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At Source

is also

Really Resilient Agriculture

Hydroponic carbon capture at source

- cut CO2, feed people, save water

CO2, but in a good way

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STOP PRESS! HCCAS didn't win ClimateCoLab 2014... but it DID make Semi-Finalist so is probably a Good Idea...

STOP PRESS 2! HCCAS selected by MIT for Solve 2016! Watch my presentation to MIT FUEL here on YouTube

HCCAS - hydroponic carbon capture at source


Because we have a Food Crisis: not ENOUGH. We have a CO2 crisis: too MUCH. We have a Climate crisis. We have little time to develop solutions. HCCAS combines existing tech to make food / biomass / biochar, absorb CO2, make oxygen and save water.

It can even convert CO2 into a high-value carbon-negative building material.

But that's only part of the Good Stuff. HCCAS appears able to raise agricultural efficiency per unit area by 300-1000% - AND it's Really Resilient. HCCAS should allow us to:

1) increase our future survivability

2) dramatically cut CO2 emissions; ANY emitter ANYWHERE becomes potentially carbon-neutral or negative

3) have agriculture that is pest- and weather-proof as well as largely immune to climate change; is vastly higher yielding; and safe even in heavily polluted environments

4) reduce agricultural pollution; there's no need for weedkiller or pesticide (which will also help restore our bee population) and it also cuts or eliminates the farming run-off largely responsible for increasing toxic algal blooms in our lakes and oceans

5) save water, allowing HCCAS to work even where water is short

6) free-up land to re-forest for near-permanent ADDITIONAL carbon capture in trees AND provide green construction materiel

7) reclaim natural areas to save our dwindling biodiversity and provide meadow for essential pollinators

8) by reducing hunger, improve the learning ability of children and the productivity of adults (as well as mitigating a major conflict driver)

9) improve general quality of life

A warped variant of HCC is already in use - many commercial greenhouses already burn fuel to MAKE CO2, which can increase yield by 50%. Crazily, nowhere do we seem to have considered using the vast CO2 generation from our myriad carbon emitters to grow stuff.

Using CO2 to enhance crop production isn't suited to conventional open field agriculture as CO2 disperses quickly in open air. BUT, combining CO2 application with enclosed high-density hydroponics (in which every aspect of the environment is controllable) and clever growing conditions could change the game completely.

We desperately need to cut CO2 - if we can feed people or grow biomass in the process, in a way immune to climate change, simultaneously freeing-up land for re-foresting to permanently capture much more CO2, AND improve our long-term survivability, what's not to like?

So - why NOT HCC?

You said something about "building material"?

Yep - it's established technology and the material has a small fraction of the carbon footprint of concrete, dramatically cutting emissions arising from cement/concrete manufacture.

The concrete industry is one of two largest producers of carbon dioxide (CO2), creating up to 5% of worldwide man-made emissions of which 50% is from the chemical process and 40% from burning fuel.

Plus, building with CO2 locks it up - permanently - in useful spaces - homes, stores, offices - instead of in useLESS spaces like holes in the ground (yep, CCS...). Plus, CO2 locked up in plant fibre in hempcrete in buildings is WAY less likely to escape than high-pressure CO2 crammed into a hole in the ground.

Why "at source"?

Once CO2 is out of the chimney or stack, it's gone. Earth's atmosphere is 11km or so high, and the CO2 diffuses through it - you could cover the entire Earth in carbon capture plants 40 stories tall and you'd only recover the bottom fraction of one percent.

Capture at source or lose it for good.

OK, but won't renewables stop CO2 emission anyway?

Recent renewables development is brilliant, and is shaping-up to significantly impact carbon resulting from power generation. That said, it needs to - global electricity generation ALONE - excluding the hundreds of thousands of industrial facilities like steel and cement works - was 66% from carbon in 2014.

Here's the thing. Many industrial facilities are BUILT around carbon fuel. They can't be renewable-converted readily, and often not at all. Even where the process itself CAN be re-configured for electrical energy supply instead of carbon fuel, the power supply network TO the plant is often unable to handle the required load meaning 1000s of miles of power grid would ALSO need building.

