routes to simply buying new ICE cars manufactured in other countries and pocketing the difference between that and the cost of the Tesla. Even assuming that politics doesn't exist and the world will do exactly what the US wants if they spend enough money. the cost of offset doesn't seem quite so expensive after all...
Just as an aside, "NASA, but for your climate" is the coolest idea for a government agency. Big climate moonshots, stuff to inspire people. I love it! I wish it could be so.
The solution to that is to subsidize production of the alternative products in your own country for export. Then subsidized US-made solar panels and electric cars would be cheaper for people in Africa and South America than burning coal, but you get all the US jobs etc.
> subsidized US-made solar panels and electric cars would be cheaper for people in Africa and South America than burning coal, but you get all the US jobs etc.
You're still giving productive infrastructure to foreign countries. A Nazi doormat could get elected running to redirect those panels and subsidies for domestic use.
If you haven't already replaced all of your own fossil fuels, redirecting them to domestic use is fine. If you have, they would have to fight all the people who want to keep their jobs making products for export.
>there is nothing at all stopping you from paying people in Africa or South America to buy electric cars
I can think of tons of problems with this.
It requires more scarce than resources like lithium to make cars.
You can be scammed by people selling the car and using that money to buy a house and a cheap commission engine. You don't have the issue with carbon capture.
Your likely to face much more political pushback for subsidizing others carbon use. "Let's make our country carbon neutral" can resonate with people as it's cleaning up after ourselves. That's much easier to convince people to do.
Can Africa and South America even use them? Is it reasonable for them, do they have the infrastructure? I know in some countries electricity can be scarce-- and power companies turn off the supply at night.
It's cheaper to scrub carbon, than it is to fix the societal and economic issues across the globe required to make passing out electric vehicles work
> It requires more scarce than resources like lithium to make cars.
What do you think it takes to capture carbon?
> You can be scammed by people selling the car and using that money to buy a house and a cheap commission engine.
How is that a profitable scam? Anybody else could buy the same car with the same subsidy. You can't resell it for more than you paid.
> Your likely to face much more political pushback for subsidizing others carbon use. "Let's make our country carbon neutral" can resonate with people as it's cleaning up after ourselves.
The only reason to do this is if you've already done that. Otherwise it would make more sense to spend the money subsidizing replacement of fossil fuels in your own country first.
> Can Africa and South America even use them? Is it reasonable for them, do they have the infrastructure? I know in some countries electricity can be scarce-- and power companies turn off the supply at night.
Solar panels and electric cars go together like hand and glove. The car doesn't care what part of the day you charge it, so you charge it when the sun is shining. And you don't need a functioning power grid to install cheap solar on your own house/business.
I'm not familiar with how exactly carbon capture technology works to be honest, but I believe it involves taking advantage of chemistry to separate carbon from air. I don't see how lithium would factor into this as there isn't any absolute need for batteries, as there are with electric cars. Carbon capture at the point of production(ie in factories themselves) could be hooked up to the grid and still have a high rate of capture
>Solar panels and electric cars go together like hand and glove. The car doesn't care what part of the day you charge it, so you charge it when the sun is shining. And you don't need a functioning power grid to install cheap solar on your own house/business.
Enough to charge a car? That's not a simple setup, that takes a serious set up. That effectively increases the cost of running an electric car by a significant margin.
>The only reason to do this is if you've already done that. Otherwise it would make more sense to spend the money subsidizing replacement of fossil fuels in your own country first.
I don't disagree with that. It's the simplest way to start, and represents the most benefit for the taxpayers paying for it.
> How is that a profitable scam? Anybody else could buy the same car with the same subsidy.
What's the subsidy level? Because people earning a few dollars a day aren't paying much more for your subsidised Tesla than they paid for their 30 year old car with an ICE. And if you start subsidising new EVs to the extent that your giving them away for less than $1k, your scheme might actually be worse for the environment (Production costs are a significant fraction of the carbon footprint of a car, especially if it isn't used very much, and directly or indirectly the subsidy makes brand new cars cheap for a lot of people in developed countries that don't need them...)
The more you consider the logistics of such a scheme, the more carbon capture makes sense, and not because I'm averse to the idea of subsidies for EVs or solar manufacture
You don't have to subsidize against the alternative of a 10+ year old car from the US or Europe if you stop selling ICE cars in the US and Europe, because in ten years the ten year old cars will all be electric too.
