China’s insatiable demand for energy has triggered a coal-mine building boom in Australia, which now supplies China with a third of its coal. With plans for 10 massive Australian coal mines worth more than $45 billion under way, investors are counting on China to keep burning the black stuff at a rapid clip to make those projects profitable. But that would a bad bet.

A report released today (pdf) predicts prices will fall as China, which consumes half the world’s coal, cuts imports to fight pollution and meet climate-change goals. As a result, says the report, Australia’s new mega-mines are likely to become money-losers. Even current coal prices would already leave four of the planned mines in the red, according to the study by the University of Oxford’s Stranded Assets Program.

The report is the latest example of a new focus on so-called stranded assets—multibillion-dollar fossil fuel projects that could become liabilities thanks to efforts to combat climate change. Bloomberg’s financial terminals now include a function that lets investors calculate the impact of depressed fossil fuel prices and carbon taxes on a portfolio’s value.

Half of Australia’s coal mines lose money when coal prices fall below $96 a tonne, the reports states. The current price? $85 a tonne for Australian coal. By 2015 it’s expected to rise only to $87 a tonne, according to a forecast by HSBC. That’s not good news for Indian mining company GVK’s $10 billion Alpha Coal Project in the Australian state of Queensland. One of the world’s largest planned coal mines, prices must hit $160 a tonne for the project to be profitable, the report states. China First, another Queensland mega mine, needs its coal to sell for $130 a tonne to be viable.

Various factors are likely to conspire to keep these prices down. First, the new mines in Australia will dramatically increase world coal supplies: The China First mine alone is expected to produce as much every year as the entire increase in Australian coal exports between 2010 and 2012. (And as we’ve written, just two of the huge coal projects would emit more greenhouse gases than 52 countries.)

Moreover, while Chinese coal demand is likely to keep growing, it may not be as fast; the report notes that prices dropped 30% between 2011 and 2013 in part because China’s coal imports grew slower than expected. Finally, the US shale gas boom has forced American coal miners to seek new markets overseas. That will only add to the competition Australia’s mines face.