Realistically, we're stuck with fossil fuels, so CO2, for decades. The question of massive-scale CO2 reduction for these point industrial emitters – refineries, steelworks, cement plants etc – is essential but has been largely ignored so far; the vast majority of clmate change mitigation effort is going into power generation. So we still have the remaining 37% of greenhouse gas emissions so far ignored (plus the huge number of smaller power plants "not worth" replacing).

There are 2 ways to handle CO2; use a form of Carbon Capture and Storage - CCS - to sequester and store it, like, forever... or find a way to use it. Using CO2 has so far proven elusive, which is why so much effort is going into CCS.

HOWEVER, conventional CCS - which pushes CO2 into holes in the ground and desperately hopes it will stay there - is expensive to build and maintain - forever; offers zero payback; and presents a long-term financial and environmental liability for our kids. Most CO2 emitters lack suitable geology anyway, so will incur high cost (financial and environmental) shipping CO2 to CCS. CCS appears very unlikely to ever be financially feasible on most locations.

By contrast HCCAS - Hydroponic Carbon Capture At Source - seems to offer an alternative we could implement on large scale NOW which USES the carbon effectively, either locked-in to a recirculating fuel-CO2-biofuel loop, OR making food (allowing the agricultural land currently used for that to be re-forested for more long-term - and rather pleasant - carbon capture), OR converting the crop to biochar, a usable - and valuable - product providing permanent carbon sequestration. And emissions from the fuel used for charring go straight back in to make more biochar!

HCCAS doesn't demand a big expensive bespoke build that takes years in the planning either - modularising as below will produce a low-cost and effective fully-scalable easily-deployed solution, workable anywhere, which since it also yields a valuable crop should achieve payback (and buy-in) quickly as well as help feed the world. It makes oxygen and recycles water. It's also immune to most external influences - like weather and pests - so largely climate change proof. According to the cost analysis done for the HCCAS 2016 MIT SOLVE entry it should even be profitable.

So what's not to like?

OK - so what IS hydroponic carbon capture?

Hydroponic carbon capture  at source- HCCAS - uses established low-cost technologyhydroponics – to capture carbon CONVERTING CO2 directly to food/biomass/biochar and oxygen. It does so using entirely natural processes, and recovers input heat and water from the emitter's flue gas. The only by-products are green stuff - either food or biomass - and oxygen.

We can also convert the green stuff to biochar to lock-up the carbon permanently as a solid (with emissions from the fuel used in charring being fed back in and themselves converted - neat huh?)

Hydroponics simply means growing plants in a soilless environment, with all the nutrients provided in the irrigation- which means a hydroponics installation can be any size and shape, on any number of levels, to fit whatever space is available - like this Japanese example. Hydroponics is well-established, reliable, no-risk, and HCC can work anywhere on ANY carbon emitter of ANY age. If you’re unfamiliar with hydroponics, here's Wikipedia's excellent page.

Hydroponic carbon capture is permanent AND failsafe; total failure would just return to pre-HCCAS CO2 levels, there’s zero risk of pollution, radiation, explosion or other bad stuff. It's ambient pressure and ambient temperature so the engineering's low-cost - that's the opposite of CCS. Unlike CCS it can’t leak, needs no long-term monitoring, won't ever fill-up, brings no security or terrorism risk, and avoids expensive shipping of CO2 to "safe" repositories. There's no expensive rare metal catalysts, no nuclear reactors, no hazardous chemicals, and no fracking. There's also no high-pressure or high-voltage systems, and no unpleasant or dangerous emissions. Finally, unlike CCS it leaves zero liability for our kids AND a better environment, cleaner air and more food.

SO: HCCAS is significant, quickly-implemented, low-cost high-efficiency carbon reduction, using TODAY’s technology TODAY, that ALSO feeds people AND freshens our atmosphere AND recycles water AND provides scope for large-scale re-forestation AND provides massively more efficient agriculture that is immune to climate change, weather and pest and is 100% scalable, flexible, and ethical and should also be profitable (or at least cost-neutral)

That's lots of reasons to like it. Incredibly, there doesn't seem to be ANY downside.


