January 09, 2024

Environmental, Natural Resources, & Energy Law Blog

Liquid Trees: Carbon Capture and Sequestration Via Mass Algae Farming and Marine Spatial Planning - Joseph Gabris

By: Joseph M. Gabris
LLM Fall 2023


Ⅰ. Introduction

Ⅱ. Why Algae?

III. Cap-and-Trade Via Mass Algae Farming as a Form of Mitigation Banking

IV. The Challenges of Algae Aquaculture – Should Humans Just Stay on Land Where We Belong?

V. Chasing the Glimmer of Hope – A Path Forward

VI. Conclusion


Capturing and sequestering carbon from the atmosphere has become an important strategy in addressing the global climate change crisis. Forestation and carbon sinks are some of the more common sequestration methods that often come to mind. However, atmospheric carbon remediation in the form of mass algae farming is often left out of this conversation. But why? Algae farming is not necessarily the end-all-be-all to cure climate change, or even to curb global carbon buildup, and utilizing this approach does not mean we should abandon currently used methods. But, it is certainly an approach we need to take seriously. After all, about 70% of the world’s oxygen is produced by algae[1], and about 71% of the Earth’s surface is water.[2] Further still, it is well accepted in the scientific community that algae are simply more efficient at photosynthesis than their terrestrial counterparts – trees.[3] Algae farming in the context of atmospheric carbon remediation would involve cultivating algae in natural and artificial water bodies throughout the U.S. for the purpose of capturing and storing carbon – similar to farming trees for the same purpose.

So why are we waiting decades for trees to grow when algae can do a better job in a fraction of the time? As this article will explain, farming algae by way of marine spatial planning and management (“MSP”) for the purpose of carbon mitigation banking could benefit our country—and the global community—immensely. This article will explore what current carbon remediation frameworks look like in the United States, and how a new framework can be introduced that utilizes algae-based carbon capture and storage (“CCS”) technologies. This article will explain both the benefits and challenges of such an approach, concluding that regulatory approaches going forward should be less “terrestrial-based” and more inclusive of aquacultural approaches.

  II. Why Algae?

In the past decade, sequestration of carbon using microalgae has been recognized as “one of the world’s most important and effective carbon sequestration methods.”[4] This is because algae are some of the best photosynthesizers on the planet. Indeed, microalgae in general has shown to be ten-to-fifty times more efficient at capturing carbon dioxide than terrestrial plants,[5] and Chlorella vulgaris, a species of green microalgae, has been shown to be four-hundred times more efficient than trees at carbon capture when used in bioreactors.[6] Algae, in many ways, is also more versatile than trees. For instance, algae-fueled photo-bioreactors throughout urban areas can be utilized in places not suitable for planting trees as a means to combat carbon pollution, especially in those places with high population densities.[7] Moreover, there are various other uses for algae other than carbon capture and sequestration: food, fuel, fertilizer, filtering (e.g., wastewater treatment, removing pollutants), and even cosmetics.[8] So why hasn’t algae received headlines as a carbon removal method like trees have? Is it because wood is … sexier? It’s not that this method has been ignored – in fact, the U.S. Department of Energy invested eight million dollars in 2021 for algae-based technology development projects for use in carbon capture.[9] Instead, this quandary seems to be more about environmental activism and carbon remediation frameworks in the United States generally, rather than algae in particular. Cap-and-trade programs in the United States are still developing. “Cap-and-trade” is a term for government regulatory programs that cap emissions of a certain pollutant – for example, carbon dioxide – thus creating a market for emissions permits that can be traded for value between companies.[10] At the time of this writing, the only state-wide carbon cap-and-trade programs exist in California, Massachusetts, and Washington.[11] Only recently has a mandatory cap-and-trade program been implemented in the United States via the Regional Greenhouse Gas Initiative (“RGGI”), and this program only covers eleven states.[12] Clearly, further developments in U.S. cap-and-trade programs are warranted across the board. Our focus here will be on what an algae-based cap and trade framework might (roughly) look like.

  III. Cap-and-Trade Via Mass Algae Farming as a Form of Mitigation Banking

Similar to how cap-and-trade programs create a market of credits and debits, so too does wetlands mitigation banking under §404 of the Clean Water Act (“CWA”).[13] Both individuals and commercial entities that wish to dredge or fill wetlands must obtain a permit from the U.S. Army Corps of Engineers that allows the dredge and fill but requires restoration of other wetlands.[14] This program could serve as a template for a cap-and-trade system involving algae-based carbon mitigation banking. Whereas wetlands mitigation banking involves the process of restoring wetlands at another location, an algae-based carbon mitigation banking program would involve farming algae in exchange for carbon emission allowances.

