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Japan is turning into a rare bright spot in the world coal market, stepping up coal-fired power generation to replace nuclear plants that went offline after the 2011 Fukushima accident.

Plans by Japanese companies to spend billions of dollars on new coal-fired plants offer a striking contrast with the U.S., which has effectively blocked new coal plants using existing technology over concerns about global warming. And they show how deeply Japan's energy picture has changed since the March 2011 earthquake and tsunami caused meltdowns at Fukushima Daiichi nuclear reactors.

On Thursday, Kyushu Electric Power Co. said it would restart a long-frozen project to build a one-gigawatt coal-fired unit in southern Japan. Other utilities including Tokyo Electric Power Co. have announced similar plans for more coal-fired power.

If the plans all come to fruition, Japan's coal-fired power capacity would increase to around 47 gigawatts over the next decade or so, up 21 percent from the time right before the Fukushima accident.

All 48 of Japan's nuclear-power plants are currently offline. While regulators are expected to allow several to restart this year and next, many older plants are too expensive to retrofit to meet tightened safety standards.

Imported natural gas is filling some of the gap, but it is costly. Solar power and residential fuel cells still account for a fraction of Japan's power demand. That leaves coal, which is relatively inexpensive, readily available from nations such as Australia and usable 24 hours a day.

"We can import coal from politically stable countries, and its prices are very competitive," said Hiroya Harada, general manager of Tohoku Electric Power Co.'s Tokyo branch. He spoke at a news conference Thursday where Tohoku Electric said it would seek contracts for 1.2 gigawatts of fossil-fuel-fired power, half of which it expects to come from coal.

The downside is the effect on the environment. Japan's coal use has already been edging higher since the Fukushima accident and as a result, the nation's carbon dioxide emissions climbed to their second-highest level on record in the year ended March 2013.

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