SEA BREEZE Sea Breeze

Transcription

1 SEA BREEZE Sea Breeze is a Self-installing Gravity Base System (GBS) WTG foundation for Any existing or projected Turbine for Waters Depths up to 60m. 1

2 SEA BREEZE Sea Breeze is designed in every aspect by Ocean Energy & Resource (Ocean) to save its owners and operators money. Sea Breeze is substantially cheaper to manufacture and deploy than comparable systems, but more than that its simple design philosophy offers huge flexibility in operation and location. Sea Breeze s design offers further ongoing advantages once in operation by reducing medium and long term cost through its ease of maintenance and its ability to be simply redeployed or recovered back to shore for refit or major repair thus maximizing economical service life. Ocean Energy & Resource Ltd Castlegate Business Park Portskewett Caldicot NP26 5AD United Kingdom Telephone: +44 (0) info@oceanresource.co.uk 2018 Ocean Energy & Resource Ltd Note: Sea Breeze is subject to patents and copyright wholly owned or controlled by Ocean Energy & Resource Ltd and Mr David Bone, Inventor. 2

3 Contents Introduction...Page 04 Description... Page 04 Production... Page 05 Partners...Page 07 Installation... Page 08 Redeployment...Page 09 About Ocean...Page 10 Introduction 3

4 Sea Breeze is a Self-installing Gravity Base (GBS) foundation system suitable for the largest wind turbine towers sited in waters up to 60m. The Sea Breeze design concept can support any size of both 2 and 3 bladed offshore WTGs as well as future Vertical Axis Wind Turbines (VAWTs). The Sea Breeze foundation is specifically designed for low cost series production using prefabrication and assembly line methods, with full onshore build and commissioning of the turbine prior to deployment. The gravity base itself is formed of three cylindrical cellular caissons constructed in reinforced concrete. The unique design permits the completely assembled Wind Turbine Generator (WTG) to be towed as a self-floating unit to its offshore location where it is deployed in a single operation within in a few hours. Once installed at its operating location Sea Breeze provides a high-integrity and stable foundation for the specified WTG. It complies with all relevant offshore Codes and Standards exhibiting industry standard factors of safety against sliding, bearing and overturning. As a gravity base design; expensive piling with its associated environmental problems is obviated. The Sea Breeze footpads are purpose designed to suit the site seabed conditions and may incorporate steel skirts or other foundation enhancements as required. Where necessary, provision is made to provide protection against scour. Description The Sea Breeze Gravity Base Structure (GBS) comprises a post-stressed and reinforced concrete tower (the sub-structure tower) located in the centre of a symmetrical group of three cylindrical multi-cellular hollow reinforced concrete caisson structures of proven design. These cells form a wide relatively shallow base for the WTG structure once installed and provide buoyancy during transport and installation. The cells are each sub-divided into discreet groups to provide for damage stability and differential ballasting during installation and set-down. The cell groups are tested for watertight integrity during construction. Each cell is fitted with a ballast system designed to allow careful control of the descent through the water column during installation and to permit the operation to be reversed if required. 4

5 The three caissons are linked by diametric walls having full moment connection with the central poststressed concrete tubular column which in turn supports the steel wind turbine tower (WTG Support Tower). The base of the steel turbine tower is connected to. A boat landing platform and ladder to the tower access platform just below the main flange allow access into the tower through a standard door. The Sea Breeze GBS and its turbine is a self-floating structure designed to withstand the environmental forces of towage and installation. When deballasted its inherent buoyancy is used to aid these operations. This means that no specialised vessels or heavy-lift facilities are required during installation thus dramatically reducing costs and project risk whilst increasing project flexibility. Once installed on location, in-place stability is provided by the on-bottom weight of the combined structure The submerged weight of the gravity base together with the weight of the steel tower and WTG and associated equipment weights and loadings are transferred to the seabed soil foundation via a patented system of detachable footpads each tailored to meet a specific site s characteristics in relation to level and seabed conditions. The use of these footpads also simplifies later removal of the platform at the end of its field life. If required, steel skirts are used to obviate liquefaction effects and mobilise stronger soils beneath the upper mobile soil layers. In certain conditions suction pile hybrids may be applicable. Once Sea Breeze is commissioned, routine servicing and maintenance will be much lower than that required for steel piles or steel jackets as concrete is stable in seawater requiring only inspection from time to time. Moreover, Sea Breeze has the huge advantage that at any time it can be easily recovered back to shore for major maintenance, such as gearbox, generator or blade replacement all at a fraction of typical offshore maintenance costs. Fabrication and Assembly Sea Breeze will be constructed using assembly line mass production techniques sited on a quayside or dock area. Bulk materials for the concrete element of the caissons will be delivered by truck or ship and likewise all other components necessary for the complete assembly of the Sea Breeze WTG Foundation will be prefabricated on or off site and be delivered for final assembly. A computer controlled batching plant will ensure the highest quality. The foundation structure will be assembled on a slipway ready. Once complete the Sea Breeze will be launched and then towed and secured at the fitting-out quay. The turbine and associated equipment and systems will be brought to site again either by boat or road and will be fitted to the foundation unit. Following fit-out full power testing and commissioning will be implemented. Testing will include all ballasting and installation systems.. 5

