Japan, with only two working nuclear power plants, has discharged a record high amount of carbon dioxide in the year ended March 31 as it relied on crude and fuel oil to support its energy requirements.

According to Bloomberg calculations based on data provided by Japan's 10 power utilities, the companies released a whopping 439 million tonnes of CO2 for the year, a 17 per cent jump from the 374 million tonnes a year ago.

Of the overall figure, Kansai Electric Power Co. contributed the most number of CO2 emissions, 40 per cent at 65.7 million tonnes. Kansai Electric Power Co. is the one of the 10 that relied most on nuclear power.

Japan is one of many nations that been a strong advocate of the use of nuclear power because the latter creates no greenhouse gas emissions that could further exacerbate the global warming status of the Earth. But it was forced to scout for alternative fuel sources as a result of the March 2011 earthquake and tsunami that devastated the Fukushima power plant, causing the worst radioactive contamination since Chernobyl in the 1980s. Japan afterwards ordered the gradual shut down of all its more than 50 nuclear power plants because of the incident.

To support its energy requirements, Japan currently relies on liquefied natural gas as well as fuel oil and crude.

The country's latest CO2 emissions data therefore stipulate it would be difficult for Japan to reach its target of reducing its contribution to greenhouse gases by 25 per cent by end of the decade. In a pledge under the Kyoto Protocol, Japan said it would reduce its CO2 emissions by 6 per cent from 2008 through 2012 from the 1990 levels.

"Objectively speaking, there is no doubt that it is more difficult to achieve the 25 per cent reduction goal than before," Naomi Hirose, president of Tepco, said in June.