In Japan, a smelly waste product is being reimagined as a potential clean fuel of the future that is powering cars and tractors.
We’re being eyed suspiciously by dozens of cows. Their breath fogs cartoonishly from their nostrils.
We are visiting one farm in Hokkaido that wants to transform the source of the pungent aroma in the air into something valuable. They are turning cattle manure into hydrogen.
When it is burned, hydrogen does not emit carbon, making it an attractive alternative to fossil fuels. There are widespread hopes it could be used as a sustainable fuel to heat homes and power cars, trains, aircraft and ships in the future.
The Shikaoi Hydrogen Farm, however, is using a different source – a waste product that there is no shortage of on Hokkaido. Around 20 million tonnes of cow manure is generated in Hokkaido annually. If not treated correctly, it can be an environmental burden, producing significant methane emissions as well as affecting water quality if allowed to leak into streams and rivers. So can it instead be used as a source of sustainable energy?
“This project to produce hydrogen from livestock manure originated in Japan and is unique to this place,” says Maiko Abe from Air Water, one of several companies involved in the hydrogen farm project. We are visiting the facility in Shikaoi, a town in central Hokkaido, to film an upcoming episode of the BBC’s TechXplore focusing on Japan. “Shikaoi accounts for 30% of Hokkaido’s cow waste and urine, so it has great potential for renewable energy.”
Launched in 2015 by Japan’s Ministry of the Environment, the project aims to convert agricultural by-products into hydrogen to supply the local, rural community in a circular economy. The cow excrement and urine is collected from local dairy farms before being fed into a anaerobic digester at a central facility. Here bacteria break down the organic waste to produce biogas and a liquid fertiliser. The biogas is then purified into methane that is used to manufacture hydrogen.
The plant now has a hydrogen production capacity of 70 cubic metres (18,500 gallons), with an onsite fuelling station that can fill around 28 vehicles fitted with hydrogen fuel cells per day, says Abe. Although the fuel can be used by cars with fuel cells, the plant’s fuelling station has been specially designed to accommodate agricultural vehicles such as tractors and forklift trucks. These farm vehicles are difficult to electrify with batteries due to their size and the type of work they do. The hydrogen-powered vehicles are used around the farms’ sites, reducing the emissions that would otherwise be created by using other fuel sources.
Cattle-made-hydrogen is also stored in canisters that are transported to provide power and heat to other facilities in the area, including a local sturgeon fish farm and the nearby Obihiro Zoo.
Hydrogen can also be stored as a liquid by chilling it to cryogenic temperatures of below –253C (-423F), but this can be energy intensive and requires large amounts of additional infrastructure.
Hydrogen has nearly three times the energy content of petrol (gasoline) when taken by mass alone. But its low molecular weight also means that by volume, the energy packed into a litre of liquid hydrogen is a quarter that of petrol. Put simply, as the lightest gas in the Universe, hydrogen takes up more space kilogram for kilogram than petrol. This means a lot more storage space is needed for hydrogen compared to fossil fuels like petrol, diesel and natural gas. It also means producing and storing it at scale can require large amounts of energy and infrastructure.
But as well as these hurdles, the hydrogen farm project in Hokkaido also faces other challenges specific to northern Japan’s climate.
Hokkaido’s subzero winters means new technologies are needed to produce the hydrogen stably without the small amounts of water vapour in the methane freezing.
Using agricultural waste as a methane source to produce hydrogen is relatively uncommon, but it ultimately uses the same process as is used to produce hydrogen from natural gas: steam reforming. Here, steam heated to 800C (1,472F) reacts with the methane to produce hydrogen, along with the byproducts carbon monoxide and carbon dioxide (CO2).
In the case of cow manure, however, says Abe, the project remains sustainable as this carbon originated in the grass the cows grazed on: “Since it was originally in the atmosphere, it is considered carbon neutral.”
In addition, it helps to prevent the methane that would otherwise have been emitted from the manure from getting into the atmosphere, where it is a potent greenhouse gas.
Leftover slurry from the manure after the biogas has been extracted is sprayed as fertiliser onto nearby fields, while formic acid – which is both used in and created by the processes – could be offered as a preservative for cattle feed, says Abe.
