Seaweed Paddock: Initial Modeling and Design for a Sargassum Ranch

Martin T. Sherman, OceanForesters
Reginald Blaylock, University of Southern Mississippi
Kelly Lucas, OceanForesters
Mark E. Capron, OceanForesters
Jim R. Stewart, OceanForesters
Steven F. DiMarco, Texas A&M University
Kristen Thyng, Texas A&M University
Robert Hetland, Texas A&M University
MH Kim, Texas A&M University
Corey Sullivan, University of New Hampshire
Zach Moscicki, University of New Hampshire
Igor Tsukrov, University of New Hampshire
M. Robinson Swift, University of New Hampshire
Michael D. Chambers, University of New Hampshire
Scott C. James, Baylor University
Maureen Brooks, University of Marlyland Center for Environmental Science
Brian von Herzen, Climate Foundation
Anthony Jones, Intake Works, LLC
Don Piper, OceanForesters

Abstract

This paper describes the “SeaweedPaddock” system to profitably grow and harvest open-ocean Sargassum sp. as a sustainable source of macroalgal biomass and biofuel. The US Department of Energy Advanced Research Projects Agency - Energy (ARPA-E) initiated the MacroAlgae Research Inspiring Novel Energy Research (MARINER) program to develop technologies to eventually sustainably harvest macroalgae at 80 per dry metric ton (DMT). The University of Southern Mississippi team is characterizing an unmoored SeaweedPaddock; analyses include tow speed and energy required to avoid hazards, farm design to minimize biomass loss, economical harvesting, and nutrient supply. Initial results indicate that nighttime “smart towing” could allow the SeaweedPaddock system to produce macroalgae at full scale at costs below the ARPA-E goal provided that Sargassum grows at sufficient rates during the day after having been confined all night in a moving fence and that sufficient nutrients are made available. Cost projections for a successful, intensive, scaled system could be competitive with current prices for fossil fuels.