CSR Charter Ⅱ Harmonizing with the Environment and Contributing to Realizing a Sustainable Society
Efforts Contributing to Realizing a Low-Carbon Society
- Principle and Outline
- Evaluation of CO2 Emissions Reduction by Reducing Electricity Use
- GHG Emissions at Daigas Group
- Efforts by the Daigas Group to Reduce and Curb CO2 Emissions
- Voices from staff: I want to play a role in diffusing energy conservation to society through our efforts to promote energy saving at office buildings of the Daigas Group.
Principle and Outline
In view of the worldwide trend to combat climate change, the Daigas Group is working to reduce emissions of greenhouse gases such as CO2 and methane (CH4) generated through our business activities in order to help bring about a low-carbon society. We are actively taking such steps as reducing CO2 emissions when transporting liquefied natural gas (LNG) and when manufacturing city gas, pursuing various efforts throughout the Group to conserve energy in offices, and verifying that energy is being conserved by those efforts.
Evaluation of CO2 Emissions Reduction by Reducing Electricity Use
Effects on reducing CO2 emissions through the reduction of electricity consumption
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)
Formula for calculating CO2 emissions reductions
The following formula is the proper method for calculating 2 emissions reductions due to reduced electricity consumption using the average 2 emission factor of the thermal power sources as the marginal power source.
- * Source
- The emission factors of thermal power sources applied in “The Plan for Global Warming Countermeasures” adopted by the Cabinet meeting in May 2016.
FY2014: 0.65 kg-CO22/kWh
FY2031: 0.66 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 CO2 emissions 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 CO2 emission factor of the thermal power sources.
As an example, calculated using the emission factors of FY2031, 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 power sources)
|0.37 kg-CO2/kWh||0.66 kg-CO2/kWh|
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 May 2016
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: 0.37 kg-CO2/kWh; average emission factor for thermal power sources: 0.66 kg-CO2/kWh
“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
GHG Emissions at Daigas Group
Initiatives to reduce CO2 emissions from energy consumption and methane (CH4)
In the Daigas Group, we work to reduce CO2 emissions from energy consumption and methane (CH4), the main component of natural gas in the gas business and in the thermal supply and power generation businesses, as well as CO2 emissions from energy consumption at affiliates. The Group's operations, however, do not emit any other greenhouse gases (N2O, HFCs, PFCs, SF6, NF3).
- * Affiliated Companies
- Of Osaka Gas's 150 consolidated subsidiaries, 64 companies are subject to the calculation of GHG emissions. Those housed in office buildings as tenants and whose environmental data are difficult to grasp and whose environmental effects are minimal are not subject to such calculation. Also excluded from the calculation are overseas companies whose environmental impacts are minimal. However, the aggregate number of companies may differ by fiscal year and by item due to company mergers and others. (As of March 31, 2017)
Group companies No. of companies Company names Energy Resources & International Business Unit 1 Marianas Energy Company LLC LNG Terminal & Power Generation Business Unit 14 Gas and Power Co., Ltd., Nakayama Joint Power Generation Co., Ltd., Nakayama Nagoya Joint Power Generation Co., Ltd., Hirogawa Myojinyama Wind Farm Co., Hayama Wind Farm, Yura Wind Farm Development, Hizen Wind Farm, Hirao Wind Farm, Senboku Natural Gas Power Generation, Osaka Gas Liquid Co., Ltd., Cold Air Products Co. Ltd., Cryo-Air Co. Ltd., Kinki Carbonic Co., Ltd., Gasnet Co. Ltd. Pipeline Business Unit 2 Kinpai Co., Ltd., Osaka Gas Renotech Co., Ltd. Residential Energy Business Unit 18 Living Maintenance Service Hokuto Co., Ltd., Living Maintenance Service Osaka Co., Ltd., Osaka Gas Cooking School Co., Ltd., Create Kansai Co., Ltd., Osaka Gas Customer Relations Co., Ltd., Aqua Brain Co., Ltd., Kansai Business Information Inc., Osaka Gas Housing & Equipment Co., Ltd., Osaka Gas Security Service Co., Ltd., Osaka Gas LPG Co., Ltd., Nissho Petroleum Gas Corporation, Nissho Propane Sekiyu Co., Ltd. Nissho Gas Supply Co., Ltd., Nagano Propane Gas Co., Ltd., Daiya Nensho Co Ltd., Ehime Nissho Propane Co., Ltd., Enes Carry Corp., Kochi Nissho Inc. Commercial & Industrial Energy Business Unit 9 OGCTS Co., Ltd., G & M Energy Service Co., Ltd., Ashiyahama Energy Service Co., Ltd., Rokko