So the subsidy is only the amount required to make a new electric car cheaper than a new gasoline car, for the people breaking into the middle class who can now afford that. That's the same as it is in the US, isn't very much, and is declining as batteries get cheaper. It may be soon that it won't even be necessary.
Battered old cars are worth more than a year's average per capita income in much of the world. They're not throwing away recently manufactured US/European/Japanese cars before 2050 just because their country's 0.1% now find subsidised Teslas more financially attractive than Fords or Mercedes. Actually, they probably won't find subsidised Teslas more appealing than Fords or Mercedes if they drive long distances, because it's a lot easy to find a roadside shack with gasoline than EV hookups.
There are already production EVs cheaper than any US manufactured car made in China, but it isn't going to make much of a dent in the residual demand for the billion ICE cars, trucks vans already in existence in places where people buy second hand and maintain forever.
US emissions are ludicrously high per capita but shrinking. The rest of the world's are higher overall and growing.
I'm not sure the mentality that it'd be rude to consider tackling the latter problem unless and until US per capita emissions drop below the global average is going to help the planet.
Don't. You can't predict prices like that. Consider that electric cars roll out of the factory having emitted more CO2 than the equivalent combustion vehicle. It takes a lot of miles to break even. If you put a price on the CO2, you may well figure out that combustion engines end up more efficient, because carbon-neutral fuel is close to being economical.
> But then they'd still be better off spending that money to subsidize electric cars or solar panels or something.
This is a huge mistake. Don't pick winners. You don't have better information than the market.
You can predict that not emitting CO2 will cost less than emitting CO2 and then recapturing it, because it's the second law of thermodynamics.
> Consider that electric cars roll out of the factory having emitted more CO2 than the equivalent combustion vehicle. It takes a lot of miles to break even.
It takes about the number of miles that the average person drives in a year. New cars last a lot more than a year. Also, the CO2 it takes to make an electric car has a lot to do with the fact that existing vehicles and power generation emit CO2, which goes away as we get more electric vehicles and non-carbon power generation.
> If you put a price on the CO2, you may well figure out that combustion engines end up more efficient, because carbon-neutral fuel is close to being economical.
So put a price on CO2. The point isn't that subsidizing electric cars and solar panels is the best solution to the problem, it's that subsidizing carbon capture is strictly worse.
> You can predict that not emitting CO2 will cost less than emitting CO2 and then recapturing it, because it's the second law of thermodynamics.
I'm not sure that's true, in two senses.
Even if the _energy_ cost is higher, the _monetary_ cost may be lower as emissions and capture don't need to be in the same place. It may be cheaper for example to just burn some petrol to cover long distances where there's less infrastructure and instead capture an equivalent amount of CO2 using energy from solar panels somewhere sunny.
I'm not certain the energy cost must be higher due to thermodynamics. If you were taking CO2 and water and recombining them to get back nat gas and oxygen then sure. But what if you're taking the CO2 and doing something else with it? If I'm thinking about this right the bond energy in CO2 is a little lower than the overall energy released. Of course things come down then to efficiencies but I don't think there's a thermodynamics point here.
> You can predict that not emitting CO2 will cost less than emitting CO2 and then recapturing it, because it's the second law of thermodynamics.
You're mixing up watts with dollars, a mistake that "green energy" stockpickers make all the time. Consider all the energy that is hitting the Sahara. It's worth zero dollars, because it can't economically be used - but what if you could capture and transport it somehow, you know, like in a fuel?
> It takes about the number of miles that the average person drives in a year.
That's the lowest estimate I have ever heard - do you have a source for that?
> Also, the CO2 it takes to make an electric car has a lot to do with the fact that existing vehicles and power generation emit CO2, which goes away as we get more electric vehicles and non-carbon power generation.
Sure, but economics of scale apply to all technologies and unless you let the market do its thing, you won't know the minima and maxima.
> So put a price on CO2.
Exactly.
> The point isn't that subsidizing electric cars and solar panels is the best solution to the problem, it's that subsidizing carbon capture is strictly worse.
You don't know that. Ideally, nothing should be subsidized. However, in a market where profit is sooner found with dog meme cryptocurrency and other harebrained schemes, subsidies are arguably necessary, and then you shouldn't put all the money into directions that have already been mostly explored.
