I know you said grid-tie isn't worth the trouble, but until the USA moves to more renewable energy for power production, that might yield the best carbon reduction, depending on how much you could otherwise sequester per KWh.

The national average CO2 emissions for power production is 947.2 lbs CO2 per megawatt-hour [1] (or 0.947 lbs/KWh).

So unless you can sequester 10-15lbs or more of CO2 a day, then you may be better off sending your excess power to the grid if your goal is carbon reduction.

Though I'm not sure how to account for the actual CO2 reduction - is the national average fair? Should you use the average per state since states vary widely in their renewable energy status? Is there some other way to determine how much CO2 you've offset?

[1] https://www.epa.gov/energy/greenhouse-gases-equivalencies-ca...

It would easily run me $10k to do all this, before I was able to cross tie a single kWh. And, in the bargain, I'd lose the standalone power system that is my office, because getting battery backed stuff approved out here is basically impossible. I tried for the house system, and after 18 months of fighting red tape that exists to fund the red tape, I gave up and built a grid tie system without a backup.

I get that it sounds easy, but it would cost more to interconnect it than the standalone system cost in the first place, drop me out of a very sweet 25 year net metering grandfathering, and leave me with a far less capable property in the deal. Sorry, just not interested in that.

I get it. I have a solar system too and there's no way in hell I'm updating it.

However, my system is also rather a good bit more reliable than the grid power on the house, which is nice for remote work.

Advocate for increased carbon taxes, extraction duties, and limits on new uses and loads.

Encourage wetlands and forest preservation and expansion. Wetlands, by unit area are the most productive carbon sequestering ecosystems on Earth.

Grow plants. Compost.

Reduce your own carbon footprint. Reduce meat consumption, use of manufactured goods (most especially with high embedded energy content), and energy useage. Reduce, reuse, and recycle, in that order.

Gardening.

If you garden without fertilizers, and compost garden waste, then you are capturing carbon in the soil. If you use a composting toilet too, you capture even more.

If you compost only the garden waste, and only( spread that compost on your garden, then the amount of stored carbon won't increase much, because a lot of what goes into your compost must have come from the soil. But if you also compost food-waste, and if you add soil-conditioners such as farmyard manure, then the amount of stored carbon will increase steadily.

But as has been noted up-comment, the easiest, cheapest way to get carbon into the ground is to not dig it up in the first place.

I'm not sure these work at such small scales, but it could at least give you a starting point and a project. If you start a blog about these experiments I'd love to follow. Hard to know if your operating emissions would be offset by your sequestration. If anyone has better ideas I'd also like to know.

There could also be a monetary reason to do carbon capture at home. There can be a lot of CO2 buildup in homes and offices with poor ventilation (read: most).

Methane is a worse greenhouse gas than CO2, but if you burn it as fuel it's a carbon-neutral energy source.

Alternatively, you could use electrolysis to make hydrogen, but hydrogen is harder to store.

(I'm not a chemist, so I have no idea if this could work. And it probably wouldn't be very practical even if it did.)

I do like your idea of experimenting with a rock crusher. The article mentions that finding the least-energy means of crushing rocks to the appropriate size is something of an open problem.

Assuming it's possible to use this process on a home scale with a decent solar grid and energy storage, it seems to me that you would be sequestering the carbon only very temporarily. Wouldn't the electrical energy used to produce the methane heat your home more efficiently (assuming you have an electric heating system) as you would be inviting energy losses through the Sabatier process?

Seems you would need to produce industrial levels of methane and distribute it (which would almost certainly be carbon expensive in it's own right) as substitute for naturally occuring methane being extracted from deposits.

It's a cool idea though. If there were a process to produce solid carbon, this would be much more promising (disclaimer: definitely not a chemist).

That's not as satisfying as just plain sequestering the carbon somehow. I mean, it would almost certainly be better to just run an extension cord to a neighbors house and let them run an electric space heater or heat pump off of the excess electricity.

Maybe methane could be used as an ingredient to make something else that's possible to store or bury long term, like some kind of plastic or liquid? (Most of what I know about the processing of hydrocarbons is probably wildly inaccurate because I learned it from Factorio.)

Probably (over) insulating the house is the most efficient way of minimizing energy loss. But then does an over-insulated house get overly warm in summer or easier to cool?

The air-sourced methane could be used for things that are hard to electrify/de-carbonify, and could reduce the use of ground based sources.

I'm wondering at what level of carbon tax it makes more sense to extract the carbon from the air to turn it into plastic than to use ground-based oil.

Trees? They make efficient use of solar energy to capture carbon and have a lot of other benefits:

https://www.cnu.org/publicsquare/2020/08/31/powerful-virtuou...

This is yet another stock/flow issue, where the sequestered carbon is a function of the stock of living trees, which itself grows with the delta of trees added - trees removed. You don't need to manually manage the lifecycle of each individual plant, just focus on the increasing the living stock, or rather, letting the living stock increase all on its own in response to more carbon in the air. So this is about land zoning and habitat protection, not building little coffins for individual trees. Let forests grow and protect their habitat, they will grow all on their own if allowed to.

