It wasn’t that long ago that the ideal of transmitting electricity long distances was limited to 100 miles or so making the need for electricity production to be close to the user base. With the advent of offshore wind in Europe in particular and advances in HVDC technology in general the number of long haul offshore transmission projects is growing rapidly.
Two excellent examples of this are the Western Link in the UK and the Maritime Link in Canada.
The Western Link project involves constructing a high voltage direct current cable that will help to bring large amounts of renewable energy from Scotland to homes and businesses in England and Wales. The amount of renewable energy being generated in Scotland is increasing rapidly, but this cannot be transferred south because the existing electricity links are running at full capacity. A new link is needed and traditional overhead corridors of high voltage are next to impossible to permit any more, so the out of site, out of mind marine alternative was chosen. Western Link is owned by National Grid and Scottish Power Transmission being developed by Siemens and Prysmian and once completed will have a transmission capacity of around 2,200MW and a length of almost 400 kilometers.
In July 2014 ABB was awarded a contract valued at approximately $400 million from NSP Maritime Link Inc., a subsidiary of Emera Inc., to supply a high-voltage direct current (HVDC) power transmission solution creating the first electricity link between the island of Newfoundland and the North American power grid.
When operational, the Maritime Link will have a transmission capacity of 500MW at a length of over 180 kilometers and be used primarily to bring Hydroelectric power from the Lower Churchill project now being constructed in Labrador to the North American grid.
The combination of growth in offshore renewable energy, the constant need for transmission investment, the difficulty of permitting overhead systems generally along with advances in long-distance transmission is resulting in real projects being build today.