It's not that simple. For instance, when there's too much electricity on the European grid because, say, wind energy is particularly strong that day in Germany, producers need to pay for someone else to take that electricity. It has negative cost. This is rare for now, but it does limit the rollout of renewables.
I thought the example of solar energy in the Sahara was rather convincing? It's a lot of untapped potential energy, it just needs a business case. CO2 prices can make that happen.
> You lose a lot of watts to heat by converting fossil fuels to CO2 and back
Again, just because it's a loss in the thermodynamic sense doesn't make it a loss in an economic sense. Fuel cells are quite efficient in the thermodynamic sense, but they're not economical when the whole pipeline is considered. That said, a technological breakthrough can turn that calculation around. You can't predict that, so you shouldn't pick winners.
> Reuters Fact Checkers made an attempt at science
Color me suspicious with that one. At least they're pointing out that other researchers arrived at far less impressive numbers.
> What market? We're talking about government subsidies for carbon capture.
I'm a strong proponent of CO2 prices. That said, if the government insists on picking winners with subsidies, they shouldn't narrow themselves down too much.
> It's not that simple. For instance, when there's too much electricity on the European grid because, say, wind energy is particularly strong that day in Germany, producers need to pay for someone else to take that electricity. It has negative cost. This is rare for now, but it does limit the rollout of renewables.
If you don't have any external pressure or subsidies on you, you can turn off solar/wind in seconds. Renewables never have to pay those fees, only slow to ramp plants do.
Those "slow to ramp" plants are necessary to provide the base load. The cause of the overload is the volatility of renewables. Whether it would be cheaper to curtail renewables and who exactly gets to foot the bill - I don't know. Doesn't seem reasonable to me that, say, France should pay Germany because their very stable nuclear plants can't accommodate for the volatility of renewables elsewhere. Either way, the cost is negative, or at least zero if you turn it off. It's worthless energy, going to waste.
> Those "slow to ramp" plants are necessary to provide the base load. The cause of the overload is the volatility of renewables.
Sure, that's true. But what I'm saying is that negative prices don't impact the rollout of renewables because renewables never have to pay them. And in a market with lots of renewables and no distortions, prices won't go below zero anyway.
> But what I'm saying is that negative prices don't impact the rollout of renewables because renewables never have to pay them.
How do you know? Do you have source on that? It doesn't stand to reason that the cost of excess electricity produced by renewables should be carried by anyone else but the producers of such electricity. It's true that these overshoots wouldn't exist if coal or nuclear plants could be regulated quickly, but it's also true that if these plants didn't exist, nothing would make up for the underproduction.
> And in a market with lots of renewables and no distortions, prices won't go below zero anyway.
Alright, let's assume there's zero cost to curtailment (not true, but close enough) and that excess energy is only produced because the compensation structure works that way: You still have wasted potential energy from curtailment. Increasing the rollout strictly increases that waste. Therefore, it is reasonable to put that energy into fuel production, especially considering that the best combination of volatile renewables today is natural gas, which can be regulated quickly.
> How do you know? Do you have source on that? It doesn't stand to reason that the cost of excess electricity produced by renewables should be carried by anyone else but the producers of such electricity.
If they're acting on normal motives, they won't produce any excess specifically because they would have to share in paying the cost.
At least with any kind of bid for production system.
I could imagine a system where negative or too-low prices trigger targeted punishment, as far as I know that would be very different from what we have. For a normal market, if prices go too low then renewables can just say "okay we're offering zero power to sell right now".
> You still have wasted potential energy from curtailment. Increasing the rollout strictly increases that waste. Therefore, it is reasonable to put that energy into fuel production, especially considering that the best combination of volatile renewables today is natural gas, which can be regulated quickly.
> It takes about the number of miles that the average person drives in a year.
I wish that was true. Volvo recently put out a statement that it takes about 70k miles to recover the initially higher energy input using the world average energy mix. Some 9 years of the average UK milage.
Of course, if manufacturing is made significantly less CO2 intensive then the maths change.
For what it's worth, even if there was no CO2 benefit I'd still be rooting for electric cars to succeed for various other reasons including noise, particulates etc.
It seems like you’re assuming our current culture stays constant. I’m pretty sure it’s going to change quite drastically after we have our first million+ death heat wave. It’s going to suddenly seem a hell of a lot more tacky to be driving a huge Chevy Tahoe.