FYI we've added 60 million hectares of forests since 2000. That process can be even expanded.

Of course that doesn't mean that reforestation isn't valuable. It certainly is. But even enormous growth of forest wouldn't make a big dent in atmospheric CO2 levels. The carbon came from underground and almost all of it will have to return underground to get CO2 levels down.

[1] https://innovate-eco.com/storing-carbon-in-plants-and-trees-...

You make it sound like a rapid process. Univ of Arizona did a study that showed CO2 emissions of dead trees was lower than living ones due to the rotting process being very slow compared to a living trees normal respiration cycle

I still favour wetlands over trees as a first priority.

I also want to say that the planting trees method is a bit more nuanced than everyone makes it out to be. But don't trust me, let's ask someone who knows better: Forrest Fleischman[0][1]. I'm not saying "don't plant trees" (do) but that this is often everyone's go to response to CCS and it is a bit naive (as explained in the threads).

[0] https://twitter.com/ForrestFleisch1/status/13062214459331297...

[1] https://twitter.com/ForrestFleisch1/status/14440088233506037...

Global warming is already pushing toward more frequent forest fires, or droughts in vast regions that if they have trees will end burning up as well.

Intensive tree planting in relatively small areas probably is a bad idea, or will have a big maintenance cost to try to avoid that risk.

But, in any case, it is the low hanging fruit of carbon capture. I just hope that it is done in the right way.

https://www.sciencefocus.com/planet-earth/how-many-trees-doe...

As far as I'm aware, the issue isn't with CO2 produced by cellular respiration, the issue is the burning of fuels dug up from the ground and the destruction of natural carbon sinks.

Had humans consumed fossilised carbon the thought would still be wrong since trees only store the carbon temporarily, eventually it is released as CO₂ when the tree burns up or rots away.

This leaves aside the whole discussion on whether there is any need to offset CO₂ from non-fossil sources - which there is not as far as I can see.

Practically, though, I'm out in some fairly high desert, and I have to pump water for irrigation out of a deep well. I can certainly do it, but I'm looking for something of a bit more "geologic scale" sequestration, if it's possible.

Here’s how it would work: you pass by a convenience store or gas station on your way home or to work, pick up some depleted battery packs, you get home and recharge those battery packs with your excess solar power, then bring the recharged battery packs back to convenience store or gas station for a bit of money. That way you don’t need to grid tie your solar installation. :P

If connecting into the grid isn't possible you could maybe attempt to charge batteries that you then take home and use there. Would require some calculations to check if it's worth it though... Would maybe be best if it were an electric car that can feed back into the grid.

Or run a desalination plant ;D

I don’t know the details of your site/situation, but I suspect any alternatives to grid-tying your system will turn out to be a lot less efficient than whatever (mostly one-time) trenching, cabling, and paperwork would be required.

Birth rate decrease -> demand decrease -> CO2 decrease

If we have the same birth rate as Korea or Japan, the population would drop more than 20% in 50 years according to the population prediction in these two countries. This means lots of demand would not need anymore, and might be the best practice which could be done by individual.

Is there any solution could really reduce around 20%? (Not to mention more than 20% and not to transfer the emission to other countries)

Each of those saves on the order of 20% of emissions and could be done in less than a decade if we put maximum effort into it.

I really doubt convincing a sufficient number of people to not have children is easier than any one of those measures. Just imagine the political backslash if the government suggested not to have kids for the climate. It's a lot easier to convince people to stop eating meat for the climate and even that is essentially impossible.

In the scale of country, East Asia did quite well without any policies (exclude China, they have a special policy on it). Just keep raising the price of estate, and then birth rate would drop and never come back.

For the part of energy, according to the EPA report[1], the emissions by electricity and heat are around 25% in total. If we want to reduce 20% in total, we need to close 80% of fossil plants. For me, it is nearly impossible. There are some countries may not have the land or safe area to place nuclear/renewable plants. (e.g. Singapore...) I know there is a plan for Singapore to buy the clean solar energy from Australia, but it only covers 1/5 of the consumption. Also, there must be security issues for transferring power between countries.

[1] https://www.epa.gov/ghgemissions/global-greenhouse-gas-emiss...

https://www.sunseap.com/SG/newsroom/2021/sunseap-signs-MOU-w...

I suspect most westerners are not going to be thrilled when receiving the government email about their mandatory sterilization.

Usually the idea floats in circles of people convinced we'll reduce the birth rate of "other" people (wink wink dog whistle yeah they're thinking of Africans)

It will just never be as efficient as an industrial scale operation.

I've got an awful lot of basalt laying around, though...

I've looked into it briefly, and came to the conclusion that the BOINC stuff (it used to be F@H but I gave that GPU to a friend for some CAD work) was more useful than crypto mining, because I simply couldn't mine enough to matter out here - a dollar or less a day sort of thing, with my annual power profile.