SuperGen Wind Phase 1 Final Assembly How R&D can assist the application of renewable generation Dave Pearce, Technical Head for Renewables, E.ON Engineering Limited, 25 March 2010
15 Technical Problems which remain to be solved if electricity generators are to meet their Renewables Targets in wind power
Project Development 1. Solve the array loss question.
Wind Farm array losses The size of the largest wind farms makes it especially important to understand array losses, & their impact on electrical yield. We can now compare performance data from individual turbines with theoretical predictions. PowerPoint-Kurzmanual April 2002 E.ON AG Seite 4
Energy Loss in large arrays Each turbine row takes energy out of the wind Energy is part replenished between rows, by turbulent mixing from above. In a large wind farm a balance is eventually reached. Suitable for combination of CFD analysis and comparison with wind farm performance measurements. Plan view of Scroby Sands, 30 x 2MW
Work under SuperGen Wind 1 Wind tunnel results can strengthen theoretical approaches, as well as helping the validation of computer models.
Wake Effects. University of Surrey 1:300 model tests based on 5MW SuperGen exemplar turbine
2. Impact of Forestry, & other major roughness elements Loughborough (CREST) is looking at this issue, which particularly affects the performance of larger on-shore wind farms in the UK and NW Europe. NB Forestry effective roughness lengths are typically quoted too low, meaning that the ability of forestry to reduce wind resource locally is often underestimated. Blue vectors: high level, above canopy. Red vectors: low level
Bowbeat, Moorfoot Hills
3. Extreme Winds Prediction, and correlation How fundamentally can we predict extreme winds, and their frequency? Can we correlate between sites?
4. What is the maximum size of a Danish Model wind turbine? Engineering constraints Economic constraints Atmospheric Boundary Layer constraints
5. Safe & Easy Access offshore
6. Design for easy replacement of equipment
7. Reliability The self healing turbine
Identifying control improvements to reduce WT loads improve reliability and reduce weight In large multi-mw WTs the production loads are a major contribution to lifetime equivalent fatigue loads on towers and blades. Loads on both can be reduced by improving WT controllers. Advanced solutions to the control design have reduced tower loads by 15-18% without compromising the WT performance. Similarly blade loads can be reduced by individual blade control, which has attracted interest from Industrial Partners.
Reliability Results can be unexpected: Direct drive WT s are not necessarily more reliable than geared WT s... Spinato et al, 2008 Partly because failure rates in larger direct drive generators have been high. However gearbox downtimes are long. Supports the use of direct drive permanent magnet generators.
8. Blade Fatigue Remote detection of cracks Remote detection of crack propagation rates Prediction of remaining life Emphasises the importance of condition monitoring
9. Reliable Power Curve measurement within an operating wind farm Draft standard IEC 61400-12-2 will help, but still not an easy process
10. Reliable thrust curve measurement within an operating wind farm.
11. Storage of Intermittent Generation, economically & reliably
12. Systems for economic and secure transmission over long distances
13. Predict the Annual Wind Resource variation for the next 10 years, for a particular wind farm. Variants of this would allow the development of a reliable wind farm Power Prediction Tool
Compared to estimated average, % With thanks to Naturlig-Energi Annual Wind Resource, Denmark 140.0 120.0 100.0 80.0 Annual 60.0 40.0 1980 1985 1990 1995 2000 2005 2010
14. Predict the impact of climate change on wind resource.
CLIMATE CHANGE European 2003 summer temperatures: normal by 2040s, cool by 2060s Met Office graph observations Medium-High emissions
15. Design, build and operate a successful Darrieus Turbine
New Possibilities Rugged design minimising components Fixed Pitch blades No gearbox Multipole generator at base Low Head mass Shared power inversion system (Vertical Wind Industry AB, supported by E.ON, Falkenberg Energi, Swedish Energy Agency)