Researchers at Virginia Tech, Oak Ridge National Laboratory (ORNL), and the University of Georgia are working to produce low-cost hydrogen through the use of polysaccharides, or sugary carbohydrates, from biomass. The production, storage, and distribution of hydrogen have long been problematic, but the team of talented researchers is attempting to solve these problems and make the fuel a leading alternative to our nation’s consumption of gasoline.
The research team hopes to address the areas in which the U.S. Department of Energy (DOE) states hydrogen needs advancements. Those areas needing advancements include production, storage, distribution, and fuel cells. Storage of the fuel can be difficult and even dangerous, and the cost of transporting and storing the gas is very expensive.
“We need a simple way to store and carry hydrogen energy and a simple process to produce hydrogen,” said Y.H. Percival Zhang, assistant professor of biological systems engineering at Virginia Tech.
The research team focuses on synthetic biology approaches in its study of sugar to hydrogen. Through the use of thirteen enzymes never found together in nature, the team can completely convert polysaccharides and water into hydrogen. Polysaccharides like starch and cellulose are used as energy storage and building blocks by plants and are stable until exposed to enzymes. The Virginia Tech Web site explains the effect of adding enzymes to a mixture of starch and water, and Zhang comments that, “the enzymes use the energy in the starch to break up water into only carbon dioxide and hydrogen.”
The research team envisions the ingredients to be mixed in the fuel tank of a car. Zhang estimates that a car with a 12-gallon tank could hold 27 kg of starch, equivalent to 4 kg of hydrogen, giving the vehicle a range of more than 300 miles.
The main hurdle in the race to make hydrogen a leading alternative to gasoline is the storage of the fuel. Zhang and the rest of the research team have achieved a storage capacity of 14.8 mass percent through the use of polysaccharides, as reported in the May 23 issue of PLos ONE online, an open-access journal from the Public Library of Science.
“Pairing our biomass conversion capabilities with facilities for studying renewable hydrogen production in the lab’s Chemical Sciences Division was a key to this project,” said Jonathan R. Mielenz, Bioconversion Group head, ORNL Biosciences Division. “This also shows the value of partnerships with universities such as Virginia Tech and the University of Georgia.”
Zhang reports that the sugar-to-hydrogen technology is, “environmentally friendly, energy efficient, requires no special infrastructure, and is extremely safe. We have killed three birds with one stone. We have hydrogen production with a mild reaction and low cost. We have hydrogen storage and transport in the form of starch or syrups, and no special infrastructure is needed.”
The next phase of the research team’s study will focus on increasing reaction rates and reducing enzyme costs. “We envision that in the future we will drive vehicles powered by carbohydrate, or energy stored in solid carbohydrate form, with hydrogen production from carbohydrate and water and electricity production via hydrogen-fuel cells.”