A Vestas V90 3 MW wind turbine erected in the Dintelhaven now towers 105 metres over Rotterdam harbour. The turbine is the largest of four Vestas machines at the harbour and has a tip height of 150 metres. It is expected to produce 8.5 million kWh a year. Permission for the four turbines was originally sought by Dutch project developer Raedthuys Groep of Enschede back in 1999. Because part of the foundations are underwater, a dam had to be built in the harbour. Over the past decade, Raedthuys has installed about 70 wind turbines in 15 projects. Employing 25 people, the company still sells its wind power through the APX energy exchange, although it is looking to sell directly to customers. Meanwhile, Groenraedt, part of the Raedthuys group, has been given the go-ahead to place three Vestas 3 MW wind turbines in the municipality of Waddinxveen. The Waddinxveen wind plant, to be online by July at a site in the Distripark industrial area, will deliver around 20 million kWh a year to 6280 households, representing 65% of the local demand. The output represents about 3.4% of the annual electricity used by ten municipalities which signed a "wind covenant" in 2002. The ten agreed they would work together to develop 45 MW of wind power in the mid-region of Holland.