Coal mined in Kalimantan, Indonesia, is loaded onto a bulk carrier, sails 3,500 km across the Indian Ocean, unloaded at Hazira port, costs roughly ?5,500 per tonne to local consumers. A tonne of lignite dug from Gujarat's own ground and transported 250-300 km to Surat costs around ?4,200-?4,400 delivered. The gap is uncomfortably narrow. In some grades, imported coal has already crossed over to being cheaper. This is India's energy paradox, and it costs the country somewhere between US$15 and US$20 billion in foreign exchange every year.  India is the world's third largest coal producer, holds the fourth largest reserves…