An undersea cable that will enable Scottish renewable energy to be distributed around the UK is viable, according to a new study by The Crown Estate.

The findings, revealed in the report East Coast Transmission Network: Technical Feasibility Study as the Scottish Parliament holds a debate on energy, confirm the technological and economical feasibility of an offshore east coast transmission line to take electricity from as far north as Shetland to the south east of the UK, with the potential to connect to the rest of Europe. Further studies will now be conducted.

In response to the growing demand for sustainable sources of clean fuel and to help overcome difficulties in providing land-based transmission lines, The Crown Estate last year began looking into the practicality of a high-capacity offshore electricity line to run down the east coast from Shetland down to Norfolk then coming onshore to continue to London. In February 2007, consultants Econnect were commissioned to examine the technological feasibility and the capital costs of the project.

The report concludes that such a project could indeed be a success and would allow new renewables projects to connect to the national grid: "An offshore network along the east coast of Great Britain linking in Shetland and Orkney is technically feasible utilising VSC HVDC technology," the report states. However, there would still need to be reinforcements carried out to the onshore transmission network.

The Scottish government last week identified grid reinforcements to support renewable energy development as a potential national development priority in the National Planning Framework which is currently out for consultation.

Alasdair Rankin, head of Marine Business Development Scotland at The Crown Estate, said: “We recognise Scotland’s massive natural renewable energy resource, which has the potential to be very valuable for Scotland. However, connection to the national grid is crucial to the long-term viability of the Scottish renewables industry, and improvements to the network are particularly important for green energy projects in the Highlands & Islands. As providing clean, sustainable energy climbs higher up the agenda, we at The Crown Estate are committed to supporting and nurturing the industry.”

Rob Hastings, director of the Marine Estate at The Crown Estate, said: “This report confirms that an undersea cable down the east coast is technologically and economically viable and we have now commissioned more detailed studies. The prospect of taking green energy right down the east coast to heavily populated areas in the south, and potentially to the rest of Europe, is incredibly exciting: today’s report brings that key infrastructural development one step closer.”

The report states that any such interconnector could transmit power from on and offshore generation, and should use Voltage Source Converter (VSC) High Voltage Direct Current (HVDC) technology because of its easier installation, flexibility and maintenance benefits:

"[This] technology . . . offers flexibility in terms of connectivity (i.e. it is suitable for a multi-terminal networks and can connect to weak points on AC systems), has a reduced conductor size (which eases subsea cable laying) and brings operational and system support benefits to the onshore AC system, such as instantly controllable power flow," the report says.

The core of the system would cost up to £1.7bn, with the total network costing around £4.8bn by 2020. The Stern Review of the economics of climate change in 2006 showed investment in clean energy can repay itself several times over, and this east coast connection could also form part of the European Supergrid proposal which is currently under consideration. The proposed network was designed around projections for substantial renewable generation off the coast of North Scotland, in the region of 5-10GW by 2020.