Offshore grid development

Power transmission via subsea cables aims to interconnect terrestrial grids, to supply power to offshore facilities or to feed power supplied from offshore renewable sources, such as wind, wave and tidal energy into terrestrial grids. The development of subsea interconnectors enables the trading of power between different countries, provides a means to share the use of renewable energy and storage options, and increases the security of electricity supply.

Presently, there are operational interconnectors with a transmission capacity of more than 15 GW in the European seas. According to the ENTSO-E’s Ten-Year Network Development Plan 2014, by 2030, some 20.000 km of new subsea cables are needed, for an estimated investment cost of €50 billion. Among these projects, the European Commission has identified numerous projects of common interest that, as such, may benefit from accelerated licensing procedures, improved regulatory conditions, and access to financial support. This represents an overall additional transmission capacity of more than 20 GW for the next 10 years.

The environmental effects associated with subsea cables are disturbance, underwater noise, heat dissipation, electromagnetic fields and contamination. They can occur during the laying, operation and/or removal of the cables.

The challenges to assess and understand the effects of subsea cables on the marine environment as well as the possible cumulative effects are real for permitting bodies, developers, investors and environmental protection organisations. There are uncertainties due to knowledge gaps that need to be filled e.g. by collecting relevant environmental data and making them available to authorities and practitioners across borders.

RGI intends to better understand the effects of subsea cables on the marine environment, identify key environmental information and possible knowledge gaps. RGI is also willing to explore the possibilities of using the grid infrastructure to raise environmental data that may contribute to closing knowledge gaps and supporting permitting procedures and environmental protection.


Cristina Simioli
Director - Offshore Energy and Nature

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RGI gratefully acknowledges the EU LIFE funding support:

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Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the LIFE Programme. Neither the European Union nor the granting authority can be held responsible for them.