Closing the Gap in Renewable Energy – the Next 80%?

by Sergey Nuzhdin, Kristen Davis, Meredith Brooks, Ann Carpenter, Pierre Wensel, and Cindy Wilcox, (Cluster for Sustainable Seaweed Solutions (CS3)/Biofuels Digest) .. (A) similar marine “Blue Revolution” is the potential key to meet global demand for biofuel, feed, and food security in an environmentally friendly way, without the requirements for fresh water, land and artificial fertilizers.

More feedstock is needed

Approximately 80% of U.S. domestic energy consumption originates from fossil fuels (eia.gov). We thank the many industry leaders in agriculture, solar, wind, and hydropower that helped convert the economy to ~20% renewable energy and to everyone continuing to make progress. One of the many challenges in closing the remaining gap is that land covers only 29% of the Earth, and in many areas, its use is highly contested. Some renewable energy sources have low energy density and are therefore land-intensive. To replace the remaining 80% of fossil fuels, the U.S. and other countries need to look to the oceans to produce abundant, affordable biomass feedstock to replace fossil fuels.

ARPA-E funds research

A number of research groups and companies in Southern California have emerged from the MARINER program. These and others are joining a proposed technology Cluster with a focus on Sustainable Seaweed Solutions (CS³), led by the University of California, Irvine. The CS³ mission is to carry out critical, industry-driven research and development on seaweed aquaculture with an overall vision of facilitating the expansion of seaweed and seaweed-based products in the U.S.

The U.S. can compete in the global seaweed industry to produce feedstock

Global production of macroalgae (seaweed) has tripled to more than 32 million tons over a decade, with China and Indonesia dominating the market, and aquaculture contributing more than 97%. About a third of farmed seaweed is consumed directly as food and/or feed. The remainder is processed into polysaccharide hydrocolloid, functional products for nutraceuticals, pharmaceuticals, and cosmetics, and to a lesser extent as fertilizers, feed ingredients, biofuels, and bioplastics.

Smaller aquaculture operations don’t typically have computational resources to optimize farm designs, or breeding and genomic facilities to develop superior competitive crops.

Developing, derisking, and documenting competitive farming practices will continue to be an important R&D domain. Permitting requirements need to be addressed since regulatory agencies, stakeholders and the public demand damage-free approaches to aquaculture. Furthermore, cascade biorefineries need to be designed, scaled, and tested to fractionate macroalgal biomass into various products.

Equally important, the seaweed aquaculture presents new job opportunities in coastal communities, especially areas with fishing expertise.

Whether or not seaweed is sequestered, seaweed aquaculture offers immediate regenerative and bio-extractive benefits to the environment by absorbing excess nutrients and/or pollutants from the ocean ecosystem which improves water quality.

First customers for farmed Giant Kelp include CR&R, Inc, a waste management company with one of the largest biomass digesters on the West Coast. CR&R currently processes lawn/garden cuttings and food waste into biogas to fuel their trash fleet. The biogas replaces diesel. They do not have enough feedstock to fuel their entire fleet and have signed a letter of intent to purchase Giant Kelp to make biogas to inject in the regional pipeline to fuel their fleet at various locations. And in bench-scale testing, Giant Kelp tested 5% better per ton than the current feedstocks.

Despite its lack of recalcitrant lignin, the high ash and water content of macroalgae makes it uniquely challenging to process. Working with teams at Washington State University and Arizona State University, Spira, Inc. has designed and developed dry and wet thermochemical conversion processes and integrated these with biochemical extractive processes to valorize macroalgal biomass. This involves using novel solvents and pre-treatments, torrefaction, anaerobic digestion, fermentation, and cost-effective, sequential hydrothermal liquefication (SeqHTL) to first isolate valuable co-products before producing bio-crude which can be hydrotreated, upgraded, and blended into aviation fuel. Spira, Inc. has also patented bioreactor technology that can be configured with macroalgal cultivation systems for the capture and conversion of atmospheric and/or point-emission CO₂ into more soluble, transportable, and storable aqueous bicarbonate. Marine BioEnergy estimates that 220,000 km² of Giant Kelp under cultivation are required to replace 10% of liquid fuels consumed in the U.S. today. That is an area the size of the State of Utah. There is space in the Pacific Ocean for 705 “Utahs”.

Primary Ocean has indicated interest in purchasing additional Giant Kelp to produce their current product, Organikelp, a bio-stimulant demonstrated to improve the plant and soil health of diverse U.S. crops like strawberries in Ventura, California and citrus trees in Florida. Primary Ocean has also conducted successful commercial trials on other crops such as cannabis, parsley, rosemary, bordeaux basil, and potatoes and is working to scale the usage of Organikelp to over 100,000,000 acres. Organikelp meets the needs of farmers by reducing the requirements for water while increasing the nutrient density of crops and the health of soil. Reducing artificial chemicals also reduces the related impact on farm workers and people worldwide.