Creating a highway humming with hydrogen cars has been a dream of scientists, policymakers and environmentalists for decades. Today, thanks to the dairy cow, we are closer than ever to making it a reality.
One of the biggest hurdles in creating hydrogen fuel until now has been the enormous amount of fossil fuel-based energy it takes to extract hydrogen from water or hydrocarbons.
Most hydrogen fuel is produced via steam methane reforming where natural gas reacts with steam in a catalytic converter to produce hydrogen gas as well as carbon dioxide. Water electrolysis, another highly utilized process, uses an electric current to separate H2O into hydrogen and oxygen gas, but it too, requires significant amounts of fossil-fuel derived electricity.
Exit the Cow
It’s well known that dairy cows contribute significantly to methane (a very potent greenhouse gas) release, both from their burps and management of their manure. as waste exits their systems, and some dairy farms have installed anaerobic digesters to capture and use as renewable energy. Inside the digester’s airless tank, organic matter is converted into biogas, which in turn can fuel combustion engines to power the farm or grid.
However, biogas does not have to power a generator. Thanks in large part to California’s emission reduction targets, a financial market is developing for biogas, scrubbed of impurities, to be injected straight into natural gas pipelines as a renewable equivalent to fossil natural gas. One use for this renewable natural gas (RNG) is an input to generate hydrogen gas. While the above-described process has not changed to produce hydrogen, the CO2 emission reductions from this renewable approach are significant.
Enter The Car
Toyota has gone all in with its efforts to take hydrogen gas—sorry—the last mile to zero emissions. Their innovation is to pump the renewable natural gas directly into a fuel cell, which is like a giant battery. This battery, though, generates both hydrogen and electricity, as well as the heat and water to catalyze the reaction.
Not all of hydrogen’s hurdles are solved. For example, there are only 39 hydrogen fueling stations across the United States, and of those, 35 are in California. Hundreds more are required before Americans invest in cars dependent upon this new technology.
Consumers will also presumably want to fuel their cars for less than $5.60 per gallon, the current cost of hydrogen fuel. Additionally, America is far behind the curve when it comes to capturing methane to create biogas. Europe, for example, had 12,496 animal waste digesters in 2016 compared to the 281 in the U.S. as of April 2018.
With the right policies encouraging methane capture from cows, the National Renewable Energy Laboratory calculates that 486,000 metric tons of hydrogen or 477 million gasoline gallon equivalents could be generated annually from dairy digesters throughout the U.S—enough to supply the annual fuel needs of nearly 730,000 U.S. drivers.
With General Motors and Honda partnering to bring their hydrogen model to market to compete with Toyota, the potential is there for huge advances in a hydrogen fuel economy, relying in part on our nation’s dairy cows to commit to their duties on a daily basis.
Dr. Craig Frear is Regenis’ Director of Research and Technology. He is also on the Board of Directors of the American Biogas Council.