Actions for Climate Change - Assessment of CO2 emission reductions -

Aspects Determined as Materiality
  • Energy

    302-1

  • Emissions

    305-5

Adequate Method to Evaluate Effects of CO2 Emissions Reduction

Method to evaluate effects of CO2 emissions reduction>

As CO2 is not emitted where electricity is used, the CO2 emitted at the power plant is considered as being emitted by the customer. This also applies when customers strive to conserve energy, and it is necessary to consider this as the CO2 reductions at the power plant. To do this, it is necessary to identify the power sources whose annual power generated are impacted by demand fluctuations. These are known as marginal power sources. Using the CO2 emission factors of these sources is appropriate to calculate reduced CO2 emission by energy-saving efforts by customers.

Method for evaluating the impact of reduced CO2 emission

What is the Marginal Power Source in Japan?

The power sources of Japan include thermal, nuclear and hydro power generation. Nuclear power plants continually generate power except when they are undergoing periodical inspections. Due to their low operational costs, hydro power plants are operated at full capacity and the amount of power generated annually is determined by the amount of precipitation (rain and snow). On the other hand, the amount of power generated by thermal power is adjusted to meet demand and so thermal power is considered the marginal power source in Japan.

■ Electricity Production by Type of Power Source (Before the Great East Japan Earthquake)

Electricity Production by Type of Power Source (Before the Great East Japan Earthquake)

Formula for calculating CO2 emissions reductions

The following formula is the proper method for calculating CO2 emissions reductions due to reduced electricity consumption using the average CO2emission factor of the thermal power sources as the marginal power source.

Formula for calculating CO2 emissions reductions
  • * Source
    The emission factors of thermal power sources applied in the Plan for Global Warming Countermeasures adopted at the Cabinet meeting in October 2021.
    FY2014: 0.65 kg-CO2 / kWh
    FY2031: 0.60 kg-CO2 / kWh

Average Emission Factor (AEF) for all power sources and the Marginal Emission Factor

Generally, CO2 emissions are estimated using the average factor for CO2 emissions for all types of power sources including nuclear, hydro and thermal (Average Emission Factor (AEF)). However, if the AEF is used to estimate CO2emissions reductions, nuclear and hydro power, which do not change with fluctuations in demand, are considered also to have been reduced. As a result, proper evaluations of CO2 emissions reductions should use the marginal emission factor, which in Japan is the average CO2emission factor of the thermal power sources.

An example calculated using the emission factors of FY2031 (see above) suggests that it is possible that CO2 emissions reduction evaluations based on AEF will underestimate the effect of introducing solar, wind, biomass, and other alternative energy sources on global warming.

■ Emission Factors Used in the Example Calculation

Average Emission Factor (AEF) for all power sources Marginal Emission Factor
(emission factor for all thermal power sources)
0.25 kg-CO2/kWh

0.60 kg-CO2/kWh

■ Example of Underestimation of CO2 Emissions Reductions when Using AEF

Example of Underestimation of CO2 Emissions Reductions when Using AEF

International / domestic standards for CO2 reduction assessment

International standards dictate that CO2 reductions as a result of reduced electricity purchased should be calculated using the marginal emission factor (in Japan, the average emission factor of the thermal power sources). This practice is employed in the Clean Development Mechanism (CDM) process, one of the mechanisms of the United Nation's Kyoto Protocol, as well as international standards such as the Guidelines for Quantifying GHG Reductions from Grid-Connected Electricity Projects, part of the GHG (Greenhouse Gas) Protocol Initiative.

In Japan, the government guidelines for energy conservation include information regarding this method.

