Gas-to-protein agriculture: decoupling food from environment

By Eloi Grignon, Ph.D. student, Member-at-Large for the GCI

Faced with a worsening climate crisis and growing food insecurity, humans have begun to produce food from the air. While you’d be forgiven for assuming this plot to be that of an Asimov story, it is, in fact, the reality that several start-ups envision for the future of agriculture. Indeed, a wave of firms have developed gas-to-protein technologies that employ bacteria to convert feed gases into an edible flour.

In truth, none of the technologies designed to date rely solely (if at all) on air. For instance, Solar Foods, a Finnish biotech company, combines carbon dioxide from the air with green (i.e. not derived from fossil fuels) hydrogen and water to feed a carefully selected bacterium. The result of this fermentation is their proprietary Solein protein, which they currently produce at a rate of 1 kg per day.1 Others in the gas-to-protein industry have developed their fermentation processes around different gases: Calysta uses methane supplied by the energy giant BP while Lanza Tech relies on the waste carbon monoxide generated by a nearby steel plant.1

Solar Foods’ recipe for their Solein protein. From [5].

The synthesized proteins are generally viewed and marketed as alternatives to other plant-based proteins, such as those derived from soy, whose cultivation is land-intensive and can come at the cost of intense deforestation.2 Here, gas-to-protein agriculture has the tantalizing potential to produce food on similar scales while requiring only a fraction of the area. A 2018 study estimated that widespread adoption (roughly 10-20% market share) of gas-to-protein could reduce farmland area by 6% and associated GHG emissions by 7%.3

Land intensity of various protein sources. From [4].

Gas-to-protein agriculture may also help phase out animal-based proteins. One suitable target for replacement is fishmeal, the powder obtained from drying and grinding the bones and offal of commercial fisheries’ by-catch.  Fishmeal, which is used as the primary source of protein for farm-raised fish, consumes approximately one quarter of the global wild fish catch and is strongly linked with the depletion of aquatic environments and collapse of local fisheries.1 As a more sustainable alternative, Calysta produces a bacteria-sourced protein with all the amino acids required to feed farmed fish. The potential impact is huge: Calysta’s CEO claims that the presence of a 100,000-tonne plant of synthetic protein can allow 500,000 wild fish to remain in the ocean.1

The boons of gas-to-protein agriculture are pushed to truly stupendous heights when CO2-consuming processes are employed. According to Solar Foods, the operation’s economic use of energy coupled with its inherent carbon sequestration could translate to a protein with only 1% of the carbon footprint of its plant- and animal-derived counterparts.1

Beyond the increased protection of forest and aquatic ecosystems along with huge water and energy savings, gas-to-protein agriculture has other, more intangible advantages. For instance, the liberation of food production from environmental dependence means that the protein’s annual tonnage need not be subject to environmental crises or day-to-day weather. Moreover, scaling production up or down can be achieved far more easily when no marginal land or animals come into the equation.

Although there is great promise for gas-to-protein firms to gain an established foothold, there remain several economic hurdles impeding widescale production. Chief among these is the high cost of green hydrogen – a key ingredient of many firms’ protein recipe. Green hydrogen is produced from the electrolysis of water and, as such, its price is contingent on the supply of low-cost electricity. It is hoped that the economies of scale associated with the advent of renewables will lower the price of electricity sufficiently to render gas-to-protein agriculture the economically favourable option. The balance may also be tipped in favour of gas-to-protein agriculture if alternative, non-monetary costs, such as those of land and wildlife, are factored into consumer decision-making.

The first agricultural revolution saw us take mastery of our environment and irreversibly change the course of human history. If gas-to-protein agriculture is to become a mainstay, could we now, 12 millennia later, be on the brink of witnessing an equally important turning point?

References

[1] Scott, A. (2020). Food from the air. CHEMICAL & ENGINEERING NEWS98(35), 18-21.

