Coal Day (Sekitan no Hi / Clean Coal Day)

What Is Coal Day (Clean Coal Day)?

September 5th is "Coal Day," also known as "Clean Coal Day." It was established in 1992 by eight coal-related organizations — including the Japan Iron and Steel Federation, the Federation of Electric Power Companies of Japan, and the Japan Coal Association — at the call of the Ministry of International Trade and Industry (now the Ministry of Economy, Trade and Industry). The date comes from a wordplay: 9 ("ku") and 5 ("ko") echo the opening sounds of "ku-rīn kōru" (clean coal). The day promotes the development of technologies to make coal — which emits more CO2 than other fossil fuels — a cleaner energy source, and aims to improve coal's image as an energy resource. Thermal power plants often hold open days around this date.

The "Black Diamond" That Powered Modern Japan

From steam engines to steelmaking, coal was a major energy source behind Japan's modernization.

• Black diamonds: From the Meiji era to the early years of rapid postwar growth, coal was called the "black diamond." Coal from mining regions such as Chikuho in Fukuoka, Joban in Fukushima and Ibaraki, and Ishikari in Hokkaido supported railways, factories, and steelmaking.
• The energy revolution: In the 1960s, Japan's main energy source shifted from coal to oil in what is called the "energy revolution," and domestic coal mines closed one after another.

Technologies for Using Coal "Cleanly"

"Clean coal," which gives the day its name, is a general term for technologies that use coal more efficiently and with less environmental impact.

• Integrated Coal Gasification Combined Cycle (IGCC): Coal is turned into gas to drive a gas turbine, and the waste heat is then used to drive a steam turbine. The aim is higher efficiency than conventional coal plants and lower CO2 emissions per unit of electricity.
• Capturing and using CO2: Research is also under way on "CCS," which captures CO2 from power plants and stores it underground, and "CCU," which uses captured CO2 to make fuels and materials.

Fascinating Facts About Coal

• A fuel made from ancient plants: Coal forms when ancient plants are buried and transformed over long periods by heat and pressure. Much of the world's coal is thought to date from periods such as the Carboniferous, about 300 million years ago, but many of Japan's coalfields are said to lie in younger strata.
• Coal mines as World Heritage: Hashima ("Battleship Island") in Nagasaki and the Miike Coal Mine (including the Manda Pit) in Kumamoto and Fukuoka were inscribed on the World Heritage List in 2015 as part of the "Sites of Japan's Meiji Industrial Revolution."
• Abundant and widely distributed: Coal reserves are said to be larger and more widely spread around the world than those of oil and natural gas, which is why coal has been valued for stable energy supply.
• A link to diamonds: Both coal and diamonds consist mainly of carbon — a connection the nickname "black diamond" happens to recall.

Tips for Spending Coal Day

• Find out what energy sources are used to generate the electricity you use every day.
• Look into museums on coal mining history or former mines that are now World Heritage sites.
• Check for events held around Coal Day, such as power plant tours.
• Read up on new energy technologies aimed at decarbonization.

A Day to Look Again at the Fuel That Powered Modern Japan

September 5th is a day to look back on the history of coal, which supported Japan's modernization, and to think about ways to use energy in harmony with the environment. Take a moment to consider the long story of energy behind the electricity and steel products we use without a second thought.