Currently, the electricity needed to produce and store the hydrogen comes from the national grid. But Abe says there’s potential to shift to green energy, given Hokkaido’s promising sea, wind and geothermal potential, thus reducing the carbon emissions of this electricity.
Still, other challenges remain. The high cost of the hydrogen compared to fossil fuels and low demand mean expanding the operation is difficult.
“The construction costs of hydrogen stations are very high,” says Abe. “Since hydrogen vehicles are not yet widespread, we’re keeping our filling capacity low to manage initial investment. As adoption increases, we’ll expand supply.”
To encourage hydrogen vehicle adoption in the area, hydrogen prices are subsidised by the plant, matching the cost of petrol. Hydrogen refuelling stations are also being developed in major Hokkaido cities like Sapporo and Muroran.
Hype Meter
The process to make clean hydrogen fuel from cow manure in Shikaoi Hydrogen Farm is worth paying attention to, especially as it also reduces methane which would otherwise be released from the manure. With other countries exploring how to use other types of waste, from pig dung to coconut husks, to produce hydrogen using similar processes, it appears this could be a model adaptable to other local contexts.
With the scale still small, however, and costs of production high, it remains to be seen how widespread this industry can be. There are also other ways of producing fuel from cow waste, such as simply using the biogas produced from manure as a fuel itself without needing to convert it to hydrogen.
Though it’s unlikely that cow manure alone will ever meet Japan’s hydrogen demand, it could contribute significantly, and Shikaoi is creating a model for a circular economy that it hopes will show how costs can fall with the economies of scale.
Meanwhile, engineers at the University of Illinois Chicago in the US recently developed another promising method to make hydrogen involving manure. In their case, they used the manure, along with sugarcane waste and corn husks, to make biochar, a carbon-rich substance which vastly reduces the amount of electricity needed to convert water to hydrogen.
“We are the first group to show that you can produce hydrogen utilising biomass at a fraction of a volt,” says Meenesh Singh, a chemical engineer at the University of Illinois Chicago who led the project.
In the southern Japanese city of Fukuoka, on Kyushu, meanwhile, another waste product is being used to produce hydrogen – and here the dung is from humans.
For more than a decade, hydrogen has been created at the city’s sewage treatment plant for use in hydrogen-powered vehicles. Most recently it has been used to fuel a fleet of zero-emission rubbish trucks.
Akira Miyaoka, hydrogen utilisation manager for Fukuoka City, says trucks that transport daily products are the town’s main source of CO2, rather than large factories as in many other cities. “So we are working to reduce CO2 emissions from commercial trucks,” she says.
The initiative started as a collaboration between Kyushu University and Fukuoka City, but now involves several major companies including Toyota.
“Sewage is something that is steadily discharged every day in the daily lives of citizens, so by making effective use of that sewage and extracting hydrogen as energy, we can achieve local production and local consumption of energy,” says Miyaoka.
Generating hydrogen from human waste starts with water from various household sources – including showers, dishwashers and toilets – arriving at the treatment plant. As the water is cleaned, the residual sludge is kept as a source of biogas and converted into hydrogen.
“Sewage and biogas contain various impurities, so the process begins with the process of removing those impurities, which I think is a little different from other hydrogen production processes,” says Miyaoka.
In 2024, Toyota helped the city launch Japan’s first hydrogen-powered service vehicle fleet, including ambulances, delivery vans and bin trucks. Officials at the sewage treatment plant say it is capable of producing 300kg (661lbs) of hydrogen in 12 hours – enough to fuel 30 trucks.
The rubbish trucks head out six nights each week, each collecting 1.7 tonnes (3,700lb) of rubbish, all while running silently and emission-free on the bodily waste of the people they are collecting other waste from.
Fukuoka’s sewage-to-hydrogen fuelling station has been around since 2015, and several other countries around the world are now adopting a similar approach.
Still, despite the promise, all of these technologies have yet to be delivered at significant scale.
Whether in rural or city landscapes, the Japanese projects we’ve seen during in filming are inspiring because they have the local community at their heart.
By reimagining waste as a resource, these projects demonstrate that energy can be found in even the most unlikely of places.
* Paul Carter is the presenter of TechXplore. You can watch his report from the Shikaoi Hydrogen Farm and on other sustainable technologies in Japan in TechXplore Japan: From North to South when it airs on 15 March 2025 on BBC News.
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