Green CCS

By Michael Rogers

On the small end – false-colour scanning electron micrograph of the unicellular algae coccolithophore Gephyrocapsa oceanica (photo: NEON ja, coloured by Richard Bartz)
On the small end – false-colour scanning electron micrograph of the unicellular algae coccolithophore Gephyrocapsa oceanica (photo: NEON ja, coloured by Richard Bartz)

Recall biology class, where we learned that growing vegetation – photosynthesis – makes use of atmospheric carbon dioxide and releases, among other things, oxygen – and that we animals use oxygen and exhale carbon dioxide. The trouble is that human activity is more than respiration, releasing far more greenhouse gasses than the natural world can deal with.

This year’s surge in Amazon rainforest wildfires focused the world’s attention on the vulnerability of this important carbon sink that’s been referred to as the “world’s lungs”.

The Amazon wildfire surge was troubling, as forests around the globe play a significant role in pulling carbon dioxide from the atmosphere. Although a large amount of carbon is absorbed by biological and physical processes in the oceans – equalling roughly a quarter of the carbon released from human activity – the largest amount of carbon absorption occurs soil and forested areas.

To renew commercial value, the traditional practice of reforestation following fire or lumber harvesting – as well as afforestation to create new forested areas – has the added benefit of combating greenhouse gas emissions. Moreover, the renewal of wetlands to support biodiversity contributes to atmospheric carbon reduction. Urban areas are also creating their own, local green carbon sinks (think parks).

Bio energy
Ranging from the microscopic to giant seaweeds, algae is already a commercial source of, among other things, food for both humans and animals, nutritional supplements and fertiliser. Likewise, as an attractive, renewable source for biofuels, algae has attracted the attention of oil majors such as ExxonMobil:

“Algae can provide a diverse and highly desirable non-food source of the important renewable molecules that can be used to produce second generation biofuels. Some strains of algae can be optimised to produce bio-diesel precursors. Other algae strains can be optimised as a source of fermentable sugars, with compositions similar to those derived from corn kernels that are used to manufacture first generation biofuels like ethanol.”

Green CCS
Research into carbon capture and storage (CCS) has yielded a number of technologies that are being applied at the source to mitigate emissions from specific industrial facilities. And non-site-specific direct air capture looks to be a promising process to extract carbon – especially in areas where renewable energy sources such as solar photovoltaics and wind turbines can power the process.

So, it’s not a great leap to imagine optimised algae as the workhorse within a biosequestration system, capturing and storing carbon dioxide by biological processes. Just as with chemical-based direct air capture methods, the support systems for the algae carbon capture system could be off the grid, powered by renewables.

More about algae
Whether you’re curious about algae farming or the latest research, there’s a good number of resources to look into.

In the US, the National Algae Association – a non-profit algae education, production and remediation trade association – covers both “good algae” (commercial applications) and “bad algae” (toxic, red tied, etc.).

The European Algae Biomass Association (EABA) works to scientists, industrialists and decision makers to promote biomass production and use.

EUBIA, the European Biomass Industry Association represents the interest of its members, including SMEs, research institutes and universities working in the biomass field.