Concrete Gravity Base Development for Offshore Wind Cost Reduction

Concrete gravity bases have an important role to play in the technical developments that will enable reduced costs of energy from UK offshore wind farms.  The new report ‘Offshore Wind Cost Reduction Pathways: Technology Work Stream’ commissioned by The Crown Estate and undertaken by consultants BVG Associates states: “Large CGBs [Concrete Gravity Bases] have been widely used in the oil and gas industry and in bridge construction” and “They are also far less affected by fluctuations in the cost of steel than other foundation types and require minimal lifetime maintenance.”

The report comes at a time when the offshore wind industry is developing innovative solutions to facilitate extensive projects located further from shore in deeper water and in harsher conditions than ever before. The report advises that the cost reductions sought by Government will be delivered through technological developments but only if there is sufficient scale of construction.

The concrete sector has welcomed the report. In particular it is encouraged by the long-term investment commitment shown towards offshore wind energy and by recognition of the role that concrete gravity bases can play in realising the cost reductions that are envisaged. “Concrete gravity bases will help deliver cost reductions for the construction, installation and operation of offshore wind farms and so enable wind energy to play a central role in the provision of cost efficient sustainable energy,” said Andrew Minson, Executive Director of MPA The Concrete Centre. “More extensive use of concrete gravity bases will realise further cost reductions as well as increase the benefit to the UK economy through the use of local materials and local labour for UK production.”

The BVG report states “CGBs offer an alternative foundation system for sites where the piling noise would have an unacceptable impact on local wildlife.” The elimination of piling noise during installation is one of the major benefits of concrete gravity bases as the impact of noise on wildlife could lead to planning conditions being applied resulting in project delays and increased costs. With this in mind, including concrete gravity bases as an option through the planning process is prudent for developers. 

The concrete sector, led by MPA The Concrete Centre, has established a working group specifically to enable the development of a supply chain to deliver cost efficient concrete gravity bases for offshore windfarms. Members who offer a complete foundation solution are now in discussion with the developers for the Round 3 sites.

Significantly, all the major materials for concrete gravity bases can be locally sourced from within the UK. Aggregates, cement and steel reinforcing bars are readily available and the quantities required, even at the time of peak demand, are well within existing industry capacity.

Ref: TCC774