Offshore Wind: some of the Engineering Challenges Ahead

Transcription

1 Offshore Wind: some of the Engineering Challenges Ahead David Infield CDT in Wind Energy Systems Institute of Energy and Environment University of Strathclyde

2 International context (from IPCC report) Greenhouse gas (GHG) emissions resulting from the provision of energy services have contributed significantly to atmospheric GHG concentrations and recent data confirm that consumption of fossil fuels accounts for the majority of global anthropogenic GHG emissions. Renewable energy has a large potential to mitigate climate change, but present world share of primary energy is only 12.9%. 2

3 World wide RE potential 3

4 UK context UK s binding EU commitment is to provide 15% of all energy from renewable sources by 2020 (RE Directive) This implies perhaps 35% of electricity from RE DECC now plans 33 GW of offshore capacity by 2020 Renewable energy technology Current contribution to UK electricity GW Potential 2020 scenario Load factor TWh % UK electricity Biomass 2% 6 50% % Wave energy <0.1% 1 34% % Tidal energy <0.1% 1 42% % Severn barrage 0% % 5 25% Wind energy 3% 37 35% % PV <0.1% 2 20% % TOTAL 40.7% 4

5 Wind energy deployment today UK has the best wind resource in Europe (on and offshore) Over 3.5 GW onshore UK has the world s first deep water wind turbines Over 1GW now installed offshore Round 2 sites under construction Round 3 sites at design stage BUT only 9 years to install 33GW of offshore wind 5

6 Offshore wind sites (Rounds 1 to 3) 6

7 Some remarks Wind turbines do experience regular major component failure very approximately up to once per year Onshore turbine availability can be high (97%+) despite these failure rates Offshore operations and turbine repair are far more expensive Offshore annual availability data in the public domain is limited but shows a wide range of figures from 67 to 95% (the latter for sheltered sites in the Baltic) Offshore turbine access limitation in high seas and winds and heavy lifting restrictions in these conditions is a major factor and results in lost turbine operation following faults Some round 3 sites are very far from shore Grid connection requires extensive sub-sea cabling 7

8 What can be done to improve offshore wind economics? Use larger wind turbines but only if reliability does not fall as a result of scaling up Improved design to achieve longer component life Design for maintainability Improved offshore turbine access Improved asset management including optimised O&M (including condition monitoring) Improved sub-sea support structures and/or develop floating wind turbine concepts Reduce cost of connection to mainland grid/s 8

9 Larger turbines and deeper water 2 Repower 5 MW turbines mounted on jackets in over 40 metres of water at Beatrice in Murray Forth 9

10 Challenge of scaling up wind technology Manufacturers are talking about a range of possible turbine designs up to 15 MW Design tools only accurate for wind turbines up to around 2 to 3 MW Larger turbines will be more flexible and more difficult to control New foundation designs will be needed for these larger turbines and to cope with deeper water sites New power collection arrangements for the GW scale offshore turbines will be required 10

11 Accessibility data from Round 1 sites Barrow Kentish Flats Scroby Sands Accessibility (%) Mean wind speed (m/s)

12 Influence of sea conditions on accessibility 12

13 Condition monitoring Condition monitoring has been used successfully in other engineering applications and is increasingly used for wind farms BUT It does have a cost It must be carefully thought through It can easily result in unwanted alarms The value to the wind farm operator (on or offshore) is not yet well quantified If the information gained from CM does not result in a change to the way the wind farms are maintained and operated, then there will be no financial benefits 13

14 Power system operational challenges Increases in plant margins (reserve) required to compensate for wind - but exact levels far from clear for high wind penetrations Relative loss of system inertia as conventional plant replaced by wind power High cost of any additional energy storage (no significant further pumped-hydro opportunities) Added complexity of power system and number of active components means that system stability is hard to guarantee New electricity loads anticipated for space and water heating (heat pumps) and electric vehicle charging 14

15 Some potential approaches Making wind farms resemble conventional power plant Using responsive loads that react to the availability of wind power (and other renewables) perhaps through new market mechanisms Using information technology and comprehensive communications to better manage loads, sources of generation and the network Use smart meters to assist in demand side management particularly in the domestic sector Make use of electric vehicle charging loads, and perhaps space and water heating loads, as a part of demand side management Introduce energy storage if it is cost effective 15

16 Brief conclusions Round 3 sites will account for most of the UK wind capacity by 2020 and are very challenging in all regards A new generation of turbines and sub-sea support structures will be required to exploit the offshore resource Managing offshore wind assets effectively will be key to future success of offshore wind power Whole system approaches to offshore wind farm design and asset management need to be developed New power collection arrangement and connection to the power system/s will be required Much research to be done to underpin these technology developments 16

17 Over to the next generation of engineers 17