10th May 2022
Algae ponds could sequester gigatons of carbon
A new method of carbon capture is being developed using microalgae grown in open-air, pond-based systems on coastal desert land. This can be achieved without the need for fresh water.
In 2015, the world crossed a grim milestone as the global average temperature reached 1°C above the pre-industrial level. The years since then have seen an increase in climate and weather-related disasters, often with multi-billion-dollar impacts and a significant toll in human lives.
On Sunday, the UK's Met Office announced that the probability of global average temperatures reaching 1.5°C above pre-industrial levels over the next five years is now almost 50:50 (48%). The agency also predicts a greater than 90% chance that a new record high global temperature will occur during at least one year from 2022-2026.
In addition, the National Oceanic and Atmospheric Administration (NOAA) has published its latest data. This shows the monthly average for carbon dioxide (CO2) now exceeding 420 parts per million (ppm) for the first time in recorded history.
If current trends continue, the world is on track for more than 3°C of global warming by 2100, with devastating economic and societal impacts. As the climate crisis worsens, the prospects for humanity this century appear increasingly bleak. Even if a rapid shift to renewables is made, the lag between cause and effect will ensure that momentum remains in global warming for some time to come.
The need for additional action – beyond just curtailing our emissions – has led to growing interest in carbon capture, utilisation, and storage. Valued at less than $2 billion worldwide in 2020, the market is likely to almost quintuple in size by 2030, with a compound annual growth rate of nearly 20%, based on research by Fortune Business Insights. It could become a trillion-dollar industry by the 2050s, removing a significant fraction of historical greenhouse gas emissions and potentially restoring Earth's atmosphere below 300ppm in the longer term.
One company aiming to establish itself as a leader in "carbon negative" systems and to create a more sustainable future is Brilliant Planet, founded in 2013 and based in London, UK. Brilliant Planet has been developing an innovative new process involving microalgae, which are grown in vast quantities within open-air, pond-based systems on coastal desert land.
No freshwater is required for the microalgae. No genetic modification is required either. Instead, thousands of local algae species are carefully searched, and the most effective strains are identified, based on location. A natural process combines nutrients, sunlight, and CO2, to deacidify seawater. The carbon sequestering is assisted by sensor technologies, high-frequency satellite monitoring, industrial automation, and machine learning, all of which can optimise the algae with unprecedented accuracy. The mature algae are harvested using fine mesh filters, dried in the open desert air, then buried 1 to 4 m (3 to 13 ft) below ground, storing carbon for thousands of years. The seawater is returned to the ocean, stripped of nutrients, but also of acidity.
The company's earlier research involved a 3m² (32ft²) experiment on the shores of St Helena, South Africa. Since then, it has demonstrated a 30,000m² (323,000ft²) production facility, using the world's largest algae growth pond in a coastal desert of Morocco. It costs less than $50 per ton of captured CO2 to run, which is half that of emerging technologies such as direct air capture.
Following nine years of research and development, including four years of pilot operations, Brilliant Planet is now preparing to introduce a commercial platform that is 10 times more scalable and deployable worldwide. Last month, it announced the closing of $12 million in Series A funding co-led by Toyota Ventures and Union Square Ventures.
The goal is to replicate seasonal ocean blooms, which can transform thousands of square kilometres in a matter of days, becoming so large that they are even visible from space. Microalgae have a photosynthesis conversion efficiency of 6-8%, while that of land plants is 0.1%-0.3%. And unlike seasonal algae blooms, this self-contained process could be sustained year-round. The company believes its operations could one day reach the gigaton scale, with large arrays capturing a significant fraction of humanity's 36 gigatons in annual CO2 emissions.
"With many of the world's largest companies announcing net-zero targets each month, we expect substantial growth in demand for high quality carbon credits over the next few years," said John Buttrick, a partner at Union Square Ventures. "This presents an important opportunity for companies that can quickly scale carbon removal, while meeting the quality standards demanded by sophisticated companies. We believe Brilliant Planet is uniquely positioned to do so."
The microalgae could also be used as an alternative food source. Earlier grant funding, through the UK government's Transforming Food Production programme, played an important role in the R&D and pilot-scale demonstration.
"It is fantastic to see Brilliant Planet attract additional investment from the private sector to build on and scale-up the technology they have developed and demonstrated through the Transforming Food Production programme," said Katrina Hayter, UKRI Challenge Director. "Setting the sector on a trajectory to realise net-zero emissions is a cornerstone of our programme. The large-scale cultivation of microalgae has huge potential to mitigate the impacts of climate change, whilst also providing opportunities as a sustainable alternative source of food."
"By using empty desert and seawater that would not have otherwise come to the surface, our solution creates 'new' Net Primary Productivity," said Chief Scientist and co-founder of Brilliant Planet, Raffael Jovine. "In other words, we employ underutilised natural resources to grow new biomass and draw down excess CO2. Per unit area, this approach sequesters up to 30 times more carbon per year than rainforests, while it also de-acidifies local coastal seawater back to pre-industrial levels."
"Nature-based solutions to climate change are normally the most scalable and cost-effective – but it is often difficult to verify the amount of carbon removed by these methods and the permeance of the storage," said Adam Taylor, CEO of Brilliant Planet. "On the other hand, man-made solutions such as direct air capture can be easily verified but are prohibitively expensive due to the significant inputs of energy, chemicals and freshwater required. Brilliant Planet has now developed a uniquely cost-effective, scalable, and verifiable nature-based system that delivers on all requirements. With the IPCC confirming that tremendous amounts of carbon will need to be removed from the atmosphere to limit global warming to 1.5°C, we feel that this is the right solution at the right time."
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