REPORT

Aichi Prefecture’ has been carrying out a project that aims to achieve carbon neutrality through the Yahagi River, which flows through the prefecture. With the river basin acting as a model, the goal is to drive the actualization of carbon neutrality through revisions of flood control and irrigation systems, optimization of forest preservation and water-supply ventures, and the application of renewable energy.
 

The river basin comprises of various phases, upstream to downstream, starting with the cultivation of forestry resources at the river’s source, to hydroelectric power generation and flood control implemented through dams, water usage (municipal, industrial, and agricultural,) and reclaimed wastewater through water-treatment processes.

Still, the governing bodies are diverse: The Ministry of Land, Infrastructure, Transport and Tourism (MLIT,) Ministry of Agriculture, Forestry and Fisheries (MAFF,) Ministry of Health, Labor, and Welfare (MHLW,) and Ministry of Economy, Trade, and Industry (METI,) each operate separately. 

The initiative aims to combat this situation by emphasizing common goals within the basin’s ‘water cycle’ and encouraging closer cooperation amongst the various ministries, promoting interdisciplinary, cross-sector collaboration through PPP (Public-Private-Partnership,) to help achieve the objective of carbon neutrality. 

 

 

Since establishing the Aichi Prefectural Carbon Neutral Strategy Council back in July 2021, deliberations about the project have continued for two years. Notably, with the expansion of the targeted area to cover the Mikawa region in its entirety, including the Toyo River Basin, the project has taken considerable shape. For this reason, I would like to take the opportunity to discuss in more detail the progress so far. 

◎Aichi Prefecture’s Portal for the Yahagi River and Toyo River Projects (Japanese)

 

 

The first measure, (enhancing dam operations through hydroelectric power,) emphasizes both the efficient utilization of pre-existing hydroelectric infrastructure, as well as the installation of smaller-scale hydropower facilities in dams without power-generation infrastructure and areas with ‘sustained flow.’ 

It’s also worth mentioning that at the Yahagi Dam located upstream of the Yahagi River, hydroelectric power generation is being strengthened.

In a similar nature, the Kise Dam upstream to the Yahagi River and the Shitara Dam upstream to the Toyo River, are both being considered for the development of small-scale hydropower and new hydroelectric power.

Furthermore, it is anticipated that artificial intelligence will be used to streamline dam operations and management, such as employing AI to predict regular flow rates as well as those during irregular conditions such as floods. 

The term ‘sustained flow’ refers to the amount of water released to ensure that downstream water supply and fishery is not adversely affected. 

 

The second measure, concerning solar power generation infrastructure in communal facilities, is established by means of floating solar power generation facilities that can be installed in water purification and sewage treatment plants, anti-flood ponds, and agricultural facilities. 

Already, plans have been made to install solar power generation facilities at the Yahagi River Water Purification Center located near the estuary of the Yahagi River, as part of the 2024 project to cover the electricity cost of the sewage treatment facility.

In addition to this, there are ongoing discussions about the potential installation of solar power generation equipment at the Hishiike Reservoir in Koda town. 

 

 

The third measure, promoting energy conservation in water infrastructure, describes the process of streamlining labor through reorganization of both water supply and sewage facilities.

As many of these establishments are becoming worn down with age, the measure pushes for greater energy efficiency through strategic consolidation.

To be more specific, there are plans already established to move forward with the collective incineration of sludge across the eleven river basin sewerage systems within the prefecture.

As an initial step, a greenhouse gas low-emission-type incinerator has been installed and is in operation at the Kinuura West Sewage Treatment Center, situated across from Chita Bay.

Furthermore, measures have been initiated to cultivate energy through waste heat. 

In addition, the redevelopment of the deteriorating Toyohashi Water Purification Plant is under discussion.

Through PPP-projects, plans are underway to establish a next-generation water purification plant that addresses the issue of carbon neutrality in its operations. 

 

The fourth measure, which addresses the streamlining of operational standards for sewage treatment, involves mitigating the density of nitrogen and phosphorus in the treated sewage effluent.

While this aids in the purification of the water, Mikawa Bay still faces a deficiency in nutrients crucial in the cultivation of phytoplankton and seaweed.

Moving forward, the aim is to alleviate the sewage treatment standards, thus reducing the energy consumed in the process of sewage treatment. 

 

The fifth measure, intended to improve CO2 absorption through sustainable forestry, involves the conservation and management of river basin forests.

Specifically, in the context of the prefectural-owned forests in the upstream vicinity of the Yahagi River, CO2 absorption resulting from forest maintenance is quantified through a system called ‘J-Credit.’

The credits accumulated are then resold to downstream companies, utilizing the generated funds to further promote sustainable forest management. 

 

Initiative six, the promotion of water cycle management via coordination between water and sewerage facilities, comprises of the optimization of pre-existing facilities that are currently inefficient due to factors such as site location or coordination.

Since the water purification facilities were developed with the population increase in mind, they tend to consume a substantial amount of electricity through the transportation of water via pumps.

By reconsidering the facilities, the goal is to increase the amount of water distribution carried out through the natural flow of the water supply, making full use of the potential energy. 

Another objective is to integrate the operation and management systems thus improving the efficiency of the water supply and drainage systems which are systematically divided between prefectural and municipal governing bodies. 

 

The seventh and final item, promoting the reduction of CO2 emissions in construction projects, as the name suggests, strives to progress carbon neutrality throughout the entirety of the construction process.

By involving numerous stakeholders in the corporate, governmental, and academic sectors, a collaborative PPP project of this kind proposes to address societal issues and revitalization of local communities. 

 

 

I’ve explained this single project at length, however, within the river basin project alone, there are numerous initiatives, such as streamlining water-supply operations, that can be implemented for the sake of carbon neutrality.

A primary characteristic of the Yahagi and Toyo River projects is, namely, the optimal categorization and cross-functional collaboration incorporating public and private initiatives, and PPP-partnership. 

The River Basin Carbon Neutral Project originated with the Yahagi and Toyo River situated in the Mikawa region of Aichi, however, moving forward, the plan is to expand the initiative to the primary rivers in the Owari region.

Through doing so, the mission is to achieve carbon neutrality throughout all river basins situated in the prefecture. 

Not limited to just the local government, the state has also expressed interest in the project.

Back in September, a promotion council was established, with mayors of the river basin municipalities and directors of the central governmental agencies in attendance. 

Nationwide, there are one hundred and nine primary river systems. By obtaining support and interest from the government after demonstrating the effectiveness of the Aichi-based projects, expanding horizontally to other river basins across Japan, we may just make the steps necessary to reach the goal of ‘Carbon Neutrality by 2050.’ 

Moreover, this project, with its origins in Japan, is expected to become an infrastructure project expanded globally. Given its potential domestically, we also anticipate its development on the global stage too.