Japan Says It Can Make Coal Cleaner. Critics Say Its Plan Is ‘Almost Impossible.’

The world’s advanced economies have committed to phasing out coal over the next seven years. But not Japan, which stands alone in insisting it can make coal less damaging to the planet.

Nowhere is that more evident than at the nation’s largest coal-fired power plant in Hekinan, a small city in central Japan where 400,000 tons of jet-black piles are spread across a plot the size of 40 soccer fields.

Starting next spring, Jera, the company that owns the site, wants to demonstrate that it can blend ammonia — which does not emit carbon dioxide when burned — with coal in its boilers. The use of this new technology is prompting a debate over whether it is better to find cleaner ways of using coal, or to scrap it as soon as possible in favor of renewable energy.

The company says the ammonia method can reduce dangerous emissions in the fight against global warming. In an effort initially conceived — and heavily subsidized — by Japan’s government, it is one of several power companies planning to use ammonia in a process marketed as “clean coal.”

With ammonia, the companies can “use the plants we have rather than building entirely new ones,” said Katsuya Tanigawa, the general manager at Jera’s Hekinan site.

Japan draws nearly a third of its electric power supply from coal, one of the world’s dirtiest sources of energy. But critics say the use of ammonia merely extends Japan’s reliance on fossil fuels and could potentially increase carbon emissions as the ammonia is produced. Burning ammonia can also produce nitrogen oxide, which is toxic to humans and is another emission to be managed.

“We need to be reducing emissions from coal power plants now, not exploring a technology that may or may not be feasible,” said Katrine Petersen, a senior policy adviser at E3G, a think tank.

Anxiety in Japan about energy has grown exponentially since an earthquake and tsunami triggered a triple meltdown at the Fukushima Daichi nuclear power plant in 2011. Right after the disaster, Japan shut down all of its nuclear plants, extinguishing 30 percent of the nation’s electricity supply overnight. To compensate, the country’s power companies scurried to build new coal plants even as the world was moving away from fossil fuels.

Japan’s prime minister, Fumio Kishida, has recently intensified efforts to reboot the country’s nuclear power network, but communities that host the plants have resisted.

Japan, the world’s third-largest economy, has few of its own natural resources, and can produce only 11 percent of its energy needs without fuel imports — one of the lowest self-sufficiency rates among the world’s wealthiest nations.

At a meeting of environment ministers from the Group of 7 leaders in Sapporo this spring, Japan was the only nation that refused to commit to bringing its coal usage down to zero by 2030.

The government and the country’s power industry point to numerous hurdles to building renewable energy sources quickly, including Japan’s geographic isolation, mountainous terrain, deep sea waters and annual typhoon season.

Along with China, which President Xi Jinping recently said would follow its own “tempo and intensity” in cutting carbon emissions, Japanese officials say their nation has its own timetable and methods, as well.

“We want to go up the same mountain to the same summit,” said Atsushi Kodaka, the director of the energy strategy office in the Trade Ministry. “But our climbing route doesn’t have to be the same as everyone else.”

The power industry is also reluctant to abandon coal because it has spent so much recently to build new plants. Since 2011, Japanese power companies have constructed 40 coal plants — nearly a quarter of Japan’s total coal-fired network — with a new Jera plant going online last month.

Together with industry, the Japanese government has committed about 152 trillion yen (about $1.1 trillion) over 10 years to help the country achieve net zero carbon emissions. By 2030, the Trade Ministry says, it will reduce coal-based generation to 19 percent of the power supply, with the ammonia technology comprising about 1 percent, and it is likely to rise.

Jera knows it has to convince a potentially skeptical public of its plans, and so it is running advertisements in movie theaters and handing out discount coupons that promote its efforts to develop “zero-emission thermal power.”

Japan also hopes to eventually export the technology to its neighbors in Asia, where it has helped build new coal plants in recent years.

“We are trying to decrease the dependence on coal itself in such countries,” said Masashi Watanabe, a natural resources and energy planner in the Trade Ministry. “Ammonia co-firing could be one solution.”

In Hekinan, welders recently secured the top of a 700-ton storage tank at the sprawling Jera plant. Multiple large orange pipes lay scattered on the ground, waiting to be fitted into a pipeline that will transport ammonia to the plant’s boilers.

During a recent test, the company blended a mixture of 0.02 percent ammonia with fist-size chunks of coal in a boiler heated to 1,500 degree Celsius, more than 2,700 degrees Fahrenheit. Meeting its next target will be a bigger challenge.

By March, the company wants to begin testing mixtures made up of as much as 20 percent ammonia, becoming the first in the world to do so.

Even if the technology works, procuring a steady, affordable and clean supply of ammonia could significantly strain the world’s supply of the compound, which is needed to produce fertilizer.

The government’s own Green Growth Strategy acknowledges that if all of Japan’s coal-fired plants used 20 percent ammonia, “they would need about 20 million tons of ammonia per year” — equivalent to the entire volume of ammonia currently traded on the world market.

Such supply constraints made the ammonia plan “almost impossible” to execute, said Hajime Takizawa, a climate and energy researcher at the Institute for Global Environmental Strategies, a government-funded, independent research group. The government, though, says that once it proves that the technology works, suppliers will meet demand.

But producing ammonia itself requires electricity, which under current methods is typically generated from fossil fuels like coal or natural gas. In one common process, water is heated to extremely high temperatures — as high as 2,000 degrees Celsius, or 3,632 degrees Fahrenheit — so that hydrogen atoms can be split off and combined with nitrogen. (Check out your high school science textbooks for the chemical formula of ammonia!)

Heating that water requires a lot of power, and the ammonia supplies that will initially flow to Japan will likely be made using so-called gray or brown electricity. So while burning ammonia in a power plant reduces carbon emissions in one place, making ammonia may generate more carbon emissions in another.

As a result, the ammonia method has “a very tiny mitigation potential,” said Masayoshi Iyoda, the leader of the Japan team for 350.org, a climate activist group.

Suppliers say they will eventually use renewable energy to make ammonia or capture the carbon emitted during the production process and bury it in the ground. Analysts say that given the costs of such methods, blending ammonia and coal will be more expensive than simply using renewable energy like wind power directly.

Ultimately, critics say, Japan is prioritizing the ammonia technology to protect entrenched industrial interests against new renewable energy suppliers. “They are fully aware that they are losers in this shift,” said Kimiko Hirata, a founder of Climate Integrate, a research and advocacy group. “So they are really big on protecting the status quo and vested interests as long as possible.”