Japanese researchers have harnessed cattle manure’s latent energy potential, successfully converting the agricultural by-product into biogas, which has reduced the agricultural industry’s carbon footprint.
According to the Japanese government, the island of Hokkaido is home to a thriving dairy hub, with over 800,000 dairy cows and is responsible for 50% of the country’s dairy production, and is now a growing source of biogas.
In 2007, the Shikaoi Environmental Preservation Centre was constructed in Hokkaido to process the vast amounts of cattle manure generated on the island into a clean odourless liquid fertiliser, called ‘digestate’, as well as biogas.
Japan’s Ministry of the Environment expanded existing biogas facilities in 2015, commissioning the construction of Shikaoi Hydrogen Farm to start producing hydrogen gas from the manure, making it the first country in the world to do so.
Senior manager of the engineering integration department, in Hokkaido, Tomohiro Inoue, said: “The project aims to build a sustainable hydrogen energy supply chain, from production to transport and use.
“It aims to promote medium- and long-term measures against global warming by demonstrating the effects of decarbonization of hydrogen production by employing renewable energy – biogas and practical utilization of hydrogen.
“We aim to be a model case for the coming hydrogen society, by creating a town that can produce and consume hydrogen which does not emit carbon dioxide,” Inoue added.
Hydrogen is derived when the methane gas extracted from manure reacts with water vapor. The hydrogen gas is transferred into racks of cylindrical tanks called curdles, which are then supplied to farms or sold to energy companies used to power local infrastructure.
140 biogas plants have since been installed in various parts of Hokkaido, ranging from small-scale plants for individual farmers to large-scale plants managed by local governments and research.
These facilities enable famers in the region to lower their production costs, as the energy derived from the biogas is used to fuel daily farm tasks like feeding, water supply, milking, milk preservation, and cleaning, resulting in lower electricity bills on farms.
This has also helped pave the way for a more sustainable agricultural industry in Japan, offsetting the national herd’s methane emissions as a result.
According to engineering professor, Shiho Ishikawa, of Hokkaido University, a dairy cow produces approximately 65kg of manure every day, with 1t capable of generating 30-35m³ of biogas.
“We believe in the basic principle of ‘circulation farming’, which involves the creation of healthy soils, feeding good food to the cows and returning the waste back to the farmland. Recycling livestock manure can help dairy farmers reduce the labor burden and costs of manure disposal,” she said.
“In Hokkaido, about 800,000 dairy cows are kept, so a simple calculation yields about 1.2 million kWh of electricity per day. This is equivalent to the electricity needed to power 130,000 households. Hokkaido had 2.5 million households in 2020,” Ishikawa explained.
In Hokkaido, the proportion of renewable energy resources used to generate electricity has risen as a result of the expansion of biogas production, Ishikawa claimed.
