Design of Large Scale Macroalgae System (MacroSystem)

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Project Term:
06/09/2020 - 12/08/2023

Critical Need:

Marine macroalgae, also referred to as seaweeds or kelp, are a group of exceptionally diverse aquatic plants. Macroalgae can be found along nearly all coastlines around the globe and, in some cases, in the open ocean. They have traditionally been used for food and feed, as well as fertilizer. In 2018, the world produced approximately 32.4million wet metric tons of seaweed, primarily through highly labor-intensive farming techniques. While macroalgae production has increased six-fold over the past quarter-century, the current approaches and technologies for macroalgae “mariculture” are not capable of supporting the scale, efficiency, or production costs necessary to develop a seaweed-to-fuels industry. Dramatically increasing productivity will require significant advancements in the domestication of macroalgae and new farming technologies. To accelerate the development of critical tools and technologies, the MARINER program is supporting projects in five areas: 1) Integrated Cultivation & Harvest System Design, 2) Critical Enabling Components, 3) Computational Modeling, 4) Monitoring Tools, and 5) Breeding & Genomic Tools.

Project Innovation + Advantages:

Ocean Rainforest will use a comprehensive experimental approach to optimize the design of their novel giant kelp cultivation system. The team will conduct tests in the open ocean of several variables, including depth and length of grow lines, seeding methods, and harvest frequency. Using an array of experiments that build on themselves each year, the team will evaluate the feasibility of their cultivation system to maximize biomass production. The project team will also test several hatchery techniques to improve seeding efficiency. Under the Phase I award, the team performed initial proof-of-concept tests and a technoeconomic analysis to show the potential benefit of their proposed technologies and experimental plan. Those results indicated that the proposed technologies have the potential to reduce the cost of biomass to $80/dry metric ton.

Potential Impact:

If successful, MARINER projects strive to develop the tools needed to allow the United States to become a world leader in marine biomass production for multiple important applications, including the production of biofuels.


Production of biofuels and bioenergy from domestically produced marine biomass could ensure that the U.S. has at its disposal a scalable, domestic source of low-carbon energy supplies.


Growing large amounts of macroalgae would not compete with land-based food crops, requires no fresh water and can be grown without the addition of energy-intensive, synthetic nitrogen fertilizer. Large-scale macroalgae cultivation may help reduce the negative effects of nutrient overload and ocean acidification in many coastal ocean regions.


A domestic macroalgae industry would not only create a valuable new source of domestic energy, but also create significant new economic and employment opportunities in many waterfront communities along the U.S. coasts from Maine to the Gulf of Mexico, Alaska, and the Pacific Islands.


ARPA-E Program Director:
Dr. Simon Freeman
Project Contact:
Javier Infante
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