Main construction of the new plant started in January 2007 and after commissioning in the early part of 2009, the plant is expected to enter commercial operation during the summer of 2009. The facility is being built under an Engineering, Procurement and Construction (EPC) contract by a consortium of Siemens plc and Siemens AG. Siemens has a long track record in building CCGT plants in the UK and overseas.

During construction of the power station and the underground gas pipeline (linking Marchwood Power to the country's national gas transmission network) a full range of measures have been being implemented to minimise the impact of the work on the local community. All contractors working on the site and the pipeline are required to follow best construction, safety management practices to comply with all planning conditions and local statutory requirements including health and safety.

A comprehensive Traffic Impact Assessment was conducted in accordance with the planning consents process as civil, mechanical and some heavy load traffic feature during the construction phase. To limit the impact of the construction traffic, transportation of major equipment to the site has entered the site via Marchwood Military Port on Southampton Water.

At every stage during construction of the plant, Marchwood Power has worked closely with the local authorities and the Environment Agency to ensure that the construction impact is carefully managed and in accordance to the planning conditions.

As part of the construction phase a 23.5km underground gas pipeline has been installed to connect the plant to the main gas network at Lockerly. The pipeline crosses farm land, the M27 and other main roads as well as the rail network.

As the new plant is being built on the site of a former power station, where possible the facility has used existing on-site energy infrastructure.