Culture Hi-Tech

Power Generation with Sweet Potatoes ???

Please permit me to ask you that “can you imagine of electric power generation with sweet potatoes?”

That is the theme of today’s issue.  Hi how are you?

In order to maintain a modernized society, electricity is a daily necessity, and various power generation methods have been adopted.

In recent years, human beings are squeezing their wisdom every day in power generation in order to break away from carbon-free society in order to prevent global warming.

Under such circumstances, have you ever seen or heard that sweet potatoes generate electricity?

Speaking of the generation of electricity, nuclear power generation, thermal power generation, hydro‐electric(water power) generation come to our mind.

As renewable energy generations that is expected to help combat global warming, such as solar power generation, wind power generation, geothermal power generation, and biomass power generation have been spotlight in recent years.

I’d like to introduce two cases of the electricity generated with sweet potatoes.

Sweet potato power generation

Now, please watch a video of one citizen’s experience generating electricity from sweet potatoes;

Local businesses and neighboring municipalities collaborate to engage in renewable energy initiatives that contribute to disaster prevention and carbon neutrality. This aligns with the principles of the SDGs and the ‘Sanpo Yoshi'(Three-way satisfaction) spirit of the Omi merchants, benefiting all three parties involved.

★ Question?

I saw a video of citizens in Konan City, Shiga Prefecture, generating electricity from sweet potatoes. The video was from 2017, six years ago. Are citizens still doing this power generation?

★ Answer

Yes, citizens in Konan City are still generating electricity from sweet potatoes.

The Konan Imo Yumezukuri Association, which appeared in the 2017 video, is still active and is generating sweet potato power through aerial cultivation at about 40 locations in the city, including elementary schools, welfare facilities, and households.

In 2022, a 20.8kW power generation facility was installed at Lake Biwa Konan City Ishibe Elementary School, a public facility. This power generation facility was constructed by raising funds from citizens in the city.

In 2023, a plan was announced to construct a sweet potato power plant that **utilizes ** fallow fields in the city. This power plant is expected to produce about 1 million kWh of electricity per year and supply it to public facilities and citizens in the region.

In this way, sweet potato power generation by citizens is playing an important role as an energy source in Konan City.

Sweet Potato Power Generation for 200 Million Yen!?

And another one is “Shouchu” (Japanese distilled beverage spirits from mostly sweet potato just like whisky from barley, brandy from grape) distillery whose name is Kirishima Shuzo.

“Kirishima Shuzo,” Japan’s Top Shochu Producer, Takes a Step Beyond SDGs

Kirishima Shuzo’s challenge goes beyond product development; they have initiated an experiment to “generate electricity from sweet potatoes” and are now generating electricity for about 2,400 households.

Mr. Takuzo Enatsu, the creator of Kuro Kirishima, serves as the President and CEO

Since 2014, we have been engaged in the power generation business, installing facilities to convert biogas generated from shochu lees and potato waste into electricity and providing the generated electricity to electric power companies.

Until then, the biogas generated by the company was only used as fuel for the shochu factory, and could not be fully utilized.

We are now converting the unused biogas into electricity and providing it to electric power companies, thereby increasing the utilization rate of biogas to close to 100%.

In addition to the production and sale of shochu, we promote the recycling business and aim to revitalize the local community without increasing the environmental burden, along with the effective use of sweet potatoes through the power generation business.

What do you think is the difference between biogas and biomass?

Biomass is a resource derived from living organisms and biogas is a combustible gas produced from biomass.

★ What are the advantages of biomass power generation?

It is a renewable energy source
Stable power generation
Carbon neutral
Fuel resources can be supplied from domestic forestry

★ Biomass Power Generation: Why Is It Not More Popular?

The main reasons why biomass power generation is not widely used in Japan include the high rate of fuel imports.
The high cost of power generation, and the availability of places to build power plants.

Japan has implemented a subsidy system and other initiatives to promote the spread of biomass power generation.

Construction of biomass power plants on a local production for local consumption model is also underway in the region.

★ Disadvantages of biomass power generation

Biomass resources are distributed over a wide area, so collection, transportation, and management are costly.

In addition, if a large amount of fossil fuel is used in the cultivation, collection, processing, and transportation of biomass fuel, there is a danger that greenhouse gas emissions will increase as a result.

★ How does biogas power generation work?

The first is the direct combustion method, in which the biomass fuel is burned directly to turn a steam turbine.

The second is the pyrolysis gasification method, in which the fuel is gasified by heat treatment and burned using a gas turbine to generate electricity.

The third is the biochemical gasification method, in which the fuel is fermented or otherwise biochemically converted into gas, which is then burned in a gas turbine to generate electricity.

★ Advantages of Biogas Power Generation

Advantage 1: Stable supply of electricity …
Advantage 2: Low greenhouse gas emissions …
Advantage 3: Digested liquid from the fermenter can be reused as liquid fertilizer …
Advantage 4: The solid content of digested liquid can be returned to farmland as organic fertilizer …
Advantage 5: Reduced costs and secured profits

What is the future of biomass fuels?

Summary: Biomass power generation has a future toward 2030. Focusing on Government Policies Biomass power generation is a theme with promising prospects against the backdrop of the government’s Basic Energy Plan.

It aims to increase the ratio of renewable energy to 36-38% in FY2023. The market for biomass power generation is expected to expand amid the trend toward achieving a decarbonized society, along with
to achieve 100% utilization of recycled resources.

What are the immediate challenges for a sustainable green earth?

COP27(Climate of Parties 27th, from Nov6, 2022~Nov20, 2022) concludes with a historic decision to establish and operationalize a loss and damage fund.

“Together, let’s not relent in the fight for climate justice and climate ambition,” said the Secretary-General in his closing messaging. “We can and must win this battle for our lives.”

Due to global warming, the following situations are issues that should be resolved immediately.

As sea levels rise, not only most populous cities but also many areas in the world could become uninhabitable by the end of this century as shown in the pictures,

On the other hand, land, rivers, and lakes have dried up as opposed to water disasters, causing tremendous damage to crops.


Finally, rather than spending energy on wars and conflicts, I sincerely hope that we will say goodbye to a fossil, petroleum, gas, nuclear energy and so on and reach a decarbonized society as soon as possible, focusing on natural and biomass energy and becoming a green earth.

About the author

古林 茂樹(Shigeki Furubayashi )