Electrical Currents

(This column was first published in the April 23, 2001 Buffalo News.)

One of the most frightening experiences I ever had was at Nauset Beach on Cape Cod. It was an early morning off-season and I was swimming alone, my wife watching me from shore. The water was very cold. I am not a strong swimmer and was still recovering from major surgery so I swam out only a short way.

But when I turned to ride the waves the twenty yards or so back to the beach, I suddenly realized that these waves weren't going that way. The sea had decided to take me to Europe. No matter how hard I swam toward shore, I made no progress; I could only slow my departure.

Oddly, I recall being afraid of two things: my increasing exhaustion, of course, but also scaring my wife. I forced myself to relax and drift for a few seconds even though that meant the distance to safety widening still further. It was then that a wonderful -- possibly lifesaving -- idea occurred to me. If the current went out here; surely it would go in nearby. I swam -- slowly now -- parallel to the shore for a few yards and found to my delight that I was right. An inbound current helped me return to that wonderful beach. My wife's greeting: "That looked like fun."

I was reminded of that experience when I read a recent article by Peter Weiss in Science News about converting wave energy into electricity. At this time of power shortages and skyrocketing fuel prices any source of energy is worth our consideration and my experience suggests that indeed the power is there.

After one false start when their first apartment-sized structure was torn apart by waves before it was completed, the Scottish company Wavegen now has a small wave-driven turbine in service. Appropriately called Limpet after those clam-like shoreline denizens, it only generates 500 kilowatts at peak power, but even that small amount is enough to serve about 400 homes.

As that sentence suggests, home use averages about one kilowatt of electricity per day, but that rises to three or four during the summer when air-conditioners threaten our national power grids. Unfortunately wave energy peaks during the winter months when temperature swings generate stronger winds and greater wave action. On the positive side, however, a study of available wave power indicates that northeastern U.S. and nearby Canada are among the world's best wave energy sources. Almost 70 kilowatts per yard of ocean shoreline is there to be tapped. For comparison, our southeastern shores could deliver only a quarter of that power. (I should have been swimming there.)

The possibilities offered by the developing technology are significant. A British analyst, Thomas W. Thorpe, projects that wave power could supply one-sixth of the world's total electricity output. That is equal to all of today's hydroelectric power production. And although wave-derived energy generation costs still remain greater than those of nuclear energy, they have already been significantly reduced and research continues.

Surfers think of wave power as a near-shore phenomenon, but it turns out that the maximum energy is found farther offshore in water 50 to 100 yards deep. There the waves retain the full transoceanic tidal power they derive from the gravitational forces of moon and sun. Farther inshore most of those forces are absorbed by the seabed.

Many devices are currently being tested. My favorite is called a nodding duck. Its tipping action pumps oil from one tank to another, which in turn drives its generator.

Wave power offers another clean response to our energy problems and it may come on line at just the right time.-- Gerry Rising