Underground Powerlines and Corona Discharge

Factual Questions
1

Around a decade ago, Cecil discussed the effects of high voltage power lines on human health. The column can be found here:

He mentioned that some people contend that corona discharge from HV lines could ionize airborn pollutants, causing them to stick more readily to the lungs (a theory, he mentions, that is not without it’s problems).

My question are as follows:

Does anyone know of any subsequent studies that either lend weight to, or cast doubt on this theory?

And would underground powerlines avoid the problem of ionising air pollutants, if that were indeed the case for the more conventional type of lines you find strung between metal pylons throughout the countryside?

2

One of my college professors was one of the early researchers into power line health issues.

The whole thing began in the late 60s or early 70s time frame. Insurance folks noticed that people who live next to power lines don’t live as long as people who don’t. Insurance folks get paid big bucks to figure stuff like this out, because statistics like these impact their insurance payouts and thus affect millions and millions of dollars.

For a long time, nobody but the insurance folks really cared much about the issue. But then came the childhood leukemia study that Cecil references in his article. That study was later discredited, but by then the genie was out of the bottle. People associated power lines with bad health, and that was that.

When cell phones started becoming popular, it wasn’t much of a stretch for people to think that if power lines can be bad, then the radio waves from cell phones could be bad too. At this point though, nobody really had any evidence of anything, other than some interesting insurance statistics.

Things went bat-shit crazy insane in the 80s. People started to panic, and folks fearing lawsuits wanted some way to protect themselves. So they started hiring “experts” who would walk around with meters measuring electric field strengths and would proclaim what areas were safe and what areas weren’t. Of course, the threshold for what was safe and what wasn’t was a rectally generated number (in other words, they pulled it out of their ass) and had no scientific basis whatsoever.

Money started pouring in to research, on both power line and cell phone health effects.

Fast forward a couple of decades, and after lots and lots of money has been spent on lots and lots of research, nobody has yet been able to prove much of anything, not with cell phones, not with power lines. Absence of evidence isn’t evidence of absence, as they say, but at this point we’ve got so much absence of evidence that it actually is starting to look like there’s really nothing to all of this.

On the other hand, the statistics don’t lie. Folks who live next to power lines don’t live as long as folks who don’t.

As my college professor pointed out, it’s entirely possible that this is due only to the fact that people who are concerned about their health and tend to live healthier lifestyles simply choose not to live next to power lines.

Your corona discharge theory is just one of many theories that have been put forward but haven’t yet been proven.

As for underground power lines, there are two main types of high voltage lines, transmission lines and distribution lines. Transmission lines carry electricity from one area to another, and they typically run at very high voltages, say 50,000 to 150,000 volts, with some running at even higher voltages than that. Transmission lines will carry the electricity to a substation, and from there it will be dropped down to distribution voltages. Distribution lines then run out to all of the businesses and neighborhoods and such, and transformers off of the distribution lines carry the electricity into your house or business. Distribution voltages aren’t as high as transmission voltages. Older systems may have distribution voltages as low as 2400 volts or so, and newer systems may be up to 15,000 or 20,000 volts, but voltages around 4,000 to 12,000 are probably the most common, with older systems tending to run at lower voltages and newer systems tending to run on the higher side of that range.

Distribution lines are often buried, as people consider them to be an eyesore. Transmission lines are not typically buried, though you will find a few, mostly in high density urban areas.

Corona discharge only happens at higher voltages, like 30,000 volts and above, so it’s not really an issue in underground distribution lines as those don’t run at that high of a voltage. High voltage underground transmission lines are often run through pipes filled with fluid or high pressure gas that circulates through the pipe and helps dissipate the heat generated by the wires as current runs through them. Converting existing high voltage transmission lines to underground lines would be prohibitively expensive, due to the high construction costs, electrical insulation issues that further drive up the cost, and heat issues that both drive up the cost and would require constant maintenance. If you have high pressure fluids or gases running through pipes all over the place, sooner or later something is going to spring a leak.

For what it’s worth, if you were silly enough to spend ungodly amounts of money to bury all of our high voltage transmission lines, that would pretty much eliminate the corona discharge / ozone issue. Since corona discharge from power lines hasn’t been proven to have any adverse effect on health at this point, you could be spending an awful lot of money to accomplish very little.

3

Excellent write-up and very informative, ecg.

On this point, cause and effect may work the other way. People who lead unhealthy lifestyles (and die sooner) may also tend to be less affluent and more inclined to buy houses that cost less because they are next to something big and unattractive.

4

I don’t think we need to even bring lifestyle habits into the equation. Simply put, poorer people don’t live as long as richer people. And poorer people are going to live near unsightly transmission lines.

I wonder if you can find similar correlations between life expectancy and proximity to rail lines. Or dumps? Interstate highways?

5

Thank you for such informative and thought provoking responses.

6

I think it’s also worth mentioning that transmission facilities (though not the lines themselves, I think) made heavy use of polychlorinated biphenyls (PCBs) for insulation and cooling until 1979. This raises a couple of questions in my mind:

  1. Does living next to power lines still correlate with shorter life expectancy?

  2. Did PCB contamination occur over a large enough area to be responsible for this effect?

7

PCBs would be found almost entirely in transformers. Not in the transmission lines themselves. So you might have some exposure near a substation. But zero along the length of the wires connecting substations.

IIRC the environmental problem with PCBs was their near-infinite half-life. Any spill would be forever. The vast majority of transformers don’t spring a leak over their lifetime. But those that do make a mess that’s very expensive to cleanup. And before the risks of PCBs were understood, any such mess was simply ignored or flushed down a nearby drain.

Bottom line: unless somebody lived next to a substation that had had a transformer fire / explosion / leak, there’d be no reason to suppose PCBs impacted their longevity.

As with power lines, poorer people live in cheaper housing that tends to cluster around infrastructure.