In a previous article, we mentioned that Hoppy excess yeast is being used in pig feed, but this yeast also plays another role. Namely, power generation. The Hamura Biogas Power Plant at the Nishi-Tokyo Recycling Center in Hamura, Tokyo, generates electricity from food waste collected from food factories and supermarkets.

Items brought here include residues from food factory production processes, expired food products, scraps of supermarket ingredients, and surplus inventory. Some of these items are packaged, but a pre-processing operation automatically separates the bags from the contents, allowing only the contents to be sent to the fermentation tank. Excess yeast from Hoppy production is also mixed into this fermenting process. In the large sealed fermentation tank, fermentation takes place using proprietary technology to produce methane gas. This gas is sent to a large engine that used in ships and other large vessels, where it is combusted and releases thermal energy to spin a generator that produces electric current.

The electricity produced here is approximately 8.5 million kWh/year. This is equivalent to the annual electricity consumption of approximately 1,550 average households. After fermentation, the residuals are turned into organic compost by removing the water content, and this high-quality fertilizer is used to fertilize crops.

Disposal of food scraps is mainly done at municipal waste disposal plants. However, food scraps with high moisture content pose many problems, such as placing a burden on combustion furnaces and requiring fuel to aid burning. By using food scraps for biogas power generation, the burden on municipal waste disposal plants is reduced. Moreover, the residue after power generation is turned into organic compost, which can be used to grow vegetables again, thereby playing a role in creating a recycling-oriented society.

episode 7
Excess Yeast Also Contributes to Biogas Electricity Production