One of the long-standing criticisms of hydrogen fuel cell cars is the costly, complicated way in which the majority of hydrogen fuel is made today. While there are cleaner, greener alternatives — such as the hydroelectric plant at Honda’s refuelling site at its UK automotive manufacturing facility in Swindon, England — the majority (around 95 percent) of hydrogen fuel is made by steam reforming fossil fuels like compressed natural gas.
That process also produces carbon monoxide and carbon dioxide as a byproduct, a greenhouse gas which opponents of hydrogen fuel cell cars say makes them as polluting as any other fuel source, although we note some steam reforming plants do sequester CO and CO2 as a gas for later use or inject it into an oil field rather than release it into the atmosphere.
It’s no surprise then that Toyota — the auto industry’s biggest supporter of hydrogen fuel cell technology — is working hard to change the public’s perception of hydrogen fuel cells and tackle criticisms of those who say fuel cells are neither efficient nor green. What’s more, it’s proving those who have called hydrogen fuel cell technology “bullshit” — including Tesla CEO Elon Musk — were at least partly right by demonstrating that you can indeed power the Toyota Miria hydrogen fuel cell car on bovine byproduct.
Just not the way that critics had intended.
The first of a series of YouTube informercials-cum-commercials directed by documentary filmmaker Morgan Spurlock (of Super Size Me fame) Toyota’s “Fueled By Bullsh•t” shows how cow poo can be collected, broken down, and ultimately turned into hydrogen fuel that can be used to power a hydrogen fuel cell vehicle.
Having grown up on a dairy farm and shoveled a lot of it in her time, this author can attest to the fact that a herd of 150+ pedigree Holstein Friesians do indeed produce a lot of waste (up to 150 pounds per cow per day).Thanks to their preferred diet, their four stomachs and the tiny symbiotic archaea microbes that live in their gut, there’s also a great deal of methane produced as grass, silage, kale and yes, even brewers’ grains and beet are turned into sweet, sweet milk.
Beef cattle — ones bred exclusively for their meat — produce similar levels of crap.
And that fecal byproduct has to go somewhere. Traditionally, it’s become fertilizer for use on crops, or left in massive slurry pits to naturally break down into drainable fluids, solid matter and methane gas. The Methane gas is then sent to combined heat and power plants to be burned as fuel or sent for manufacturing certain chemicals.
As Toyota explains in the video above, that methane gas can be captured and processed just like compressed natural gas from the ground can, turning the methane for cow poop into hydrogen fuel and carbon dioxide in those massive steam reforming plants we mentioned at the start of the article.
If we’d had to guess, we’d suspect the rest of Toyota’s Fueled by Everything series will focus on other natural methane-producing processes, including decomposing household trash, certain algae and of course, water electrolysis.
From a farming perspective, using cow shit as a fuel is at least one way to dispose of the massive amounts produced on a yearly basis for even a modest-sized herd. But with international meat consumption on the rise and bovines and other ruminates charged with producing a massive percentage of the methane and other gasses that are currently contributing to global warming, we need to do more than just repurpose cow poo in order to help keep our planet safe for future generations. We need to consider switching our cattle from westernised ‘superbreeds’ to smaller, non-western breeds found in places like India, which interestingly produce far less greenhouse gasses than their counterparts in the west.
(It’s worth noting too that the majority of a cow’s methane production is expelled through belching and flatulence, not through the passing of stool, so using gardener’s gold as a way of making hydrogen only accounts for a tiny proportion of Daisy’s total methane production.)
We digress. While turning cow manure into hydrogen fuel for use in a hydrogen fuel cell car like the Toyota Miria is indeed a form of renewable energy, the process itself still uses a great deal of energy: water must be superheated to somewhere between 700 and 1,000 degrees celsius in order to split the methane in the presence of a metal-based catalyst.
While it’s still greener to repurpose the brown stuff than it is to use methane mined from the ground, using hydrogen produced from the electrolysis of water is a greener solution, especially if powered by electricity generated by photovoltaic solar panels. Even that production method however is far from energy-efficient: although there are now cleaner, more efficient methods being investigated, it takes around 56 kilowatt-hours of electricity and nine litres of water to produce one kilogram of hydrogen using current industrial electrolysis methods.
In the Toyota Mirai fuel cell sedan — which is expected to have a fuel efficiency of around 60 MPGe — that’s good enough for about 60 miles of zero-emission travel since one kilogram of hydrogen has about the same energy density as one (US) gallon of gasoline.
Using the same amount of electricity generated in the same way, a BMW i3 electric car could travel 207 miles, drawing many plug-in advocates to argue that hydrogen fuel cell vehicles are an unnecessary diversion.
For certain applications however — such as long-distance trips in extremely remote areas with no power where electric cars might struggle — maybe cow poop is the way forward.
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