What if you could burn ammonia instead of coal and cut CO2 in the process? In a coastal city south of Nagoya, four colossal tanks are rising from the grounds of Japan's largest coal power station. Each stands 40 meters tall and 60 meters wide, designed to store a fuel that produces zero CO2 when burned. Here's why Japan is betting big on ammonia power generation, and why the rest of the world isn't sure what to make of it.

Why Ammonia? The Logic Behind a Surprising Fuel

About 40% of Japan's CO2 emissions come from the power sector, and coal-fired generation is the single largest contributor. As an island nation with limited domestic energy resources, Japan can't simply shut off coal overnight; it needs stable, baseload power to keep its massive manufacturing economy running.

Enter ammonia (NH3). When burned, ammonia breaks down into nitrogen and water, releasing no CO2. It can be transported and stored as a liquid, using technology that's been refined for over a century in the fertilizer industry. And here's the critical advantage: existing coal power plants can start burning ammonia by simply modifying their burners, without tearing down and rebuilding the entire facility. That means lower upfront investment and a faster path to emissions reduction.

Hekinan: Japan's Largest Coal Plant Goes Experimental

The JERA Hekinan Thermal Power Station, located in Hekinan City, Aichi Prefecture, is a behemoth. With five generating units and a total capacity of 4,100 megawatts (MW), it's Japan's biggest coal-fired plant. JERA, a joint venture between Tokyo Electric Power Company (TEPCO) and Chubu Electric, supplies roughly 30% of Japan's electricity.

Hekinan was also once ranked among the world's top 10 most carbon-polluting coal plants. That's exactly why decarbonizing it matters so much.

A World-First Demonstration: Promising Results

From April to June 2024, JERA and engineering firm IHI conducted a groundbreaking trial at Hekinan's Unit 4 (1,000 MW capacity). They replaced 20% of the coal fuel with ammonia by heat value, the first test of this scale at a commercial coal power plant anywhere in the world.

The trial was funded by NEDO (Japan's New Energy and Industrial Technology Development Organization). IHI developed specialized ammonia burners that were integrated into the existing coal burner system, with ammonia supplied through orange-colored pipes running along the boiler ceiling.

The results were encouraging. Nitrogen oxide (NOx) emissions were equal to or lower than coal-only operation. Sulfur oxide (SOx) dropped by about 20%. Nitrous oxide (N2O), a potent greenhouse gas, was below detection limits. And the plant's operational performance was unchanged.

The Giant Tanks That Went Viral

In January 2026, JERA opened its doors to media to showcase four massive ammonia storage tanks under construction. Each tank is approximately 40 meters (130 feet) tall and 60 meters (200 feet) in diameter, with a capacity of 40,000 metric tons of ammonia.

Japanese media noted that the dome-shaped structures resemble Mongolian "ger" (also known as yurts), the portable round tents used by Central Asian nomads. Set against the backdrop of the Pacific Ocean, the scene sparked an unexpected sense of the exotic, drawing widespread attention on social media.

The ammonia will arrive by specialized ships, chilled to minus 33°C (minus 27°F) in liquid form, and travel roughly 4 kilometers (2.5 miles) through pipelines from the port to the tanks. Initially, JERA plans to source approximately 500,000 metric tons annually from an ammonia production facility in Louisiana, USA, in which it holds a stake.

Commercial Operations Set for 2029

JERA aims to begin 20% ammonia co-firing commercial operations at Hekinan Unit 4 by fiscal year 2029, another world first for a large-scale commercial coal plant.

The roadmap doesn't stop there. JERA plans to raise the co-firing ratio to 50% by the 2030s, with a demonstration at Unit 5. The ultimate goal: 100% ammonia-fired generation, complete "mono-firing" with zero coal, by 2050.

Beyond power generation, the ammonia delivered to Hekinan will also supply fuel to nearby factories operated by Toyota Industries Corporation and NGK Insulators, creating a regional ammonia fuel ecosystem.

