When President Joko “Jokowi” Widodo unveiled his ambitious plan to add 35 gigawatt of energy, including 19 GW from coal, he probably thought he had done his math: Indonesia has huge reserves of cheap coal, there would be plenty of demand from the growing economy and a future built on coal would be good for the country.



None of those assumptions holds true when looked at in more detail.



Indonesia does have plenty of coal reserves — for the moment. But for how much longer? The international consultancy firm, PwC, believes economically retrievable reserves could be depleted by 2033.



Then there is the demand. Jokowi’s energy program assumed economic growth of 6 percent a year, with an increase in power demand of 7 percent from 2015 to 2019. But economic growth was well below this last year, and growth in electricity demand only 2 percent. So rather than facing a...