Invasion of "Monster" Towers

The Santa Fe New Mexican did a story today on the Public Service Company installing huge steel towers for power lines along Rufina street and Zafarano Drive. The 60-foot high, 3-foot thick towers replaced smaller ones that were reportedly 50 years old.

Some local residents are concerned. This might be justified. But, while the bigger towers look scary, if the old lines are replaced, residents may in fact be exposed to lower magnetic fields than before.

A magnetic field is created when electrical current flows. As more current flows, a bigger magnetic field is created. As demand for power increases more current must flow on the lines for a given voltage.

Voltage is energy. Image the energy in something compared to dropping a baseball from a tall building. The higher you drop the ball the more energy it will have on impact. To get the same amount of energy from dropping one ball from 100 feet you would need to drop 10 balls from 10 feet.

Power lines are the same way. You can either run less current on higher voltage lines (big and scary looking ones), or more current on smaller power lines (the old lines). The old power lines reportedly carried 45 kilovolts; the newer ones 115 kilovolts. Thus, the newer lines can provide the same amount of power with less than half the current.

Some residents have asked that the lines be buried underground, in which case the magnetic fields would be nearly zero. Contrary to popular belief, this is not because putting them under ground shields us from them. Magnetic fields are not blocked by dirt, steel or concrete. The reason burring them eliminates fields is because the lines are closer together underground; on the tower the lines are several feet apart.

Why do we care? There has been some debate over the heath effects caused by magnetic fields associated with power lines. However, most scientists agree that they affect us biologically. Laboratory studies have reported changes in hormones including melatonin, bio-rhythms, brain activity, heart rate and alterations in the immune system (1).In related news, it was reported that PNM is now requesting the right to run power lines through parks and over trails without having to ask for approval. Currently they need the approval of City Council.

Parks and trails don't belong under or near power lines, yet this is often the case because it's a cheap way for municipalities to get space. Utility companies often donate or lease land for as low as $1 a year.

PNM may say they can’t afford to bury power lines underground. What they really mean is 1) stock holders won’t approve unnecessary spending; and 2) if they bury lines under the perception of a health risk they will open the flood gates –everywhere people would insist that power lines by their homes be buried.

In most cases, burring lines is not necessary to avoid exposure. It is surprising how quickly the magnetic fields emanated from power lines drops off with distance away from the lines. In most cases, burying the lines is not necessary to avoid exposure inside a building. This is not the case in parks and open spaces where people may actually hike under or be very close to them. These power lines should be buried.

References
1 Questions and Answers About EMF, Electric and Magnetic Fields Associated with the Use of Electric Power, National Institute of Environmental Health Services and U.S. Department of Energy, U.S Government Printing Office, Washington, D.C, January, 1995, p.23.


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