The Ministry of Power has declined Tata Power`s (Q,N,C,F)* request for one million metric standard cubic metres a day (mmscmd) of gas from Reliance Industries` K-G basin for one of its power generating units at Trombay and has asked the latter to first install a gas-based turbine, reports Business Standard. 

The unit, with a capacity to produce 150 Mw of power, has been shut since March 2009. Prior to its closure due to environmental reasons, the unit was running on liquid fuel.

The ministry has said that gas cannot be allocated since the unit, which operates on a gas-fired boiler-steam turbine, would have an efficiency of 35% and this would mean inefficient use of gas.

A combined cycle gas turbine (CCGT) would improve efficiency to 50%, it said.

Shares of the company closed down Rs 20.75, or 1.95%, at Rs 1,045.60. The total volume of shares traded at the BSE was 43,543 (Monday).