Power tariff is set to move up by approximately 10 paise a unit on an average, due to a “rationalisation” in railway freight with effect from Tuesday. The announcement, which came as a surprise to Coal India Ltd (CIL) and the power producers, this evening, will lead to an approximately 20 per cent hike in freight rate at Rs 120 a tonne on an average. For a benchmark travel of 700 km of Indian coal, the tariff has moved up by Rs 132 a tonne to Rs 792 a tonne.