Which is to say that things that seem impossible politically might suddenly become very politically possible.
Either way the actions people will take for adaptation/mitigation are often at odds with the "prevention" path. Similarly, building flood defences would be expected to require a lot of steel and concrete, which are energy and carbon intensive. I suppose people in more marginal circumstances will need to make some tough decisions.
If we're going to talk insanely expensive moonshots, maybe the US should install and maintain free point-of-emission carbon capture for anyone anywhere in the world who wants it, and put the technology behind it in the public domain for anyone who doesn't want it from us.
Point of emission capture is at least technologically feasible.
Kind of like how some cities / states already subsidize solar panels / heat pumps / electric appliances etc.
But even more like how some organizations (like PurpleAir, maybe thats the only one though?) will get you connected with the hardware necessary to be a part of their air quality monitoring network.
Except this is a way more interesting idea for a lot of reasons.
I think the economies of scale are such that it needs to be large installations that regular people can only donate money to. Or do volonteer work, I guess.
The carbon goes down a hole in the ground, somewhere with the right geology. You can think of it as a gas well run in reverse.
As soon as you add that requirement to coal power plants, they become immediately uneconomic to build or operate. They are already borderline due to the fall in cost of renewables.
With a meagre Carbon Tax of $15/tonne, coal costs double in the US.
There's nothing that can be done to fix coal power apart from just shutting it all down.
Isn't that the whole appeal of our economic system? To root out these inefficiencies?
If it is not economically feasible to run a coal plant if they do not externalize the pollution cost, how is that my problem? And if the demand justifies it, the cost for coal-generated electricity will go up.
It's a matter of priorities and resource allocation.
Why do we allow coal operators to enrich themselves at the cost of everyone else?
The negative externalities are too many degrees of separation and to many years away from any immediately obvious perception of harm.
"Officer, these men are stealing my lawn, a few blades of grass a day as they walk by!" This doesn't engender a threat response until there's visible damage, and even then the solution is likely to involve signs and warnings, since the responsibility for total damage is so widely distributed. We need a fence around the climate lawn, and we can't leave the gate open for some people and not others, if you catch my drift.
We're beginning to see global acknowledgment of the problems and gradual progress towards reducing emissions. Once technology can accurately measure the cost of the negative externalities, they can be priced in. If the cost is on an exponential trend, where each ton of co2 is now seen to cost the operator an additional .0000001 cents, but 100 years later might cost millions, with regards to preventable damage, markets currently are accurately pricing in the costs. They're just not equipped to assess global climate and long term planning as relevant. That has to come from legislating sane and scientific and fair rules.
There's nothing inherently wrong with burning coal if there's a globally recognized system of accountability. Since there's not likely to ever be such a hegemony, you get what we have now - slow, frustratingly bureaucratic incremental progress, and therefore the need for mitigation as well as sustainable energy tech.
The EU has much higher pricing of CO2 (currently at 60 eur / tonne [0]) and yet Germany was using more coal power than expected, forced by the fact that there was a scarcity of wind. [1]
Of course, that caused the prices of electricity for households to jump up. [2]
Carbon Tracker calculates that the majority of coal plants in Europe are already cost negative.[1] They live off uncompetitive tariffs and subsidies. Germany's reverse auction for coal plants over the last year ended up accepting a lot of very low bids, as coal owners were desperate to get out from under stranded assets. Even they were widely criticized as over-priced given the state of the industry.
If you're considering whether coal plants would exist at all, you need to compare to the price of things like batteries. (Unless we make a ton of nuclear.)
It would be great to do sane carbon policy, but politics is the limiting factor at the moment. Carbon capture is one of the few universally popular solutions.
Maybe not. Imagine what a rhinoceros is worth to someone in an Africa. It's (hypothetically making up numbers here) a car or a house or food for a year.
For the right person in the US the cost of keeping that rhino alive in their backyard (or safe from poachers in a reserve in Africa) is much much more but both not an inconceivable amount to pay and not an undesirable one.
The best part CO2 capture is that motivated resourced people could in theory act without the worlds cooperation. People who aren't motivated and/or resourced could choose to not act and the problem could still get solved.
Currently the only way to achieve that kind of effect is to help under-resourced people to act by giving them resources. I would suggest that for a lot of reasons this is a very tricky solution.
