How to calculate CO2 absorbtion by my Garden

[studiot]

I was wondering how much CO₂ my garden removes from the atmosphere and how to develop a calculator for this purpose for other gardens.

 

First thoughts are to do it by ground area and to separate the ground area into zones of different plant size (height) thus:

 

Zone 1 - Grass and low plants less than 0.5 m high

 

Zone 2 - Plants 0.5 to 3.0 m high eg shrub borders , hedges tall vegetables etc

 

Zone 3 - Small trees and other plants 3m to 6m high

 

Zone 4 - Trees taller than 6m high

 

I would welcome comments on whether these are sensible divisions and any steers on how to obtain average CO₂ reductions for them.

Edited October 9, 2016 by studiot

[Sensei]

I would welcome comments on whether these are sensible divisions and any steers on how to obtain average CO₂ reductions for them.

How about:

 

For annual plants,

measure mass of their remains,

at the end of season.

 

You know molecules they are made of, how CO₂ + H₂O turn into them, during photosynthesis,

so reverse equations,

and you will have moles of CO₂.

 

Or dehydrate remains, so there will be almost only Carbon.

Measure mass. Divide by 12 g/mol. And you have moles of CO₂.

 

For tree, measure its circumference year by year, always in the same place (so mark it).

Difference is what it gained by year. Allowing you to calculate increase of thickness, and volume gained by the main trunk.

From volume and density you can estimate mass.

But it won't tell you about branches and leafs.

But if you're at the end of season putting leafs to composter (you should), you can measure their mass also.

Edited October 9, 2016 by Sensei

[studiot]

Thanks, Sensei for the suggestions.

 

Ever the practical man I see.

 

I fear that would be rather inaccurate, however.

Don't forget that plants produce often at least as much material below ground as above.

I would also need to add in the weights of heavy crops such as potatoes and apples.

Grass, too, though not weighty is cut many times a year.

 

I was really hopong that someone from the life sciences would respond with some average figures I could plug in.

[Sensei]

I was really hopong that someone from the life sciences would respond with some average figures I could plug in.

That would be even more imprecise than my method.

How can somebody know what you have in your garden?

Each garden is different arrangement of plants, different quantity, at different stage of life.

Do you expect average CO₂ absorption per single apple (or rather per kg of apples)... ?

Then you need quantity of apples (or rather their mass) to know and plug in equation..

 

I know mass of my grapes, as I measured them and put in db, prior making wine.

From 1000 g of dark/black grapes, with mass 1000 g, I got 600-650 mL of juice for fermentation, during 1st extraction.

 

Don't forget that plants produce often at least as much material below ground as above.

My peppers grew very large above the ground, and miniature of roots (5:1 or more), if they had plentiful of water.

I know because 3 times I was relocating them to bigger and bigger containers.

The one which had little water, exactly reverse.

They spend energy on growing roots to find water.

Edited October 9, 2016 by Sensei

[Danijel Gorupec]

For some reason, people that have their own gardens always positively impress me ... I am a dummy in this field, but I just remembered a table from wikipedia about biomass production rate, https://en.wikipedia.org/wiki/Biomass_%28ecology%29 , maybe it can help you to make a rough estimation (look under the 'global rate of production' section). Obviously, if you want to maximize your CO2 'removal' you should grow a swamp, lol.

 

Another random idea.... Maybe you can estimate the upper limit by finding insolation data where you live and then multiply it with photosynthesis efficiency (maybe you can find more precise efficiency data form some specific plant groups).

 

I was wondering how much CO₂ my garden removes from the atmosphere and how to develop a calculator for this purpose for other gardens.

 

 

But as I understand, you are actually asking about metabolism rate (more or less) as, if I understand it correctly, gardens do not remove CO2 from atmosphere overall - unless, of course, every year you take some of plant material and store it so that it can never decompose.

[imatfaal]

But as I understand, you are actually asking about metabolism rate (more or less) as, if I understand it correctly, gardens do not remove CO2 from atmosphere overall - unless, of course, every year you take some of plant material and store it so that it can never decompose.

