CHENNAI: Unit 1 of the Kudankulam nuclear power reactor restarted generation at 7.12am on Saturday. The power generation has begun seven months after the reactor was shut down for annual maintenance on June 23, 2015.“We have synchronised the unit 1 with the grid and 250MW is being generated since morning. The unit will generate power for a few more hours after which we have to do some tests,“ site director S Sundar told TOI. “Power generation will resume on Sunday, and within two days we are hoping to reach full capacity of 1000MW,“ he said.Unit 1 attained criticality on January 21 and since then tests of the reactor were in progress with officials from Atomic Energy Regulatory Board (AERB) monitoring them.“It is only after AERB officials gave permission that power generation began,“ said Sundar. The capacity factor (which determines the reactor's power generation capacity) of unit 1 is lowest among all reactors. It is 22% whereas all other reactors have more than 40% on an average.Tamil Nadu gets the maximum, 560MW, from the 1000MW unit 1.But electricity demand has been on the rise even though it is January when temperatures are low and consumption is expected to be less.“The demand has crossed 13,000 MW and we have been waiting for unit 1 to get operational. It will help us meet the high demand during summer,“ said a senior TNEB official. “We only hope the unit generates power continuously even during summer as we expect the demand to cross 14,000MW in the coming months,“ the official said.The demand has been on the rise as many small industries are working three shifts and need more electricity.“Apart from industries, domestic consumers are also drawing more power in the cold weather by using geysers, especially in the mornings," said the official.