Biorefinery concept presents Hawai‘i a future of possibilities, says UH Hilo energy engineer

Professor Shihwu Sung, an expert in environmental engineering, says Hawai‘i Island is perfectly poised to succeed economically in the technology of biorefineries.

By Lara Hughes.

Shihwu Sung in office.
Shihwu Sung

Hawai‘i Island is primed for the creation of biorefineries designed to use waste from cattle, and possibly from humans, to create biofuel, says Shihwu Sung, professor of applied engineering at the University of Hawai‘i at Hilo. Sung has been at UH Hilo for a year now, housed in the College of Agriculture, Forestry and Natural Resources, working on developing a bioenergy conversion lab and renewable energy program.

At a recent public talk, Sung spoke about the possibilities for bioenergy and renewable resources on Hawai‘i Island. He also addressed the issue of human overpopulation and the challenges that the human race faces. He believes that climate change is the single biggest problem confronting the environment and humanity today.

“Humans so far use all kinds of non-renewable resources like fossil fuel,” he says. “(But) we want sustainability.”

Sung holds a doctor of philosophy in environmental engineering from Iowa State University. Before his academic career, he was a consultant for designing industrial and agricultural waste-to-energy conversion projects. He also helped the United Nations build similar types of facilities in developing nations.

Before coming to UH Hilo, Sung was at Iowa State University where he excelled in his field of environmental engineering and became well-respected globally for his expertise. At Iowa State, he served as the environmental engineering and water resource division coordinator and professor in the Department of Civil, Construction and Environmental Engineering.

His research interests include pollution prevention and waste treatment technologies with an emphasis on waste-to-energy recovery and production of valuable byproducts.

The energy-food-water nexus

Sung explains energy, food and water security are a nexus and the three aspects are inextricably linked. Actions in one of these areas, more often than not, will have an impact on the others and as the world population continues to grow and the demand for higher standards of living increases, it becomes all the more important to adopt a conscious stewardship of these three necessary resources.

Different steps are being taken around the world to address the concerns involving energy, food and water security. There have been great advances in solar, hydro and geothermal energy, while other alternatives and renewable sources are sought out. Food production and distribution are being researched and progress in food safety and nutritional value are being made. Water conservation efforts are increasing, and the storage, purification, recycling and reuse of water are seeing large strides in improvement.

Sung uses the production of sea asparagus as one example that takes into account all aspects of the energy, food and water nexus. Sea Asparagus, also known as olakai, is being farmed here in the Hawaiian Islands. This is a plant that grows in salt water and does not require fresh water. It can be used as a nutritional food source and to produce sea oil. Once refined, sea oil becomes biodiesel, which is being used to fuel jets in Abu Dhabi today.

The biorefinery concept

Large red metal structure.
The construction phase of an integrated biorefinery in Kapolei on O‘ahu, 2011. Courtesy photo.

A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, and chemicals from biomass. The biorefinery concept is analogous to today’s petroleum refineries, which produce multiple fuels and products from petroleum. Industrial biorefineries have been identified as the most promising route to the creation of a new domestic biobased industry.

Sung explains that to produce biodiesel, a process called anaerobic digestion is used. Anaerobic digestion is an essential part of the biorefinery process and takes place when there is no oxygen available.

Sung uses the example of coastal biomass-based refineries to illustrate the necessity and opportunity afforded by anaerobic digestion. Micro and macro algae can be harvested using offshore oceanic agriculture, which would also cleanup coastal nutrient pollution such as the hypoxia occurring in the Gulf of Mexico. The algae can be used for human and animal consumption or it can be processed to extract bio oil and refined to produce biogas using anaerobic digestion.

A similar process uses cow manure to produce biogas, which also cuts greenhouse gas emissions since it is utilizing waste materials that would otherwise decompose in landfills or be burned off, producing methane and carbon dioxide that would wind up in the atmosphere. Biogas can be used to produce biodiesel, jet fuel and generate electricity.

A future of possibilities: Biorefineries on Hawai‘i Island

Sung left the comfort of his well-established and well-funded research program at Iowa State to move to Hilo last year to explore emerging alternative energy opportunities that he says will benefit the people of Hawai‘i and be sufficiently scalable to have a positive global impact.

“This island (has) never had a single anaerobic plant,” he says. “We can build this entire (biorefinery) platform together.”

Cattle grazing in pastures.
Cattle grazing in pastures in Waimea on Hawai‘i Island.  Photo W. Nowicki.

Sung wants to apply the concept of biorefineries using waste biomass from local cattle operations, and possibly even from humans, to create biofuel. He has had experience and success using these processes in the past and has personally designed and invented many anaerobic digesters.

As an exercise, Sung drew up a plan for a dairy farm on Hawai‘i Island that currently houses 2,000 cows and is looking to double that number. He points out, “In Wisconsin (if) you have 1,000 head of dairy cows, you can easily make a profit (using a waste biorefinery).”

He feels Hawai‘i Island is perfectly poised to succeed economically in this technology, especially since more money can be made per kilowatt-hour here than in Wisconsin, and heating is not required here as it is there.

Sung is currently drawing up a plan that he says would change the local municipal waste water plant into a power production plant.

He hopes to one day expand the bioenergy conversion lab at UH Hilo to include expert faculty on thermochemical conversion, which would allow for research and development involving other important aspects of biorefining responsible for the production of adhesives, fuel additives and surfactants.

Upcoming courses of alternative energy

Sung will be teaching courses this coming spring on Engineering the Future (ENGR102) and Biochemical Energy Conversion (ENGR 498).


About the author of this story: Lara Hughes is a junior at UH Hilo majoring in business administration. She is a public information intern in the Office of the Chancellor. 

-UH Hilo Stories

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