 

Long term perhaps - but I am pretty sure that the hundreds of tonnes of trees around my parents garden that were not there when my father bought the house in 1953 are a fairly good short term sequestration of carbon

 

Even in the the longest time periods you can think of it like this - take two patches of land, one is kept arid and infertile and the CO2 sequestration is zero, the other goes from bare earth via grasses and mosses to a mature forest and the CO2 sequestration is substantial. ie an unchanging garden does little but the growth from grass to mature forest does a lot. And not all wood decays (my chair hopefully not), most fruit is eaten, animals are about 17 percent carbon etc. eventually all the cycle will come to an end - but that is pretty longterm

[Sensei]

Sodium Carbonate Na₂CO₃ has density 2.54 g/cm^3 = 2540 kg/m^3 (anhydrous),
and 41.5% of it is CO₂, 27.3% of it is Carbon.
2540 * 41.5% * 27.3% = ~287.8 kg of Carbon per m^3 of Sodium Carbonate.

Catching CO₂ just needs large deep lake with Sodium Hydroxide (or similar compound readily reacting with CO₂),
and pump and turbines to push air to the bottom.

Edited October 10, 2016 by Sensei

[StringJunky]

 

Long term perhaps - but I am pretty sure that the hundreds of tonnes of trees around my parents garden that were not there when my father bought the house in 1953 are a fairly good short term sequestration of carbon

 

Even in the the longest time periods you can think of it like this - take two patches of land, one is kept arid and infertile and the CO2 sequestration is zero, the other goes from bare earth via grasses and mosses to a mature forest and the CO2 sequestration is substantial. ie an unchanging garden does little but the growth from grass to mature forest does a lot. And not all wood decays (my chair hopefully not), most fruit is eaten, animals are about 17 percent carbon etc. eventually all the cycle will come to an end - but that is pretty longterm

CO2 sequestration need not be permanent to be useful. The important part is that the CO2 balance is tipped more one way than other at any given point in time, on average.

[John Cuthber]

Sodium Carbonate Na₂CO₃ has density 2.54 g/cm^3 = 2540 kg/m^3 (anhydrous),

and 41.5% of it is CO₂, 27.3% of it is Carbon.

2540 * 41.5% * 27.3% = ~287.8 kg of Carbon per m^3 of Sodium Carbonate.

 

Catching CO₂ just needs large deep lake with Sodium Hydroxide (or similar compound readily reacting with CO₂),

and pump and turbines to push air to the bottom.

That makes roughly as much sense as saying "we just need to pump it into space."

The manufacture of NaOH by the traditional pathway releases CO2 into the air- using it to trap that CO2 back again would be a waste of effort..

 

The more modern- electro-chemical- method would require the use of a lot of energy. Since most energy production releases CO2 it wouldn't produce a net benefit.

 

The idea that a garden sequesters CO2 is interesting.

If you have a a lawnmower- for example- you are certainly making more CO" "off-site" to power it.

In the long run I suspect the most CO2 friendly garden involves not actually gardening.

[Sensei]

That makes roughly as much sense as saying "we just need to pump it into space."

The manufacture of NaOH by the traditional pathway releases CO2 into the air- using it to trap that CO2 back again would be a waste of effort..

Production of CaO/Ca(OH)2 from CaCO3, indeed releases CO2.

 

Traditional pathway is:

Ca(OH)2(aq) + Na2CO3(s) → CaCO3 ↓ + 2 NaOH(aq)

 

According to wikipedia

https://en.wikipedia.org/wiki/Sodium_hydroxide

 

"Sodium hydroxide is industrially produced as a 50% solution by variations of the electrolytic chloralkali process. Chlorine gas is also produced in this process. "

 

https://en.wikipedia.org/wiki/Chloralkali_process

 

2NaCl + 2H2O -> Cl2 + H2 + 2NaOH

 

The more modern- electro-chemical- method would require the use of a lot of energy. Since most energy production releases CO2 it wouldn't produce a net benefit.

It will, if people won't burn Carbon to produce energy, but f.e. have concentrated solar power in the middle of desert.

 

So whole process would look like: desert solar power tower is producing energy, which is used to run turbines pumping salty sea water, to special lake in the middle of desert.

Water will naturally evaporate, giving brine, which will be electrolyzed producing NaOH, which will react with Carbon Dioxide from air.

