Hydrogen Production from Biomass and Organic Waste
Connor Dolan
By Mark Luth, FCHEA Intern
Approximately 4.4 pounds of waste are produced daily per person in the United States alone. Responsibly addressing and disposing of this waste will involve a wide range of solutions that reduce the amount of material placed in landfills or offer ways to utilize biomass to generate other products. Fuel cell and hydrogen technologies are offering a pathway to turn environmental hazards into clean and renewable power instead, including by generating hydrogen, which can then be used in a stationary fuel cell or for other purposes, such as transportation. The fuel cell industry’s products include different types of fuels cells that are able to run off various fuels and feedstocks, including methane, pure hydrogen, and waste gas from biomass sources.
One method of generating hydrogen from biomass begins with processing the organic materials at high temperatures, but without combustion. When combined with oxygen and steam, the reaction results in carbon monoxide, carbon dioxide and hydrogen gas. This gasification process can take the carbon monoxide that is produced and combine it with additional steam to produce additional hydrogen and carbon dioxide, which is recycled through the natural plant respiration cycle and generate additional biomass. Alternative options may involve biological agents, such as anaerobic bacteria or fermentation, or pyrolysis, which uses the same gasification process, but without the presence of oxygen. Each of these methods provides clean hydrogen gas that can be used for energy storage or directly in fuel cells.
Past
Biogas has functioned as a fuel source in hydrogen production for decades, starting with wastewater treatment plants in the 1990s. At those plants, fuel cells reduced the emissions produced and simultaneously contributed to powering the plant itself. Once the uses were demonstrated in the public sector, private enterprises such as hog farms, breweries, and wineries began to also utilize fuel cells to help reduce waste and supply their own power.
One advantage to producing hydrogen with biogas as the fuel source was demonstrated in 2011, when a Department of Energy-funded project operated by FCHEA member FuelCell Energy produced electricity, heat, and additional hydrogen gas for other uses from a wastewater treatment plant in Fountain Valley, California. This form of “tri-generation” opened new possibilities in the production of hydrogen. Used for supplying a hydrogen refueling station for fuel cell vehicles, that same hydrogen could also be stored for future use in a stationary fuel cell system or injected into natural gas pipelines to reduce their carbon intensity. Locally producing hydrogen via these processes reduced the need for transportation on cargo trucks and fully decarbonized the hydrogen from production to consumption.
Present
As was previously published in our In Transition blog on port vehicles, this tri-generation process first demonstrated in 2011 is set to be introduced soon to the Port of Los Angeles, where FuelCell Energy and fellow FCHEA member Toyota have teamed up to provide hydrogen and clean power produced from renewable biogas. This hydrogen gas would be used at the port to fuel a fleet Toyota’s heavy-duty fuel cell truck prototypes. This pilot project may indicate a future solution for other ports, as it has the potential to reduce the environmental impact of a port significantly.
Another FCHEA member, Doosan Fuel Cell America, continues to expand the installation of fuel cells and hydrogen generation equipment at wastewater treatment plants. As with earlier installations, the fuel cells installed at the treatment centers can operate with feedstocks that come from the plant or through natural gas piped from other locations. With several plants constructed in Connecticut in recent years, Doosan helps provide a saving on electricity for local municipalities and reduce emissions significantly.
FCHEA member Bloom Energy is embarking on a pilot project with the Southern Company to generate electricity and hydrogen from a landfill. Instead of flaring or combusting the methane, Bloom has installed a cleaning unit attached to the fuel cell. The conditioning removes the impurities, then sends the methane into the fuel cell, where it produces clean electricity that is sent on to the grid.
An example landfill with the potential to generate hydrogen gas. Source: Bloom Energy
Future
Research in this field is suggesting new ways to improve efficiency and increase the implementation of hydrogen generation from biomass. Along with analysis that shows that biomass feedstock usable for energy production should be plentiful, the future usage of hydrogen production techniques related to biomass should continue to grow. Looking toward further opportunities, research being conducted promises to develop bacterial and microbial actors that increase production efficiency, while additional efforts focus on methods to lower both production costs and the costs of obtaining the feedstock.
One such technology that is moving towards larger scale testing combines a microbial fuel cell with solar generation in the same location. In testing, the new cells produced a small, continuous stream of hydrogen that can be used in further powering the plant or other needs, while also contributing to significantly cleaner water within the system. Alongside the more prevalent gasification processes that generate hydrogen from solid wastes, wastewater treatment plants play a key role moving forward in the expansion of clean hydrogen generation.
Another exciting future possibility is the potential to turn plastic waste materials into hydrogen, alongside biomass waste. With concerns growing around the plastic waste distributed throughout the world, turning that material into clean and renewable energy would address two goals at one time. This process, known as photoreforming, involves putting a catalyst onto the plastic waste, then submerging the item in an alkaline solution. This produces hydrogen, along with small organic molecules, instead of plastics that do not biodegrade. While the research is currently ongoing, small-scale tests carried out by researchers at Swansea University and the University of Cambridge were able to successfully complete the process in real-world settings. This success outside of the pure environment of the lab indicates the potential of the technology. In April 2019, the plan for the first commercial plant to test this process in a live setting were announced in the UK, with the goal of treating up to 25 tonnes of plastic waste daily, while providing energy and hydrogen to the local community.
As the various ongoing projects and research demonstrate, hydrogen production offers a clean, renewable path to addressing the challenges associated with large amounts of waste material produced globally.