Researchers from the , in affiliation with Duke and Cornell Universities, have authored a study that suggests making croplands more efficient through algae production could unlock an important negative emission technology to combat climate change.

The authors include Colin Beal and Ian Archibald of UH �ᾱ����’s (CAFNRM), Mark Huntley and Charles Green, who are affiliated with both CAFNRM and Cornell University, and Zackary Johnson of Duke University. Their study creates a new, combined process to remove carbon dioxide (CO2) from the atmosphere, produce food and electricity and reduce deforestation.

“Bioenergy with Carbon Capture and Storage (BECCS)” burns wood to generate power, captures the resulting carbon dioxide and buries it underground. But BECCS has been strongly criticized for threatening land and water resources that support natural forests and agriculture production.

Marine microalgae as a promising source

Marine microalgae has emerged as a promising source for food and biofuels. The tiny plants can be produced using seawater, grown in higher quantities than land crops and in areas unsuitable for agriculture. The main drawback is that algae growth requires large quantities of electricity and carbon dioxide.

The study’s authors combine BECCS with algae production to create a new synergistic process called “Algae with Bioenergy with Carbon Capture and Storage (ABECCS).” A conceptual model is created by replacing soybean cropland with an algae production facility that requires less land to produce the same amount of higher quality protein. The leftover land is then used to grow timber for a BECCS system to generate power and carbon dioxide to drive the algae production. By using less land, additional electricity can be exported and the carbon dioxide sequestered, or the excess land can be returned to natural forest.

The financial viability of an ABECCS system remains an area of active research. The proposed system in its current form requires a sale price for algal biomass that is significantly greater than that for soybeans or many other terrestrial crops. Options include targeting algal protein for human consumption to provide a higher value product instead of replacing soy as a source of animal feed.

“The motivation for this study was to evaluate the potential for an alternative BECCS system that integrates algal biomass production to sequester CO2 without reducing agricultural output,” the authors wrote. “Based on these results, and with favorable economic conditions, ABECCS could be a leading candidate to contribute to the reduction of CO2 in the atmosphere in a sustainable way.”

The study, “Integrating Algae with Bioenergy Carbon Capture and Storage (ABECCS) Increases Sustainability,” is funded by a U.S. Department of Energy award and .

—By Alyson Kakugawa-Leong

Researchers at the are committed to the environment and are doing their part to help �鶹��ý Island industries utilize more renewable and sustainable energy sources. Research into sustainable energy is an ever-growing field with plenty of space for innovation.

Shihwu Sung, professor of applied engineering at UH Hilo, is currently conducting research on converting waste into biodiesel energy.

“I’ve always been very interested in the environment,” Sung says. “Through my research I want to focus on decreasing the amount of fossil fuels used, and increasing the amount of renewable energies on �鶹��ý Island.”

Sung’s research is currently being conducted in the Renewable Energy Lab on the UH Hilo campus, where he has built a lab scale of an upflow anaerobic sludge blanket (UASB) reactor, a single tank wastewater treatment system.

The project is funded by and in conjunction with Big Island Biodiesel, a Keaʻau based plant committed to “a sustainable, community-based vision.”

The research

“This UASB reactor machine starts with wastewater, undergoes processes of conversion, and ultimately produces a biogas that contains methane,” Sung explains. “The produced biogas can then be used as a primary source of energy.”

The wastewater that goes into the reactor is an organic product, containing natural carbons. The carbons break down through the use of anaerobic organisms, which, through a continuous upward flow, creates biogas.

“The lab scale UASB reactor was created to test the method on a smaller scale and determine if this process is compatible for the Big Island,” says Sung. “We also have a pilot scale at the biodiesel plant, and eventually, we will have a full scale UASB reactor.”

, who received his PhD in molecular biosciences and bioengineering from UH Mānoa, is now a postdoctoral researcher on this project.

Sawatdeenarunat emphasizes the universality of waste conversion technologies. “It can be used in practically any industry, any company that uses a lot of energy can make use of this technology and turn their waste into fuel, becoming more sustainable,” he says.

