Sustainability Site Terminology


Ballast water

Because a ship is more prone to capsize when it carries less cargo, water is pumped into an unloaded cargo ship to provide stability. This water, serving as a counterweight, is called ballast. Water used as ballast is called ballast water, which is usually taken from coastal port areas. It is concerned that the contained organisms in the ballast water could be non-native species and thus may harm the ecological system of the seawater in the next port of call area when it is discharged.


Biogas is a combustible gas derived by methane fermentation of anaerobic microorganisms in organic waste such as raw garbage, livestock manure and sewage sludge. The principal components of biogas are methane and carbon dioxide. It is an unused renewable energy source, of which efficient use is expected to contribute to the mitigation of global warming.

Boiler operating efficiency

Overall boiler efficiency after long-term use, which takes into account load changes when the boiler is switched on or off.


Cleaning up the site

A method that conducts on-site purification without excavating contaminated soil.

CO2 Emissions from Energy Consumption

CO2 generated and emitted associated with the burning and use of fuel.

Coefficient of performance (COP)

COP represents cooling and heating abilities by 1 kW of electricity consumption capacity. It is a coefficient showing energy consumption efficiency.

Compressed Natural Gas (CNG)

CNG is usually stored in a pressure-resistant container for transportation and storage.


A type of ultra-light crude oil that exhibits similar characteristics to naphtha and gasoline.

Cryogenic power generation

Osaka Gas imports LNG, that is natural gas liquefied in producing countries. This LNG is a liquid with a temperature of minus 160 degrees Celsius, and when it vaporizes back into natural gas it absorbs heat from the surroundings giving it cooling properties (cryogenic energy). This energy is equivalent to about 240 kWh of electricity per ton of LNG. Recovering this as kinetic energy and using it for power generation is referred to as cryogenic power generation.


Demand response

Demand response represents efforts by the demand side or electricity users to strike a supply-demand balance of electricity by saving their power consumption.

Digester gas

Digester gas is made by anaerobic fermentation in sewage sludge where no oxygen exists. It is mainly composed of methane and CO2.


A structure set up around an LNG tank to prevent the spread of LNG in the vicinity of the tank in the event of a leak.

Double Power Generation

Double power generation is an electricity-generation system combining gas cogeneration and solar power-based electricity generation.

Downstream business

Downstream business mainly refers to operations at LNG terminals, the generation of electricity, distribution and sale of gas and power, and energy services. The downstream business Osaka Gas is currently involved in overseas are the IPP business in North America, and retail gas sales and energy services in Southeast Asia.


Excavated soil

The earth, sand, and asphalt that are dug up when gas pipes are constructed under roads or when gas pipes are moved.


FIT electricity

FIT stands for feed-in-tariff. FIT is a mechanism designed to spread the use of renewable energy sources such as solar power and wind power by obliging utility companies to purchase such energy sources from renewable energy producers at fixed rates set by the state for a certain period. FIT electricity is electricity generated using renewable energy sources purchased under this mechanism.


Gas cogeneration system

An energy-efficient system that runs on city gas, generating the power and heat where they are used such as homes and businesses, and using the waste heat from the system to heat or cool the air, or to heat water. Electricity is generated by kinetic energy from gas engines and gas turbines, and by fuel cells, which are powered by a chemical reaction between hydrogen and oxygen. Two types of energy, electricity and heat, are generated from these systems fueled by a single energy source.

Gas pipeline service business

Business of supplying gas using specified pipelines of which maintenance and operation are consigned by the company.

Gas pipes

The pipes that make up the pipeline for the delivery of gas to customers. There are three types of gas pipes depending on the pressure of the gas running through them: high-, medium-, and low-pressure gas pipes. The gas that leaves LNG terminals flow through a high-pressure pipeline. A pressure regulator adjusts the pressure to medium- and low-pressure levels before the gas is delivered to our customers through a low-pressure pipeline.

Gas turbine combined cycle power generation method

A high-efficiency power generation method in which gas turbines and steam turbines are combined. City gas, mixed with compressed air, is combusted in the burner, and the pressure generated by the combustion drives a turbine to generate electricity. Next, the heat of the exhaust gas from the turbine is used to generate high-pressure steam in a waste-heat collecting boiler, and this steam drives a steam turbine to generate electricity. This use of heat from the exhaust gas gives the gas turbine combined cycle method a high power generating efficiency.


Higher heating value (HHV)

HHV is amount of heat released when fuel undergoes full combustion, which includes the latent heat of condensation of water vapor generated (heating value used to transform vapor into water).

Home energy management system (HEMS)

HEMS contributes to residents' energy saving with features such as visualization of energy consumption, giving energy advice to residents and automatic control of various housing services.

Hydrogen filling station

A facility that provides hydrogen to vehicles running on fuel cells. Hydrogen is a super-clean energy since it emits no CO2, a greenhouse gas, during combustion.


Independent power producer (IPP)

IPP is a private entity that generates electricity and sells to power companies. Under revisions to Japan's Electricity Utilities Industry Act in 1995, IPPs can take part in competitive bidding with power companies.


J-Credit system

CO2 emission reductions achieved by small and medium-sized companies through the introduction of high-efficiency equipment are converted into credits and are purchased by large companies. The scheme, called the J-Credit system, is designed to cut CO2 emissions in Japan.


Lower heating value (LHV)

LHV is the amount of heat released when the fuel undergoes full combustion, which excludes the latent heat of condensation of water vapor generated (heating value used to transform vapor into water).