Island Energy Service Co., Ltd., Enetec Kyoto Co., Ltd., Enetec Osaka Co., Ltd., Nabari Kintetsu Gas Co., Ltd., Toyooka Energy Co., Ltd., Shingu Gas Ltd. Group Headquarters 8 OG Sports Co., Ltd., Osaka Gas Autoservice Co., Ltd., Osaka Gas Finance Co., Ltd., Osaka Gas Business Create Co., Ltd., Active Life Inc., KRI Inc., Osaka Gas Engineering Co., Ltd., i-support Co., Ltd. Osaka Gas Urban Development Group 3 Osaka Gas Urban Development Co., Ltd., Osaka Gas Facilities Corp., Kyoto Research Park Co., Ltd., OGIS Research Institute Group 6 OGIS-RI Co., Ltd., Sakura Information Systems Co., Ltd., SIS Techno-Service Co., Ltd., JOE Corp., Ltd., Ube Information Systems Inc., System Answer Inc. Osaka Gas Chemicals Group 3 Osaka Gas Chemicals Co., Ltd., Minabe Chemical Industries Ltd., Mizusawa Industrial Chemicals, Ltd. Total 64
GHG Emissions* (1,000 t-CO2e)
|Consolidated companies (Osaka Gas and its affiliates)||77||77||74||69||65|
- * GHG emissions
- (CO2 emissions)
CO2 emissions calculated using the average emission factor for thermal power source are subject to management in the Daigas Group so that the benefit of reducing the consumption of purchased electricity can be properly evaluated.
CO2 emissions for FY2017 were calculated using the average emission factor of 0.65 t-CO2 /1,000 kWh, a figure decided under a government plan to combat global warming, approved by the Cabinet in 2016. CO2 emissions through FY2016 were calculated using the factor of 0.69 t-CO2 /1,000 kWh, a figure shown in an Interim Summary Report compiled in 2001 by the Target Attainment Scenario Subcommittee under the Global Environmental Committee of the Central Environmental Council.
CH4 emission is calculated using the global warming factor of 25, defined in the UNFCCC reporting guidelines on annual greenhouse gas inventories published in 2012. Greenhouse gas emissions are defined as the aggregate of CO2 emissions and CO2 equivalent of CH4 emissions.
(Reference) GHG Emissions for Comparison* (1,000 t-CO2)
- * GHG emissions for comparison
- For calculation of the yearly CO2 emissions of purchased electricity, the most recent emission factor of the Kansai Electric Power Co., Inc. is used. (e.g. The CO2 emission factor of FY2015 is calculated based on the emissions during FY2014) CO2 emissions of FY2016 and after are calculated using emission factors of electric companies from which we purchased electricity. The yearly CO2 emissions of purchased electricity is calculated by multiplying the year's electricity consumption by the year's emission factor.
CO2 emissions from Osaka Gas's city gas business
CO2 emissions in Osaka Gas's city gas business for FY2017 were 127,369 tons, resulting in CO2 emissions per cubic meter of gas sold (emissions intensity) of 14.7 g-CO2/m³ . Compared to 1990, the Kyoto Protocol's benchmark year, total CO2 emissions were down 52% and emissions on a per-unit basis fell by 76%.
Reasons for this decrease include the use of cogeneration systems at city gas processing plants, a reduction in purchased electricity as a result of the active use of cryogenic power generation, energy efficient operations, and aggressive efforts to conserve energy in office buildings.
In 1979, Osaka Gas became the first company in the world to begin operation of a cryogenic power generation facility, and now the Senboku Terminal and the Himeji Terminal produce approximately 74.40 million kWh cryogenically each year (actual figure for FY2017).
We will work toward further CO2 emission reductions by aggressively using electricity produced by unused energy such as LNG cryogenics and gas pressure of gasification, as well as by promoting energy saving in office buildings.
CO2 Emissions from the City Gas Business of Osaka Gas
Methane emissions from Osaka Gas's city gas business
In the city gas business of Osaka Gas, methane (CH4) gas is emitted during measurement of gas quality and gas fitting work. We therefore strive to reduce emissions by introducing a system that can recollect gas without it being released into the air after the measurement, by employing a no-blow gas shutting-off method and using an Eco Purge vehicle.
Methane gas missions were 75 tons in FY2017, down 17 tons from the previous year.
Methane Emissions at Osaka Gas
|Methane emission (t-CH4)||116||103||94||92||75|
CO2 emissions from affiliates
CO2 emissions from affiliate companies amounted to about 4,104 thousand tons in FY2017. Most of the total comprised CO2 emitted at fossil-based power stations. The Daigas Group is striving to curb CO2 emissions from its business operations by introducing energy-efficient fossil-derived power stations and promoting energy saving through the use of renewable energy sources.
