by Jerome a Paris
Wed Apr 13th, 2011 at 07:20:25 AM EST
A lot of what we hear about the supergrid is hype, but some progress is made on actual new infrastructure which makes sense:
BritNed power cable boosts hopes for European supergrid
It stretches 260km under the North Sea, contains 23,000 tonnes of copper and lead, and may represent the first step towards a renewable energy revolution based on a European electricity "supergrid". The £500m BritNed cable, which has just entered operation, is the first direct current electricity link from the UK to another country in 25 years.
The high voltage cable, a joint venture between the UK National Grid and the Dutch grid operator TenneT, has a capacity of 1,000MW, the equivalent of a nuclear power station. It runs from the Isle of Grain in Kent to Maasvlakte, near Rotterdam, in the Netherlands.
The hype, mainly, is about a grid that would connect offshore wind farms to one another in the North Sea in a sort of "offshore superhighway" - that makes no sense. What projects need is not a connection to each other, but a connection to the main grid. And given that each offshore wind project nowadays are 500MW or more, they basically each need their own cable to the grid (or, as in Germany, to special transformer platforms near the coasts which are then connected to the main grid via cables of even larger capacity).
What does make sense in terms of the overall grid is more connections between the semi-separate parts of the grid - connecting the UK, or Spain, or Italy, or Scandinavia, which are each to various degrees electricity "islands" (or peninsulas) off the main continental grid will have a lot of value, by allowing power to be managed over a large resource base. Shortfalls or surpluses in one area can more easily be managed if that area is well connected to other areas. On land, big transmission projects have been blocked - even more than generation projects - by local protests and it is really hard to build new high-voltage lines. The long planned second France-Spain line was finally authorised when it was decided to build it underground rather than above ground, something which more than doubled its cost.
Offshore power lines are much easier to permit, and allow to connect new parts of the grid together (bringing Icleandic geothermal or Norvegian hydro into the European mix, for instance), so they have a lot of value - but at the grid level, not on an individual project level. So the "supergrid" will not help offshore wind projects get built, but it will help improve the overall reliability of the power grid and facilitate the integration at a lower cost of various power sources in different places, including of course offshore wind.