Sawatdeenarunat continues, “This is the first waste to energy conversion process being researched on the Big Island. It is good for the island, and we are able to continue our research because the people of Hawai‘i have their own environmental concerns.”

The pilot scale model of the UASB reactor is located in Keaʻau at Big Island Biodiesel, a branch of Pacific Biodiesel, a company that converts used cooking oil and grease into biodiesel fuel. If the pilot scale reactor proves to work in its intended environment, the full scale model will allow the plant to convert its waste products into biogas, which will supplement the energy needs of the plant.

Sung believes that �鶹��ý Island is a prime location for this type of research. “We need biofuel here, because, well, the energy practices are not very good right now,” he says. “Creating more sources of renewable energy and technologies of waste conversion will help �鶹��ý become more independent. Everyone should believe in this idea.”

for more about the project and how Sung and Sawatdeenarunat are also helping �鶹��ý Island coffee mills become more sustainable.

—A UH Hilo Stories article written by Jamie Josephson, a public information intern in the Office of the Chancellor

• , October 10, 2017
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Two potential biofuel crops in �鶹��ý—sugarcane and napiergrass—may sequester more carbon in soil than is lost to the atmosphere, according to a study published January 4, 2017 in the open-access journal by Meghan Pawlowski from University of �鶹��ý at Mānoa and colleagues.

From a climate change perspective, replacing fossil fuel with biofuel makes sense only if the latter has a smaller greenhouse gas footprint. Sugarcane and napiergrass are promising biofuel crops because, like other tropical C4 grasses, they have a large carbon-storing root biomass that could offset carbon-dioxide fluxes occurring during cultivation.

To test this, Pawlowski and colleagues monitored conventional sugarcane and non-tilled napiergrass crops in �鶹��ý over two years, measuring the above- and below-ground biomass and assessing the greenhouse gas flux. In addition, these thirsty crops were grown with either conventional or deficit irrigation, which is half that of the current commercial practice.

The researchers found that by the end of the two-year study, both crops had successfully sequestered more carbon in the soil than was lost from the soil surface—the largest component of the greenhouse gases in this case. For example, soil in the sugarcane plots had three times as much carbon as was lost to the atmosphere. Deficit irrigation boosted soil carbon sequestration but also reduced yield, though this tradeoff was less pronounced for napiergrass, which can be harvested more than once a year. The authors suggest that, with zero tillage conservation management, sugarcane and napiergrass biofuel feedstocks could therefore sequester carbon in soil. However, they caution that further study is necessary to determine whether this will continue over the long term and which crop may be best.

, co-author and assistant professor in the notes, “A common misperception persists that biofuels are non-viable because of inefficiencies and net carbon losses that negate the potential for climate change mitigation. These results show that in the right system, coupled with the right crop and management, biofuels can be an important contributor to sustainable renewable energy portfolios.”

—By Marcie Grabowski

�鶹��ý Island is primed for the creation of biorefineries designed to use waste from cattle, and possibly from humans, to create biofuel, says Shihwu Sung, a professor of applied engineering at the .

Sung moved to Hilo last year to explore emerging alternative energy opportunities that he says will benefit the people of �鶹��ý and be sufficiently scalable to have a positive global impact. As faculty within the , he is working on developing a bioenergy conversion lab and renewable energy program.

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

Sung explains that 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 making it all the more important to adopt a conscious stewardship of these three necessary resources.

A future of possibilities: biorefineries on �鶹��ý Island

A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power and chemicals from biomass. To produce biodiesel, a process called anaerobic digestion is used.

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. 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.

“This island [has] never had a single anaerobic plant,” he says. “We can build this entire [biorefinery] platform together.” Sung wants to apply the concept of biorefineries using waste biomass from local cattle operations to create biofuel.

He feels �鶹��ý Island is perfectly poised to succeed economically in this technology, especially since more money can be made per kilowatt-hour here versus on the continental U.S. and heating is not required. Sung is currently drawing up a plan that he says would change the local municipal waste water plant into a power production plant.

• Learn more about Sung’s work at .

For Hilo students, Sung will be teaching courses this coming spring on Engineering the Future (ENGR 102) and Biochemical Energy Conversion (ENGR 498).

