Reducing Waste Emissions by Using Fuel Cells and Hydrogen

In the United States, a significant portion of agriculture and consumer food ends up disposed of in landfills. According to the U.S. Department of Agriculture, Americans throw out as much as 40% of their food, for a total of approximately 133 billion pounds of food annually. In addition to financial loss, the waste creates harmful greenhouse gas emissions (GHG) from a variety of sources, including landfill emissions from decaying food, redundant transport energy, and more. The World Resources Institute estimates that if food loss were its own country, it would be the third-largest GHG emitter at 4.4 gigatonnes (~4.85 gigatons) per year. Food is not the only culprit. Waste in all forms decomposes over time and produces GHGs. In response, researchers and corporations have sought ways to reduce the emissions and pollution from waste by leveraging its decay for energy. A highly efficient and clean way to use waste-harvested energy is through fuel cell and hydrogen technologies.

Waste is comprised of carbon-rich organic compounds and nutrients that can be used to make biofuels like biogas. As organic materials break down, methane-rich biogas is released into the atmosphere. Companies often burn off the methane biogas in a process called “flaring,” which essentially reduces the impact of the gas by converting it into carbon dioxide. However, this method is extremely wasteful. In response, some energy providers have taken to collecting this waste gas and using it for more productive purposes, including as a fuel feedstock for stationary fuel cell systems.

Biogas and Fuel Cells

Several stationary fuel cell companies utilize biogas generated from various forms of waste in their products today. In Connecticut, FCHEA member Doosan Fuel Cell America has installed fuel cell systems at municipal wastewater treatment plants in the cities of Fairfield, Naugatuck, Waterbury, and West Haven. Doosan uses phosphoric acid fuel cells configured to run on biogas collected from the wastewater. According to Mayor N. Warren “Pete” Hess of Naugatuck, the fuel cells save the city three million pounds of carbon dioxide each year, a substantial amount equivalent to removing 250 cars from the streets each year.

FCHEA member FuelCell Energy also has a proven track record installing fuel cells at wastewater treatment plants and landfills, with the most recent one being a 2.8 megawatt molten carbonate fuel cell system at the Tulare, California, wastewater treatment plant. The fuel cell will be powered by the City’s biogas, which would have otherwise been flared.

Fuel cells have found a role in reducing emissions from industrial farming. Dairy farming waste emits large quantities of methane. FCHEA member Bloom Energy is working with California Bioenergy to capture emissions from cow manure. Bloom’s strategy is to capture the methane biogas, purify it, and use it within the company’s solid oxide fuel cells, which normally run off of natural gas.

Bloom Energy dairy waste power. Source: Bloom Energy

Hydrogen from Waste

Businesses are also looking at other wastes to produce hydrogen. Renewable energy companies like Ergostech are developing a production facility that converts sewer-waste into bio-made hydrogen. It is estimated to potentially produce around 3,800 tons of hydrogen per day. In this process, waste remediation and biological hydrogen production are combined in a process where large quantities of hydrogen can be collected, free of other gaseous species from the fermentation. The hydrogen produced in this facility will primarily be used to power farm equipment, heavy-duty trucks and vehicles, forklifts, and backup generators in Lindsay, California. 

Energy can be produced using electrolysis of wastewater as well. Australia-based company switcH2 is using wastewater from breweries as a source of hydrogen. According to switcH2, every liter of beer produced also creates four liters of wastewater. However, the company has a different approach: instead of using bacteria to create hydrogen, they opt to use onsite solar to electrolyze the wastewater into hydrogen. Converting the water into hydrogen ensures that there is less waste produced from the brewery.

In addition to these commercial efforts already underway utilizing biogas and waste, research is continuing to advance this process further. A team of researchers at Purdue University has developed a method to improve the production of hydrogen from food waste using yeast. The yeast performs a metabolic reaction to produce different chemical compounds. The type of end product depends on the intensity of infrared light the yeast is exposed to, as well as the temperature and nutrient concentration. Under certain conditions, the researchers were able to speed up the decomposition process to produce hydrogen gas. The Purdue Northwest Energy Efficiency and Reliability Center has estimated the Purdue system could lead to a 20 to 25 percent increase in efficiency when producing hydrogen from food waste compared with current methods.

The Purdue method uses yeast to break down food waste to clean hydrogen for further use with minimal preprocessing steps. Source: Purdue University

Plastic is another example of waste that can be converted to hydrogen gas. Scientists at the University of Cambridge have developed a method that processes finely cut plastic with an alkaline solution and sunlight irradiation. The chemical reaction results in byproducts of hydrogen gas and oxidized polymers that can be recycled. Essentially, this method finds one final use for plastic by converting it into an energy source and ensuring the recyclability of the remaining products. Two UK companies, Peel Environmental and Waste2Tricity, have recognized the benefits of converting plastic to hydrogen and are developing a waste plastic processing plant to generate hydrogen fuel for fuel cell vehicles. The companies are currently building the first of 11 facilities for this purpose.

Fuel cell and hydrogen technology provides an opportunity for companies to both reduce waste and generate clean energy. By offsetting emissions from decomposing waste, or creating hydrogen from it, the environmental impacts are significant on multiple fronts.

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