The majority of Keadby Power Station is to be shut down with the loss of up to 45 jobs.
A programme of upgrade works have been taking place at the facility over the last 12 months to upgrade efficiency.
But owners Scottish and Southern Energy (SSE) said current market conditions has forced it to delay the re-commissioning of the gas-fired plant.
It will instead be “deep mothballed”, meaning many of the systems will be completely shut down.
Over the next six months there will be a phased reduction in staff numbers, falling from the current 55 to a total of between 10 to 15 by late summer.
Paul Goodson, power station manager, said: “The economics of electricity generation at gas-fired power stations remain very poor, and they do not appear likely to improve in the short to medium term, so it makes little sense to bring Keadby back into full operation.
“This decision has still not been an easy one to take, particularly when we have had to make it despite the successful completion of the upgrade investment and the best efforts of the team at Keadby to do everything possible to improve the productivity and efficiency of their generation plant.”
SSE expects the plant to remain “deep mothballed” for the next two years. The company said it hopes to redeploy staff to other facilities, such as the new wind farm being constructed near to the plant.
The £350 million ‘Keadby 2’ scheme, which could create 490 jobs, to build a second plant at the site will go ahead unaffected.
But the firm said a decision on investment to build the plant will not be made until at least 2016.