Hawaii company proposes deep-sea limu farm for food and fuel

Thirty-three feet below the ocean surface 1.5 miles off Kaiwi Point on Hawaii island is a spot that could spawn industry-disrupting change for producing a popular and pricey ingredient in poke.

The ingredient is limu, or seaweed, and a Hawaii company believes offshore waters like the site off Kaiwi Point can be a new frontier for farming the high-value commodity more economically and possibly in big enough quantities for use as animal feed and biofuel in addition to the dish of diced raw fish.

Typically, edible seaweeds popular in poke are collected in nearshore waters or raised on land-based farms in Hawaii. The ocean offshore, while expansive, lacks nutrients for limu to grow.

Kampachi Farms LLC is seeking state and federal permits to test whether it can raise four native limu species on an array of submerged lines at its proposed test site, where the ocean is 400 feet deep, by supplying the plants with nutrient-­rich water from depths roughly between 600 and 2,000 feet.

The company describes its approach as innovative, with the deep water piped up using a wave-powered pump and dispersed from a fixed point around which the limu-growing array can rotate 360 degrees with the current so that nutrient-rich water always flows down-current to the limu. Additionally, harvesting would be done largely labor free with a mechanized cutting system guided by one worker.

“This is an innovative and disruptive approach that, to our knowledge, has never before been tested for macroalgae cultivation,” the company said in a draft environmental assessment published by the state Office of Environmental Quality Control on June 8.

Kampachi Farms has dubbed its project “Blue Fields” in reference to the color of the ocean serving as the “field” for the crop.

The proposed research project follows a year of work by Kampachi Farms studying seven limu species in tanks on land supplied with deep seawater through pipes at the Natural Energy Laboratory of Hawaii Authority in Kona.

Lisa Vollbrecht, research manager at Kampachi Farms, said results from the land-based tests were good. “We’ve learned a lot,” she said. “This has been pretty cutting-edge work.”

The research on land was funded by a $500,000 federal Department of Energy grant that included engineering designs and environmental assessment work for the ocean-based system.

To fund Blue Fields, Kampachi Farms is seeking a $1 million grant from the same agency because the ultimate goal is to use limu to make biofuel to produce electricity. However, limu grown offshore also could be used as it has been traditionally as food as well as feed for pigs, chickens, farmed fish and other animals.

“Food-feed-fuel is the mantra we keep chanting to ourselves,” said Neil Sims, CEO of Kampachi Farms, which also has been working to advance commercial prospects for raising fish in ocean pens in Hawaii.

Sims added that limu absorbs carbon dioxide and can produce an environmental benefit by counteracting ocean acidification if grown on a big-enough scale.

The environmental report said this carbon uptake will improve water quality, and that the distribution of nutrient-rich deep seawater near the surface should have no significant negative impacts on the water around the project area because nutrients would be largely absorbed by the limu.

A one-hour pulse of deep seawater daily is planned and would represent a mix of 1% deep seawater and 99% surrounding water.

“Only minor and nearly immeasurable impacts on water quality are anticipated in the immediate area of the Blue Fields demonstration project,” the report said.

The size of the planned array for growing limu is about 4,300 square feet.

The four endemic species to be grown are limu manuea or ogo (Gracilaria parvispora), limu kohu (Asparagopsis taxiformis), limu kala (Sargassum echinocarpum) and sea grapes (Caulerpa lentillifera).

Kampachi Farms, which is seeking a three-year permit for a two-year production trial, estimates it might produce 12.5 tons of limu. The company said it would make the limu available to organizations such as a local food bank or community college culinary program.

The potential for large-scale commercial limu farms in offshore waters is big, according to Kampachi Farms, which said in its environmental report that the global market for fresh seaweed is projected to be $22 billion by 2024.

However, the company also said such farms likely are far off, even if the demonstration project succeeds.

“The potential for commercial-scale development of such systems is still several decades in the future,” the report said. “This demonstration is fundamental frontier research.”

To proceed with Blue Fields, Kampachi Farms needs regulatory approvals including a state Department of Land and Natural Resources conservation district use permit, a state Department of Health water quality certification and a permit dealing with navigable waters from the U.S. Army Corps of Engineers.

DLNR plans to schedule a public hearing for the conservation use permit. The public may comment on the environmental assessment, which can be found at health.hawaii.gov/oeqc.

Sims said it would be possible to start the project by the end of this year if permits can be obtained without unexpected delays.