installation, operations & maintenance

Transcription

1 installation, operations & maintenance

2 Contents Introduction... 2 The offshore wind opportunity... 2 Innovation in offshore wind... 2 The cost of offshore wind projects... 2 Offshore wind foundation, turbine and cable installation... 3 Offshore wind operations and maintenance... 4 The challenges... 5 The opportunities... 6 The market for operations and maintenance... 7 How Scottish Enterprise supports innovation... 8 Summary... 8 Useful Links... 9 Sources... 10

3 Introduction This paper is the third in a continuing series detailing the findings of technology and market based research carried out by Scottish Enterprise to identify opportunities open to Scottish industry, higher education and other organisations in segments of the energy market. The offshore wind opportunity The potential investment of 100 billion (BN) UK offshore wind markets over the next 10 years offers a significant economic growth opportunity for Scotland. World class offshore oil & gas operating experience, engineering and higher education expertise and the ports infrastructure Scotland possesses, together with its wind resources, means we are well positioned to reap the benefits that offshore wind development offers. Success in Scottish & UK markets could be a springboard for Scottish companies to access global markets. As a result offshore wind has been identified as a key strategic priority by Scottish Enterprise and the Scottish Government (1). Innovation in offshore wind With respect to offshore wind innovation, these papers aim to highlight ways of: cutting the cost of energy of offshore wind projects by 30% (a challenge outlined in the Offshore Wind Industry Route Map) (1), particularly at more challenging sites (for example with deeper water, difficult seabed conditions, smaller weather windows) reducing the risks and uncertainty associated with these projects promoting the mass manufacture and deployment of offshore turbines in order to deliver economies of scale and meet ambitious renewable policy targets enabling companies to win more value from local projects and grow their export earnings This paper outlines some opportunities for the application of innovation in the installation and operations and maintenance (O&M) phases of offshore wind projects. The cost of offshore wind projects Current estimates of the overall cost of energy of an offshore wind project are in the region of 150/MWh and installation and O&M costs make up a significant portion of this. Figure 1 (right) shows that approximately 11% of the cost of an offshore wind project is associated with installation work and another 19% with the O&M costs. Figure 1: Offshore wind project cost share Source: Douglas-Westwood (2) 2

4 Offshore wind foundation, turbine and cable installation Calm weather and stable sea conditions are key variables affecting installation work. Being unable to work year-round is a problem that affects these projects, which generally need to adopt multiseason installation schedules. Foundations and support structures need work before they are fixed in place. Holes need to be drilled for pilings that must be installed before subsequent installation of jacket structures and gravity base foundations need a very level base to rest on and, once they are lowered onto the seabed, need large amounts of ballast to be added (usually concrete). The installation method varies depending on foundation and support structure type, for example, a jacket support structure is installed using a crane barge and is transported offshore and installed in one piece. The transportation and installation of offshore wind turbines is a process conducted over several phases, usually in sequence. It normally requires six crane lifts to install the tower, nacelle and blades. At Beatrice wind farm a pioneering method was used to have the entire turbine installed in one piece. There are several factors that can turn this process into a challenge due to offshore site conditions or technical limitations of the installation vessels. Very tight installation specifications are required by turbine suppliers or turbine design warranties are breached. Delays are costly as hired vessels are expensive. Currently the installation of foundations and turbines is mainly achieved through the use of jack-up barges. Typically these have 4-6 legs that extend into the seabed and lift the vessel completely out of the water. Jack-up vessels can currently install in depths up to 35m (3). Beyond this depth (or where the seabed cannot support jack-ups) floating installation vessels, as pioneered at the Beatrice demonstrator, are required. These vessels need specialist controls to provide high accuracy positioning, novel crane and loading arrangements and roll reduction in poor weather conditions. In time larger turbines could require larger installation cranes than currently available (4). Cable installation vessels use a cable plough that digs a shallow trench in the seabed and buries the cables. Faster more accurate cable laying would cut costs and avoid interruptions to wind farm power export caused by damage to these cables. Offshore wind installation techniques have not yet been optimised for high volumes and speeds. For example, at the moment a vessel will put in a single pile then reposition itself to do another, whereas a vessel that could do multiple piling would save time (and cost). There could be opportunities for wind turbines, foundations and grid connections to incorporate design modifications to ease the installation process. A good example of this is work to design gravity base foundations and support structures that can be floated to their sites rather than loading them onto vessels (5). Generic challenges for installing offshore include: Installing in depths of greater than 35m Reducing the cost of installation Faster installation rates Widening the weather window for installation Many of these challenges could be met by developing new classes of installation vessels. 3

