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Macroalgae as a Biomass Feedstock: A Preliminary Analysis (PNNL-19944)

Meeting the Energy Independence and Security Act (EISA) renewable fuels goals requires development
of a large sustainable domestic supply of diverse biomass feedstocks. Macroalgae, also known as
seaweed, could be a potential contributor toward this goal. This resource would be grown in marine
waters under U.S. jurisdiction and would not compete with existing land-based energy crops.
Very little analysis has been done on this resource to date. This report provides information needed for an
initial assessment of the development of macroalgae as a feedstock for the biofuels industry.
The findings suggest that the marine biomass resource potential for the United States is very high based
on the surface area of the marine waters of the U.S. and rates of commercial macroalgae production in
other parts of the world. However, macroalgae cultivation for fuels production is likely a long term effort.
Analysis of the available data showed that considerable scale up in cultivation over current world-wide
production and improvements in processing throughout the supply chain are needed.
Despite the high resource potential, the United States does not currently have a macroalgae production
industry and would have to develop this capability. In order to meet current renewable fuels goals, the
scale of the effort would have to be high in comparison with activity in other parts of the world. For
example, replacing 1% of the domestic gasoline supply with macroalgae would require annual production
rates about ten and one-half times current worldwide production. This could be accomplished through
cultivation on 10,895 km2 of ocean surface, based on current rates of production reported for the
international macroalgae cultivation industry. Advances in cultivation technology already being tested
could potentially increase production from three to ten fold with a corresponding decrease in the area
needed for cultivation to meet specified production goals. While it is no surprise that the cost estimates to
produce fuel from macroalgae are currently high, it should be noted that this is based on a limited amount
of available data and that production costs for macroalgae can benefit from increased efficiency and scale.
A thorough analysis is warranted due to the size of this biomass resource and the need to consider all
potential sources of feedstock to meet current biomass production goals. Understanding how to harness
this untapped biomass resource will require additional research and development. A detailed assessment
of environmental resources, cultivation and harvesting technology, conversion to fuels, connectivity with
existing energy supply chains, and the associated economic and life cycle analyses will facilitate
evaluation of this potentially important biomass resource.

Roesijadi, G
Contact Person
G. Roesijadi
Contact Organization
Pacific Northwest National Laboratory
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Bioenergy Category
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