Written Question · S2W-10114 · Session 2
What research it has carried out, and what information it has, on the cost differentials between overland and underground high voltage tran…
The question
To ask the Scottish Executive what research it has carried out, and what information it has, on the cost differentials between overland and underground high voltage transmission lines for wind farm output.
The answer
The Scottish Executive has carried out no specific research into the cost differentials between overhead and underground high voltage electricity transmission lines. However, in December 2003 a report to the European Commission entitled Undergrounding Electricity Lines in Europe reported the following cost differential factors in European countries :
| Construction Cost Factor for Undergrounding at 380/400 kV
Austria
| 8
Denmark
| 7.2
France (rural)
| 10
Italy
| 5.9
Norway
| 6.5
UK (National Grid)
| 15-25
Costs are subject to many variable factors including the technology employed and the nature of terrain involved. The report suggested that a construction cost factor of 15 for a 400 kilovolt underground line could reduce to 7-12 owing to lower operational costs over its lifetime. It was also estimated that undergrounding 25% of the high voltage and extra high voltage network in the UK would increase the cost of electricity by 3-5%.
| Construction Cost Factor for Undergrounding at 380/400 kV
Austria
| 8
Denmark
| 7.2
France (rural)
| 10
Italy
| 5.9
Norway
| 6.5
UK (National Grid)
| 15-25
Costs are subject to many variable factors including the technology employed and the nature of terrain involved. The report suggested that a construction cost factor of 15 for a 400 kilovolt underground line could reduce to 7-12 owing to lower operational costs over its lifetime. It was also estimated that undergrounding 25% of the high voltage and extra high voltage network in the UK would increase the cost of electricity by 3-5%.
In the Official Report
No contribution in the Official Report cites S2W-10114 by reference.