OCEAN BREEZE Ocean Breeze is a Deeper Water Wind turbine Foundation System for The Largest Wind Turbine Towers Sited in Waters up to 200m Ocean Energy & Resource Ltd 1
OCEAN BREEZE Ocean Breeze is designed in every aspect by Ocean to save its owners and operators money. Ocean Breeze is vastly cheaper to manufacture and deploy than comparable systems, but more than that its simple design philosophy offers huge flexibility in operation and location. Ocean Breeze 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 re deployed or recovered back to shore for refit thus also maximizing economical service life. Ocean Energy & Resource Ltd Castlegate Business Park Portskewett Caldicot NP26 5AD United Kingdom Telephone: +44 (0)1291 40 80 88 Email: info@oceanresource.co.uk 2018 Ocean Energy & Resource Ltd Note: Ocean Breeze is subject to patents and copyright wholly owned or controlled by Ocean Energy & Resource Ltd and David Bone, Inventor. 2
Contents Introduction Page 03 Description... Page 03 Production... Page 07 Installation... Page 07 Re-Deployment... Page 08 Specification... Page 08 About Ocean... Page 09 3
Introduction Ocean Breeze is a deeper water wind turbine foundation system for the largest wind turbine towers sited in waters between 60metres and 200 metres deep, designed for low cost series production using pre fabrication assembly line methods. Ocean Breeze uses a concrete and steel cellular Floating Gravity Base tethering a buoyant steel hull structure below the ocean surface to support the Wind Turbine above. The gravity base is a rectangular, cellular reinforced concrete structure, comprising several separate ballast compartments. It is designed to sit on the sea bed and to resist the lateral forces imposed upon it by the buoyant structure and WTG above. The buoyant hull and turbine support structure consists of four independent steel watertight tanks linked to a central turbine support column through a truss system. The structure is designed to remain well below the surface with only the turbine column protruding above the surface, minimising wave loading and fatigue. Design Philosophy Ocean adopted a problem-led approach to firstly create a holistically designed structure from top to base specifically to overcome the fatigue and corrosion issues plaguing the meteorological masts currently employed offshore by the wind industry. Ocean Breeze has a design life of 25 years. Secondly, Ocean has designed from the start on the basis that flexibility of location and the ability to easily and cheaply relocate meteorological masts is paramount to wind farm developers to ensure that they can maximise the design, density and size of any potential wind farm zone. Thirdly, Ocean acknowledged that Ocean Breeze must be easily deployable and recoverable with nothing more than standard offshore tugs in order to offer wind farm developers both the flexibility of very short lead times for deployment and re location and remove the current cost impediments of doing so. It is expected that by utilising Ocean Breeze, wind farm developers can not only install and commission deepwater wind farms more cheaply than they are currently doing so with traditional jackets and plies inshore, but that large scale arrays can be commissioned in a single season through the use of mass production and expedited installation and commissioning procedures. 4
Description Ocean Breeze uses a buoyant hull and wind turbine support structure consisting of four large watertight buoyancy chambers at each corner, interconnected by a lattice framework with a central wind turbine support column. The buoyant hull is designed to remain well below the breaking waves to reduce fatigue damage. The turbine support column is also watertight and terminates above the waterline with a flange designed to match the desired WTG column. Landing platform and access decks are provided to allow boarding from a boat. The Ocean Breeze buoyant structure is attached to its gravity base through high strength multiple tether cables anchored into the foundation through force dissipating outriggers. Each tether is attached at each buoyancy chamber to the foundation through a pair of cables. Each tether is easily capable on its own of withstanding any load the buoy could place upon it introducing redundancy and minimising risk. Each tether comprises a spiral steel bridge strand wire, galvanised and sheathed in high density polypropylene for corrosion protection. The exterior of each tether has a silicon based antifouling coating to reduce marine growth. On the buoy these tether cables are attached through fabricated universal joints with low friction bearing surfaces to outriggers. The tether system is designed to eliminate any bending forces upon the Structure. This arrangement of tension legs is the most stable for a floating WTG platform and Ocean Breeze offers this in the industry s lowest cost package. 5
6
Foundation The Ocean Breeze buoy is attached to a Gravity Buoyant Structure (GBS) through tether cables anchored into the foundation through force dissipating outriggers. Each tether comprises a spiral steel bridge strand wire, galvanised and sheathed in high density polypropylene for corrosion protection. The exterior of each tether has a silicon based antifouling coating to reduce marine growth. On the buoy these tether cables are attached through fabricated universal joints with low friction bearing surfaces to outriggers positioned below the ocean surface. The concrete Gravity Buoyant Structure (GBS) typically comprises a rectangular multi-cellular hollow reinforced concrete structure of proven design. It is self-floating and when de-ballasted its inherent buoyancy is used to aid towage and installation. No specialised vessels or heavy-lift facilities are required during installation hence reducing costs whilst also increasing project flexibility. During sea tow and installation, the GBS and sealed tubular hull provide buoyancy and are designed to withstand the environmental forces of towage and the hydrostatic pressure of submerging to up to 60m. The buoyancy is augmented by additional temporary buoyancy which is provided to aid installation. Typical GBS 7
8