For every resourced person motivated to capture co2 there will be another resourced person motivated to release it. Do we really want to find out who is gonna win the race. No matter how you spin it, we won't solve the emissions problem without politics.
You don't need permission to pay people to install wind turbines either. What you need is money. And if you have money, and a dollar spent installing wind turbines goes further than a dollar spent extracting CO2, why are you going to spend it on the inefficient thing?
A wind turbine is only profitable if you can physically connect it to someone who needs energy while the wind is blowing. That will get harder as more are built.
CO₂ is not the only factor driving ecological damage and indeed, the mass extinction event currently in progress.
There are simply too many humans for the way in which we as a species currently behave.
Either we need single parent families, globally, for a few generations, to get numbers down to a sustainable level, or, we have to convince/force 7 billion people to accept and adhere to major changes in how they live their lives.
CO₂ is a basically easy problem, compared to this, if it is possible to take the route of geo-engineering, because, as you say, it's not necessary to change how people behave; but I think no matter what, there is a need to change how people behave, or billions die from famine and economic failure, induced by ecological collapse.
I don't think people will change (indeed, there will be large numbers of people vocally against change), I think Governments will at best effectively do nothing "(we're building lots of renewable! but we're also building lots of gas at the same time!"), or more likely make things worse ("we'll phase out coal by 2070"), so my expectation is human suffering on a scale never seen before in all human history.
Humans are kākāpō; we're over-reproducing, having as they did no meaningful natural predators to keep us in check, and sooner or later, that leads to ecological collapse.
(The kākāpō went through several cycles of this and evolved to reproduce very, very slowly, and so came into balance with their environment, and then were very nearly almost completely wiped out when humans arrived.)
Dude, its not the 50s, most of the world is under replacement rate of reproduction. The problem now is largely the opposite, shortage of young minds to invent carbon free energy grids and young hands to build them. You can cut human population by half and still have a problem of excessive carbon emissions or transition to carbon free economy and have net zero per capita emission.
Also I don't want humanity to be almost completely wiped out.
I may be wrong, but I think the world population is growing more quickly than you portray, and will be for some decades yet, and we currently have far too many people for how we conduct ourselves as a species.
I may also be wrong to think it, but I would expect if you halved the world population, assuming it was done equally across the world, you would indeed halve human carbon emissions; half as many people, half as many homes, cars, power stations, etc.
Based on current trajectories, the world's population is not going to double again (or even increase by 50%), it will level off at about 10 billion and at that point perhaps start to shrink. It's possible this level is not sustainable with an acceptable standard of living, but it's not obvious and it certainly isn't inevitable that humanity will reproduce out of control.
The planet can't cope now - the environment is falling apart right now, already - and the mid-range estimate there's another two or three billion people to come over the next few decades.
There are estimates in excess of this, there are estimates lower. Estimates which have population declines see slow declines only.
I've not seen any real understanding of why the fertility rate is dropping, particularly in first world countries. That's a concern; what happens if the factors causing this to happen are transient?
That's part of why the estimates are only estimates, of course.
Can you provide a source for the mid-range estimate you mention? Global population is on the brink of decline rather than further growth. [1]
> I've not seen any real understanding of why the fertility rate is dropping, particularly in first world countries. That's a concern; what happens if the factors causing this to happen are transient?
The cited article discusses several potential causes and none are going away in the near future. On a global basis, humanity's current demographic profile locks in decades of either very low growth or a decline in most regions. Worth noting that these changes have all come about at a much faster pace than even the most aggressive estimates.
Despite this as our overall numbers will start shrinking, resource consumption will grow and its growth can't be prevented by force without conflict. The only class of realistic solutions to environmental degradation are technological ones. Tapping into new stockpiles (likely out in space) and increasing efficiency slash decreasing resource intensity of economic activity are more viable if one aims to avoid armed confrontation.
You are so right but nobody wants to hear it. We are incredibly short-sighted and incapable of accepting inconvenient truths. Every child conceived (and their children) is an enormous burden to the earth and all of us (in the grand scale of things) but because more population is in the best interest of every individual family, city, region and country, no reduction will ever happen, at least not voluntarily.
Third world children consume less, but their parents engage in deforestation and bushmeat hunts to sustain their families. This is an environmental burden as well.
