A European Supergrid - Energy and Climate Change Contents

2  Background

What is a supergrid?

9.  The term "super grid" was first used to describe the unified British national electricity transmission system over fifty years ago. The concept of a UK supergrid is defined in the British Grid Code as a transmission system operating at voltages above 200 KW. In the 21st Century, however, the term "supergrid" is used to describe a number of different kinds of interconnection between international electricity systems, often incorporating generation assets as part of the system. In other words, the same transmission lines would connect up different countries' electricity systems as well as a variety of power generators such as offshore wind farms. Ideas range from a more integrated offshore grid in the North and Irish Seas to a network of "super highways" across Europe and into Africa and Asia.

10.  A supergrid was defined by the Friends of the Supergrid as an electricity transmission system, mainly based on high voltage direct current (HVDC), designed to facilitate large-scale sustainable power generation in remote areas for transmission to centres of consumption, one of whose fundamental attributes would be the enhancement of the market in electricity.[6] As well as enabling the transmission of electricity from areas of excess supply to where it is needed, a supergrid could also enable wider access to physical electricity storage options, such as pumped storage in Scandinavia and the Alps. This could help to balance out fluctuations in intermittent renewables supply with affordable, low-carbon generation.[7]

11.  Friends of the Supergrid have set out suggestions for Phase I of a supergrid, which would integrate the UK's offshore renewables resources with interconnection with Germany and Norway.

Figure 1: Friends of the Supergrid, Phase 1

Source: Ev 68 (Friends of the Supergrid), section 3

12.  A supergrid could represent a revolution in the scale and ambition of interconnection and offshore grid integration. At the moment, national electricity systems remain largely separate, each state providing for its own supply to meet demand. The UK is particularly insulated from its neighbours. A supergrid implies that a much greater degree of interconnection between national electricity systems would be possible, allowing them to draw on shared resources to meet demand. John Scott, of the Institute of Engineering and Technology, told us that whilst the UK currently had a 2 GW link with France, a 20 GW link could be possible.[8] He suggested that "you have to think of [a supergrid] as a system, not as a series of electrical pipes. It has to become a system, which means that it has to be balanced in real time between generation and demand". [9] In other words, a supergrid could be a complex transmission network, potentially coordinating dispatch and supply of electricity across several jurisdictions.

13.  However a supergrid is not just about increased interconnection, it is also about integrating offshore renewable generation into the transmission system in order to optimise the output of technologies like offshore wind, marine and tidal energy. At the moment, these resources are connected to the onshore system individually by "radial" or "point-to-point" connections.[10] A supergrid could integrate these connections into the transmission system itself, saving money, reducing the need for new connections and enabling more efficient sharing of resources.

14.  Stuart Cook, from Ofgem, explained that a supergrid could entail different mixes of interconnection and integration of offshore renewables within the transmission system:

The range of options that the transmission companies in Europe have looked at span from, at one end, something that simply is point-to-point, which is more or less the way that the system has evolved so far; to a system that involves optimisation of the onshore connection; to a system that involves the optimisation of the onshore connections and the interconnections across countries; to something that, at the extreme, is a meshed system looking like a grid on the sea.[11]

15.  In this Report, we will refer to an offshore grid, integrating renewable generation and interconnection, as a kind of "supergrid". Further details of the different visions for a supergrid currently under development can be found in Annex II.

6   Ev 68 (Friends of the Supergrid) Back

7   Ev 47 (DECC), section 17; Ev 56 (Ofgem), section 1.12 Back

8   Q 2 [John Scott]; Ev w32 (Centrica), section 14 Back

9   Q 2 Back

10   Q 1 [Eddie O'Connor] Back

11   Q 62 Back

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© Parliamentary copyright 2011
Prepared 22 September 2011