The qualities of Nexans superconducting cable as exhibited in the German city of Essen over the past two years have shown it to be an ideal fit for an urban setting, as indicated by growing interest from utilities worldwide.
Dietmar Steinbach, Director of Sales and Marketing at Nexans, spoke to Power Engineering International about what the cable can do for city centres, the integration of renewable power and the bottom line.
The Ampacity project has been serving Essen’s power grid since March of 2014 and features the world’s longest superconductor cable at 1 kilometre in length. The efficient and space-saving technology transports five times more electricity than conventional cables.
The medium voltage cable, at 10 kV, replaces the previous high voltage 110 kV cable yet transmits the same energy.
“The consequence of that for a large city centre like Essen is simple” Steinbach says. “For a 110 kV cable to transport energy you have to have a substation more or less the size of a garage. If you replace HV with medium voltage cable you can replace a big 110 kV substation with medium voltage switchgear.”
“The big advantage with superconductivity is we can save space in city centres- our target is these urban areas where there is a real advantage”.
It’s not just that characteristic which has caught the eye of city grid planners, always conscious of space and potential business disruption.
“In addition to lay a 110 kV cable or more parallel medium voltage cable in a city centre you need a lot of space on the cable route and it is very difficult to place a cable in a city – the superconducting cable is very compact with a reduced diameter design and a lower right of way requirement it can transmit the same energy as the HV cable so it also saves space on the cable route.”
With governments placing more and more emphasis on decarbonising cities and making them more efficient, the Essen Ampacity experiment is timely. While Nexans has demonstrated the superconductive cable in Greenfield sites and laboratories the German city is the first to be proven in an urban environment.
Steinbach says utilities are typically conservative and careful about moving forward on innovations, which makes the interest in its product all the more gratifying.
“They waited to see what was happening in Essen. Utilities calculate for 30 years or so but for most of the last two years no big problems or issues have arisen and it has been in continuous operation. Now we are seeing growing interest from other utilities and are at the moment in discussion with several – mainly in Germany but also across Europe and North America. We are close to signing a deal in North America and hope that will be concluded soon. TenneT has announced to install a demo project in the Netherlands in the near future. Now it is proven as reliable we can promote it more.”
Development of the cable started back in 2000 with an initial installation being the LIPA Project in New York City in 2006. Most of the cable is manufactured in Hannover, Germany with support from the Nexans Competence Centre for accessories in Calais, France.
It helps to have one of Germany’s top utilities championing cable’s merits.
A major promoter of Nexans’ technology is RWE- a key partner in the success. Earlier this year the companies decided to market and sell the concept of Ampacity together.
“The real benefit of this solution is the optimisation of the distribution grid in the city centre. And together we can create a system advantage. We combine our resources with RWE. Nexans are the systems supplier while RWE performs the integration of grid and networks and do the civil engineering and project management. Together with them we can offer a complete turnkey solution.”
“Ultimately using the experience of RWE in network design you can look at the network and recreate the advantage on a network system level.”
In tandem with the much-publicised cable the company also has as part of its range a superconducting fault current limiter, a device in tune with the growing demands being placed on the modern grid.
The device benefits by managing short circuits and can connect several grids together and is in that respect a new approach to grid design. Traditionally grids weren’t connected like that so if accidents or outages occurred only one grid would be impacted in isolation.
“Now with more and more renewable energy it is an advantage to mesh grids. That’s a direct and significant contribution to energy transition and the integration of renewables.”
While an official report has not yet been concluded on the overall impact of the Ampacity project, an initial study comparison between the conventional and superconductive cables indicated for capital and operational expenditure over a 40 year lifespan, Nexans product would have an advantage of almost 10 per cent.
Now that the technology is proven the next big challenge for the company is getting the word out and influencing the key decision makers.
“Stage 2 is about informing those designing grids about the beauty of the solution. We get the planners and technicians of the grid and relevant utilities aware and in the boat and they persuade governments of the merits of this technology.”
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