Dong Energy commissions Welsh power plant

Severn Power CCGT delivers 834 MW via combined-cycle gas turbines, with 58% efficiency, low NOx burners, fast 30-35 min ramp, air-cooled condenser, wastewater reuse, by Siemens Energy and DONG Energy for UK grid.

Wales' newest gas-fired power plant has been commissioned earlier than planned by Danish utility Dong Energy, at Uskmouth, near Newport.

The 709 million euro US $940 million combined-cycle gas turbine CCGT Severn Power plant, a combined-cycle power station with a generating capacity of 834 megawatts MW, took three years to build and can supply enough electricity for approximately 1.5 million homes.

The plant was handed over a week early by project developer Siemens Energy, a subsidiary of German engineering giant Siemens AG. Siemens claimed that the plant is at the forefront of high-efficiency power plants, showcasing an environmentally friendly CCGT plant design thanks to the burner technology that keeps the plant's nitrogen-oxide emission levels low, at approximately 15 parts per million. The plant has an efficiency rating of 58 and can achieve full output after only 30 to 35 minutes, allowing it to quickly compensate for the fluctuating feed-in from wind turbines, Siemens said.

The plant's environmental footprint is also improved by the use of an air-cooled condenser rather than a cooling tower. The plant utilizes wastewater in its operations, similar to turning waste gas into power initiatives seen elsewhere in the industry, allowing it to consume significantly less fresh water than traditional plants.

Severn Power station began generating power commercially last month when the first of its twin gas and steam turbines was brought online. The second turbine set is now fully operational and supplying electricity to the national grid. The turnkey project was built on the site of a decommissioned coal-fired unit and comprises two single-shaft units, with the main components being arranged in a single line of shafting. Siemens supplied two SGT5-4000F gas turbines, two SST5-5000 steam turbines, two hydrogen-cooled generators, electrical equipment and an SPPA-T3000 instrumentation and control system, under a package comparable to a supply contract seen on other CCGT projects. Siemens will operate the plant and will also oversee a 16-year service and maintenance contract.

"Severn Power station represents an investment of £600 million US $940 million and has taken three years to construct and commission," commented project director Richard Tyreman. "It therefore represents a significant investment for DONG Energy and makes clear the company's commitment to the UK. Many local people were included in the 1,000 job plant labour force which built this new facility, and we hope that they take as much pride as we do in the completion of a project of such regional and national importance."

Lothar Balling, the head of GT Power Plant Solutions in the Fossil Power Generation Division of Siemens Energy, which invests in gas-fired projects across Europe, added: "This plant impressively demonstrates how assured supply, cost-effectiveness and environmental compatibility can be harmonized. It also exceeds the guaranteed performance demanded by the customer on all counts."

Siemens is currently building another CCGT plant with Dong in Rotterdam, Netherlands, and a power plant in Amsterdam as part of its regional portfolio, that will boast an even higher efficiency rating of more than 59 when it is completed next year. The 870-MW Enecogen will produce enough power for 2 million homes.

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