The point is that upfront investment cost of developing industry specific carbon neutral solution doesn't have uniform ROI and can be (either economically or politically) quite expensive or sometime infeasible. This is an extremely long tail problem and we do need a more general solution applicable even after we exhausted all the low hanging fruits. This is what "upper bound" means in the parent post. So in the ideal scenario, it's more like we eliminate 80% of low hanging emission sources, significant reduce 15% of them and negate the rest with carbon removal to achieve carbon neutrality.
In addition to this, removing historical accumulated carbon is also pretty important. The expected cumulative damage at the point of 2050 will be catastrophic even in the most optimistic projection.
Depends on what the dollar cost of not burning fossil fuels turns out to be. I think being able to close the carbon loop is extremely important, there will inevitably be use cases where burning fossil fuels is the superior or only option. Rocket launches immediately jump to mind and are looking to be an area that will continue to experience explosive growth throughout the next century. We had better have a viable option for capturing those emissions along with the long tail of emissions generated during an orderly transition away from burning fossil fuels.
Rocket fuel isn't gasoline, it's hydrazine. It's not pumped out of the ground, it's synthetic.
This is a good lesson for the carbon capture economics.
We know how to make synthetic fuels and biofuels. As a general rule, making them costs around the same as carbon capture. "Grow some plants or something" is actually one of the most efficient known methods of carbon capture.
Biofuels cost more than pumping crude out of the ground. They also cost more, in most cases, than electric cars. So if you don't care about CO2 then fossil fuels win over biofuels because they're cheaper and if you do care about CO2 then electric cars win over biofuels because they're cheaper. Basically nobody uses biofuels unless they're subsidized. But we know how to do it; we just also know of something better to use in 98% of cases.
Then you have the other 2% of cases. Like aircraft. Existing batteries are too heavy for aircraft and we don't know if or how long it'll be before we have sufficient ones. But we could use biofuels for that. Put a carbon tax on fossil fuels and that's what might happen, because for a plane that might be the most cost effective alternative.
So you say hey, maybe it'd be better to keep using fossil fuels in planes and then use carbon capture. If carbon capture has a cost similar to biofuels, that could be competitive. But it's not. Because biofuels produce fuel. With carbon capture you still have to pay to buy petroleum.
Hydrazine is not used very much as a rocket fuel. It's expensive, toxic, mutagenic, carcinogenic, flammable (not escaping that though), and explosive. It also has a freezing point too high to be used in space (MMH, monomethyl hydrazine, is used in spacecraft with NTO as the oxidizer.)
The best fuels for the first stage of launchers are hydrocarbons, due to their low cost and good density. And the first stage is where most of the propellant in a launcher is consumed. The cost of propellant becomes increasingly important as the cost of the launcher is reduced; for SpaceX it is very important. The use of cheap propellants also allows more testing of their engines.
Some launch systems fly on hypergols (hydrazine is one of them; it is not used in the West anymore as a main fuel, being too toxic), some burn hydrogen with oxygen, some burn kerosene (RP-1), a new system is coming online that actually uses methane (Starship).
And these were just the liquid propellants. There are also solid fuel rockets.
Hydrolox could certainly use all electric production but all of the others require hydrocarbons as their feedstock. Take hydrazine, it's synthesized by oxidizing ammonia and the main feedstock for ammonia production is natural gas and it's synthesis produces CO2 as a byproduct. So we're right back where we started. Why don't we just use hydrogen and oxygen? It's true that storage is a problem since hydrogen must be kept at cryogenic temperatures to remain liquid but a bigger problem is hydrogen's low density. Low density means more volume and that leads to inefficiencies in the size of the rocket. Methane is generally the better option and coincidentally could use captured CO2 as a feedstock.
I tend to agree, at least from the point of view that even if we continue to burn fossil fuels that it would be much cheaper to require CO2 removal where it is produced, and thus in extremely high concentrations, than trying to waft it out of the atmosphere where it's only 400 ppm.
Electrification of transportation would also make this much easier, because instead of having billions of little fossil fuel burners all over the planet, you could concentrate that burning to just power plants. At that point there would be a lot fewer places where it would be difficult to sequester carbon (e.g. planes, large ocean vessels).
> It seems hard to believe that removing CO2 from the atmosphere could ever be less expensive than not emitting it to begin with.
