Turbines

The five High Winds turbines are German-built Enercon E70 turbines, each rated at 2.3MW. The E70 is a popular machine and is especially useful at sites with high wind speeds. The rotor is three bladed and each fibreglass blade rotates clockwise. The length of the blade is 35.5m, the hub height is 64.0m making the height from ground to tip 99.5m. The rotor turns in the speed range 6.0-21.5 rpm and the rated power is produced at wind speeds of 15m/s (the equivalent of 33mph) and above.

ENERCON storm control - ENERCON wind turbines run with a special storm control feature. Storm control enables reduced wind turbine operation in the event of extremely high wind speeds, and prevents typical shutdowns which cause considerable yield losses.

The blade profile is like that of an aircraft wing and the pitch-the angle of attack to the wind- is variable according to the wind speed. The tips of the blades are turned up (like a modern aircraft wing) and reduce the air turbulence at the tip resulting in less noise.

There is a control system to achieve maximum output under all weather conditions. The turbine has yaw control, that is, internal machinery moves the rotor to face the wind direction according to an anemometer on the nacelle.

There is no gear-box: the rotating rotor shaft passes through the centre of an annular generator. This means that there is no noise produced compared with the arrangement with an intermediate gearbox, that there are few rotating components leading to reduced mechanical stress, operating and maintenance costs.

Generator and other Components

The nacelle complex is constructed from two cylindrical tapering steels towers, bolted to reinforced concrete foundations. The foundations are relatively wide and not very deep-think toy soldier bases.

The output voltage and frequency vary with the speed of the rotor. Additional equipment ensures that the output power is regulated according to the grid specification required. Within the turbine, a transformer increases the voltage from 400V to 11KV, which electricity flows to the on-site sub-station, where it is metered. Using the former underground Baywind cable, electricity passes to the Ulverston sub-station where it enters the Grid.

Construction

The turbine components were shipped to Barrow docks and the escorted to site using an improved route for abnormal loads. The route was widened and smoothed around bottle neck corners and, where necessary, the verges were widened and hardened. On site, new stoned tracks were laid for access to the turbine positions together with a crane hard standing area and a separate rotor assembly platform. Rather than lift the rotor hub and then fit the blades one by one, the rotor was assembled on the ground and lifted in one piece by a very large crane.

Maintenance

The turbines are maintained by Full Circle through a long term Operation & Maintenance contract. This includes twice annual service and general breakdown cover.

Power Purchase Agreement

High Winds has entered into a contract with Octopus Energy to sell the electricity and claim the Renewable Obligation Certificates (ROCs).