Our current portfolio of projects includes eleven Offshore Transmission Owner (OFTO) projects under management or at preferred bidder stage, three interconnector projects in development and four Grid Stability projects in development or under construction.

Offshore Transmission Owner (OFTO) Projects

Since 2009, Ofgem has run competitive tenders through which successful bidders can own and operate offshore transmission networks which connect offshore wind generation to the onshore power system.

The offshore transmission networks have to date been constructed by the offshore wind farm generators, and then transferred to the successful bidders shortly after commissioning.The offshore transmission networks usually comprise an onshore substation, one or more onshore and offshore high voltage export cables, and one or more offshore substations.

There have been more than 25 offshore transmission networks tendered to date.

Interconnector Projects

Since 2014 interconnector projects have been able to apply for Ofgem’s ‘Cap and Floor’ regulatory framework. This framework was developed by Ofgem to support interconnector developers and investors by providing a guaranteed minimum level of return. Ofgem continues to use Cap and Floor windows to support bringing forward further interconnector projects to help meet the UK Government’s Net Zero climate change targets.
Due to the distances involved in connecting between countries, electricity interconnectors predominantly utilise HVDC technology. This reduces the cost of operating the link and provides increased flexibility to support System Operators in ensuring supply and demand can always be balanced. HVDC interconnector assets usually comprise of two onshore converter stations connected by two sub-sea HVDC cables.

Grid Stability Services

Grid Stability Services (GSS) are services required by the GB System Operator to maintain voltage and frequency on the system and to manage system constraints. Some of these services have historically been provided by large coal, gas, and nuclear power plants, however, the energy transition is resulting in an increasing proportion of renewable generators on the system, which currently cannot provide these services.

The GB System Operator identified the need to introduce alternative service providers, who can provide Grid Stability Services separately from delivering real power, in a way that supports the zero-carbon ambition. The GB System Operator therefore launched NOA Pathfinder tenders, starting in 2019, to procure Grid Stability Services. The NOA Pathfinder tenders have now ended, and the GB System Operator is implementing enduring stability market arrangements.