Efforts by the Daigas Group to Reduce and Curb CO2 Emissions
Efforts to reduce CO2 emissions in LNG transportation
In October 2016, Osaka Gas put into service the fuel-efficient “LNG MARS” for the transport of LNG, an essential material for city gas. “LNG MARS” has become the eighth tanker of our fleet deployed for LNG transport. Osaka Gas adopted new SAYAENDO type vessel, which was instrumental in reducing the vessel's air resistance significantly. The tanker also adopted a new steam turbine, improving fuel efficiency by more than 20% compared with conventional tankers. These features curbed the tanker's CO2 emissions and transport costs.
Efforts to curb CO2 emissions at city gas manufacturing plants
We are endeavoring through a variety of energy conservation activities to curb CO2 emissions at city gas manufacturing plants.
Reducing CO2 emissions at offices
At offices of each company of the Daigas Group, efforts to achieve targets for energy consumption and CO2 emission are being made under the environmental management systems (EMS), established based on standards such as ISO 14001, Eco Action 21 developed by the Ministry of Environment and the Osaka Gas Environmental Management System (OGEMS).
Under the EMS, each and every employee strives to reduce his or her own energy consumption by turning off lights and office equipment not currently needed or in use, and setting air conditioning to reasonable temperatures in line with set targets.
The Daigas Group has actively been implementing advanced energy-conservation measures and measures to reduce CO2 emissions when its buildings are renewed or renovated. Measures deemed effective for energy saving are horizontally applied to all office buildings of the Daigas Group under the “Green Gas Buildings” project. As of August 2017, the “Green Gas Buildings” project is applied at nine of the Group's business offices.
When we renovated the Hokubu Gas Building (Takatsuki City, Osaka Prefecture), Osaka Gas incorporated the “Behavioral Observation Method” *1 into the building design process to further promote energy saving. Observation and analysis of the tenants' behavior on energy saving according to the method allowed us to realize reduction of CO2 emissions.
Our offices also introduced monitoring systems such as the “Motto Save,” which is aimed at promoting energy saving at office buildings by deciding their optimal energy use based on building size and the type of building operation. In addition, the Fukiai office of Osaka Gas, located in Kobe City, Hyogo Prefecture, introduced “BCP-Lite,” *2 an emergency power-supply system that enables even a small-sized building not usually equipped with a backup power generator to continue the minimum level of business operations in the event of a natural disaster. Following its introduction, the Fukiai office confirmed that the system could function as designed. The “BCP-Lite” is a system in which the concept of a business continuity plan (BCP) was added to our conventional energy-saving equipment. We expect this to help the building of a low-carbon society in the future while supporting our business continuity in the event of a contingency.
The "hu+g MUSEUM," a showroom of Osaka Gas, is equipped with facilities with high energy efficiency, including cogeneration systems, regional air-conditioning systems, solar power generation systems, and solar-heat systems. Furthermore, the Group has built a Smart Energy Network in Osaka City's Iwasaki District where the showroom is situated. The network has played an important role in promoting the region's overall energy saving by establishing an optimal energy control system to ensure the most efficient use of energy (electricity and heat) generated in buildings and devising a high energy security system that can effectively respond to unscheduled power outage.
The Daigas Group received the “Building Energy-efficiency Labeling System (BELS)” *3 assessment for two of its properties in fiscal 2017. The most recently constructed buildings of the Fukiai Office and the hu+g MUSEUM received four stars and five stars, respectively, under the five-star BELS system for their excellent energy conservation performance. Their respective energy-conservation rates in the year were a high 33% and 39%.
- *1 “Behavioral observation”
- “Behavioral observation” is a methodology for identifying and presenting solutions based on the academic analysis of facts and findings obtained through the observation of people's behavior.
- “BCP-Lite” is an emergency power supply system for office buildings in which electricity can be supplied without interruption even if power outage occurs following a natural disaster. A self-driven gas engine heat pump (GHP) is incorporated into the system.
- BELS stands for “Building Energy-efficiency Labeling System.” The labeling system for buildings and housing is aimed at evaluating the energy-saving ability of nonresidential buildings based on the Act on Improvement of the Energy Consumption Performance of Buildings. The evaluation, certified by third parties, is given on a scale of one to five stars. The evaluation result is represented by a number of stars displayed on a special plate.
I want to play a role in diffusing energy conservation to society through our efforts to promote energy saving at office buildings of the Osaka gas Group.
Observing energy-saving standards became mandatory at newly constructed office buildings when the Act on Improvement of Energy Consumption Performance of Buildings came into force on April 1, 2017. This has made corporate energy-conservation activities all the more important.
I believe that, under these circumstances, boosting energy conservation performance at office buildings of the Osaka gas Group and using our experiences and expertise in the field for society are an important mission of Osaka Gas in view of its anticipated role as an energy service provider.
