Electricity Grid

The UK grid was planned and laid out in an era of coal and gas fired power stations. This was usually in a radial hub and spoke arrangement with central power production delivered out to the periphery. This was very evident in Scotland where power stations were situated in the industrial and high population density areas in the Central Belt and East Coast. Transmission and distribution networks then fed this power out to more rural and remote areas including the Scottish Islands.

Today the rise of renewable power, and of offshore wind in particular, has turned this situation completely on its head. Most of the best wind resources are on the periphery and, away from the East Coast area, mostly in areas of low population density. In order to service this new paradigm we need to design grid infrastrure that will bring electricity from offshore wind farms to the centres of demand in the UK.

Government and industry are now working together to solve this new challenge and repurpose the UK grid infrastructure for the 21st Century. In 2020 the Department for Business, Energy and Industrial Strategy (BEIS) launched the Offshore Transmission Network Review (OTNR). This has now resulted in the Holistic Network Design (HND July 22) which is aimed at adding 23GW of offshore wind to the UK system by 2030, 12.5GW of which is in Scotland.           

Scotland has been a major exporter of energy for decades. Not just from its oil and gas fields of the last 50 years but by also exporting power from its onshore wind and hydro power facilities during peak periods. Scotland's ability to export green power is about to increase exponentially over the next 10 years with almost 50GW of wind power in its project pipeline. The bulk of this new production, 38GW, will come from offshore wind.

Holistic Network Design

The HND project consists of both onshore and offshore upgrades and extensions. It includes HVAC and HVDC elements as well as multi-terminal HVDC systems. The list of Scottish projects in scope for HND is set out below and although we await a Detailed Network Design (DND) as a follow up to HND this list represents the ScotWind projects most likely to connect to the grid before 2030. A further HND report is already underway and is due to be published before the end of 2023. It will look at adding all the remaining ScotWind projects, along with some INTOG projects, to the system. 

Please note that the HND is not proposing to connect the full capacity of some of the above projects but just their initial phases as shown in the capacity figures in the list.  

The map below shows the position of all the offshore wind projects in the list, the newly proposed 1.8GW HVDC Western Isles link along with the HVDC Shetland link which is currently under construction. The four proposed HVDC Eastern Links are also numbered on the map. 

These are:

Eastern Green Link 1 – Braxton to Hawthorn Pit

Eastern Green Link 2 – Peterhead to Drax

Eastern Green Link 3 – Fife to South Humber

Eastern Green Link 4 – Peterhead to South Humber

With an overall cost estimate of between £6.5bn-£8.5bn, these links will help speed up the delivery of other ScotWind projects.