Environmental groups have criticised the construction of a new gas-fired power station, which will be officially opened today in Pembrokeshire.

The owners of Pembroke Power Station say it'll generate enough electricity for half the homes in Wales. The gas powered plant, which employes 100, is estimated to be worth £10 million a year to the local economy.

The site will be opened by new Parliamentary Under Secretary of State for Wales Stephen Crabb MP, in his first official appointment since being appointed to the Wales Office ministerial team.

As a Pembrokeshire resident and MP, I have been fortunate enough to see first hand how the strong collaboration of RWE npower, local businesses and the wider community has led us to where we are today. I am delighted to be here to see all that hard work come to fruition

Friends of the Earth says the development uses "outdated technology" and claim that it will pollute Milford Haven.

Friends of the Earth has raised concerns over the efficiency of the site, and its impact on the nearby estuary. It's calling on the First Minister Carwyn Jones to boycott the opening.

The claim that the new Pembroke power station would be the most efficient gas-fired power station in Europe is incorrect. Pembroke power station is expected to achieve an efficiency of around 58% while a comparable power station at the Isle of Grain in Kent will achieve an efficiency of around 73%. The reason for this is that the Kent power station will use the waste heat to re-gasify LNG (Liquified Natural Gas) that is imported in tankers from the Middle East. At Pembroke, it is planned to dump this waste heat into the very important Pembrokeshire Marine Special Area of Conservation posing a threat to marine life. In energy terms, the waste heat is equivalent to 40 per cent of Wales' electricity demand

Operator RWE npower says the site will have a total generating capacity of around 2,000MW, and will produce enough energy for around three and a half million homes.

In November 2000, the 731ft high chimney of the derelict Pembroke Power Station was demolished.