[2] Phillips, D. (2020). The Cerrado: how Brazil’s vital ‘water tank’ went from forest to soy fields. https://www.theguardian.com/environment/2020/nov/25/the-cerrado-how-brazils-vital-water-tank-went-from-forest-to-soy-fields

[3] Pikaar, I., De Vrieze, J., Rabaey, K., Herrero, M., Smith, P., & Verstraete, W. (2018). Carbon emission avoidance and capture by producing in-reactor microbial biomass based food, feed and slow release fertilizer: potentials and limitations. Science of the Total Environment644, 1525-1530.

[4] https://www.calysta.com/feedkind/. Accessed February 20, 2021.

[5] https://solarfoods.fi/impact/#bioprocess. Accessed February 27, 2021.

Canada Becomes a Leader in Carbon Capture

Canada Becomes a Leader in Carbon Capture

By Karlee Bamford, Treasurer for the GCI

The attention of international media has been captured by the remarkable success in CO2 sequestration achieved by the Canadian company Carbon Engineering, located in Squamish, British Columbia. Sustainability-related, world-saving initiatives often have an easier sell in the media than, say, incremental advances reported by researchers on equally sustainable academic pursuits (rough, eh?). In this instance the craze over Carbon Engineering’s advances has been amplified by the news of their recent partnerships with household-name energy and oil giants, such as Chevron, BHP, and Occidental Petroleum, in the form of a CAD $68 million investment.  So, what is this incredible advance?

From the success of their pilot plant and the data they’ve accumulated thus far, Carbon Engineering implementation of their technology has achieved capture of The technology in question can be split into two major advances. Referred to as direct air capture, or DAC, the first process developed by Carbon Engineering involves the transfer of gaseous CO2 from ambient air to an absorber fluid, a strongly basic solution of sodium or potassium hydroxide. The transfer process is achieved using an air-liquid contactor, designed and described by the company in 2012,4 that involves an array of fans, pumps, cheap PVC piping and structure, and fluid distributors. These components are fundamentally no different than those commonly found in cooling towers used as heat exchangers for water cooling. However, the orthogonal geometry (Figure 1) of air (atmospheric, ~ 400 ppm CO2) and fluid (the absorber) flow differs significantly, making repurposing of existing cooling tower designs for DAC an inefficient and expensive strategy for CO2 capture.

Picture

Figure 1. Commercial realization of air-fluid contactor designed by Carbon Engineering. M = Na or K. Image obtained from CanTech Letter and modified.5

The CO2 taken up by the alkaline absorber fluid is converted to carbonate (CO32-) salts and can be precipitated from the aqueous solution by treatment with calcium hydroxide to give calcium carbonate pellets. The captured CO2 can thus be stored as calcium carbonate or can be cleanly regenerated as pure CO2 gas, with elimination of a CaO , at high temperatures (650 °C) for commercial resale. The byproduct CaO may even repurposed by conversion back to Ca(OH)2 in a lime slaker, using water.1 Carbon Engineering has been piloting this process at their facility in Squamish since 2015, according to their website, after having tested a smaller prototype from 2010 and published the performance results in 2013.6 At the time of Carbon Engineering’s founding and until as recently as 2018, no commercial-scale air capture systems had been developed, which was a direct result of the anticipated inefficiency of CO2 capture using conventional cooling tower designs.4 Undeterred, Carbon Engineering has proven otherwise with their innovative use of cross-flow geometry.

The second break-through technology from Carbon Engineering is their patented Air To FuelsTM process, which they’ve been piloting since 2017. Taking the stored CO2 from their DAC process, Carbon Engineering has successfully produced a clean, sulfur-free, source of hydrocarbon fuel that requires no further modification for consumer consumption. The process involves passing the regenerated CO2 gas through a reactor containing hydrogen (H2) gas to generate synthesis gas (syn-gas), a mixture of CO and . The syn-gas is then passed through a Fischer-Tropsch reactor where the synthetic hydrocarbon fuel is thermally generated over a heterogenous base-metal catalyst (e.g. iron, cobalt, nickel).7

The technologies have been developed by the research groups of founder and U of T alumnus Prof. David Keith. Prof. Keith is currently faculty at Harvard University in the School of Engineering and Applied Sciences. To date, the company has filed 13 patents and produced numerous publications describing their innovations. According to media reports,8 recent multimillion-dollar investments will allow their and the company has already signed a memorandum of understanding with Squamish First Nations about their intentions.9

One of the most attractive aspects of the DAC and Air to FuelsTM technology is location. Plants could, hypothetically, be built anywhere, as CO2 is well mixed in the atmosphere and Carbon Engineering’s technology does not require that CO2 capture occur at the point of CO2 generation as in, for example, CO2-scrubbers used in exhaust systems.

