Alternative fuels, for both transportation and power generation, are an important component of Hawaii’s efforts to reduce its dependence on imported petroleum. HNEI conducts research, testing and evaluation, supporting the development of alternative fuels including biomass and biofuels, hydrogen and solar fuels, and methane hydrates. HNEI also conducts analysis and planning to to assess the potential for alternative fuels, including the use of LNG to meet Hawaii energy needs.
In support of Hawaii's Clean Energy Initiative, HNEI continues to conduct a wide range of assessments for various alternative fuels including biomass and biofuels, hydrogen, and LNG.
Biomass & Biofuels
Energy from biomass has, historically, been a significant part of Hawaii’s energy mix. With the decline of the sugar industry and aggressive State goals to reduce fossil fuel usage, there has been considerable effort in the state to identify new, cost effective means to produce biofuels and/or energy from biomass. Biofuels and bioenergy products often require development of a value chain that includes production of the biomass resource, resource collection logistics, conversion technology(s), product distribution, and end use. While HNEI works with partners inside and outside the University to inform and enable development of the entire value chain, HNEI’s activities are focused primarily on the development of cost-effective conversion technologies and management of various technical and resource assessments (See Alternate Fuel Assessments, below). Ongoing work includes research on biocarbons, gasification technology, anaerobic digestion and bio-oil extraction, and the development of bioplastics and other high value products from waste streams. These activities support efforts to improve energy, food, and water security for Hawaii and the US.
HNEI’s work in biomass and biofuel development spans the value chain:
Biocarbons are a key ingredient in the production of silicon, are used to clean water and cook food, and are used as a substitute for coal in powerplants. The latter use greatly reduces harmful emissions of CO2, SOx, and heavy metals. HNEI's efforts in this area focus on scale-up of the Flash-Carbonization™ technology; improving the speed, efficiency, and economics of the carbonization process; and the reducing emissions during processing. Studies of the pyrolysis of biomass in pure oxygen at elevated pressure in sealed vessels has been initiated.
Biomass and Fuel Processing (Gasification)
Biomass from agricultural, silvicultural, and urban sources can be used as the starting material to produce electricity, fuels, and higher value products. Chemical and fuel properties of these materials can vary significantly. Processing can serve to reduce variability and improve properties for a targeted end use application. Processes under investigation include biomass fractionation and thermochemical conversion of biomass to intermediate products. Research in gasification focuses on producing liquid fuels from synthesis gas. This spans the spectrum of biomass energy conversion including pretreatment, conversion processes, and downstream processing.
Anaerobic Digestion & Bio-Oil Extraction
HNEI is conducting research to develop cost-effective high rate anaerobic digestion (HRAD) of dilute waste to develop integrated platforms that efficiently treat wastewater, with the concomitant recovery of energy, nutrient rich irrigation water, and soil amendments.
With its partners, HNEI personnel collaboratively conceptualize and evaluate early stage translational research on (i) immobilization media that improve yield and reaction rates, (ii) system designs that integrate HRAD with pre-existing aerobic digestion technology, and (iii) biochar addition to soils as a means to improve their productivity and long-term resiliency to long-term irrigation with anaerobically treated wastewater. Researchers in the Biochemical Engineering Laboratory are also developing liquid solvents with unique chemical and physical properties to improve extraction and separation of oil from biomass. Research on solvent properties includes ionically charged electrolytes, hydrophobic/hydrophilic molecules and structural considerations.
Bioplastics and High Value Products
HNEI is developing a new technology to produce liquid fuel from the syngas. The technology includes: (a) catalytic conversion of CO and H2O into CO2 and H2; (b) capture and conversion of CO2 and H2 by an autotrophic bacterium into polyester; and (c) thermal degradation of polyester into a liquid fuel.
Researchers in the Bioprocessing Lab are also developing a novel microbial process in which polyhydroxyalkanoates (biopolyesters or “bioplastics”) are biologically synthesized from renewable feedstocks and waste streams. The biopolyesters can be converted into green chemicals and other value-added materials, as well as a renewable, “drop-in” gasoline.
HNEI is working with a range of partners to develop, test, and evaluate hydrogen infrastructure  in support of fuel cell electric vehicles and to provide ancillary services to the electric utility grids. HNEI is also conducting research to develop cost effective processes for the production of hydrogen from renewable resources including the development of novel materials and photoelectrochemical processes to produce hydrogen gas directly from sunlight and water (solar fuels ).
Hydrogen infrastructure is the system that produces, compresses, stores, delivers, and dispenses hydrogen for an end-use transportation application. The ultimate challenge for introducing hydrogen in the transportation sector is to reduce the cost of hydrogen dispensed at the nozzle. In order to displace fossil fuels hydrogen must be economically competitive with other transportation fueling options. Light-duty vehicles such as cars have largely been designed to use high pressure (700 bar) onboard hydrogen storage systems while heavy-duty vehicles such as buses, use lower pressure (350 bar) storage systems. HNEI has been working on several major projects that address these infrastructure challenges. Our dual pressure hydrogen fueling station at Marine Corps Base Hawaii is demonstrating a state-of-the-art, dual pressure 350/700 bar fueling dispenser to fuel General Motors Equinox fuel cell electric vehicles. Our Hawaii Volcanoes National Park project demonstrates the use of 350 bar hydrogen dispensing for fuel cell electric buses. Hydrogen delivery from a central hydrogen production plant utilizing hydrogen transport trailers (HHT) is another area HNEI is investigating using our fleet of four HHTs. HNEI is also looking at novel ways of utilizing electrolyzers as variable loads to help regulate grid frequency. This has the potential for the grid to add bigger amounts of intermittent renewables such as solar and wind on the grid while at the same time offsetting hydrogen cost by providing an ancillary service for grid regulation that has a monetary value. This monetary value can be applied to offset the cost of the hydrogen. Our project based at the Natural Energy Laboratory Hawaii Authority (NELHA) is testing the viability, durability, and performance of an electrolyzer to potentially regulate grid frequency and produce transportation hydrogen. In non-technical areas, HNEI is supporting state policy makers by developing implementation plans, and making recommendations for new policy to support the introduction of hydrogen infrastructure. Please follow the following links to learn more about our projects.
Research is being performed to develop new materials and new device structures for the photoelectrochemical production of hydrogen .
Since 2002, HNEI has conducted research to understand the formation and decomposition of methane hydrates for use as a fuel; and to explore engineering applications of hydrates such as for gas separation and water desalination. Methane hydrates, comprised of a crystalline water lattice stabilize by the presence of methane are found in deep ocean sediments and arctic permafrost. Estimates of the amount of methane gas contained in hydrate deposits indicate an energy content exceeding that of all known coal, oil, and conventional natural gas reserves. In this collaboration with the Navy Research Laboratory, (NRL) has been the lead on field investigations, while HNEI has focused on associated laboratory and modeling studies.
Methane hydrates (yellow color) on the sea floor in the Gulf of Mexico