[John Cuthber]

Production of CaO/Ca(OH)2 from CaCO3, indeed releases CO2.

 

Traditional pathway is:

Ca(OH)2(aq) + Na2CO3(s) → CaCO3 ↓ + 2 NaOH(aq)

 

According to wikipedia

https://en.wikipedia.org/wiki/Sodium_hydroxide

 

"Sodium hydroxide is industrially produced as a 50% solution by variations of the electrolytic chloralkali process. Chlorine gas is also produced in this process. "

 

https://en.wikipedia.org/wiki/Chloralkali_process

 

2NaCl + 2H2O -> Cl2 + H2 + 2NaOH

 

 

It will, if people won't burn Carbon to produce energy, but f.e. have concentrated solar power in the middle of desert.

 

 

So whole process would look like: desert solar power tower is producing energy, which is used to run turbines pumping salty sea water, to special lake in the middle of desert.

Water will naturally evaporate, giving brine, which will be electrolyzed producing NaOH, which will react with Carbon Dioxide from air.

And, if we had enormous reserves of cheap energy

(1) we wouldn't need fossil fuels so CO2 would be a solved problem and

(2) we could reduce the CO2 back to coal and bury it again.

Equally- as I said, we could shoot the CO2 into space.

 

But we haven't, so, for the time being, your suggestion is about as useful as saying we could shoot the CO2 into space.

[Sensei]

And, if we had enormous reserves of cheap energy

People have it. And always had. It's called "Sun".

And people are/were using it all the time. Even before founding out fossil fuels (it was created by the Sun millions years ago).

What you ate today is result of this "cheap" energy..

 

(1) we wouldn't need fossil fuels so CO2 would be a solved problem and

 

People don't need fossil fuels at all. Fossil fuels just release energy faster, than other "compounds which store energy"..

 

You can burn methane, to create fire, and cook something, scrambled eggs, for breakfast (honestly I have methane oven at home),

But you can also make your own solar oven,

concentrating solar power at one spot,

which will have the same effect,

but don't BS @ me, this thread is pro-ecologic, while you're supporting petroleum industry..

Unlike you Studiot, bothers about CO₂, and wants to reduce it, while you do everything to discourage everybody from doing anything (?!?!).. And it's over and over visible in your threads ?!

(if it's not planned, you should rethink your own attitude to the subject, or attitude to people you talk with, don't let your own "little wars" "becloud" development of humankind)

 

You don't bother and care about CO₂, so SKIP this thread..

Otherwise, come with any SINGLE idea to absorb CO₂ gas from atmosphere,

in such way, it will be stuck in newly created molecule (that's not organic like tree or plant).

We're waiting patiently for your idea.

 

(2) we could reduce the CO2 back to coal and bury it again.

Equally- as I said, we could shoot the CO2 into space.

 

But we haven't, so, for the time being, your suggestion is about as useful as saying we could shoot the CO2 into space.

 

.....

 

Have to self-censorship, all the time, my own threads while replying to you..

Edited October 17, 2016 by Sensei

[Endy0816]

That is a large part of the problem though. You have a concentrated source of energy and one whose drawbacks can be easily externalized.

 

They are looking at utilizing brine for CO2 capture though. Byproduct of desalinization and somewhat ironically drilling operations. Not a complete solution, but would help mitigate the damage while being agreeable to market forces.

[John Cuthber]

People have it. And always had. It's called "Sun".

And people are/were using it all the time. Even before founding out fossil fuels (it was created by the Sun millions years ago).

What you ate today is result of this "cheap" energy..

 

 

People don't need fossil fuels at all. Fossil fuels just release energy faster, than other "compounds which store energy"..

 

 

but don't BS @ me, this thread is pro-ecologic, while you're supporting petroleum industry..

Unlike you Studiot, bothers about CO₂, and wants to reduce it, while you do everything to discourage everybody from doing anything (?!?!).. And it's over and over visible in your threads ?!

(if it's not planned, you should rethink your own attitude to the subject, or attitude to people you talk with, don't let your own "little wars" "becloud" development of humankind)

 

You don't bother and care about CO₂, so SKIP this thread..

