We are pleased to announce that the "Project to Create a Model Case for Promoting Decarbonization of Housing Complexes by Introducing Bulk Power and Distributed Energy Sources" (hereinafter referred to as the "Project"), which was carried out in collaboration with the City of Kitakyushu (Mayor: Kazuhisa Takeuchi), has won the Grand Prize at the NIKKEI Decarbonization Awards.

This project will create Japan's first (*1) business scheme to maximize the rate of on-site consumption of renewable energy (including real renewable energy, hereinafter referred to as "renewable energy") by combining a PPA project utilizing the roofs of apartment complexes, a bulk power receiving system, and storage batteries. This system, which accelerates the introduction of renewable energy while solving existing problems, can be used for all types of housing complexes, whether publicly or privately owned (for sale or rent), and will make a significant contribution to reducing CO2 emissions in the residential sector and realizing a decarbonized society.

The award ceremony is scheduled to be held on Tuesday, March 11, 2025 at a symposium (*2) hosted by Nikkei Inc.

◾️What is the NIKKEI Decarbonization Award?
The NIKKEI Decarbonization Award, sponsored by Nikkei Inc., recognizes the efforts (projects, technology development, research, etc.) of companies, local governments, NPOs/NGOs, organizations, individuals or groups that are ambitiously working toward the realization of a decarbonized society, thereby supporting these efforts.

The selection process was based on the NIKKEI Decarbonization Project's goal of "contributing to the realization of a safe, secure, and sustainable decarbonized society." Six companies and organizations were awarded the Grand Prize in FY2024 out of 26 applications.

◾️About this project
Outline of this project
This project is an initiative to create a model case for promoting decarbonization in the residential sector by combining PPA projects, bulk power receiving systems, and storage batteries to increase the rate of on-site consumption of renewable energy in housing complexes.

PPA business is a business in which an electric power company installs solar power generation equipment on a customer's premises and sells the electricity generated directly to that customer. Customers can install renewable energy at no initial cost, which has the advantage of reducing electricity rates and environmental impact. In the bulk power receiving system for housing complexes, the bulk power provider or building manager purchases high-voltage power in bulk, converts it to low-voltage power, and then supplies it to the individual units. In addition to reducing electricity rates, this scheme makes it possible to supply renewable energy on a building-by-building basis.

In addition to these, the installation of storage batteries will enable the management and control of electricity supply and demand, thereby increasing the building's on-site energy consumption rate.

[Points of this project model
(1) Maximize the use of roof area of housing complexes
Solar power generation in housing complexes is generally used in common areas, so the generated renewable energy power cannot be fully consumed within the building, which limits the installed capacity of solar power generation equipment even in housing complexes with large roof areas (Figure-①).

However, since the project will use a lump-sum power receiving system, it will be possible to use electricity throughout the entire building, including private areas (Figure-2). Furthermore, by utilizing storage batteries, electricity can be used outside of the daytime when power generation is high. This can also contribute to improving the ratio of on-site renewable energy consumption by maximizing the use of the roof area (Figure-3).

(2) Enables the supply of renewable energy-derived electricity to entire housing complexes
If the demand for electricity at a housing complex exceeds its own consumption, we will supply electricity using non-fossil certificates from our company, thereby achieving 100% renewable energy at one housing complex.

Normally, the cost of electricity with non-fossil certificates tends to be higher, but this project also made it possible to reduce residents' electricity bills through a combination of several schemes of electricity management.

(iii) Facilities can be installed without financial or administrative burdens on the building owner
The installation of solar power generation equipment and storage batteries involves high costs and management burdens, and there have been cases where owners and managers of housing complexes have given up on installing them.

In this project, MHI will bear the installation costs of the solar power generation equipment required for the PPA project, thereby reducing the City's cost burden. In addition, the City will not be burdened with any operational costs since MHI will also handle the meter reading, billing, and facility management associated with the bulk power receiving system. In addition, the city, as the owner of the PPA project, will receive a certain amount of income each year in the form of roof rent, which will help ensure profitability.

(4) Contribute to improving the resilience of multi-family housing
The equipment installed in this project can be used as an emergency power source in the event of a power outage such as a disaster. In recent years, many municipalities have recommended evacuation of people from their homes in housing complexes in response to the intensification of natural disasters, but securing power is essential for this to happen.

In addition to the use of renewable energy during normal times, the project has also established a system in which electricity is supplied from storage batteries to common facilities such as meeting rooms and water pumps in the event of an emergency. The combination of storage batteries and photovoltaic power generation is expected to provide a continuous supply of electricity even during power outages, contributing to the improvement of the resilience of housing complexes.

Potential contribution to decarbonization of the household sector
This project is an initiative in conjunction with the reconstruction of public housing in Kitakyushu City, but the scheme can also be used in private housing complexes. CO2 emissions from the residential sector in Japan account for 161 TP3T (*3), of which approximately 691 TP3T is from electricity, so the CO2 emission reduction impact that can be expected from the introduction of renewable energy in the residential sector is not small. Taking this award as an opportunity, we aim to apply this model to a wide range of collective housing to promote the decarbonization of the residential sector.

1 Combining a PPA project that utilizes the roofs of public housing with a lump-sum power receiving system to maximize the rate of on-site consumption of renewable energy (survey by Kitakyushu City, October 2024).
(Reference)Project for private photovoltaic power generation PPA (Roof Rental) at municipal housing in Yonaguro Danchi
2 Symposium will be held on Monday, March 10 and Tuesday, March 11, 2025
(Reference.NIKKEI Decarbonization Project SymposiumAbout
*3Ministry of the Environment Greenhouse Gas Emissions and Absorption in FY2022 (FY2022)

◾️ Mitsuhiro Sato, General Manager, Public Service Development Team, Distributed Energy Business Division, Resil Corporation Comments
Various initiatives are underway in various municipalities to achieve carbon neutrality by 2050. While efforts are well underway, decarbonizing the household sector remains a major challenge.

We have know-how and experience in providing services for multi-dwelling units, which we have been providing for many years, and we proposed this initiative in Kitakyushu City as one solution.

While each municipality has its own challenges and solutions, we will continue to contribute to decarbonization and stable energy supply through energy management by leveraging our expertise in supplying electricity to condominiums, which we have cultivated over the past 20 years to realize our mission of "making decarbonization not an intractable problem.

◾️ Contact for inquiries regarding decarbonization of public housing
Please contact us at the email address below with "Decarbonizing Public Housing" in the subject line.
・MAIL：info_dev@rezil.co.jp
Contact: Public Service Development Team, Distributed Energy Business Division