I first proposed hydroponic carbon capture in my letter in the May 2014 IET Magazine (scroll down - the "lead" letter appears on the website last!).

IET letter June 2014.pdf
Here's the original Magazine Letters page from the IET May 2014 Magazine - the pdf is only 228 kb
And HERE is the detailed proposal sent to UK Government and the Climate Change Group at on 18 June 2014. pdf, 98kb

Nice idea but can plants REALLY do this?

According to a study by The University of Applied Sciences in Dresden using Hedera helix 'Woerner' (shown right) as the test plant, "nearly 2.4 kg of carbon dioxide is bound and 1.7 kg of oxygen is released per square metre of hedge area and per year." That's ONE SQUARE METRE - imagine what a serious installation could achieve. Looking at water demand, the same study concludes "One square meter of the element area 'Hedges by the Metre' requires 1012 kg of water per year..." BUT "Only 0.76 per cent of the water remains in the plant." - rest transpires so is easily recoverable.

But that's just typical hedging in normal conditions. Now it gets REALLY good.

FIRST, higher CO2 levels increase CO2 uptake so since HCC can optimise CO2 levels for maximum effect the process should see 30-40% improvement in CO2 uptake. That's also 30-40% quicker greenery production.

SECOND, this LED lighting boosts growing speed 50% so add that to the above, you're looking at something that not only absorbs lots of CO2 but that ALSO should outperform conventional open-field agriculture by 80-90%.

THIRD, hydroponics eliminates weed and pest damage - a significant factor in yield loss - and does so super-organically by simply keeping them out. No chemicals

FOURTH, it's immune to weather - so virtually immune to climate change. With global food supplies increasingly threatened by a warming world, that has to be good.

FIFTH, chemicals are delivered exactly where they're needed, in exactly the right amount - no mass spraying of fields that wastes 90% of the chemicals, and no run-off pollution (which also means less toxic algal bloom in our seas and lakes)

So maybe now we're 2x or 3x more efficient per sq ft than open field agriculture.

BUT - square feet are FLAT. You can STACK hydroponics. So 2 levels = 4 - 6x better than flat field, 3 levels = 6 - 9 x better, and so on. That's WAY better land utilisation, WAY better yield, and WAY more CO2 absorption per unit area.

There's more. A modular container approach as below allows multi-tier planting in a container, stacking crops AND stacking containers. So a 4-tier container stacked 4-high is 16 times better land utilisation.

So potentially a well-run 4-tier 4-high install can grow produce at (+40% +90%) x 4 x 4 = 40 times more efficiently. And that's EXCLUDING savings pest or weed damage, AND from chemical wastage.

THAT's worth having.

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What if you're short of water?

Growing stuff takes water. Lots and lots of water. So this may look unworkable in drier areas. It isn't.

Because in conventional agriculture, most of the water you apply (99.24% in the above Hedera helix example) is wasted - it transpires straight to atmosphere so it's gone, so you need to get more. HCC is a closed environment, meaning the transpired water is condensed back out and re-used.

But where do we get the water from in the first place? From basic chemistry. We know burning carbon fuel releases lots of CO2 - but it also releases lots of water.

Here's the equation for wood burning, but other fuels are broadly similar:



6 O2


6 CO2


6 H2O

So when HCCAS recovers the heat from the flue gas we'll ALSO condense out LOTS of water.

There's another reason to reduce water vapour emission.

Recent science identifies rising water vapour as magnifying global warming - scavenging water this way dramatically cuts water vapour emission to atmosphere.

SO now we're reducing CO2, making food, biomass, or biochar, making O2, providing resilient agriculture AND reducing water vapour's global warming impact. And can do so profitably, producing funds for the local economy or more environmental projects.

That's pretty cool for a few plants.

Won't HCCAS cost as much as CCS - or more - to implement...?

Highly doubtful. Think about it: CCS needs complex pressurized long-distance transport infrastructure; HCCAS doesn't.

CCS demands large-scale secure "burial" sites which subsequently need to be guarded and monitored, forever; HCCAS doesn't.