Because the U.S. Army Corps of Engineers has regulatory jurisdiction of all waters of the United States and navigable waters,[15] it would play a critical role in implementing an algae- based carbon mitigation banking program by serving as the conduit for approving algae bankingprojects (at least within natural water bodies). However, such projects would take a lot of planning. Because algae grow in aquatic environments, marine spatial planning is needed.

UNESCO defines Marine Spatial Planning (“MSP”) as “a public process of analyzing and allocating the spatial and temporal distribution of human activities in marine areas to achieve ecological, economic and social objectives that have been specified through a political process.”[16] MSP is an important tool “for implementing ecosystem-based management, reducing user conflicts, and ensuring the sustainable use of ocean and coastal resources.”[17] The National Oceanic Atmospheric Administration (“NOAA”) provides recommendations to the federal government for national coastal and marine spatial planning.[18] This planning, in part, includes impact assessments of “sensitive species and habitats.”[19] Of course, this is just one of the many factors that must be considered when mapping out coastal and marine development.

MSP is meant to map out and address the flaws of a project before it is implemented. While it is true that any sort of coastal or marine project would require MSP to at least some degree, because the focus of this article is on algae-based projects, we will turn our attention only to some of the potential challenges that algae-based carbon mitigation projects—and CCS technology in general—face.

  IV. The Challenges of Algae Aquaculture – Should Humans Just Stay on Land Where We Belong?

A. Ecosystem Impacts

As already mentioned, MSP involves impact assessments of species and habitats. One of the challenges of mass-farming algae is that too much algae in any given space—like too much of any living organism—can cause problems within the ecosystem. For instance, algae block sunlight from reaching plants directly below them.[20] Furthermore, toxic algae blooms can be extremely harmful to both aquatic life and humans.[21] Though most algae do not produce toxins, even nontoxic blooms can harm the environment,[22] and in any case these are definitely points still worth considering.

B. Economic Challenges

To add, economic costs will certainly be a hurdle for these algae farming projects as well. According to one study, current algae-based capture and sequestration technologies cost between $702 to $1585 per tonne of carbon dioxide captured and sequestered.[23] Compare this to another study that estimates the average global cost of current CCS technologies to lie between $15 to $340 per tonne, depending on emission source, technology, and approach.[24] Considering that the carbon removal efficiency of novel algae-based CCS technology lies between 51% to 73%,[25] there is still a lot more room for algae-based CCS technology to evolve.

C. Durability

Finally, perhaps the most critical yet most overlooked problem is algae’s durability to store carbon. Photosynthetic algae are very efficient at capturing carbon and using photosynthesis to convert that into oxygen (and sugar). [26] However, the lifespan of algae is relatively short – and once the algae die, carbon is generally rereleased into the atmosphere, making algae-based CCS technology seem more like a temporary solution rather than a sustainable one.[27] But not all hope is lost. Recently, a U.K. company by the name of Brilliant Planet has been experimenting with solutions that trap carbon-saturated algae in sediment before it decomposes.[28] This process occurs naturally in the ocean, when dead algae sometimes sink to the ocean floor where it gets stuck.[29] Brilliant Planet has recently been doing something similar by drying the algae, then burying it in the desert, thus creating a sort of sealed carbon sink that is able to lock away the algae-captured carbon “for thousands of years.”[30]

  V. Chasing the Glimmer of Hope – A Path Forward

To the extent we have discussed the challenges of implementing an algae-based carbon remediation program, our discussion has not been exhaustive. That being said, even if such an approach to climate change does not at this time seem to be the best strategy, we need to be bold. Government needs to immediately start subsidizing and stimulating research and development to facilitate acquiring more information on how to meet the challenges above, while utilizing MSP to map out potential projects. Additionally, educational campaigns to inform the public of potential algae-based climate solutions are also warranted. Even if those challenges still remain, in a cost-benefit analysis, investing money in algae-based technologies now will be much cheaper than dealing with the billions, if not trillions, of dollars of damage we have experienced and will continue to experience from climate change. Indeed, the effects of climate change in just the U.S. have cost about $165 billion in 2022 alone.[31] To reiterate, this is a very limited discussion, and I candidly invite the reader to consider more and do their own research – after all, public discourse is important in this field. That being said – the fact of the matter is, again, we simply do not have the time to try every possible solution one at a time and need to take advantage of all potentially promising solutions to the global climate crisis and threat of human extinction.