This is the "get rich by saving money" fallacy. Imagine all the CO2 of a century of industrial development had not been emitted. We'd be enjoying a life without man-made climate change, but also without any of the amenities of modern life.
Consider that air-to-fuel companies are pretty close to profitability with just a modest increase in carbon taxes. Consider also that countries like Germany spent a lot of money on transitioning to renewables, with very little to show for it. Once you picked the low-hanging fruit, there are no more "savings" to be had without drastically cutting down on production. At that point, you might as well turn some of that production into sequestration.
> So the whole thing seems like a fraud.
I get the same feeling with electric cars, solar panels and wind turbines. Why? Because these have all rolled out on account of lavish subsidies, not because the market decided they are the most efficient solution. Just put a price on CO2 and watch the market figure that one out. Results may be not what you expect.
> Imagine all the CO2 of a century of industrial development but also without any of the amenities of modern life.
Most people on earth still live in conditions that are nowhere near the kind of development you are likely enjoying. They are also those who will feel the effects of man-made climate change most.
That is why this argument falls flat. We didn't buy this kind of living standard with some future self-inflicted suffering: your amenities of modern life are bought with the suffering of others.
But the deal is done and over. Now a debt is owed.
I get that, but what are the implications? Consider that the vast majority of CO2 emissions today are coming from the countries that are still developing to that standard we enjoy. We have no right to ask them to cut down. Therefore, we have no choice but to invest into sequestration, because that's the only way to pay down that "debt".
As an alternative, would it be worth it to help developing countries build green solutions now, maybe the economies of scale will help offset some of the short-term cost?
You're right that it's not right to force still developing countries to halt their progress. I just wonder if there's a way to help them develop in a way that is better long-term.
Absolutely, technology that scales out to the rest of the world is the only hope to actually make a substantial difference. That includes sequestration, renewables, but also nuclear fission and (hopefully) fusion.
Unfortunately, most of the activism seems to revolve around "us sinners" needing to abstain from our indulgences.
"Most people on earth still live in conditions that are nowhere near the kind of development you are likely enjoying. They are also those who will feel the effects of man-made climate change most."
They still benefit from industrial development, even though with a certain time lag compared to us (because that is it: time lag. Living standards in poorer countries lag behind those of Europe or Japan, but they rise nonetheless.)
For example, about 90 per cent of humanity has electricity and uses some electrical appliances. Few people live in truly pre-industrial conditions.
Capturing it at the point of emission seems like it should be the priority. Way, way easier to get it at that point. But that would make fossil fuels more expensive, and we can't have that right?
Maybe we should just massively subsidize point of emission carbon capture for fossil fuels. We need it for some use cases that renewables don't work for anyway (yet).
I suspect the public would be on board with these type of policies if the cost to the poor and middle class were subsidized.
Any legislation that increases cost of energy will impact poorest the most, but for some reason cost of energy to the poor is not brought up much in climate discussions.
And of course China is the biggest emitter by far, so something special needs to be done there. Likely first world countries would have to subsidize third world country energy costs.
It may be easier to develop one efficient process to extract CO2 from the atmosphere than to develop numerous efficient alternatives to every CO2 producing activity.
If you had process that only needs electricity then you run it only when power is cheap (usually when renewables are producing it).
Depending on efficiency this could be better solution than energy storage (instead storing energy you pull CO2 and then burn it later if energy is needed).
Carbon capture techniques do not necessarily allow you to easily burn the captured carbon again. For example, consider a process where calcium oxide is used to capture CO2, converting it to calcium carbonate (that’s how masonry mortars work). You can’t convert calcium carbonate to energy.
It could never be less expensive in the same way a a sled will continue to slide forever on a frictionless surface: theoretically.
Material limitations, and technical limitations may make it cheaper practically.
As an example, let's look at rockets. Which is cheaper, removing the CO2 after release, or developing switching technologies, for instance, to using O2 and H. Well, for certain applications, where the energy density and logistics of the fuel matter, pulling the CO2 out afterwards makes more sense.
Now, yes, that is a small example, but my point is just to show thermodynamic efficiency doesn't translate directly to cost effectiveness for all applications.
There is a moral hazard here, but the reality is that we’ve passed the point where emissions reductions alone can get us where we want to be. We will need both reductions and removal.
It's more plausible to me when you think about centralization vs decentralization.
Sure, it would clearly be cheaper to emit less if the emissions were mostly coming from a small number of controlled facilities.
