One of these two projects, 132 MW Teesta Low Dam Project(TLDP)-III over river Teesta in Darjeeling hills with expected generation of 594.07 MU annually, was initially scheduled to be completed by March 2007 with estimated cost of Rs.768.92 crore. But, finally it became operational in March 2013 with a revised cost of 1628 crores. The other one is, 160MW TLPD IV, planned to be completed by September 2009 with estimated cost of Rs 1061.38, has already consumed around Rs 1600 crore but not likely to come to life before October 2015.

As per the agreement following these cost and time overrun, per unit power tariff of TLDP III has gone up from Rs 2.52 to Rs 6.07. For TLDP IV, it is an escalation from Rs 2.54 to Rs. 4.23. "The figures are as of July 2010. For now, these will be around 40% higher," said officials.

As a whole, total annual payable amount for 720 Million unit output of TLDP IV and 594 Million Unit of TLDP III will be over Rs 900 crore against initially estimated payable of Rs 315 Crore.