The weblog version of this message is at:
Due to a few transmission line controversies happening at the moment in Australia, New Zealand, Canada and elsewhere, I thought it was opportune to revisit an old message from June of 2005:
The Dutch Ministry of Housing, Spatial Planning and the Environment has set a precautionary policy by setting a 0.4 uT (4 mG) exposure limit for new transmission lines, and banning the construction of buildings and developments that would exposure people to prolonged magnetic fields of 0.4 uT.
In response, the Dutch utility Tennet, planning for the future, has designed a whole new generation of high voltage lines to meet the ministry’s requrements. Check out the link below and download a copy of Tennet’s pamphlet.
This is usefull news for those communities fighting the innappropriate siting of transmission lines through their communities.
From “Frans Holland”:
In The Netherlands the policy of the government now is not to build where the magnetic field is more than 400 nT. TenneT (the Transmission System Operator (TSO) in the Netherlands) has introduced a new high voltage system:
The magnetic fields by the Wintrack powerline system are decreased, because the lines are always six in a perfect circle (before, they were in triangles). The magnetic fields neutralize each other extensively. Moreover there are conductors in the ground, I don’t understand exactly how, I think they take stray fields away. Ask them: email@example.com
AND from TenneT:
TenneT and Holland Railconsult develop high voltage transmission line [HVTL] featuring reduced magnetic field intensity
June 18, 2005
TenneT in tandem with Holland Railconsult is delighted to present a new high voltage line concept featuring significantly reduced magnetic field intensity compared to existing lines. The innovative design, which has been named ‘Wintrack’, uses pylons that are largely to be made of plastic, with only a few metal components, as a key development in view of the planned adoption by the Dutch Ministry of Housing, Spatial Planning and the Environment of a more stringent ordinance which would result in the ban on new-build development in close proximity to existing high voltage lines being extended, for reasons of magnetic fields, to a greater area than is currently the case, as well as clamping down on the scope for construction of new lines. Application of the new standard to a standard 380kV line would imply a ban on new-build development along a strip of some 300 metres either side of the line, compared with only 75 metres if the Wintrack technology were applied.
The innovative features of the new Wintrack high voltage line with its substantially reduced magnetic field strength offer considerable perspective in densely populated areas where space is at a premium. Construction of new high voltage lines using the current state of the art would be significantly more costly if the Ministry´s more stringent standard had to be adhered to. Compared moreover with the alternative of constructing underground high voltage lines (cabling), the new Wintrack concept is considerably less expensive.
The new Wintrack pylons are quite a bit smaller and look considerably less intimidating than their traditional steel counterparts. Although they will cost more at the investment stage, a major benefit of plastic pylons will be their low maintenance requirement, which should enable cost savings to be made in the longer term as well as being more environmentally friendly. The reduced maintenance requirement moreover would enhance the reliability of supply, as the new lines would not need to be taken out of service due to maintenance work being carried out with the same frequency as is currently the case.
People are exposed to magnetic fields in all kinds of situations, for example when they use their electric shaver, hair dryer, microwave oven or PC. The potential impact of human exposure to magnetic fields in relation to high voltage lines has given rise to anxiety in the community as well as sparking public debate. The precautionary policy of the Ministry of Housing, Spatial Planning and the Environment is aimed at avoiding people being exposed to high voltage line-generated magnetic fields for any length of time. The current exposure threshold is set at 100mT (micro Tesla, as the unit of measurement for magnetic field strength), whereas TenneT for its part has in recent years applied 20mT as its reference. However, the Ministry in the context of the new scheme will be adhering to the significantly lower threshold of 0.4mT to be applied to plans for new-build development in close proximity to existing high voltage lines.
A comprehensive Wintrack trial programme is being launched in the second half of the current year. Once this stage has been successfully negotiated, a Wintrack prototype is to be built in 2006 and a trial run organised involving an entire 1,500-metre stretch of Wintrack high voltage line.
A digital brochure is available and can be downloaded by the link.