Safety Measures: Ammonia Is No Ordinary Fuel

Ammonia is classified as a "deleterious substance" (gekibutsu) under Japanese law. It's colorless but has a sharp, pungent odor, and inhaling large quantities can cause respiratory failure.

JERA has implemented extensive safety infrastructure. The tanks and piping are engineered to withstand a Nankai Trough megaquake, one of Japan's most feared seismic scenarios. The facility is also designed to endure the worst-case storm surges, floods, and tsunamis on record. Ammonia leak detectors and surveillance cameras have been installed throughout the plant, with 24-hour remote monitoring. In the event of a leak, water sprays dissolve the ammonia gas, which is then contained within protective dikes. Joint emergency drills with fire departments, police, and the Japan Coast Guard are also planned.

"We will be handling ammonia on an unprecedented scale," said Hekinan plant chief Mitsutaka Ban. "We're strengthening safety measures above and beyond anything we've done before."

The Controversy: Lifeline or Lifeline for Coal?

Despite the technical achievements, ammonia co-firing faces significant criticism from multiple directions.

Limited CO2 reduction at 20%. A 20% ammonia mix reduces emissions by roughly 20%, meaningful but modest. Worse, most commercially available ammonia today is "grey ammonia," produced from natural gas via the Haber-Bosch process. Manufacturing one ton of ammonia emits approximately 1.6 tons of CO2. When lifecycle emissions are factored in, the net climate benefit shrinks dramatically.

Higher costs. Japan's government estimates that 20% co-firing raises the cost of generation by about 20%, to roughly 12.9 yen per kWh (about $0.09/kWh). Transitioning to "green ammonia" produced with renewable energy would solve the lifecycle emissions problem but could push costs even higher.

"Prolonging coal's life." Japan is the only G7 nation that has not joined the Powering Past Coal Alliance. While other G7 countries have pledged to phase out coal by around 2030, Japan's strategy of co-firing ammonia is seen by European critics as a way to keep coal plants running indefinitely. The RE100 international corporate initiative has announced that from 2026, electricity from coal-ammonia co-firing plants will not count toward renewable energy targets.

Understanding Japan's Energy Reality

To be fair, these criticisms must be weighed against Japan's unique circumstances.

About 70% of Japan's land is mountainous, severely limiting sites for large-scale onshore wind farms. Offshore wind is promising but challenging, as Japan's coastal waters are often too deep for conventional fixed-bottom turbines. Solar deployment is already among the world's highest per unit of flat land. Nuclear restarts are progressing, but public acceptance remains complicated by the 2011 Fukushima disaster.

Japan is also the world's third-largest economy and a manufacturing powerhouse. Stable, reliable electricity isn't a luxury; it's an industrial necessity. Renewables alone can't yet guarantee the 24/7 baseload power that factories, semiconductor plants, and data centers demand.

In this context, ammonia co-firing is positioned not as a final answer but as a pragmatic first step, a "bridge technology" that buys time while renewable capacity grows and next-generation solutions mature.

Ambitions Beyond Japan

JERA sees Hekinan as a proving ground for technology it hopes to export across Asia. Countries like Vietnam, Thailand, the Philippines, Malaysia, and Singapore have numerous young coal plants that are economically impractical to shut down immediately. For these nations, ammonia co-firing could serve as a realistic transition tool.

However, organizations like IEEFA (Institute for Energy Economics and Financial Analysis) warn that this strategy risks delaying renewable energy adoption in the region, potentially locking countries into fossil fuel infrastructure for decades longer than necessary.

Japan is choosing not to abandon coal but to transform it, a path that's both pragmatic and controversial. It may not be the perfect solution, but it reflects the real-world tension between energy security and climate action. How is your country tackling the decarbonization of thermal power? Should we keep coal plants running while reducing their emissions, or is a full shift to renewables the only way forward? We'd love to hear your perspective.

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