To achieve the lowest ever price for offshore wind (£39.65/MWh) when it won in the UK's third Contract for Difference auction, the Sofia team drew on RWE's long-term offshore wind heritage and expertise, capitalised on technological and other value opportunities and worked closely with potential supply chain partners.
The project continues to innovate by enabling new technology, capitalising on value opportunities, through its close relationships with suppliers and as part of our ongoing consents activity.
Sofia was the first project in the world to commit to a state-of-the-art 14MW wind turbine when it was still in its early development stage. This article provides a background as to how innovative turbine design can reduce the cost of energy.
Sofia will also feature recyclable blades, at the time the order was placed with Siemens Gamesa, this was the world's largest order of such blades, which feature a specialist resin that facilitates the recyclability. It also paved the way for more a more sustainable offshore wind sector globally.
To maximise the wind farm’s export capacity, the project pushed the high voltage direct current technology with voltage source converters to 1320MW, along with the associated increase in grid connection, up from the originally planned 1000MW.
Planning for the construction of what will be – at the time its built - the world’s longest export cable (220 kilometres) in challenging ground conditions - required complex engineering solutions.
The challenges in planning a wind farm located 195 kilometres from shore and on a site the size of the Isle of Man called for cutting edge design and innovation at every stage of development.
Sofia will be the first offshore wind farm to use the world’s most advanced cable laying vessel – Leonardo da Vinci. The vessel features include: the highest carousel capacity in the market; double industry average capstan capacity; DP3 system; hybrid propulsion; 90-day operational autonomy and will be able to carry out deepest power cable installations of up to 3,000 metres.
For its onshore HVDC cable, Sofia will use a new 100 percent recyclable, eco-sustainable, high-performance cable technology based on a patented thermoplastic material - High Performance Thermoplastic Elastomer (HPTE) - and on a zero-emission process that reduces CO2 emissions by 40 percent.
Sofia will utilise a purpose-built service operations vessel (SOV) for the operations and maintenance phase.
Onshore civil engineering contractor JMS has utilised a number of innovative construction techniques including:
V-buckets - a bespoke design that reduces excavation time and number of times machinery is required to pass along a trench.
Duct trailer - which removes the need for personnel to be in the trench during the duct installation, reducing the number of passes along the trench and also the risk of accidents.
Sand cart – another evolving innovation, which reduces the amount of time personnel are required to be in the trench during cement bound sand installation.
The Sofia team developed the most cutting edge, heavily optimised array layout to maximise the wind farm’s energy generation capability.
The design of the offshore converter platform was considerably slimmed down, compared to those previously built in Germany, saving on materials and costs.
Through working jointly with the neighbouring Dogger Bank project, both Sofia and Dogger Bank C are on track to achieve mutually beneficial technical, engineering and cost advantages.
Using a holistic approach to procurement and leveraging our offshore wind experience, the team worked closely with its potential supply chain partners throughout the pre-tender phase to calculate the most economic way to allocate risk.
The approach enabled us to line up our contracting models, ensuring the lowest overall project cost. This was achieved within our lean development budget but still enabled us to achieve our record breaking levelized cost of energy.
The integration of both light detection and ranging (LiDAR) and traditional digital aerial surveys to measure seabird flight heights offshore. LiDAR is an established technology but the application to ornithology monitoring is both novel and pioneering for pre-construction surveys. Read all about it here.
Proposing the use of low order deflagration as the preferred method of UXO clearance. This essentially ‘burns’ out existing explosives and avoids the need for a high order detonation. It potentially has cost/time benefits as well as reducing underwater noise impacts to marine mammals and fish.
RWE is involved in strategic environmental forums, such as ORJIP II and OWSMRF which seek to identify high priority knowledge gaps to reduce consenting risk.
