There is a strong case for putting the cables underground.
When we tell people about this overground cable route almost the first question we get asked is "Why can't they put them underground?" or "I thought they put them underground these days". It seems such an obvious thing to do. We have raised this with National Grid. They say that the cable will be a combination of overground and underground, however, typically there will only be about 5% of the total length underground. The assumption is that the cable will be on pylons unless there is a very good reason to put it underground.
Pylons are 1920's technology and are not fit for the 21st Century. This powerline will be with us for many years and National Grid should be installing an infrastructure which is up to date and efficient. There are established modern technologies such as Gas Insulated Lines (GIL) and High Voltage DC (HVDC) which could be used. National Grid already have a project to install 40km of underground cable across the Wirral using HVDC.
Comparing the Costs
In order to finance the project National Grid raise money by various means. It is not given money by the government. Ultimately the cost is covered by the Electricity Bills.
National Grid say that it costs 12-17 times more to put the powerline underground, however this is a rule of thumb and not specific to this project. This figure only takes into account the capital cost and not the lifetime cost. National Grid admit that if you look at the lifetime cost then the ratio is much less although undergrounding is still more expensive. But the effect on your electricity bill is very small. The figure also does not take into account the cost to the local economy when pylons are put through an area.
When National Grid carry out the initial study they make an assumption that the powerline will go overground so all the corridors put forward are based on that assumption. We think that when the initial study is carried out they should include an option which looks at a corridor which is optimised for undergrounding rather than overgrounding. If you don't do that then the cost comparison is not valid because they are taking a corridor which is optimised for overground and then comparing the cost of the same corridor put underground. They should compare it with a corridor optimised for underground.
The consultancy KEMA and the Institution of Engineering Technology (IET) are due to publish a report on the comparative costs of overground and underground. The report was due to be published in March 2011 but it has been delayed and no date has been put forward for it's release. As a consequence National Grid have extended the deadline on their consultation.
They are doing it in Denmark. Why not here? Here is an extract from a website (http://www.europacable.com) for European cable manufacturers which shows much lower costs than National Grid are quoting.
Case Study 1: Use of Cables in Areas of Outstanding Natural Beauty
The Denmark Aalborg - Aarhus line/cable is a classic example of the use of cables to protect areas of outstanding natural beauty.
To reinforce the 400kV network in the western part of Denmark, Eltra built a 140km link between Aalborg and Aarhus. The line, with a capacity of 1200MW, is mainly overhead but is buried in three sections in areas considered to be of scenic or ecological interest:
- Southwest of Aalborg, a 7km section was put underground in an urban area but also one of historical significance.
- Further south, the 150kV overhead line that crosses the Mariager Fjord was dismantled and 2.5km of 400kV and 150kV cable was laid.
- Still further south, a 4.5km section passing through the Gudena Valley was placed underground as OHL was not considered appropriate through a picturesque area of lakes and wooded hills.
The cables used were aluminium with a conductor size of 1200 m2 and were arranged in a double circuit in a trench at a depth of at least 1.2 meters.
The total cost of the project was around €140m. The underground part represents about 10% of the total length and is estimated to have cost €35m (25% of the total). The project took 11 years of political negotiations, but only one year to engineer and two years to construct.
National Grid are deliberately misleading people about putting the cables underground :
They say - The land under which the cables runs is sterile and cannot be used for farming.
We say - This is rubbish. There is a restriction on deep ploughing but the land can be readily used for grazing livestock.
They say -The additional cost of burying the cables will mean higher taxes.
We say - This is wrong. The extra cost of burying the cables will be met by all electricity users and the additional profits they make will go to shareholders. They don't take into account of the cost to the local economy due to loss of income from tourists, visitors and walkers who come here to enjoy the countryside.
They say - It is easier to maintain powerlines which are on pylons.
We say - Cables on pylons need far more maintenance and break down more often because they are exposed to the elements. Underground cables need very little maintenance and break down rarely.