However, with the excitement surrounding Carbon Engineering’s projected ability to capture CO2 at low cost and high volume, controversy has inevitably been close to follow. The interest from large oil corporations in this technology may not be as principled in sustainability as it appears but driven in part by their need for large volumes of CO2 for so-called green fracking (hydraulic fracturing). Supporting further oil extraction in this way goes completely counter to the need for elimination of emissions that the 2018 Intergovernmental Panel on Climate Change (IPCC) report clearly indicates must accompany advances in carbon capture and storage.10 Still, perhaps the positives outweigh the negatives in this instance. This very week, Environment and Climate Change Canada reported that Canada is warming at twice the rate of the rest of the globe.11 The need for efficient technologies to address climate change has never been more immediate. Fortunately, Carbon Engineering is not alone: at least two other companies with commercial plans for CO2 capture have started in Switzerland (Climeworks)12 and the USA (Global Thermostat).13 Whether the Canadian solution is adapted worldwide will depend not only upon Carbon Engineering, but also upon how these alternative approaches evolve.  For once, it is probably best not to pick a team to cheer for but, instead, hope that each country’s company develop a complimentary capture strategy to address the international dilemma that is climate change.

References:

  1. Keith, D. W.; Holmes, G.; St. Angelo, D.; Heidel, K., Joule 2018, 2, 1573-1594.
  2. American Physical Society. Direct Air Capture of CO2 with Chemicals: A Technology Assessment for the APS Panel on Public Affairs. June 1, 2011 https://www.aps.org/policy/reports/assessments/upload/dac2011.pdf ; accessed April 24, 2019.
  3. Carbon Engineering, https://carbonengineering.com/ .
  4. Holmes, G.; Keith, D. W., Trans. R. Soc. A 2012, 370, 4380-403.
  5. Artist’s rendition of a commercial scale Carbon Engineering contactor, CanTech Letter. https://www.cantechletter.com/2016/10/squamish-b-c-s-carbon-engineering-begins-scale-co2-capture-new-deal/ ; accessed April 4, 2019.
  6. Holmes, K. Nold, T. Walsh, K. Heidel, M. A. Henderson, J. Ritchie, P. Klavins, A. Singh and D. W. Keith, Energy Procedia, 2013, 37, 6079-6095.
  7. Heidel, Keton et al. Method and system for synthesizing fuel from dilute carbon dioxide source. WO2018112654A1, 2017.
  8. BBC News, Matt McGrath. Climate change: ‘Magic bullet’ carbon solution takes big step. April 3, 2019 https://www.bbc.com/news/science-environment-47638586 ; accesed April 3, 2019.
  9. CBC News, Angela Sterritt. In fight to combat climate change, Squamish Nation joins forces to capture carbon. November 29, 2018. https://www.cbc.ca/news/canada/british-columbia/in-fight-to-combat-climate-change-squamish-nation-joins-forces-to-capture-carbon-1.4924017 ; accesesd April 4, 2019.
  10. Intergovernmental Panel on Climate Change 2018 Summary for Policy Makers, Global Warming of 1.5 °C. https://www.ipcc.ch/site/assets/uploads/sites/2/2018/07/SR15_SPM_version_stand_alone_LR.pdf ; accessed April 4, 2019.
  11. Environment and Climate Change Canada, Canada’s Changing Climate Report, April 1, 2019. https://www.nrcan.gc.ca/environment/impacts-adaptation/21177 ; accesed April 4, 2019.
  12. Climeworks, http://www.climeworks.com/
  13. Global Thermostat, https://globalthermostat.com/