UH Hilo-led algae research could combat climate change

The study creates a new, combined process to remove carbon dioxide (CO2) from the atmosphere, produce food and electricity, and reduce deforestation.

Microscopic image of algae, green dots.
Microalgae – Nannochloropsis sp. Photo credit: CSIRO.

Researchers from the University of Hawaiʻi at Hilo, in affiliation with Duke and Cornell universities, have co-authored a study that suggests making croplands more efficient through algae production could unlock an important negative emission technology to combat climate change.

Bruce Mathews
Bruce Mathews

The research, “Integrating Algae with Bioenergy Carbon Capture and Storage (ABECCS) Increases Sustainability,” is funded by a U.S. Department of Energy award and was recently published in the journal Earth’s Future. This funding is a Marine Algae Industrialization Consortium (MAGIC) grant for which Bruce Mathews, dean of the UH Hilo College of Agriculture, Forestry and Natural Resource Management (CAFNRM), serves as the facilitating principal investigator at UH Hilo. Duke University subcontracted the overall project out to multiple institutions, including UH Hilo.

Lead authors are Colin Beal and Ian Archibald of the college at UH Hilo, and Charles Green who is affiliated with both UH Hilo and Cornell University. Co-authors are Mark Huntley of UH Hilo and a Cornell visiting scholar of biological and environmental engineering, and Zackary Johnson of Duke University’s biology department and marine laboratory.

Cornell reports the study creates a new, combined process to remove carbon dioxide (CO2) from the atmosphere, produce food and electricity, and reduce deforestation.

An unconventional mélange of algae, eucalyptus and bioenergy with carbon capture and storage (BECCS) appears to be a quirky ecological recipe. But, scientists from Cornell, Duke University, and the University of Hawaii at Hilo have an idea that could use that recipe to help power and provide food protein to large regions of the world – and simultaneously remove a lot of carbon dioxide from Earth’s atmosphere.

“Algae may be the key to unlocking an important negative-emissions technology to combat climate change,” said Charles Greene, Cornell professor of Earth and Atmospheric Sciences and a co-author of new research reported in Earth’s Future, published March 24 by the American Geophysical Union.

“Combining two technologies – BECCS and microalgae production – may seem like an odd couple, but it could provide enough scientific synergy to help solve world hunger and at the same time reduce the level of greenhouse gases that are changing our climate system,” Greene said. Based on an idea first conceptualized by co-author Ian Archibald of Cinglas Ltd., Chester, England, the scientists call the new integrated system ABECCS, or algae bioenergy with carbon capture and storage.

The study: Creating a new model

Bioenergy with carbon capture and storage (BECCS) burns wood to generate power, captures the resulting carbon dioxide and buries it underground. But BECCS has been strongly criticized for threatening land and water resources that support natural forests and agriculture production.

Marine microalgae has emerged as a promising source for food and biofuels. The tiny plants can be produced using seawater, grown in higher quantities than land crops and in areas unsuitable for agriculture. The main drawback is that algae growth requires large quantities of electricity and carbon dioxide.

The study’s authors combine BECCS with algae production to create a new synergistic process called algae with bioenergy with carbon capture and storage (ABECCS). A conceptual model is created by replacing soybean cropland with an algae production facility that requires less land to produce the same amount of higher quality protein. The leftover land is then used to grow timber for a BECCS system to generate power and carbon dioxide to drive the algae production. By using less land, additional electricity can be exported and the carbon dioxide sequestered, or the excess land can be returned to natural forest.

“BECCS is proposed as a key technology for the planets future and it will not work unless something is done about reducing its negative effects upon natural forests and agricultural land,” says Mathews. “And micro algae are crucial to the proposed potential solution. If the problems with BECCS can be resolved then an important technology for reaching climate change mitigation goals is enabled while also offering the world a nutritious new foodstuff.”

The financial viability of an ABECCS system remains an area of active research. The proposed system in its current form requires a sale price for algal biomass that is significantly greater than that for soybeans or many other terrestrial crops. Options include targeting algal protein for human consumption to provide a higher value product instead of replacing soy as a source of animal feed.

“The motivation for this study was to evaluate the potential for an alternative BECCS system that integrates algal biomass production to sequester CO2 without reducing agricultural output,” the authors write. “Based on these results, and with favorable economic conditions, ABECCS could be a leading candidate to contribute to the reduction of CO2 in the atmosphere in a sustainable way.”

Media release.

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