Low-pollution vehicles

Osaka Gas' “Green Distribution Policy” encourages to use low-pollution vehicles throughout its business operations. Low-pollution vehicles include natural gas vehicles, bi-fuel vehicles, electric vehicles, hybrid electric vehicles, methanol vehicles, or vehicles certified as having low levels of fuel consumption and emissions (vehicle types for which automobile taxes are reduced due to their low environmental impact status) and new-generation vehicles of lower pollution level, such as fuel cell vehicles.


Micro-cogeneration system

Gas cogeneration system of up to 100 kW of generation capacity.

Mobile gas-generating facility

A mobile facility aimed at providing gas to meet spot demand, with gas generated using compressed natural gas or propane gas filled inside the cylinder installed at the facility. This mobile facility is deployed in the event of emergencies such as earthquakes to provide city gas to public facilities including hospitals and welfare homes for the elderly.


Native seedlings

Native seedlings are those that have been grown from locally gathered seeds. One of the important points is that their production process is clarified.

Natural gas vehicle (NGV)

NGV is a vehicle equipped with a natural gas-powered engine.


Once-through boiler

In a once-through boiler water is supplied to a pipe and steam is produced from the other end. The boiler can produce steam quickly because it is compact and not much water remains in the pipe of the boiler.
Once-through boilers are categorized into three types, which are regular boilers, small-sized boilers and compact boilers, according to the maximum pressure used and the width of the heat transfer area. Compact once-through boilers are the smallest of the three types. They require no operating license.

On-site containment

A method for containing soil on-site that does not meet the environmental criteria by means of diaphragm (water-blocking) walls or other devices.


Peak demand cut

Responding to power shortages, changing the settings for home appliances and avoiding the use of electricity during peak times can contribute to energy savings and reduction in peak demand.


A system of continuous fixed, above-ground or below-ground pipes that transport gas to its destination. An efficient network of gas pipelines, consisting of a high pressure trunk pipeline and medium and low pressure gas lines, which has been developed in line with our long-term supply plans developed to meet the growing demand for gas.

Polyethylene (PE) pipes

Polyethylene (PE) pipes used for underground installation. They are flexible and highly resistant to earthquakes. PE pipes were confirmed quake-resistant because they were not damaged by the Great Hanshin Earthquake. PE pipes also have an excellent corrosion-resistance for underground use.

Polymer electrolyte fuel cell (PEFC)

PEFC is a type of fuel cells that uses a polymer film as the electrolyte. Hydrogen is ionized and the hydrogen ions pass through the electrolyte, reacting with oxygen and generating electricity.

Principles for Responsible Investment (PRI)

PRI are principles launched in 2006 by the UN Secretary General at the time, Kofi Annan. They were established through a joint collaboration between the United Nations Environment Programme Finance Initiative (UNEP FI) and the United Nations Global Compact to ensure institutional investors take environmental, social and corporate governance (ESG) issues into account in investment decisions.


Rated boiler output efficiency

The rate of absorption of heat by the steam generated against the total quantity of heat supplied to the boiler during rated output.

Replacing pipes without excavation

This is a method of burying polyethylene (PE) pipes in which only each end of the construction stretch is excavated. Not only does this these methods result in less excavated soil, it they also reduces the impediment of traffic around the construction site.

Reverse power output flow

A situation in which redundant power output from distributed electric sources, such as solar power and cogeneration systems, are flowed back into commercial power distribution networks.


Sand blasting

Sand blasting occurs when high-pressure fluid is blown out from a water pipe buried underground. Sand particles blown off by the water squirting out of the pipe hit the gas pipe buried adjacent to the water pipe, and wear down and break through the gas pipe wall, and eventually water penetrates into the gas pipe.

Shallow pipe installation method

A method of placing pipes shallow underground. Like the Vermeer method, this method reduces the amount of excavated soil generated when burying gas pipes.

Solid oxide fuel cell (SOFC)

SOFC is a type of fuel cells that uses ceramic as the electrolyte. The oxygen is ionized and the oxygen ions pass through the electrolyte, reacting with hydrogen and generating electricity. A unique feature of SOFCs is that they can use carbon monoxide (CO) as well.


Unused energy

Energy previously not made use of; for example, household wastewater, industrial water and sewage water, river and ocean water, waste heat from substations and factories, and waste heat from the cooling and heating systems of subways and underground malls.

Sustainability of
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President's Commitment
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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
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Supplier Assessment
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Training and Education
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Diversity and Equal Opportunity
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Economic Performance
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Creating Value for Customers
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Contributing to the Sustainability of the Environment and Society
(Charter Ⅱ)
Engaging with and Contributing to Society (Charter Ⅲ) Respecting Human Rights
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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 - Daigas Group×Stakeholders Achieving a Low Carbon / Carbon Neutral Society Establishing Lifestyles and Businesses Adjusted to the New Normal Enhancing Resilience of Customers and Society Back Numbers of Special Features
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Creating Value for Customers (Charter I)
Charter I Index Management for Creating Value for Customers Safety and Security 1:
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Safety and Security 2:
Processing Stage
Safety and Security 3:
Distribution Stage
Safety and Security 4:
Consumption Stage
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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 Social Contribution Activities Corporate Volunteering Activities under the Small Light Campaign Activities for Promoting Communication with Society 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
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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
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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
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