< PREVIOUS ]   [ 2009 Index ]   [ Ed Quillen HOME ]   [ SEARCH ]    [ NEXT >


Mercury for green energy

Published 13-Aug-2009 in The Denver Post
Copyright ©2009 by Ed Quillen. All rights reserved.

About a fortnight ago, Gov. Bill Ritter opposed a federal proposal to store mercury in Colorado.

Also known as quicksilver, mercury is toxic, affecting joints, hair and nervous system. Our phrase mad as a hatter (mad as in crazy) may come from the effects of the mercury compounds used by the makers of felt hats several centuries ago.

Mercury is a shiny metal that is liquid at room temperature. Its freezing point is 40 below zero, either Celsius or Fahrenheit, as the two scales cross at that point. When I was a kid, mercury was all over the place -- thermometers, barometers, light switches.

I played with it in the school laboratory -- mercury's strong surface tension makes for little balls that skitter across a table top -- and now, 45 years later, my joints often ache, sometimes I have trouble remembering things, and I've lost hair. Must be the mercury, right?

Our governor says toxic chemical waste should be stored close to where it was originally generated, not shipped across the country to be dumped in Colorado.

No cinnabar (the main ore of mercury) has been mined in Colorado. But the mercury flask was just as much a part of the old-time prospector's gear as his burro and gold pan.

Seldom does a placer deposit yield big nuggets; generally the result of panning is tiny gold flakes mixed with black iron sand. Mercury has the unusual property of amalgamating with gold and silver (that's why it was used to make tooth fillings). The prospector poured mercury on the fine sand, discarded what didn't blend, then boiled off the mercury to get his precious metal.

Almost every mountain gulch has been examined by mercury-toting prospectors, so Colorado is a place where it was originally generated. Mercury was useful here then, and it could be useful here now in meeting Ritter's goal of a green-energy economy.

Start with sunshine and wind. The sun doesn't shine all the time, and the wind doesn't blow all the time, except for South Park year-round and Salida in April. They're not reliable sources for generating electricity, which we need in daylight and darkness, in gale and calm.

Note that some energy providers use pumped storage. When surplus power is available, water is pumped up to a reservoir. When electrical demand is high, water is released to run through turbines that spin generators. Xcel Energy does this at Cabin Creek near Georgetown, as does the U.S. Bureau of Reclamation at Twin Lakes.

You could use solar or wind energy, when available, to pump the water uphill. And if you sized it properly, you could get reasonably reliable 24-hour generation of electricity from a sporadic wind and sunshine.

But water freezes, and its reservoirs and penstocks need to be pretty large. So why not use mercury, with sealed reservoirs at top and bottom? It's unlikely to freeze. Since mercury is 13.6 times denser than water, the facility could be much smaller, and thus cheaper to build and operate.

That is, to get the same kinetic energy as dropping one cubic foot (1,728 cubic inches) of water per second for 100 feet, you'd need only 127 cubic inches of mercury.

Granted, mercury can be hazardous, but we've found ways to work with other hazardous substances, like bleach and gasoline.

Storing toxic waste anywhere can be risky, on account of neglect. But if we refined the mercury and put it to work turning turbines, we'd keep a keen eye on it. Gov. Ritter should welcome the quicksilver and put some engineers to work designing solar- and wind-powered pumped-mercury-storage electrical generating plants.


< PREVIOUS ]   [ 2009 Index ]   [ Ed Quillen HOME ]   [ SEARCH ]    [ NEXT >