5 Offshore wind operations and maintenance To date offshore wind turbines are, largely, versions of the largest onshore wind models designed to be suitable for higher capacity factors. The engineering and quality control challenge required to operate in the marine environment is considerable. Higher wind speeds coupled with the corrosive effect of saltwater means that structural and mechanical component failure is more common, especially where off-the-shelf components designed for onshore applications are transferred to the marine environment. Yet, due to the significantly higher costs of access and maintenance, higher levels of reliability are needed in offshore wind applications than onshore. Re-designing or removing components subject to failure; improving their robustness; and, better condition based monitoring or maintenance, all have the potential to raise reliability. The Renewable Energy Information System on Internet (REISI) provides product information and operational results from operational wind turbines. Reliability is measured by a combination of frequency of failure and the downtime (i.e. the time required to make the component, and therefore power, available again following a failure). Figure 2: Annual failure frequency and related downtime of major wind turbine components Source: SKM (6) This shows that, in terms of overall impact, the electrical systems, generators and gearboxes cause the most down time. Reliability improvement should thus be focussed on these components. The primary cause of most of these failures was defective parts (7) so better quality assurance, as adopted by many North Sea oil companies, could have a significant impact on improving availability. In O&M, the priority is to maximise the reliability of wind turbines and minimise unscheduled repairs while keeping the costs of doing this down. 4

6 A variety of O&M interventions may have to be carried out in the course of a wind farm s life. These interventions range from light duty lifts (for inspection purposes of perhaps 1 or 2 tonnes of equipment and personnel) to the heavy lift of a gearbox or generator. In terms of access to do repairs, replacing electrical components is far less problematic than say replacing a generator or gearbox, each weighing 20 tonnes or more (8). The limited track record of offshore wind farms makes estimating O&M costs difficult and it is generally felt that underlying cost trends will only become apparent after a sustained period (5 years+) of operation. In the relatively small near shore projects built to date, annual O&M expenditures have varied hugely but the main components of the cost are as shown in figure 3 (right). Figure 3: Annual O&M cost breakdown Source: Douglas-Westwood (9) The cost of replacement equipment represents the largest proportional cost of offshore wind O&M. This cost is representative of the requirement to repair/replace components (gearboxes etc). Access for technicians, tools and replacement parts is a major determinant of availability. One of the main challenges of servicing turbines is transferring personnel onto a turbine. Fast crew boats currently achieve accessibility of 80% annually for near-shore sites, but this can drop to below 50% in winter (because of weather and waves). In order to increase offshore wind availability to onshore levels of 95% repairs on demand will be required (9), necessitating new access technology. Scottish offshore sites, particularly those off the west coast, are likely to be particularly challenging to access. Heavy duty installation and repair vessels are typically chartered for major repair and overhaul work which cannot be completed by personnel transfer, e.g. changing out a delaminated wind turbine blade. New strategies for O&M are likely to be needed to raise offshore wind turbine reliability. These could include strategies using different means of access (boat, helicopter) in different seasons or holding stocks of equipment and parts at portsides or offshore. O&M could also be conducted from offshore accommodation facilities, in a similar manner to oil rigs. This could leverage the economies of scale from a collection of large offshore wind farms, and significantly reduce travel times, downtime and thus cost (10). The challenges As mentioned previously a limited history of operation is mostly based on the relatively small, near shore projects built to date, and though O&M expenditures have varied hugely, annual offshore wind O&M spend is in the region of 80/kW/pa twice the spend for onshore wind O&M ( 40/kW/pa) (11). These costs are high because the frequency of offshore O&M work and the cost of doing this work are significantly higher than onshore. There are particular cost challenges for O&M at Scottish offshore projects. Smaller weather windows (relative to the southern North Sea) at these sites could have a significant impact on the cost of installation and O&M. 5