—A UH Hilo Stories article by Lara Hughes, a junior at UH Hilo majoring in business administration and a public information intern in the UH Hilo Office of the Chancellor

Creating gasoline and biodiesel from readily available microbial organisms may sound too good to be true, but that is exactly what researchers at the at the are doing. A by �鶹��ý Natural Energy Institute Postdoctoral Fellow Shimin Kang and Researcher Jian Yu.

“As we refine this process, we will be able to simplify and bring down the cost of converting renewable feedstock to commercially viable transportation fuel,” said researcher Kang.

Biomass to biofuel

There are several different types of feedstock—defined as any renewable, biological material (biomass)—that can be used directly as a fuel or converted to another form of fuel or energy product. Common examples of biomass feedstocks include corn starch, sugarcane juice and purpose-grown grass crops that can be used to derive fuels like ethanol, butanol, biodiesel and other hydrocarbon fuels.

For a fuel to be considered good enough to use in modern high performance automobiles, it needs to have a high antiknock quality (octane number) and low oxygen. Since biomass generally has high oxygen content, it can be a challenge to create a high quality fuel without using multiple complex steps under high pressures and temperatures that can result in high costs of equipment and operation. Researchers are addressing this challenge by testing alternative feedstocks and new processing technology.

Bacterial biomass and a solid catalyst

Like starch and oil accumulated in plants, polyhydroxybutyrate (PHB) is an energy storage material accumulated from renewable feedstock in many microbial species. Following up on studies showing that PHB could be reformed into oil in liquid phosphoric acid solutions, Kang and Yu tested the process using a solid phosphoric acid as a catalyst. They were able to produce high quality bio-oils, a light gasoline-grade biofuel and a heavy biodiesel-grade biofuel, in a simple .

“By using a solid catalyst we were able to increase the aromatics content, thereby raising the octane number, while reducing the water content in the resulting commercial grade oils,” said Kang.

With this new, more efficient, method researchers were able to achieve results with reaction temperatures low in comparison to catalytic conversion of conventional biomass. This may help bring down the cost of conversion to biofuel. With future work building on these results, they hope to develop a standard method to create a consistent fuel.

Imagine if fields of tropical grass in Waimʻnalo, which grows like weeds year-round, could be turned into electricity, jet fuel or even gasoline for automobiles. The University of �鶹��ý at Mānoa’s is in the process of determining if that dream could become a reality.

The college is looking into locally produced, renewable energy that would end �鶹��ý’s severe dependence on foreign oil and serve as a model to the world.

“When people ask me is it economically viable at this point, I say we don’t have the answers yet,” said Professor Andrew Hashimoto of CTAHR. “That’s why we do the research.”

CTAHR and its project partners have been for the research. This grant is part of a $41 million investment for 13 projects nationwide. The goal is to spur innovation in bio energy.

“There is a big emphasis on the sustainability,” said Hashimoto. “How much input? What’s the impact on carbon by these processes? What’s the impact on the environment? What’s the impact on the communities that sustain these processes? It’s a very comprehensive project.”

It starts with the fast growing tropical grass and a lot of questions.

“It’s not so much finding the best crop but really which crops do the best in the different environments,” said Hashimoto. “And it’s not only yield but how much input is required like water, fertilizer, pest control and things like that.”

Researchers are also looking into the harvesting, pre-processing and the conversion of the grass or biomass into fuel like diesel and gasoline.

“We need to convert biomass from a solid form to something we can use in our everyday life,” said Professor Scott Turn of the .

A research reactor operated by HNEI converts the biomass into carbon monoxide and hydrogen that can be made to produce electricity or be converted into liquid fuel. It is one of the many conversion methods being examined. No stone is being left unturned as UH researchers look into every aspect of biofuel and its future in �鶹��ý.

“Getting off of petroleum is very important for us,” said Turn. “For energy security, for economic development and to help put some of our agriculture lands back into production.”

“It’s really going to come down to the economics and basically, the sustainability,” said Hashimoto. “Are you benefiting the environment and the community as well as economically?”

Those are among the questions the UH researchers hope to have answered in the next two to four years.