CCS consumes a lot of energy doing what it does, so you actually need to produce lots MORE energy just to CCS the CO2 that you've made from, er, producing the energy to operate the CCS... go figure. HCCAS doesn't.

CCS presents a high-value attractive terrorist target with a very long and largely unprotectable perimeter (including 1000s of miles of pipeline);  HCCAS doesn't.

BEST OF ALL HCCAS can reach all the places in the world CCS can't (economically) get to, it's infinitely flexible, it feeds people, improves our air, encourages re-forestation (and biodiversity) and it's greener than a very green thing so - unlike CCS - will be welcomed by local populations rather than resisted. That should also help re-invigorate rather-jaded levels of public enthusiasm for green projects.

And because HCCAS is all the same, once the first is built subsequent builds are easy. Extending that logically to mass-produced modules means we can do lots and LOTS of installations very, very fast and very cost-effectively. According to the cost analysis done for the HCCAS 2016 MIT SOLVE entry HCCAS can even be cash-positive.

And that's something CCS will never be.

Here's another interesting thing about CCS. Trying to find a way - any way - to improve its dire economics, a use has been found for the CO2 the CCS has buried. Any guesses what? You'll love this... it's used for EOR.

"EOR"? Yep - Enhanced Oil Recovery. The CO2 is pushed down dying oil wells to squeeze out more oil. The best use CCS has for its captured CO2 is extracting MORE fossil fuels to make MORE CO2. Yep, seriously. D'uh.

Ask yourself:

    -   Would you rather spend money ONCE on something that keeps on GIVING BACK, like HCC?
    -   Or would you rather KEEP ON spending lots of money on something that will keep on TAKING - forever - like CCS?

Use brownfield = save greenfield

HCC doesn't need fertile soil, a sunny aspect, the right rainfall, or much else.

It doesn't need to be in an attractive area with shops and schools, or handy for the motorway.

So it's ideal for brownfield site that's unworkable for conventional agriculture and unsuitable for people, meaning it frees-up greenfield land for people, reforestation, or nature. Don't know how that pans-out financially, but I'm pretty confident how it pans out rationally.

Hang on - aren't we talking 1000s of tonnes of plants a day?

Yep. The planned Drax 100% biomass-fuelled 300MW power station was expected to burn 1.4 million tonnes of biomass annually (that's just under 4000 tonnes a day). So, for an emitter that size, yes.

BUT think that through - we're ALREADY planning to handle that much biomass, shipping it in. So there's nothing inherently scary about handling big numbers of biomass. Now imagine if we could MAKE the biomass locally instead of shipping it in, converting emitted CO2 back into more biomass right there on site. We won’t achieve 100% capture, but if we assume just 30% then as well as releasing 1000's of tonnes of oxygen, in one year HCC on this installation would save:

  • all the cost and emissions created by shipping 30% of 1.4 M tonnes - that's 420,000 tonnes - of biomass (most UK consumption is sourced from overseas)
  • the global warming impact of the 30% of CO2 recovered; if we assume biomass to be around 40% carbon, we have of the order of 40% of the recovered 30% of 1.4M = 168,000 tonnes of carbon (that's roughly 620,000 tonnes of CO2).

  • The agricultural land you'd need to GROW 420,000 tonnes of biomass. So it could be used for reforestation, or for people, or...

If your emitter can't use biomass - say you have a gas-fired plant or a coal- or oil-fired cement works - HCC can produce food instead, or can produce a fast-growing crop for biochar to sequester carbon directly.

Quickly, cheaply, flexibly. Did I mention it makes O2 as well? And the food HCC makes - really efficiently - means you free-up 1000s of acres of conventional agriculture, so you can re-forest that land and those trees will near-permanently sequester carbon (as well as aiding biodiversity, greatly improving our environment, and providing a source of green building materiel).

Biomass, biochar, or food, if I'm right about HCC we can spend a few billion implementing it to achieve permanent carbon reduction AND all these other benefits.

Or, we can spend many trillions re-locating populations, draining floods and starving from drought while we watch the Earth turn into Venus.

Here's an overview of HCCAS: