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Industry will probably need fossil/bio-fuels for decades. HCCAS converts resulting CO2 to O2 AND makes food/biofuel.



Much industry is built around carbon fuel, and the cost of electrical conversion means it will remain so for decades. That means CO2.

Conventional CCS traps CO2 and buries it. It's expensive, pays back zero, and  is a liability for future generations Most emitters aren't on top of suitable geology so also incur high cost shipping CO2 to CCS.

Hydroponic Carbon Capture At Source - HCCAS - uses CO2-rich flue gas on-site to grow plants hydroponically in a soilless environment and/or breed algae, for food or biofuel. There's more detail on my site.

The process scrubs flue gas of nasties, recovers the heat (to heat the hydroponic units - HUs), then feeds the CO2-rich gas to the HUs in which controlled environment optimizes plant/algae growth.


Low-tech and low-cost. Ambient pressure, ambient temperature, and simple (so workable anywhere regardless of local technical ability).

Low-risk combining established technologies.

Failsafe; worst-case failure would return CO2 emission back to pre-HCCAS level. No pollution, explosion, radiation or other bad stuff.

Cheap to run. Much input heat is from flue gas heat recovery. High water throughput, but plants transpire most which can be recycled without further treatment. Low-power lighting would supplement ambient light. Installations also EARN income by producing marketable green produce.

Farmland saving. All greenery produced saves on valuable agricultural land use.

Scalable and portable - HCCAS lends itself to an ISO-container format pluggable module design.

Retrofit-friendly to anything. Can be installed on any point emitter of any age - cement plants, steelworks, power plants...

CCS compatible. While HCCAS can't capture all emitted CO2 emission can be dramatically reduced. HCCAS can work with CCS; reducing CO2 sent to CCS makes CCS easier/cheaper and fills CCS facilities more slowly.

Reduce CO2, make O2, feed people. Here's a schematic:

What actions do you propose?

  1. Agree funding outline.
  2. Build an expert forum - chemical engineers, hydroponicists (is that a word?), systems guys...
  3. Set up a sponsoring project for research and development. Since the tech combines existing established technologies (see for example this article on Japanese hydroponic farming) rather than being entirely new, by partnering academic and real-world expertise in each field research time should be quite short and move on to development scale quite quick.
  4. Develop a pilot-scale operation on a smaller-scale emitter; perhaps a local power station.
  5. In parallel, research into optimal plant/algae choices for operation in a high-CO2 atmosphere. Current research such as this or this article from on common conventional species indicate that elevated CO2 does increase growth, so we can expect considerably greater productivity from HCCAS than from "normal environment" farming. However, it is likely that other species may be more suitable for a biofuel application; plants similar to some prehistoric species which flourished when CO2 levels were much higher may be a better bet. It should be stressed that this research is NOT on the critical path and can be in parallel with HCCAS roll-out, as improved plant performance can be simply brought on-line later by substituting whatever is then being grown.
  6. Once tech is proved pursue 2 directions:
    a) Custom build for large-scale emitters, installation built around available footprint etc for optimal efficiency
    b) Mass-produced modules for the many smaller-scale emitters, with the technology built into ISO-container format pluggable modules allowing an installation of any size to be assembled from standard parts that can be readily shipped, stored and handled and have globally-standardized maintenance and support.
  7. Roll-out as quickly as economies can permit. If wider predictions are correct, spending NOW on this will cost only a fraction of what it will cost later to handle the forced migration and probable resource-driven conflict that will result if we fail to act.


Who will take these actions?

Initially I'm looking for a sponsor or academic-industrial partnership to pick up the idea for the development phase; I'm in no position to do myself sadly.

I'm not looking to make a million (although it would be nice) and am quite happy for said partnership to run with the idea.

Once development is done and concept proven I'd hope that industry, NGOs and governments would pick up globally and run with the idea on a global scale. The numbers and social acceptability should be better than CCS and I think momentum will simply take over.

Honestly, I'm happy to watch - I have a contented life and don't want or need the hassle of delivering this myself. But a credit would be nice   : )

Where will these actions be taken?

Can be in any location. Ideally I'd like to see a global project with contributing experts from everywhere. The key word in "global warming" is global - it's everyone's problem and our leaders need to act together.

It's essential we recognise that local factors can affect implementation. It's highly unlikely we can agree on one single model that will work in everywhere, but the concept should be very portable. Detailed implementation at local level will inevitably differ and the project must not get bogged down - like so many - in designing a "one size fits all" model. That will fail, and will consume valuable years we may not have.