BELS is a government-sponsored energy conservation evaluation system aimed at diffusing energy-efficient buildings. Our recent energy-saving efforts included the promotion of highly energy-efficient cogeneration systems and air-conditioning systems powered by gas, which the Osaka gas Group received the highest evaluation under the BELS system. Furthermore, we have stepped up our public relations activities introducing such efforts. We will continue to disseminate information useful for our consumers regarding our energy conservation activities.
Smart Energy Network
Osaka Gas structured a district heating and cooling system at the area surrounding the facilities of the Company in Nishi Ward in Osaka City. The system also functions as the Smart Energy Network, where heat and electricity generated in the area are accommodated in the community. The system can be controlled optimally from the perspective of the entire area, realizing an approach to urban planning that allows energy to be used efficiently.
Efforts to reduce CO2 emissions from the power business
Adoption of a gas turbine combined-cycle power generation method
The Senboku Natural Gas Power Plant (total power output capacity of 1,109,000 kW), operated by Senboku Natural Gas Power Generation of the Daigas Group, employs a gas turbine combined-cycle power generation system using a combination of a gas turbine and a steam turbine.
Natural gas is combusted in the gas turbine's combustor, and the combusted gas then turns the gas turbine to generate electricity. In addition, the heat of the gas turbine's exhaust gas creates steam in an exhaust heat recovery boiler that turns a steam turbine to generate electricity. This gas turbine combined-cycle power generation is thus able to attain high efficiency in producing power by recycling the heat of exhaust gas.
The Senboku Natural Gas Power Plant uses a 1,300℃-class gas turbine to achieve a high power generation rate of about 57% (Lower heating value (LHV) standard), helping conserve energy and curbing CO2 emissions.
Energy Efficiency of Gas Turbine Combined-Cycle Power Generation
Biomass-combined coal-fired power generation
Nakayama Nagoya Joint Power Generation Co., Ltd., an Daigas Group company, has adopted a biomass-combined coal-fired power generation method at the Nagoya Power Plant (coal-fired plant) and the Second Nagoya Power Plant (coal-fired plant) to curb CO2 emissions. The method uses woody biomass in the base fuel of coal.
The fuel used at the Nagoya Power Plant (with a total output capacity of 149,000 kW) contains 5% woody biomass. The rate of woody biomass stands at 30% for the fuel used at the Second Nagoya Power Plant (with a total output capacity of 110,000 kW). The plants are operated jointly with the aim of increasing operational efficiency in power generation and coal transportation.
Introduction of cogeneration-based electricity sources
Energy-efficient natural gas cogeneration facilities are set up on the premises of a client plant. Electricity and heat (steam) generated using the cogeneration system are provided to client companies. The Daigas Group uses part of the electricity generated as an electricity source for its power business, which helps improve the cogeneration facility utilization rate, and further promotes efficient energy use and curbs CO2 emissions. Gas and Power Co., an Daigas Group company, operates such facility at two locations—one at the Uji Energy Center for Unitika Ltd. and the other at the Settsu Energy Center for Kaneka Corp. The power output capacity is 66,800 kW at the Uji Energy Center and 17,460 kW at the Settsu Energy Center.
Efforts to spread renewable energy sources
As part of its efforts to reduce CO2 emissions, the Daigas Group promotes power generation using renewable energy sources such as wind power and solar power.
Efforts to reduce 2 emissions through district heating and cooling systems
District heating and cooling systems are designed to promote efficient use of energy sources by having people and offices in the same area use energy systems such as air conditioners, heaters and hot-water supply equipment together. In the case of the Daigas Group, such systems were first introduced in Japan in 1970 in the Senri Chuo district of Toyonaka City, Osaka Prefecture. Since then, various energy systems have been adopted by the group in various regions in Japan, each system developed in an optimal manner to reflect each region's needs under its urban development project. The Daigas Group introduced such systems in totaling 10 districts in Osaka, Kyoto, Nara and Kobe. The Daigas Group was ahead of other companies in introducing gas cogeneration systems under the framework of regional-based air-conditioning and heating systems. The group has been also active in starting new businesses, such as accepting waste heat generated under cogeneration systems run by customers and supplying electricity to certain customers as a registered Specified Electricity Utility.
The Daigas Group has been also working to secure stable heat supplies, promoting the advanced use of energy, increasing efficiency in administrative management and cutting business costs. More recently, the group built a Smart Energy Network in Osaka City, which is an energy network system focusing on the utilization of natural gas cogeneration and renewable energy sources. All these measures represent the Daigas Group's efforts to promote both energy conservation and energy security.
The Daigas Group is redoubling its efforts to further increase energy system efficiency by introducing high-efficiency equipment in conjunction with the renewal of facilities Kobe and Senri district.