7 The opportunities The following tables are extracts from work done by Scottish Enterprise on cost saving opportunities, which relate to how installation and O&M costs could be improved through innovation. Installation challenges include speeding up installation rates; extending the operating envelope of installation vessels; and, minimising re-work. O&M challenges include rates of failure offshore and access restrictions due to weather and wave conditions. Potential solutions include new vessel and access systems; more remote management; and, new O&M strategies. Potential innovation opportunities with respect to installation: Component/ innovation Implementation of floating lifts of foundations (i.e. towing) Implementation of floating lifts of WTGs Implementation of single unit skidding of WTGs Floating build and installation Minimise offshore commissioning requirements Subsea rock piledrilling Multi-pile installation Piling noise control New installation techniques Source (12) Synopsis New techniques for foundation installation could reduce the cost of the vessels required and the time on site. As for floating lifts of foundations, new techniques could reduce the cost of the vessels required and the time on site. Installation of complete turbines (as at Beatrice) would shorten the installation period, reduce the need for offshore installation staff and their transfers, and perhaps reduce the vessels required. Floating build (i.e. in sheltered water, without needing a major port or onshore construction facility) was used in the oil and gas industry, and the technique could be revisited for batch production of gravity bases (or other structures), which are then floated direct to site. Reducing commissioning activities offshore would reduce costs and the need for staff transfers, and shorten the construction programme. In some sites, particularly Scottish waters, the soil is not suitable for conventional piling. Techniques for drilling rock at sea will be required. Pile installation is a major cost and weather risk for foundation concepts based on multiple piles. Techniques could be developed to install several piles at once. Piling noise may affect marine life, and could become a major restriction on the construction timetable. Reducing the transmitted noise could reduce the problem considerably. There is an over reliance on oil and gas installation techniques that may not be appropriate for offshore turbines. New surveying, handling, positioning and installation techniques for foundations could reduce the cost of the process or the cost of vessels required or time on site. This could include the development of specialist vessels, equipment and electro-mechanical control systems for installation work. Estimated cost saving effect of innovation on subsystem/ activity Overall project cost of energy improve- ment 10% 0.5% 25% 0.5% 25% 0.5% 25% 1.3% 5% 0.1% 10% 0.5% 10% 0.5% 10% 0.5% 10% 0.5% 6

8 Potential innovation opportunities with respect to O&M: Component/ innovation Test and prove next generation of all weather access solutions Purpose designed heavy lift/deep water O&M vessels Strategic solution for far offshore O&M Condition based monitoring Improve turbine design standards through better validation Identify key components for targeted reliability improvement Develop new offshore specific wind turbine design Increase project design life - structural integrity management measures Novel drive train sub system improvement Source (13) Synopsis Access for technicians, tools and replacement parts is a major determinant of availability, and this will become more important as distance offshore increases. There is no shortage of possible future concepts: the important step is to prove performance in order to give confidence to wind farm developers and O&M contractors. Solutions will be defined mainly by the lift requirements t for personnel and light equipment but improving the weather window of operation is also important for Scottish sites (e.g. 2m mean wave heights) A new class of vessels able to operate in 35m+ depth and do floating (i.e. not jacked-up) lift-outs of heavy equipment (gearboxes, blades) is likely needed. Requires co-operation between device suppliers and service companies, vessel suppliers and marine warranty surveyors to develop. Improving their weather window of operation is vital. Far-offshore wind farms may achieve higher availability with new approaches to O&M, especially crew access and accommodation. Detailed analysis and costing of the alternatives is needed. Already established but further application to OW an opportunity given challenges of offshore operation and scale up of turbines Design standards for offshore wind turbines have developed from onshore. Validation by measurements on operating offshore turbines could identify areas of conservatism. Detailed analysis of operational data has proved valuable for onshore wind turbines, and the same exercise offshore could identify components or component classes which are having a disproportionate effect on availability. This knowledge would assist Scottish firms win equipment refurbishment work. It has long been recognised that, freed from constraints of noise emissions and visual appearance, the optimum design of offshore wind turbine could look very different from present concepts. High rotor speed, two blades, downwind machines are concepts worth investigating, but this category could also include high-redundancy concepts, floating turbines, and other ideas. Project economics may benefit from an increase in design life, for example to match design life of major turbine components to the foundation design life. It should also be beneficial to establish means of increasing structure lifetime in service, should it prove to be required in particular locations. Additional support is likely to be needed to enable core concepts to be commercialised. Several novel designs specifically improve the reliability of drive trains by removing or improving components with high failure rates. Estimated cost saving effect of innovation on subsystem stem/ activity Overall project cost of energy improve- ment 25% 2.3% 25% 1.5% 25% 5.0% 1% 0.3% 5% 2.3% 7% 3.0% 10% 4.5% 6% 2.5% 20% 1.9% The market for operations and maintenance Using recent information on UK sites the table below estimates geographical market sizes for O&M 7