6 Typically the same dock will be used for the delivery by ship of turbine towers, nacelles and blades. A permanent crane will be used for both unloading of components and commissioning. Sea Breeze can be fitted with the turbine blades inshore thus further reducing the complexity of offshore operations. This is the preferred installation option and it should be noted that our hydrodynamic analysis (using verified software) and model testing demonstrate that the installation loads encountered during transport and installation are considerably lower than operational design loads. If, however, client planning precludes this option the blades may be installed offshore without the use of heavy lift vessel using proven offshore lifting techniques. 6

7 Partners To ensure that Ocean has the resources, capability and facilities to produce and deliver Sea Breeze in partnership with offshore wind farm developers, Ocean has engaged the following companies: Interserve plc is one of the world's foremost support services and construction companies. Based in the UK and listed in the FTSE 250 index with gross revenue of 2.3 billion and a workforce of over 50,000 people worldwide. Interserve focuses on framework agreements, private finance initiative (PFI) projects and long-term maintenance contracts. Interserve has a progressive approach, working in true partnership and forming long-term relationships with clients and supply chains through each stage of the project life cycle. In addition, Interserve's specialist business RMD Kwikform is a global leader in formwork, false work and associated safety and access equipment. These systems, all created by their own design engineers, provide moulding forms and temporary support during the creation of substantial concrete structures. The key benefit is that they enable construction processes to be designed optimally, providing added value to customers that can be measured - such as lowest in-use cost and reduced construction cycles. RMD Kwikform as partners in the Sea Breeze JV, provides expert knowledge on pre-cast concrete construction. 7

8 Tow Out & Installation Sea Breeze is towed out using two offshore tugs (around 4500 HP and 1500 HP non-oil industry tugs). The second tug provides redundancy for safety purposes and is also used to assist with positioning and installation. Once on location Sea Breeze is manoeuvered and secured into its operational position. The ballasting system is connected and tested and once commissioned the unit is installed by controlled ballasting. The installation vessels control the plan position of the Sea Breeze during installation. Position control will be effected by DGPS at the surface and high frequency sonar transponders subsea. Position will be visually checked by ROV throughout the operation. 8

9 The procedures are well understood and have been developed and used by Ocean personnel on many occasions. Only seawater ballast is used during this procedure thus avoiding the cost of expensive solid ballasting operations. When the GBS descends below the surface, the descent is controlled and the tower remains vertical throughout using a reusable buoyancy frame. The foundation can easily be held just off the sea bed to ensure accurate placement. Once the GBS has settled on the sea bed in the desired position it is fully ballasted with sea water. Seabed preparation is generally not necessary and several structures exist using the technology applied in this application. If scour protection is required following installation then, this can be provided with rock dump/scour mats or artificial seaweed. At this point, the installed WTG, tower and foundation are secure. Subsequent operations may follow on immediately or can be implemented later in accordance with overall wind farm planning. From now on all tie-in and commissioning work attaching the WTG to the grid is carried out from the work platform at the top of the sub-structure tower (approximately 10 metres above MSL) with vessel support. Temporary power when unmanned is supplied from a generator/battery to support navigation, aircraft warning and tower internal lights when manned. Redeployment The removal and redeployment process is essentially the reverse of installation. Decommissioning costs are therefore relatively light. Furthermore, the ease of removal offers the opportunity to implement major repairs or refit/modernisation can be implemented inshore at lower cost and greater flexibility. Patented techniques permit easy and safe deballasting. Typical Specification WTG Size- Water Depth - Central Column height- Foundation Base - Caisson Diameter- 6.2 MW 60m Maximum 10m above Mean Sea Level (MSL) 55m outer diameter 22m 9

10 About Ocean Energy & Resource Ltd Ocean Energy & Resource Ltd (Ocean) has gained unsurpassed experience in subsea and ocean engineering worldwide, providing a wide range of complex and innovative engineering to the offshore petrochemical, energy and defence industries building, installing, maintaining and operating these systems on a turnkey basis. Ocean understands the issues in building offshore wind farms and know that the designs offered on these pages, when utilised will completely re-write the accepted economics of developing, commissioning and operating a wind farm. We offer simple innovative and radical solutions to the complex issues involved, driving maximum cost efficiency in construction, servicing, maintenance and ultimately disposal. The purpose of Ocean s offshore energy products is to completely Re-Engineer the economics of offshore wind energy. Ocean s products have the potential to generate enormous additional profits for the power companies that deploy them because in the first instance they drastically reduce the installation and near term costs of establishing wind farms. Ocean understands that offshore wind energy quickly needs profitability without subsidy to garner public support and be fully sustainable. Ocean s products will also generate and deliver their power far more cost effectively over the medium and long terms, prolonging the useful life and ongoing viability through much cheaper servicing and maintenance, thus ensuring that the operator, consumer and taxpayer receives the best possible value and maximum sustainability of supply. Telephone: +44 (0) info@oceanresource.co.uk 2018 Ocean Energy & Resource Ltd Note: Sea Breeze is subject to patents and copyright wholly owned or controlled by Ocean Energy & Resource Ltd and Mr David Bone, Inventor. 10