When it is installed at its operating location, the GBS s function is to maintain the stability of the mast by providing a fixed support structure for the mast without the need for expensive piling. The gravity base is inherently very strong obviating the need for reserve buoyancy during towage. Once the floating gravity base structure is in position, the cell groups are ballasted with seawater through ballasting pipes cast into the gravity base itself. The ballasting process is controlled through an equalising system to ensure even distribution of seawater throughout all cell groups. The installation procedure can be reversed by pumping air in to the air vent pipes, also located on the gravity base top slab at any time. A watertight manhole located at the top of each cell provides access for inspections and during construction. In general no sea bed preparation is required. The submerged weight of the gravity base and the applied loadings are transferred to the seabed soil foundation via footpads set in the underside of the gravity base. These pads can be tailored to meet a specific site s characteristics in relation to level or other seabed conditions (i.e. cohesion free or cohesive soil, silt etc.). The GBS is free draining to stop any liquefaction of poor soils from hydrodynamically induced pressures, and if required a steel skirt can be attached to the outside perimeter of the gravity base that will penetrate into the foundation soil to provide better lateral resistance and a level of scour protection. Where soil conditions are very poor the skirt can also be designed as a suction pile. Any erosion would be considered on a site by site basis, but will be mitigated if necessary through the use of artificial seaweed or a small rock dump. Fabrication & Assembly Ocean Breeze will be constructed using assembly line mass production techniques typically sited on or close to a quayside or dock area. Components for the system will be delivered by truck or ship and likewise all other components for the complete wind turbine generator will be pre fabricated off site and delivered in for final assembly once the buoyant structure is floated off on to a water borne moving production line within the dock or along the quayside. The foundation will also be assembled on a quayside or simple slipway to a dock into which it will be launched once complete. This same dock will be used for the delivery by ship of turbine towers, nacelles and blades. A permanent onshore crane will be used for both unloading of components and commissioning. Once the buoyant structure is floating in the dock, the turbine tower will be lifted and fixed into place, followed by the nacelle. Finally the blades will be attached and the whole turbine unit can be fully tested 9
in situ in the dock ready for deployment as a complete unit that simply needs connecting to the grid once anchored at its location.. Ocean Breeze is designed to be much simpler and cheaper to commission than traditional offshore masts, with all of the Wind Turbine Generator commissioning work taking place onshore. Two stage installation. The Gravity Buoyant Structure (GBS) foundation base is launched and towed out using two basic offshore tugs. Once on location, the cell groups are ballasted with seawater through ballasting pipes cast into the top slab of the gravity base. The ballasting process is controlled through an equalising system to ensure even distribution of seawater throughout all cell groups. Pumping air in to the air vent pipes, also located on the gravity base top slab can reverse this procedure at any time. An airtight manhole located at the top of each cell provides access for inspections and during construction. The submerged weight of the gravity base is transferred to the seabed soil foundation via patented footpads set at the corners of the gravity base each tailored to meet a specific site s characteristics in relation to level. If required, a steel skirt attached to the outside perimeter of the gravity base will also penetrate into the foundation soil to provide better lateral resistance and a level of scour protection. (2) The buoyant structure is then towed into position and drawn below the surface by winching cables connected to a pad eye on the foundation. The tethers are then connected and allowed to take the 10
loads from the buoyant structure in an operation lasting only a few hours. The tower is then safe and ready for the transmission cable to be connected to a Sea Node substation. This rapid process using only standard tugs needs only two eight hour weather windows for completion, considerably raising efficiency and slashing installation costs by some 90%. Ocean Breeze is designed to be much simpler and cheaper to commission than traditional offshore masts, with over 80% of the commissioning work taking place onshore. Re Deployment Ocean Breeze is designed so that the buoyant structure and its wind turbine can easily be recovered back to shore for major maintenance or refits. The process is just as quick and simple again only requiring standard tugs, but works in reverse, The buoyant structure is simply detached from its tethers and towed back in to shore for servicing, whilst a fully serviceable replacement could be immediately attached in its place. 11
Specification Nacelle Height- 72m Rotor Ø - 90 to 100 Water Depth- 60m plus Wave Height- 20m Floating Structure Steel Weight- Overall Diameter- Tower Height (above MSL) - Operating Draft- Buoyant Chamber- 702 tonnes 40.5 metres 72.75 metres 60-200+ metres 4 X s Ø 8 metres Gravity Base Structure Overall Dimensions- 44m x 44m x 3.5m Weight:- 2000 tonnes approx. Tether System Each Outrigger- UBS- Multiple Galvanised Wire Ropes 1200 tonnes per Tether Assembly 12
Our Partners Interserve 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. We have a progressive approach, working in true partnership and forming long - term relationships with our clients and supply chain through each stage of the project life cycle. Our SeaBreeze Joint Venture with Interserve and Shepherd Offshore is driving down the cost of offshore wind energy. www.interserve.com In addition Interserve's specialist business RMD Kwikform is a global leader in formwork, falsework and associated safety and access equipment. These systems, all created by our 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 our customers that can be measured such as lowest in-use cost and reduced construction cycles. RMD Kwikform are partners in the SeaBreeze JV, providing expert knowledge on pre-cast concrete construction. www.rmdkwikform.com 13
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)1291 40 80 88 Email: info@oceanresource.co.uk 2018 Ocean Energy & Resource Ltd Note: Ocean Breeze is subject to patents and copyright wholly owned or controlled by Ocean Energy & Resource Ltd and David Bone, Inventor. 14