Aside from the obvious challenges that come from implementing a brand-new refuelling infrastructure capable of safely storing and pumping compressed hydrogen (and the costs associated with building hydrogen fuel cell stacks), the other major problem with using hydrogen as a fuel source is that right now, the majority of hydrogen produced around the world comes from the reforming of fossil fuels like compressed natural gas or waste gasses produced during the fracking of oil.
That fact puts a massive dent in the claim that hydrogen fuel is the zero carbon fuel of the future. And while there are plenty of other ways you can produce hydrogen — electrolyzing water with an electrical current to split H2O into its constituent elements for example — most require a large amount of external energy in order to produce meaningful amounts of hydrogen. Unless that energy is produced from renewably-generated electricity such as photovoltaic solar or wind power, there’s still some inherent carbon footprint.
But two weeks ago the California Air Resources Board gave contingent certification to FuelCell Energy, Inc.’s Tri-Generation Fuel Cell waste plants under the California Low Carbon Fuel Standard (LCFS), laying down a future path where hydrogen could be generated with a carbon neutral or even carbon negative footprint.
While tri-generation processes can operate on a variety of different fuels, the system contingently certified by CARB uses waste biogas from the anaerobic digestion of solid waste and waste water to produce electricity, heat, and hydrogen. Because it captures methane and other biogasses which would naturally be released into the atmosphere through natural decomposition processes, a Tri-Generation Fuel Cell plant can actually be carbon negative.
To make the plant work, a steady supply of solid and treated liquid wastewater is fed into the anaerobic digestion chambers, where bacteria decompose the waste and produce a mixture of methane and carbon dioxide. These gasses (known as biogas) are fed into specialized fuel cells where the biogas is converted into a hydrogen-rich mixture, heat, and electricity. Then, through a process known as water-gas shift, hydrogen is produced from the hydrogen-rich mixture.
Some of the hydrogen generated can be used to power the wastewater treatment plant attached to the facility, while some of the excess heat from the fuel cells can be used to provide extra heat to the anerobic digestion chambers, thus speeding up the waste-to-gas process. Any remaining excess heat can be used to heat nearby buildings or homes, while the remaining hydrogen produced can be compressed and stored for use in an onsite hydrogen filling station or compressed and transported elsewhere for use in hydrogen fuel cell stacks or hydrogen fuel cell cars.
“Our commercial solution for generating hydrogen is technologically, operationally and financially superior to conventional hydrogen generation alternatives and our ability to generate renewable hydrogen affordably and with private capital is a game-changer that addresses the challenges faced by regulators and auto manufacturers,” said Chip Bottone, Chief Executive Officer, FuelCell Energy, Inc. “The key aspect of supporting the hydrogen infrastructure necessary for widespread fuel cell electric vehicle adoption is a clean and carbon-friendly solution that is priced competitively to the cost of gasoline, which is what we can deliver.”
The certification itself comes from the completion of a successful three-year tri-generation project where a fuel cell system has been used to produce electricity, heat and hydrogen from biogas at the Orange County Sanitation District in Fountain Valley, California.
Of the plants already in operation (including one at Inland Empire, California and next to a data center in Cheyenne, Wyoming) FuelCell Energy says its largest unit produces around 1,200 kilograms of hydrogen per day from the biogas reformed through its fuel cell unit. That, it says, is enough to refuel around 300 hydrogen fuel cell cars or 50 hydrogen busses.
Additionally, 2 megawatts of excess electricity is produced alongside 2 million BTUs of heat, which can provide heat to nearby homes.
“The economics [of hydrogen] change dramatically for would-be fueling stations owners and investors because they can sell the electricity and thermal energy alongside the hydrogen, or use it to offset their own on-site operating costs,” a spokesperson for FuelCell Energy told us via email.”In terms of hydrogen, the process does not require a water input as other methods do either.”
While some would argue that hydrogen fuel cell electric vehicles are still far less efficient than battery powered ones due to the energy losses that occur during the production of hydrogen and the conversion of hydrogen and air into electricity, water and heat inside an average fuel cell stack, this particular way of producing hydrogen is one of the cleanest we’ve seen to date.
Additionally, given the scales involved, it points to a future where hydrogen can be mass-produced cheaply and easily while reducing total greenhouse emissions. And if that happens, both hydrogen fuel cell cars and hydrogen range-extenders for electric vehicles become far more practical. Although it is our opinion that battery electric vehicles present a more sensible option for the majority of use cases, range-extenders operating on cleanly-generated hydrogen are by far preferable to ones operating on fossil fuels like gasoline.