Last summer, nearly half of India's sweltering population suddenly found the electricity shut off. Air conditioners whirred to a stop. Refrigerators ceased cooling. The culprits were outmoded power generation stations and a creaky electricity transmission grid.
But another problem stood out. India relies on coal for 55 per cent of its electrical power and struggles to keep enough on hand.
Coal remains a critical component of the world's energy supply, despite its bad image. In China, demand for coal in 2010 resulted in a traffic jam 120 kilometers, or 75 miles, long caused by more than 10,000 trucks carrying supplies from Inner Mongolia. India is increasing coal imports.
So is Europe, as it takes advantage of lower coal prices in the United States. Higher-priced natural gas on the Continent is creating demand for more coal imports from the U.S., where coal is taking a drubbing from less costly natural gas.
Dirty, fickle and dangerous, coal may seem an odd contender in a world where promising renewable energy sources like solar, wind and hydroelectric power are attracting attention. Anathema to environmentalists because it creates so much pollution, coal still has the undeniable advantages of being widely available and easy to ship and burn.
The biggest attraction, however, is low cost. By many estimates, including that of Li Junfeng, longtime director-general of the National Development and Reform Commission of China, burning coal still costs about one-third as much as using renewable energy like wind or solar.
Coal is not subject to the vagaries of windless or sunless days and can easily meet base-load demands of electricity consumers without interruption. So can nuclear power, but the nuclear industry is still reeling from the March 2011 disaster at the Fukushima Daiichi power plant in Japan. Countries like Germany have turned away from nuclear reactors.
Global demand for coal is expected to grow from 7.9 billion tons this year to 8.9 billion tons by 2016, with the bulk of new demand - about 700 million tons - coming from China, according to a Peabody Energy study. China is expected to add 240 gigawatts, the equivalent of adding about 160 new coal-fired plants to the 620 operating now, within four years. During that period, India will add another 70 gigawatts, via more than 46 plants.