  VI. Conclusion

In conclusion, because algae are generally very efficient at capturing carbon, algae-based carbon remediation solutions should, at the very least, be seriously investigated. Of course, there will be many challenges, such as long-term storage, as well as costs associated with early development, but as the past has revealed, these challenges can be overcome with ingenuity and creativeness. Thus, we need to look more into algae-based carbon remediation frameworks and consider using MSP to map out potential projects. This would include subsidizing algae-based carbon offsetting projects, funding research and development within this field, and employing educational campaigns to inform the public. What is the takeaway here? The point is that, while challenges and risks in adopting such technologies do exist, we are at a breaking point, and the risk of not doing anything is far greater. Humans, and every other living species on the planet, are facing a crisis, and we need to be creative and forward thinking in climate solutions – which is why algae-based CCS technology should be seriously supported and studied as a viable solution. Just because algae are small compared to trees does not mean they should be ignored. After all, “the Sun does not forget a village just because it is too small.” – African Proverb


[1] Oxygen Levels, U.C. BERKELEY, https://ugc.berkeley.edu/background-content/oxygen- levels/#:~:text=Photosynthesizing%20algae%20in%20the%20ocean,photosynthesizing%20bacteria%20that%20produce%20oxygen (last visited Oct. 25, 2023).

[2] Water Science School, How Much Water is There on Earth?, U.S. GEOLOGICAL SURVEY (Nov. 13, 2019), https://www.usgs.gov/special-topics/water-science-school/science/how-much-water-there-earth#: ~:text=About%2071%20percent%20of%20the,Water%20is%20never%20sitting%20still.

[3] See Fabrizio Di Caprio, et al., Catalysis, Green Chemistry and Sustainable Energy, 179 STUDIES IN SURFACE SCI. & CATALYSIS 7 (2020), https://www.sciencedirect.com/topics/chemistry/photosynthetic-efficiency.

[4] Helen Onyeaka, et al., Minimizing Carbon Footprint via Microalgae as a Biological Capture, CARBON CAPTURE SCI. & TECH. (Dec. 2021), https://www.sciencedirect.com/science/article/pii/S2772656821000075.

[5] Id.

[6] Ben Lamm, Algae Might be a Secret Weapon to Combatting Climate Change, QUARTZ (Oct. 1, 2019), https://qz.com/1718988/algae-might-be-a-secret-weapon-to-combatting-climate-change. See also Nick Lavars, Algae-fueled Bioreactor Soaks Up CO2 400x More Effectively Than Trees, NEW ATLAS (Sept. 18, 2019), https://newatlas.com/environment/algae-fueled-bioreactor-carbon-sequestration/; Jess Thomson, New ‘Liquid Trees’ Divide the Internet, NEWSWEEK (Apr. 3, 2023), https://www.newsweek.com/viral-post-liquid-tree-algae-carbon-dioxide- 1792214#:~:text=The%20algae%20is%20also%20more,to%20biotechnology%20company%20Hypergiant%20Industries.

[7] The First Algae Purifier in Serbia, U.N. DEVELOPMENT PROGRAMME (Sept. 9, 2021), https://www.undp.org/serbia/news/first-algae-air-purifier-serbia.

[8] See Daniel B. Fishman, 6 Commercial Products You Probably Didn’t Know Are Made with Algae: You Probably Ate #3 for Breakfast, OFF. ENERGY EFFICIENCY & RENEWABLE ENERGY (Aug. 18, 2017), https://www.energy.gov/eere/bioenergy/articles/6- commercial-products-you-probably-didnt-know-are-made-algae-you-probably; Kanika Arora, et al., Potential Applications of Algae in Biochemical and Bioenergy Sector, NAT’L LIB. OF MED. (May 24, 2021), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8144266/.

[9] Department of Energy Invests $8 Million for Projects to Develop Algae-Based Technologies to Capture Carbon Dioxide for Use in Products, OFF. OF FOSSIL ENERGY & CARBON MGMT. (June 23, 2021), https://www.energy.gov/fecm/articles/department-energy-invests-8-million-projects-develop-algae-based-technologies-capture.

[10] See Will Kenton, Cap and Trade Basics: What It Is, How It Works, Pros & Cons, INVESTOPEDIA (Dec. 5, 2020), https://www.investopedia.com/terms/c/cap-and-trade.asp.

[11] See U.S. State Carbon Pricing Policies, CTR. FOR CLIMATE & ENERGY SOLUTIONS (May 2021), https://www.c2es.org/document/us-state-carbon-pricing policies/#:~:text=RGGI%20is%20the%20first%20mandatory,trade%20program%20in%20North%20America.

