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U.S. sets goal to drive down cost of removing CO2 from atmosphere

reuters.com

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Re: U.S. sets goal to drive down cost of removing CO2 from atmosphere

#341

Post by Dylan16807 »

incrudible wrote: post #338
Dylan16807 wrote: post #331

Earlier quoted context omitted.

> 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 regulat…

> 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.

Yep, all true.

Re: U.S. sets goal to drive down cost of removing CO2 from atmosphere

#342

Post by Robotbeat »

ashtonkem wrote: post #310
Robotbeat wrote: post #276

Earlier quoted context omitted.

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'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 relat…

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.

Re: U.S. sets goal to drive down cost of removing CO2 from atmosphere

#343

Post by ashtonkem »

Robotbeat wrote: post #342
ashtonkem wrote: post #310

Earlier quoted context omitted.

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 relat…

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.

Re: U.S. sets goal to drive down cost of removing CO2 from atmosphere

#344

Post by worik »

throaway46546 wrote: post #166
worik wrote: post #141

What about compost? Surely the best place to sequester carbon is in topsoil where we can use if to grow food. I have not done the maths, but I do do a lot of composting myself and it makes me wonder as I watch my soil get deeper.

Doesn't composting actually release greenhouse gasses?

No. The resulting soil is mostly carbon.

I think....

Re: U.S. sets goal to drive down cost of removing CO2 from atmosphere

#345

Post by ratboy666 »

alltakendamned wrote: post #163

Can someone point me to an explanation how CO2 is removed from the atmosphere ? What's the process and what happens to it ?

CO2 is combined with sunlight by plants to produce wood (carbon) and O2. We take in the O2, combine it with carbon, and produce CO2. Its a cycle

https://oceanservice.noaa.gov/facts/carbon-cycle.html

https://pubs.acs.org/doi/10.1021/acs.energyfuels.8b02803

which is CO2 to calcium carbonate. This happens in nature and is used by coral.

So, all that CO2 in the atmosphere can become trees and coral.

Re: U.S. sets goal to drive down cost of removing CO2 from atmosphere

#346

Post by ratboy666 »

tschellenbach wrote: post #57

Without a price on carbon emissions all these measures seem unlikely to really change things.

But where I live, it would be difficult. Yes, there is a "CO2 tax" here. Twenty years ago I converted my wood-burning fireplace to natural gas. That was being, in my opinion, environmentally friendly (I prefer burning wood -- more pleasant). If the cost of NG goes too high I can revert to wood. Electricity is out, because the local power company prices it at around 7 times higher than natural gas. $800 per month to heat my house. $125 for natural gas. Wood? 3 to 6 cords should do... At 1 cord per acre, I would need 3 to 6 acres. I could buy 40 acres, put up a house, and produce my own biofuel as well. No "price on carbon emissions". If you can convince me that CO2 is an existential threat, that is one thing. I can move to Memphis where I don't need to heat my home. You cannot deny me the right to do that, if you think that CO2 is that threat. Otherwise, you can tax me until I refuse to participate.

Re: U.S. sets goal to drive down cost of removing CO2 from atmosphere

#347

Post by phtrivier »

oblak wrote: post #81
phtrivier wrote: post #46

Earlier quoted context omitted.

As other commenters pointed out, the other trickiest problem (beyond feasibility and energy requirement) of CO2 removal is that it's not clear who would be paying for them, since you want to sequester the CO2 and not use it. So in the end, it will be either a voluntary deal, or paid by the taxpayers as part of the maintenance of the infrastructure that is earth. Do people make money out of road and bridge maintenance…

Trickiest problem? Not clear who's going to pay for all this? The people are going to pay for all of it and then some. That's the entire point of this operation. As for the second part of your post: are you playing devil's advocate here? Planting trees, sustainable agriculture - that's not great way to generate fantastic profit at everyone's expense. It's not going to happen any time soon. Sorry for being a nihilisti…

Who is `The people` here ? The taxpayers ? That's entirely possible, and it would probably be the only scalable way to fund it (treat "the atmosphere" as an infrastructure that we have to maintain without directly benefiting from it.)

What I mean in my second post is that a private investor can put money into a forest, plant the trees, and recoup some of the costs by sell the fruits.

This is a silly image to tell that if you're a private investor (no insult here), and want to sequester CO2, you either "need to have CO2 sequestered as a byproduct of a project that makes money ; or need to have money generated as a byproduct of a project that sequesters CO2."

If you're a public investor (aka "the handler of taxpayer's money"), or a charity (aka "the handler of rich people's spare money"), the deal is not the same.

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