The future of energy starts here!
JERA lights the fire of hope for decarbonization

No CO₂ emissions! A breakthrough in thermal power generation

What kind of scenery comes to mind when you hear the words "thermal power plant"? Many people—including me—imagine black smoke pouring from tall smokestacks. Today, there is an accelerating global movement to halt the construction of new coal-fired power plants and phase out those that already exist.

The last thermal power plant operating in Austria, where I live, closed in 2020. Many countries around the world have announced that they will be carbon neutral by 2050.

Japan, of course, is one of them. However, considering that roughly 70% of the electricity generated in Japan comes from thermal power plants fired with fossil fuels, extraordinary efforts will no doubt be needed to achieve net-zero CO₂ emissions.

For this article, I visited Hekinan Thermal Power Station in Hekinan City, Aichi Prefecture—the largest coal-fired power plant in Japan and one of the largest in the world. Why are thermal power plants still the mainstay power generation facilities in Japan? Katsuya Tanigawa, General Manager of Hekinan Thermal Power Station, provided answers.

With electricity, we need to exactly match the amount we use and the amount we produce. The main means of generating electricity are nuclear power, renewables (solar, wind, hydro, etc.), and thermal power. Nuclear generates stable power without any CO₂ emissions, but the amount of electricity generated cannot be fine-tuned. In addition, the amount of nuclear power generated in Japan has fallen since the Great East Japan Earthquake in 2011. Renewables are another important power source that does not emit CO₂, but the amount of power they generate is easily affected by weather and other natural conditions. Neither nuclear nor renewables are good at generating power flexibly at just the right time or just the right amount. And that’s where thermal power generation comes in. (Tanigawa)

Despite thermal power’s flexibility to adjust the amount of power generated and its necessity in supplying Japan with stable power, we won’t be able to stop emitting CO₂ as long as we continue using fossil fuels. This is the biggest issue with thermal power, and JERA is tackling it head on through its "JERA Zero CO₂ Emissions 2050" objective of achieving net-zero CO₂ emissions by 2050.

“For JERA, Japan's largest power generation company, to reduce CO₂ emissions to zero will have a huge impact," said Mr. Tanigawa. “The way we’ll accomplish this is by generating as much renewable energy as we can while also using thermal power that emits no CO₂.” Zero-emissions thermal power, he explained, means zeroing out the negative of CO₂ emissions while retaining the positives such as the ease of adjusting the amount of electricity generated. The keys to achieving this, he added, are ammonia and hydrogen.

Ammonia and hydrogen emit no CO₂ when burned. To start, we will reduce CO₂ emissions by mixing ammonia with coal, and hydrogen with LNG. Gradually increasing the proportion of ammonia and hydrogen, ultimately, by 2050, we will achieve ammonia-only and hydrogen-only thermal power generation. The first step is to conduct demonstration testing of thermal power generation with a 20% substitution of ammonia for coal. That will take place here at Hekinan Thermal Power Station in March 2024. (Tanigawa)

It's been more than 140 years since Thomas Edison built the world's first thermal power plant at the end of the 19th century. Thermal power generation, which began with coal and has long relied on fossil fuels, is approaching the greatest turning point since its inception.

First-in-the-world demonstration testing at Japan's largest coal-fired power plant!

Hekinan Thermal Power Station is the largest coal-fired power station in Japan, with a total output of 4.1 million kilowatts. Its coal storage area stretches across 460,000 square meters. “We can store as much as 880,000 tons of coal here," Mr. Tanigawa noted, and indeed there seemed to be mountains of coal. With so much fuel available, I was sure the station would be able to generate a lot of electricity. As Mr. Tanigawa explained, though, "We have a large amount of coal, but it only lasts about a month. Therefore, a ship arrives every two or three days bringing more in. We get about 80% of our coal from Australia and Indonesia. After the coal is placed in the coal storage yard, it is scraped off by a wheel-like machine called a reclaimer and sent to the boiler by belt conveyor."

Hearing this, I looked again across the vast coal storage yard. I use electricity every day without thinking very much about it, but as we left the coal storage yard I had a new appreciation for just how many resources are needed to produce it. We followed the coal being carried by conveyor to the boiler room.

“Coal is difficult to burn as-is,” Mr. Tanigawa explained, “so it is first crushed into small pieces—almost like flour—before being transported to the boiler where it is burned by 48 burners. This boils water to create ultra-high-pressure, high-temperature steam, which turns a turbine at the end of the boiler to generate electricity.” He invited me to look into a hole to see the coal burning for myself. When I peeked in, I could see orange flames glowing so brightly that it was difficult to look at them for long. Tanigawa said the temperature inside the boiler reaches 1,500 degrees Celsius, and that the 48 burners will play an important role in the substitution of ammonia for coal in combustion.

The burners need to be modified to burn ammonia as well as coal. In 2021, we retrofitted two of the 48 burners and conducted a small-scale combustion test using a mix containing 0.02% ammonia. This confirmed that there were no equipment problems such as the burning of ammonia impacting metal materials. We are currently working on further burner modifications in preparation for demonstration testing in March 2024 in which 20% of the fuel will be replaced with ammonia. (Tanigawa)

Using ammonia as a new fuel naturally requires equipment modifications and related costs. They also need to construct tanks to store the ammonia and a means of transporting it to the boiler. On the other hand, starting by testing 20% substitution of ammonia only requires the modification of burners. When I heard that this would be a “first-in-the-world demonstration test," I had imagined something so large-scale that they would have to replace all the power generation equipment, so this came as a pleasant surprise.

Looking around the world, many coal-fired power plants have only recently been built, especially in Southeast Asia. Mr. Tanigawa noted that if JERA can achieve thermal power generation using ammonia, it will be possible to generate CO₂-free thermal power in such countries using existing thermal power plants with only minimal modifications.

The last thing Mr. Tanigawa showed me was a tank for storing ammonia to be used in the next demonstration experiment. I wasn’t able to see the entire spherical storage tank, which was under construction and surrounded by fencing, but he said it was about the same size as the Great Buddha statue at Todaiji Temple in Nara. Although it towered above us, Mr. Tanigawa said it’s actually pretty small for a fuel tank.

After the demonstration testing is done and we start using ammonia as fuel year-round, we plan to construct multiple tanks that are about 25 times the size of this one. (Tanigawa)

During my tour of Hekinan Thermal Power Station, I was continuously overwhelmed by the scale of Japan’s largest thermal power plant, starting from the coal storage area that can accept 880,000 tons of coal and ending with the construction of ammonia storage tanks 25 times larger than the current one. I was able to feel for myself that they are about to take a major step toward creating new solutions to the energy issues facing Japan and the world.

The demonstration testing underway at Hekinan Thermal Power Station has the potential to change the history of thermal power generation. While setting ambitious goals, JERA is also committed to working in harmony with the local community that sustains it. The power plant has facilities that are shared with the local community such as a "JERA Garden Hekinan" with a central lawn where local residents can relax and a "JERA Museum Hekinan" which is immersive museum at the forefront of zero-emissions thermal power generation. Hopes are high for the future of Hekinan Thermal Power Station, which in this way is also pioneering new ground as a power plant open to the community.