December 25, 2009


Tokyo Gas - Developing Next-Generation Natural Gas Energy to Create a Sustainable Social System

Keywords: Newsletter 

JFS Newsletter No.87 (November 2009)
"Towards a Sustainable Japan -- Corporations at Work" (No. 85): (English)

Japan depended on oil for nearly 80 percent of its energy supply until just before the "oil shock" of 1973. Since then, the proportion of oil supplying its energy dwindled, reaching around 50 percent in recent years as oil was replaced with natural gas and nuclear energy.

The proportion of Japan's primary energy supplied by natural gas was about 2 percent in 1970. The promotion of natural gas as an alternative to oil has led to an increase in this proportion to 15.7 percent in 2007. Used for thermal-power generation and city gas, natural gas has become a major energy source for Japan.

Natural gas's share is expected to continue growing, partly because natural gas is considered cleaner than oil or coal in that gas combustion emits less carbon dioxide (CO2) than other fossil fuels. This is an important factor in today era of international concern about global warming.

In Japan, 211 gas companies supply natural gas as city gas. The largest among them is Tokyo Gas Co., which was established in 1885 and operates in and around Tokyo. It introduced liquefied natural gas (LNG) for the first time in Japan in 1969, and since then has been promoting LNG use: It now supplies LNG to more than 10 million customers.

Tokyo Gas launched a mid-term management plan in April 2009 to promote "Three E's" - Creation of Eco-friendly values, Excellent service to customers, and Expansion in its market depth and size as a comprehensive energy service provider with natural gas as its core.

This article introduces residential fuel cells and biogas use in Japan. We interviewed Keiichi Katayama, Manager of the Corporate Planning Department, and Teruichiro Hasunuma, Deputy Manager of the Planning & Promotion Section of the Environmental Affairs Department at Tokyo Gas.

Aiming to Change the Concept of Housing from Energy-Consuming to Energy-Producing

The type of household natural gas equipment that is now attracting the most attention in Japan is a residential fuel cell cogeneration system called Ene-Farm. This new system has the potential to change the present underlying concept of housing units as consumers of energy sources such as gas, electricity and kerosene oil are consumed, into one that considers them as energy producers as well. This is a new approach for creating a low carbon society.

Ene-Farm is capable of generating electricity at home using city gas produced from LNG in storage tanks. This system can also heat water with waste heat created during electricity generation, raising its energy use efficiency to as much as 80 percent. If we consider that the utilization efficiency of electricity delivered from thermal power plants to homes through power lines is said to be 37 percent it is clear that Ene-Farm uses primary energy very efficiently.

It is estimated that introducing this system alone can cut the current primary energy consumption of a household by about 33 percent and current CO2 emissions by about 45 percent. Katayama says, "You can make a contribution to the environment without changing your way of life. If you replace your existing gas range with a more energy-efficient one in addition to introducing Ene-Farm, you can cut CO2 emissions even further."

While it pursues environmental and energy-saving efforts, Japanese society is also facing another big issue -- an increasing number of households in which senior citizens live by themselves. In response, electric utilities are promoting the "all electric home" as a safer housing design for the elderly, and demand for this type of housing is growing. Gas supply companies are also making an effort to significantly improve the safety of gas ranges and expand demand for Ene-Farm in order to encourage households to continue to use gas.

"Amid growing environmental awareness, I think we can make Ene-Farm more widely available if housing manufacturers incorporate it as part of the appliance system in new houses. As for retro-fitting it into existing houses, its bulky size could be one obstacle; thus we are pursuing technological development to downsize it and lower its cost," says Katayama.

When there is not enough space for an Ene-Farm system, a condensing water heater called Eco-Jozu provides another option for residential houses. Its water heating efficiency has been enhanced up to 95 percent, and this can reduce CO2 emissions by 13 percent compared to conventional water heating systems. In fiscal 2008, a total of 72,164 units of these new water heaters were installed in Tokyo Gas's service area, helping reduce residential CO2 emissions.

Both Ene-Farm and Eco-Jozu can help further cut CO2 emissions when they are combined with solar power. The so-called "double power generation" achieved by combining Ene-Farm and photovoltaic (PV) power systems is attracting attention because of its high environmental performance. Meanwhile, in September 2009, the Japan Gas Association's gas energy promotion council, organized by gas supply companies, announced that member companies will also promote water heaters powered by solar heat. Tokyo Gas also plans to emphasize potential reduction in CO2 emissions by combining Eco-Jozu with a solar water heater that can be mounted on a balcony, and aims to launch a marketing campaign aimed at housing manufacturers and other businesses in 2010.

Use of Bioenergy

In Japan, the Act on Promotion of Use of Non-Fossil Energy Sources and Effective Use of Fossil Energy Material by Energy Supply Operators, also known as the Energy Supply Structure Sophistication Act, was adopted in July 2009 and went into force in August 2009.

This law requires gas utilities to promote wider use of bioenergy. In response, Tokyo Gas and Osaka Gas Co., two major gas utilities, decided to use biogas produced from bio-origin resources starting in fiscal 2010.

Tokyo Gas plans to purchase biogas from a food residue recycling plant, mix the biogas into existing city gas sources and supply the mixed gas to ordinary households. They plan to purchase approximately 800,000 cubic meters (city gas equivalent) of biogas annually, equivalent to the amount of gas used by about 2,000 households. This measure is expected to cut about 1,830 tons of CO2 emissions.

As a preparatory step, Tokyo Gas released its basic conditions for purchasing biogas in April 2008. As an incentive for suppliers to offer biogas for use as city gas, these provide that the company will purchase biogas at a price nearly equal to the price of regular city gas pricing for large-lot customers. In November 2008, Tokyo Gas, in cooperation with the Tokyo Environmental Public Service Corp., started a demonstration experiment for recovering biogas from paper waste and garbage generated in office buildings and other facilities. This experiment was carried out as a project for technology development to address global warming under the aegis of Japan's Ministry of the Environment.

Tokyo Gas Starts Purchasing Biogas

The experiment team has been trying to develop technologies for optimal co-combustion of biogas and city gas, and is also trying to devise a system that uses a smaller biogas storage tank or even no tank. In this way, Tokyo Gas has been preparing the ground for biogas use starting in 2010.

The reserves/production ratio of natural gas is said to be approximately 60 years as of 2008, and new natural gas resources such as non-conventional natural gas and methane hydrate are being developed. "U.S. President Obama has proposed smart grids. However, as a gas supplier, we will follow a course of building a 'Smart Energy Network' structure, which will aim at optimal use of all energy resources, from conventional electricity, gas and heat to promising new energy sources such as hydrogen," says Katayama.

With the aim of providing a stable energy supply to the next generation, Tokyo Gas, as a sustainable energy supplier, continues to conduct research for more effective use of natural gas; development of a system for using gas and other energy sources complementarily; and the use of solar energy (both sunlight and solar heat), wind power, biomass and hydrogen energy as future energy sources.

Written by Reiko Aomame