Otherwise, come with any SINGLE idea to absorb CO₂ gas from atmosphere,

in such way, it will be stuck in newly created molecule (that's not organic like tree or plant).

We're waiting patiently for your idea.

 

 

 

Have to self-censorship, all the time, my own threads while replying to you..

OK, let's start with the easy one

"come with any SINGLE idea to absorb CO₂ gas from atmosphere,

in such way, it will be stuck in newly created molecule (that's not organic like tree or plant).

We're waiting patiently for your idea."

 

 

http://theconversation.com/eco-cement-the-cheapest-carbon-sequestration-on-the-planet-10978

I'm not claiming it's original- but at least it's workable.

 

" while you're supporting petroleum industry.."

Nope, I'm supporting facing up to reality.

At the moment we actually really burn a lot of fossil fuel to get convenient energy.

If you want to use solar power to sequester carbon dioxide from the air, then there's a very simple way to do it.

Plant trees where there are currently none (large swathes of exploited rain forest would be a good place to start)

 

I wonder if you are just annoyed that I pointed out that there's no "magic" source of NaOH.

Yes you can make it, but in the real world, today, doing so generates a lot of CO2

 

That's because today (no matter what might happen in the future) we generate most of our electricity from fossil fuels.

So today your "solution" would create more CO2 than it absorbs.

 

In the real world in which we live (rather than some renewable powered utopia) we don't have energy to spare for making caustic.

 

So, you have provided a "solution" for a fairy-tail world.

Just to make things more absurd, in that imaginary world, the problem would be self-solving- because we wouldn't need fossil fuels, and we would be more or less carbon neutral..

 

If we did live in that world, the OP's question would be irrelevant. Sadly, as a species, we have yet to adopt a sensible approach to energy use.

 

And meanwhile, back to the chemistry.

Yes, you can indeed make NaOH from salt- and they do.

The side products are chlorine and hydrogen.

And the fate of the chlorine is - eventually- to become chloride (zero- and positive- oxidation states of chlorine are unstable in the biosphere).

Similarly, the fate of the hydrogen is to produce hydrogen ions.

So, the long term net fate of those elements is to form HCl.

Industrially, that's also the commonest fate for the two gases as produced by the NaOH manufacturing plant- They burn the Cl2 and H2 together to make HCl (and they recover some of the energy).

https://en.wikipedia.org/wiki/Hydrogen_chloride#Direct_synthesis

 

OK, so your "CO2 free" method for making NaOH produces HCl as a by-product, in a 1 for 1 mole ratio.

Essentially you use a lot of (CO2 -intensive, electrical,) energy to reverse the usual reaction.

NaOH + HCl --> NaCl + H2O

 

Some of the Cl2 is tapped off for other uses; for example PVC and other halogenated organics.

In the long run, those are hydrolysed in the biosphere (or burned in refuse incinerators) and the Chlorine is released as HCl.

So, all the chloride from the salt you used gets turned into HCl.

Eventually, that ends up back in the environment and dissolves into water.

 

 

That water will contain carbonates and bicarbonates (all sea, river and ground water does).

Adding acid (like HCl) to that water releases CO2

So, in the end, the HCl from your "not actually going to exist in this world" "solution" ends up producing CO2

And, by a "remarkable coincidence"- it ends up producing half a mole of CO2 for each mole of NaOH- exactly the same as the CO2 that the NaOH can absorb.

 

 

Let's summarise that.

You say we should use energy to turn salt into NaOH, (with CO2 as an inevitable long term by-product) and then use the NaOH to absorb that CO2. (Obviously, that's pointless)

In doing so you will need electricity.

That electricity is, in the real world, largely made by burning fossil fuels.

To do this on a "grand" scale, you need lots of electricity- so you need to burn lots of fossil fuel.

 

You propose to burn lots of fossil fuels- to achieve nothing.

And yet you say "this thread is pro-ecologic, while you're supporting petroleum industry.."

My view is don't piss about with lakes of caustic- stop wasting energy and start using renewables.

Well, perhaps you could "rethink your own attitude to the subject, ".