Government guidelines employing the Marginal Emission Factor (the average factor of thermal power sources)

The Plan for Global Warming Countermeasures adopted at the Cabinet meeting in October 2021

Average emission factor for all power sources in FY2014: 0.57 kg-CO2 / kWh; average emission factor for thermal power sources: 0.65 kg-CO2 / kWh
Average emission factor for all power sources in FY2031: 0.25 kg-CO2 / kWh; average emission factor for thermal power sources: 0.60 kg-CO2 / kWh

[Reference]

“Interim Summary Report by Target Attainment Scenario Subcommittee” compiled by the Global Environmental Committee, Central Environmental Council (2001)
Average emission factor for all power sources: 0.36 kg-CO2 / kWh; average emission factor for thermal power sources: 0.69 kg-CO2 / kWh
Environmental Reporting Guidelines (FY2013) published by the Ministry of the Environment (April 2012)
Average emission factor for all power sources: 0.36 kg-CO2 / kWh; average emission factor for thermal power sources: 0.69 kg-CO2 / kWh


Sustainability of
the Daigas Group
President's Commitment Transition Finance
Values and Sustainability Promotion of the Daigas Group
Daigas Group's Values Daigas Group Charter of Business Conduct and Management Policy Daigas Group Code of Business Conduct Sustainability Promotion System and Management Stakeholder Engagement Initiatives the Daigas Group Participates In Commendation from the Outside
Sustainability Management and Value Creation Process
Value Creation Process of the Daigas Group Long-Term Management Vision 2030 Medium-Term Management Plan 2023 Daigas Group Carbon Neutral Vision
Actions on Materiality
Materiality of the Daigas Group Materiality Review Cycle Creating Value for Customers
(Charter I)
Contributing to the Sustainability of the Environment and Society
(Charter Ⅱ)
Engaging with and Contributing to Society (Charter Ⅲ) Respecting Human Rights
(Charter IV)
Complying with Laws and Regulations (Charter V) Providing Work Environment That Supports Employees’ Personal Growth (Charter VI)
Corporate Governance
Corporate Governance Risk Management Compliance Messages from Outside Directors
Value Chain and Sustainability
Consideration for the Value Chain and Stakeholders Social Impact of Business Activities in Our Energy Value Chain and Our Efforts toward Sustainability
Daigas Group's Efforts for SDGs
Special Features: Co-create Value for a Sustainable Future - Initiatives to Achieve Carbon Neutrality Back Numbers of Special Features
FY2022 Activities Report
Creating Value for Customers (Charter I)
Charter I Index Management for Creating Value for Customers Safety and Security 1:
Procurement Stage
Safety and Security 2:
Processing Stage
Safety and Security 3:
Distribution Stage
Safety and Security 4:
Consumption Stage
Incorporating Customer Opinions Proposing New Value
Contributing to the Sustainability of the Environment and Society (Charter Ⅱ)
Charter Ⅱ Index Management toward Contributing to the Sustainability of the Environment and Society Environmental Management Environmental Management: Indicators, Targets and Results Actions for Climate Change: Recognition of and Action on Risks and Opportunities Actions for Climate Change: Method to Evaluate Effects of CO2 Emissions Reduction Actions for Climate Change: Working to Reduce CO2 Emissions in Business Activities Actions for Climate Change: Working to Reduce CO2 Emissions at Customer Sites Efforts in Resource Recycling Conserving Biodiversity Developing Environmental Technologies Addressing Environmental Risk Promotion of Green Purchasing Environmental Communication
Engaging with and Contributing to Society (Charter Ⅲ)
Charter Ⅲ Index Management of Engagement with and Contribution to Society Activities for Promoting Communication with Society Corporate Volunteering Activities under the Small Light Campaign Social Contribution Activities Activities at Osaka Gas' Foundations
Respecting Human Rights (Charter IV)
Charter IV Index Status of Management regarding Respect for Human Rights Human Rights Due Diligence Action on Human Rights
Complying with Laws and Regulations (Charter V)
Charter V Index Management for Complying with Laws and Regulations Compliance Promotion Efforts Efforts for Protection of Personal Information Information Security Consultations and Reports from Partner Companies
Providing Work Environment That Supports Employees’ Personal Growth (Charter VI)
Charter VI Index Status of Management to Support Employees' Personal Growth Employment Acceptance of Diversity Balancing Work and Family Human Resource Development and Rewards Communication Between Employees and Company Improving Occupational Health and Safety
Reporting Guidance and Guidelines and ESG Data
Reporting Guidelines
ESG Data
Environmental Performance Data Social Data Governance Data
Reports
Policy on Reporting Sustainability Activities Third-Party Verification Download Sustainability Site Terminology Search by Purpose Course Taken Since the Company's Foundation Sustainability Site Map We Value Your Feedback Topics backnumber Osaka Gas in brief