The new power plant will have an output of approximately 2,000MW, supplying power to around three million households.
It will include five Alstom GT26 turbines and accompanying core components supplied by Alstom.
According to Alstom, the plant will be able to be run as efficiently at low load as at full capacity during peak hours, allowing the operator to respond to fluctuating energy demands.
This project is the second that Alstom has signed with RWE npower in the UK. In 2007 Alstom was awarded a contract for the gas-fired 1,650MW Staythorpe power plant, which is currently under construction in Nottinghamshire.