Perhaps you might even go in for some "self-censorship"

Edited October 18, 2016 by John Cuthber

[Sensei]

http://theconversation.com/eco-cement-the-cheapest-carbon-sequestration-on-the-planet-10978

I'm not claiming it's original- but at least it's workable.

 

AFAICS, it's suggesting replacing CaCO3 by MgCO3.

You were complaining that I wanted to do electrolysis of brine to get Sodium, while, as we can see on Magnesium wikipedia page:

https://en.wikipedia.org/wiki/Magnesium

"The metal is now obtained mainly by electrolysis of magnesium salts obtained from brine,"

C'mon!

While electrolysis of sea brine, there will be more Sodium created than Magnesium.

 

It's way to reduce production of CO2 in the future, while not fighting with existing right now CO2 in atmosphere.

 

Going your thinking path from couple above posts "energy for electrolysis must be from burning fossil fuels". (which is obviously not true, that's why I proposed other sources of energy from Sun. In 2014 year, 38% of electricity in UK was made from renewable/nuclear energy sources according to wikipedia and growing year by year).

So what Mg in cement will catch from air, will be first released to obtain energy for electrolysis...

Edited October 18, 2016 by Sensei

[John Cuthber]

Sorry, wrong process

http://www.nature.com/news/rock-s-power-to-mop-up-carbon-revisited-1.14560

 

Since nobody (except you) is talking about making magnesium metal, the rest of your post is irrelevant, though, for the record, you are still wrong about this

" there will be more Sodium created than Magnesium".

Strange as you may think, the process for making magnesium makes magnesium, rather than sodium- because they have the sense to largely separate them before they electrolyse the chloride.

 

Did you really think that they "accidentally" made more sodium?

 

Incidentally, you seem to have deliberately misrepresented what I said.

I said " we generate most of our electricity from fossil fuels."

and "That electricity is, in the real world, largely made by burning fossil fuels."

 

while you pretend that I said "energy for electrolysis must be from burning fossil fuels".

then go on to (correctly) say more or less what I said "UK electricity 38% is made from renewable energy source"
Well, some is nuclear but 53% (i.e. most) is from fossil fuel

http://www.energy-uk.org.uk/energy-industry/electricity-generation.html

 

But it doesn't matter because the electrolytic process you propose does not actually sequester CO2.

 

So, to summarise,

OK I posted the wrong link- oops- sorry

The correct link shows how you can do what you asked of me- use magnesium silicates to sequester CO2.

 

Your idea about lakes of caustic (in addition to being a nightmare from a safety / environment point of view) is dead in the water because it doesn't actually sequester CO2

Not even if you can drive it from renewables.

 

And then you wasted some time posting about the process for the production of metallic magnesium- which is interesting enough as a bit of industrial chemistry and vitally important in some high performance engineering- but it has

Nothing to do with the issue.

 

How's the self-censorship going?

Edited October 18, 2016 by John Cuthber

[studiot]

John I think I would need much better scientific convincing than that article before I swapped OPC construction for talcum powder, although I have always liked this

 

 

Juvenile Reflection by Ogden Nash

 

A little talcum is always walcum

 

Further, and as a matter of interest, carbonation by absorbtion of atmospheric carbon dioxide has long been known as a degrading factor for OPC concrete.

 

Sensei, thank you for your thoughts, but those installations are not the sort of 'plant' I have in my garden.

 

 

I really had hoped some bio/eco scientist here might know the % carbon in kg / kg for soft plant material such as leaves and harder plant material such as roots and wood.

 

Nor is it true that plant material, especially woody material, returns to atmospheric carbon dioxide in any rush.

I have considerably increased the heart my soil by a vigorous composting programme that has greatly increased the organic content of my soil over the last 30 years. Perhaps in 300 years time i will have generated some high quality Somerset peat.

[John Cuthber]

John I think I would need much better scientific convincing than that article before I swapped OPC construction for talcum powder

I don't blame you- but it's still a better option than Sensei's caustic bird bath /"water feature" which dissolves any creature that lands in it.

As I said, planting trees is the easy way to sequester carbon in the fairly long term (decades to centuries).

Compost and peat production are likely to generate methane which is a potent greenhouse gas.

Edited October 19, 2016 by John Cuthber