Offshore wind experience in Denmark

Transcription

1 Offshore wind experience in Denmark Sten Frandsen, Risø National Laboratory Workshop on Deep water wind energy research & development planning October , Washington DC

2 Offshore projects in Denmark Technology trends Offshore potential Giant wind farms loosing too much energy?

3 Offshore projects in Denmark Vindeby 450 kw Tunoe Knop 450 kw Middelgrunden (Copenhagen) 40MW Samsø 20 MW Nysted 166 MW Horn Rev 160 MW

4 Two large Danish demonstration projects (km) Horns Rev Nysted

5 Wind turbine System component Horns Rev WF Nysted WF Rated power 2.0 MW 2.3 MW Rotor diameter 80 m 82.4 m Gearbox Yes Yes Power limitation Pitch Active stall Rotational speed Variable RPM 14/11 RPM Generator Induction Induction Slip rings Yes No Substructure material Steel Concrete Substructure type Mono pile Gravitation

6 Investigations Prior to construction: Environment flora and fauna Technical soil and climate and structural loads (wind, waves and ice) Wave height Bølgehøjde Wind speed Vindhastighed

7 Horns Rev (North Sea) Steel monopile water depths: 10-15m

8 Horns Rev Wind Farm: Layout

9 Construction: Transport by boat..and by helicopter

10 .and Nysted: Demonstration project in the Baltics Concrete, gravity foundations Water depths: 5-10m (km) Nysted

11 4 wind turbine units per shipping (one already erected here) Putting in place concrete foundations

12 Investment cost per MW Component Investments 1000 /MW Share % Turbines ex. work, including transport and erection Trafo-station and main cable to coast Internal grid between turbines 85 5 Foundations Design, project management Environmental analysis etc Miscellaneous 10 <1 Total 1680 ~100%

13 Cost per kwh 6 5 c /kwh Balancing costs O&M-costs Investments 0 High costs 3800 h/year Average 4200 h/year Low costs

14 Technology tends

15 Foundations: how far can the present technology be stretched? Monopile, Steel Maybe up to 30m water depth, depending on soil conditions Weakness is the limited stiffness For larger depths the pile must be supported Gravity, concrete Maybe up to 50m water depth, depending on soil conditions A European project at 30m water depth is presently out for tender Strength is the large stiffness Weakness is weight Beyond present technology Floating concepts?

16 Future design of offshore wind power plants Issue State of the Art Future Trend Size H=100m, D=100m, P max =3MW H=150m, D= m, P max =10MW Costs correspond to Operation & approx. 50% of initial maintenance investment Halving of O&M cost Water depth 5-20m 10-50m Foundation/ Mono-piles; tripods; bucket; various Gravity and mono-piles Substructure floating concepts Blade tip speed m/s m/s Structural design Passive; some active control Active control: limitation of loads on all structural components Materials Chosen for strength In addition also as consequence of lifecycle analysis Control Separate wind turbine/farm In conjunction with regional grid; commercial optimization Grid Normal terminal; national Island-operation; storage; international grid connections Production Market requirement is 12- forecast 36 hours Market requirement reduced to 2 hours Production strategy Maximum energy Maximum revenue Transmission AC alternate current HVDC high voltage direct current

17 Offshore potential

18 European prospects: (In terms of capacity) 20GW 70GW 600GW Probably much more Offshore potential Rest of world: (In terms of energy per y) theoretical - 5 TWy/y practical TWy/y World electricity consumption 1.5 TWy/y From Shaw et al (2002) From Siegfriedsen et al (2003).

19 North Sea water depths

20 Electricity from (deep water) offshore wind power plants: The North Sea alone would do just about half of the world s present need.

21 Giant wind farms loosing too much energy?

22 Energy yield of giant offshore wind farms When large enough wind farms are excellent windbreaks Consequence may be serious depletion of production in the down wind end of the wind farm What is large,and when large what is the effect? Must the wind farm be broken up into smaller ones and what should the separation be? Prevailing winds

23 Prioritized R&D? Innovation: Economic foundations for water depths > 40-50m development of significantly more accurate design tools including aggregation of these A strategy for layout of giant wind farms is need to avoid production depletion in the downwind end of the wind farm O&M though maybe becoming relatively less at large water depths?