[12] Id. See also Regional Greenhouse Gas Initiative (RGGI), CTR. FOR CLIMATE & ENERGY SOLUTIONS, https://www.c2es.org/content/regional-greenhouse-gas-initiative-rggi/ (last visited Oct. 26, 2023).

[13] 33 U.S.C. §1344(a) (1987).

[14] Id.

[15] 33 U.S.C. §1344.

[16] INTERGOVERNMENTAL OCEANOGRAPHIC COMM’N, Marine Spatial Planning, UNESCO, https://www.ioc.unesco.org/en/marine-spatial-planning (last visited Oct. 26, 2023).

[17] Jordan Diamond, et al., Marine Spatial Planning in US Waters: An Assessment and Analysis of Existing Legal Mechanisms, Anticipated Barriers, and Future Opportunities, ENVT. L. INST. (Dec. 2009), https://www.eli.org/research-report/marine-spatial-planning-us-waters-assessment-and-analysis-existing-legal-mechanisms.

[18] Spatial Planning, NATL. OCEANIC ATMOSPHERIC ADMIN., https://coastalscience.noaa.gov/science-areas/offshore-wind-energy/spatial-planning/ (last visited Oct. 28, 2023).

[19] Id.

[20] NATL. OCEAN SERVICE, Are all algal blooms harmful?, NATL OCEANIC & ATMOSPHERIC ADMIN. (Jan. 20, 2023),


[21] Id. See also Avoid Harmful Algal Blooms, CTRS. FOR DISEASE CTRL. (May 25, 2023), https://www.cdc.gov/habs/be-aware-habs.html#:~:text=Harmful%20algae%20and%20cyanobacteria%2C%20sometimes,sick%20and%20affect%20the%20environment.

[22] Harmful Algal Blooms, U.S. ENVT. PROT. AGENCY, https://www.epa.gov/nutrientpollution/harmful-algal-blooms (last visited Oct. 29, 2023).

[23] Garrett M. Cole, et al., Integrated Techno-economic and Life Cycle Assessment of a Novel Algae-Based Coating for Direct Air Carbon Capture and Sequestration, J. OF CO2 UTILIZATION (Mar. 2023), https://www.sciencedirect.com/science/article/pii/S221298202300032X.

[24] Bruna Alves, Global Cost of CCS & CDR Solution 2023, By Approach or Technology, STATISTA (Oct. 6, 2023), https://www.statista.com/statistics/1304575/global-carbon-capture-cost-by-technology/.

[25] Cole, supra note 23.

[26] See Algae Are the More Efficient Plants, MAX PLANCK GESELLSCHAFT (Jan. 28, 2022), https://www.mpg.de/18171816/algae-are-the-more-efficient-plants.

[27] See Bacterial Degradation of Algal Blooms Seems Surprisingly Simple, MAX PLANCK GESELLSCHAFT (July 26, 2019), https://www.mpg.de/13758572/bacterial-degradation-of-algal-blooms-seems-surprisingly-simple.

[28] Thomas Page, Growing and Burying Algae in the Sahara is the Latest Solution for the Climate Crisis, CNN (Aug. 18, 2023), https://www.cnn.com/2023/08/18/africa/brilliant-planet-algae-carbon-removal-climate-morocco-scn-spc- intl/index.html#:~:text=In%20the%20roughly%2030%20seconds,of%20years%2C%20the%20company%20claims.

[29] See Robert Höglund, Carbon Can Be Temporarily Stored for a Long Time, MEDIUM (Sept. 24, 2022), https://roberthoglund.medium.com/carbon-can-be-temporarily-stored-for-a-long-time- 4bd7f94e3156#:~:text=In%20a%20similar%20manner%2C%20biomass,certain%20to%20be%20re%2Dreleased.

[30] Victoria Seabrook, Can Growing Algae in the Desert Help Undo Some of Our Damage to the Climate? Start-Up Brilliant Planet Thinks So, SKY NEWS (May 28, 2023), https://news.sky.com/story/can-growing-algae-in-the-desert-help-undo-some-of-our- damage-to-the-climate-start-up-brilliant-planet-thinks-so- 12887480#:~:text=%E2%80%9CWe%20then%20dry%20the%20algae,semi%2Dsealed%20%E2%80%9Ctomb%E2%80%9D.

[31] The Importance of Measuring the Fiscal and Economic Costs of Climate Change, WHITE HOUSE (Mar. 14, 2023), https://www.whitehouse.gov/omb/briefing-room/2023/03/14/the-importance-of-measuring-the-fiscal-and-economic-costs-of-climate-change/.