According to a survey conducted by KEMA, in total some 680 square kilometres of the Dutch continental plate is suitable for wind energy production, giving the Netherlands an offshore installed capacity potential of 4000-6000 MW. The first phase of Dutch offshore development is likely to comprise two hundred 3 MW turbines standing in 20 metres of water in an area of ten square kilometres in the North Sea outside the Netherlands' 12 mile zone, Novem believes. Ultimately, some 30-50% of the country's target of 2750 MW of wind must be generated offshore by 2020. Before the first North Sea turbine can be placed, however, a number of technological and legal hurdles have to be cleared, making any development highly unlikely before 2005.
Turbines of 3 MW needed
At an estimated cost of NLG 2.5-3 billion, a 600 MW plant will have to produce 2000-2350 GWh a year to be economically viable. This will require wind speeds of 9-10 m/s and consequently a site outside the Netherlands' 12 mile zone. At the same time, construction costs-with foundations making up one-third of the total cost per unit-dictate that plant be sited in water less than 20 metres deep.
At present neither the technology nor the legal framework exists to enable such a project. Balancing unit yield against construction costs, optimum turbine capacity has been fixed at 3 MW and it is anticipated that turbines in this range will be commercially available only from 2004.
Land-based testing of multi-megawatt machines is expected to begin in 2002 and a 100 MW near shore pilot plant, vital for refining offshore technology, is also scheduled for completion that year. In the interim the legal framework for developments outside the 12 mile zone has to be put in place. This will require amendments to both national and international legislation, and with no international agreement on jurisdiction outside the 12 mile zone, is likely to prove a major obstacle.
Given the resolution of technological and legal problems, however, the report foresees no difficulties with offshore electricity on the Dutch grid. Existing infrastructure could accommodate some 10,000 MW offshore capacity and the economic value of offshore power is calculated at NLG 0.058/kWh for 1500 MW, dropping to NLG 0.046 cents for 10,000 MW. Offshore wind energy is the cheapest form of renewable power available, the report concludes, and by 2020 could supply 60% of the total renewables market.