How much will emissions be reduced or sequestered vs. business as usual levels?

Depends on the installation, which will depend on funding, land,  local environment etc.

I would think reduction in emitted CO2 of 30-50% possible. Better reduction may require combining hydroponics and algae (which adds complexity so may be unachievable in lower-tech areas).

A study by The University of Applied Sciences in Dresden using Hedera helix 'Woerner' states, "nearly 2.4 kg of carbon dioxide is bound and 1.7 kg of oxygen released per m2 of hedge area per year." And "One m2 of the element area ...requires 1012 kg of water per year... of which only 0.76% remains in the plant." - the rest is transpired so easily recoverable. The capability of plants to capture CO2 is proven; this improves by 30-40% in higher CO2 concentrations. Much better performance should be attainable with the right crop.

Infrastructure required WILL be large, handling 100s or 1000s of tonnes of plants per day. However, this is a cash crop so pays-back, and frees-up equivalent farmland as well as cutting CO2.

What are other key benefits?

  1. Reduced CO2 emissions
  2. Higher O2 - fresher healthier air
  3. Green biomass product as food or biofuel
  4. Savings in agricultural land not needed to grow the same product
  5. Savings in transportation costs and emissions that would otherwise result from shipping the substituted biomass
  6. Reduced residual CO2 so lower CCS costs (if still required)
  7. Extended life of CCS facilities as they'll fill more slowly
  8. Operation - employment opportunities - in a clean, green environment
  9. Build - a whole new industry to boost economies and employment
  10. Cheaper more plentiful food, particularly in less fertile areas where a hydroponic solution may massively improve livelihoods.
  11. It's big, highly visible and VERY green. If it can also bring down food costs - as I expect - it will also be very popular. So politically, it will encourage a swing away from distrust of murky environmental policy toward belief in a highly-visible beneficial one. This in turn will pave the way for other projects.

What are the proposal’s costs?

I don't have the information I need to cost up effectively, sadly. However, I'd reckon ball-park costs for a custom installation for a large-scale emitter may be similar to installing CCS (and considerably less if we take into account the long-term operating costs of CCS).

If the mass-produced scalable modular concept described above proves effective the system could be implemented on the myriad smaller emitters far more cheaply (I think) than could CCS.

Comparing the 2 approaches, it seems to me that CCS has a high build cost, zero payback and continued ongoing costs for maintenance and security. It requires expensive transport of CO2 from emitter to CCS facility, and ultimately yields a long-term risk to our children should containment fail.

Initial build cost of HCCAS depends entirely on how much CO2 we wish to capture; the concept is fully-scalable with a fairly small fixed-cost element (collector, scrubber, heat recovery), allowing the facility to start small and develop over time. Obviously greater green produce output equals higher payback; input costs (as described above) will be fairly low so greater output should more quickly recoup build costs.

The proposed modular approach transforms the economics for smaller emitters, eliminating the need for costly bespoke infrastructure and allowing fast cheap deployment of pluggable modules using readily-available ISO-container handling equipment.

One more very significant factor to build-in, although unquantifiable, is that to feed growing populations we'll need more production. To achieve that will almost certainly require hydroponic solutions. So if you're going to build hydroponics anyway, why not do so where CO2 is much more concentrated - i.e. carbon emitter flues - than it is in the general atmosphere, which should dramatically increase output?

Time line

This is established tech that's simply being brought together, so we should be looking at incremental development only.


3-4 years to pilot.

7-10 years to scale-up and debug.

5 years to build a significant installation. HOWEVER, since the tech is all the same there's no reason multiple plants can't be HCCASd simultaneously; there's no need to switch off the plant during the build and diverted flue gas can be gradually increased as build progresses. The HCCAS could be operational within a few months of breaking ground, accepting more and more CO2 as the build extends.

The modular systems would be developed in parallel so should be deployable I would think on a 10-15 year schedule. Deployment rate is really down to how fast we want to build the modules.

Looking longer-term fossil fuel sources will deplete; however the technology will work perfectly well in a biomass-fuelled environment so can continue in service for the foreseeable future.

Related proposals

My own in the Energy sector contest, no others that I'm aware of.


Based on an internet search and (web-based) patent search, the concept appears to be novel. The points made and benefits are I think largely self-explanatory.

I'd like to thank the University of Dresden for providing core numbers on the efficiency of carbon fixing by plant growth; here is the link to their study.