ENERGY: UNDERGROUND POWER CABLE OPTION UNDER THE MICROSCOPE.
Pros and cons.
Apart from having a zero visual impact, unlike overhead lines, which are much disliked by environmentalists, they also need less land and lower maintenance, particularly in wooded regions. Underground cables are impervious to weather conditions, which is a key factor to bear in mind in the wake of the terrible storms that roared through France and Northern Europe back in December 1999, bringing down many overhead power cables in their wake. Most European countries have undertaken to underground two-thirds of their low- (200-400 V) and medium-voltage (10-50 kV) networks. The likes of Germany and France are pulling out all the stops to reach an acceptable threshold. The Netherlands is aiming for 100%.
As for high-voltage cables (60-150 kV) and extra-high-voltage (220-400 kV) cables, solely four countries have reached levels of between 10 and 20% in terms of high voltage and 2% on average for 220-300 kV and 0.5% for 380-400 kV. The higher the voltage, the more expensive it is to underground the cables: from two to 25 times the price of an overhead line. Up to now, this option has been adopted solely to cross urban areas or because it was the sole technical solution available. However, with the advent of the EU internal market for electricity, the situation could well change. Inter-country trade is set to grow, making it possible for undergrounding to become cost-effective in macroeconomic terms.
Another advantage lies in lower maintenance costs, with the average rate of failures said to be 0.072/100km/year, compared with 0.170 for overhead lines. Plus the fact that underground cables last longer and are better able to deal with overloads, which depends on the ambient air temperature and wind speed in the case of overhead lines. They are generally used up to 40% of their capacity owing to weather conditions, a factor not encountered with underground cables. The downside, apart from the price, is that it takes longer to correct failures (two to 25 times longer, depending on the sources). As for health risks, the report does not go into much detail, but points to the lack of any electrical field above the cable and a magnetic field above trenches that is higher than for overhead lines, but still below European thresholds.
No European action seems to be required for undergrounding low- and medium-voltage cables, but the European Commission believes EU-wide measures could be on the cards for high-voltage lines, with it being up to the Member States to decide the optimum grounding level, in the light of a cost/benefit analysis. As for priority European projects, the Commission refers to the scope offered by underground cables, with an economic demonstration into the bargain, to counter the opposition to the Franco-Italian interconnection projects. As for Spain, a submarine cable is too expensive and an overhead line is, unfortunately, the best solution. As for the other priority routes, the Commission takes stock of the progress made with interconnections, where undergrounding could play a role. The report also makes a detailed country-by-country review of the situation for underground power cables, as well as a global series of projects underway for undergrounding high or very high-voltage cables, including certain European projects. An annex is used to make a survey of the various technologies used, and how they affect the costs.
|Printer friendly Cite/link Email Feedback|
|Date:||Jan 31, 2004|
|Previous Article:||GREEN LIGHT FOR EU TO SIGN INTERNATIONAL TREATY ON PLANT GENETIC RESOURCES.|
|Next Article:||EESC URGES MORE SUPPORT FOR RENEWABLE ENERGY.|