9 Forecast of installed capacity by 2020 Approximate no. of installations by 2020 Forecast installation spend ( ) Forecast annual O&M spend on projects by 2020 Forecast annual O&M spend on projects by 2020, excluding equipment and grid costs ( M) (23%) Potential market size Installed capacity 2010 (MW) (MW) (a) (b) ( M) (c) ( M) (d) All Scottish sites (e) 190 9,130 1,826 3, Non Scottish sites 1,151 17,800 3,560 6,660 1, UK total 1,341 26,930 5,386 10,236 2, Rest of Europe 1,623 28,200 5,640 10,631 2, Rest of World 102 8,100 1,620 3, Non UK total 1,725 36,300 7,260 13,830 2, Global total 3,066 63,230 12,646 24,066 5,058 1,163 (a) after Scenario A numbers - Vision for Offshore Wind (b) assumes 5MW turbines (c) assumes 0.4M/MW (d) assumes 80/kW/pa = 0.08M/MW/pa (e) leasing capacity less Bell Rock, Forth Array, Kintyre, Wigtown Bay and Solway Firth sites Source: Scottish Enterprise, developed from (14)(15) In other words, leading up to 2020 over 10 billion will be spent on installation in UK waters plus almost 14 billion elsewhere in the world. O&M spending will increase with each new project to the point where, annually, there is a potential UK market for O&M of around 2.2 billion and around 2.9 billion elsewhere in the world. Taking out the costs of replacement equipment and those associated with grid connection shows a potential UK market of around 0.5 billion and around 0.7 billion elsewhere in the world, annually, for companies with innovative approaches to O&M that can cost effectively maintain or improve offshore wind turbine availability. Summary Reducing the costs of installation of offshore wind turbines goes a long way to reducing the initial capital investment required and therefore is likely to help increase or accelerate investment decisions. Being able to maintain or increase the availability of offshore wind farms whilst reducing both the need for maintenance (planned and unplanned) and the cost of O&M is crucial to reducing the overall cost of producing energy from offshore wind. Companies who can develop solutions to achieve these goals will be well placed to participate in a multi-billion pound market. 8

10 How Scottish Enterprise supports innovation Scottish Enterprise has worked with partners to develop the National Renewables Infrastructure Plan to set out a clear framework for delivering the investment required in our port infrastructure that will open up opportunities for the growth of a strong Scottish supply chain. In addition to the targeted inward investment in areas of supply chain gaps being pursued by Scottish Development International, Scottish Enterprise has developed a programme of support for Scottish companies to help them make the most of the offshore wind opportunity. This programme includes providing market intelligence, awareness raising events, workshops and one-to-one expert help and advice. A database of Scottish companies skills and capabilities relevant to offshore wind is also available. In addition to investing in companies in the sector through the Scottish Seed Fund, Scottish Co-Investment Fund and Scottish Venture Fund, Scottish Enterprise, is helping attract international investment liquidity into Scottish low carbon opportunities with our partners in the Scottish Low Carbon Investment Project. Working closely with the Scottish industry, areas have been identified where Scottish companies have a lead in innovation and where innovation support can be focused, for example substructures and innovative installation methods. Scottish Enterprise has a number of Research & Development and Innovation support mechanisms that can assist companies from the early stages of investigating market and technical feasibility; through product, process or service development; to market launch. Where a company s R&D or Innovation project presents a convincing technical and commercial case Scottish Enterprise will identify how best to support your project. This could include reimbursement of eligible costs at: up to 75% for technology feasibility studies up to 45% for close to market Research & Development projects Research and Academic Institutes with early stage, proof of concept projects that present a convincing case could be awarded up to 100% reimbursement of eligible costs. Useful Links Scottish Enterprise Business sectors Energy Offshore wind Scottish Enterprise Fund your business Scottish investment bank Equity funding Scottish Enterprise Fund your business Innovation and R&D grants Scottish Enterprise Start your business Proof of Concept Programme Scottish Enterprise Scottish Energy Laboratory 9

11 Sources 1. Offshore Wind Industry Group (OWIG), Scotland's Offshore Wind Route Map: Developing Scotland's Offshore Wind Industry to 2020, September 2010, 2. Scottish Enterprise, Innovation in Offshore Wind, Carbon Trust, Offshore Wind power: big challenge, big opportunity, September 2010, page Garrad Hassan, Techno-Economic Foresighting for Offshore Wind: Phase I report, 2010, page 8 5. Arup Associates, Briefing paper: Gravity base foundations, SKM, Condition Monitoring of Wind Turbines, August 2006, figure 8, page As ref 6, page Crown Estate, A Guide to an Offshore Wind Farm, 2011, page Douglas-Westwood, Offshore Wind Innovation - Final Report, March 2011, table 6, page As ref 4, page As ref 9, page As ref 2, Appendix C 13. As ref As ref 9, various pages 15. IPA, Scottish Offshore Wind: Creating an Industry, August 2010, page 26 (Scenario A) 10