But when the sources are millions of tailpipes and smokestacks across the globe, it's at least plausible that a centralized, new recapture solution would be cheaper than decreasing emissions in millions of old places.
It also depends a lot on price of electricity. Norway has a lot of electric cars because it is a rainy country with terrain very suitable for dams and cheap hydro production.
With enough small modular reactors, we might get to the same point elsewhere. The German renewables mix does seem to drive prices up, especially in certain peaks, because nature is unpredictable and you can absolutely have a freak streak of several windless, dark, cold days in the winter.
Sure, for now. But pretty much all of Europe, large parts of the US, much of China have plans to ban gas vehicles in the near future (< 15 years). Once that happens most of the rest of the world will follow quickly because there will be just less supply chain support for gas vehicles, and what remains will quickly become a diminishing fraction of the total.
I definitely see this happening much faster than any attempts at atmospheric capture would even make a tiny dent.
If taken from a purely economic standpoint, yes. But once politics get involved, a more expensive often can feel "cheaper" if it gets everyone moving in the same direction or produces some level of agreement.
Sure, in an ideal world, we would just all do the right thing. But that is not the world we live in.
At a superficial level of analysis, yes, but you can't turn off all the coal plants, stop oil extraction, convert ice to electric, and distribute sufficient power storage to keep modern life going at a snap of the fingers. If you can offset the emissions while at the same time moving toward renewable and sustainable energy, you're mitigating necessary inefficiencies.
Mitigation is better than fantasizing about rapid fossil fuel elimination. There are way too many lives that depend on maintaining the status quo, in terms of power and economics and chemical resources. Progress will be gradual, like cleanup of the pacific garbage patch.
Sadly the amount of CO2 in our atmosphere even if we stopped polluting today. Will still bring about huge negative effects down the road. We need to decarbonize our society(listed first because it’s the first priority) AND remove CO2. Source & a great read: https://www.orbuch.com/carbon-removal/
If you want to learn about carbon dioxide removal check out AirMiners: https://bootup.airminers.org/ they have a useful self paced curriculum
We do, but right now we have to start somewhere. It'll take less energy and effort and production resources to reduce emissions than capture the same amount.
Once we get closer to zero emissions it makes more sense to think about capture IMO.
Edit: oh wait I think you are saying the same as you mention reduction is first priority, sorry.
If efficiency was ever a concern we wouldn't be burning fossil fuels in the first place. A gasoline engine only extracts a small portion of the energy in the gasoline, most of the energy gets wasted as heat.
> An excuse to keep emitting CO2 while claiming that you'll do something about it "tomorrow."
While paying the higher price today to have it removed? That's not much of an excuse, that's buying your way out of it. If people want to go that route and they pay for their own emissions (there, of course, is going to be the problem) then be my guest. If you'd rather go the typically cheaper route of changing the technology or lifestyle (e.g. drive electric or ditch the car altogether), that's also fine.
Renewables don't all have steady load, so it could be an alternative to batteries/hydro batteries. Use natural gas peakers when renewables don't produce enough, use excess renewable power to remove CO2 from the air when they are producing more than you need. Basically it's using the atmosphere as a reverse-battery
The alternative there is to do pre-combustion CO2 capture on the methane, storing hydrogen (or hydrogen + nitrogen) for use in the peaking turbines.
Another possibility is to store CO2 underground, and when "charging" use a solid oxide electrolyzer to turn it to carbon. When discharging, it would be run as a SOFC and produce CO2, which would be cooled and stored again. I believe Noon Energy is looking into schemes like this.
It all comes down to the cost of energy. If the current improvements in renewable energy are sustained, or if the promise of fusion comes to pass, or even a considerable improvement in the economics of fission, then yes it could make sense to emit carbon dioxide now and recapture it later.
With the way capitalism works there'll be a lot more takers to solve a harder but more measurable problem that someone will pay them for (remove the CO2 we'll pay by the ton) than there will be to solve a less measurable problem (prevent CO2 being released generally). Perverse incentives for sure but within the existing parameters likely more effective.
It seems hard to believe that removing CO2 from the atmosphere could ever be less expensive than not emitting it to begin with. You're working against thermodynamics.
So the whole thing seems like a fraud. An excuse to keep emitting CO2 while claiming that you'll do something about it "tomorrow."