Nuts and Volts - July 2014

Tower of Power

No, we're not alking about the classic soul band, so we won't be "Diggin' on James Brown."

We're focusing on Solar Wind Energy, Inc., which is offering "a bold new approach to overcome the current limitations of conventional wind energy sources." The company has announced the acquisition of a 600 acre chunk of real estate in San Luis, AZ, for the first US installation of its patented Solar Wind Energy Tower (SWET). The SWET is what is generically referred to as a solar wind downdraft tower. In operation, a mist of water is injected into the hot dry air at the top of the tower. The air absorbs the water, and thereby becomes cooler and denser. As a result, it drops downward at speeds up to 50 mph and is diverted into wind tunnels at the bottom where turbines are projected to generate up to 1,250 MW per hour.

It may be bold, but the concept isn't entirely new; it's really a twist on the solar updraft tower first proposed in 1903 by Isidoro Cabanyes, a Spanish army colonel. This design sucks hot air up through the tower using the chimney effect and generates power in pretty much the same way. An experimental model was in operation south of Madrid from 1982 to 1989, when its guy wires corroded and it fell over. The 33 ft ( 10 m) dia chimney rose to a height of 640 ft (195 m) and used a collection area (greenhouse) that covered 110 acres. The maximum output came in at about 50 k W. Several others have been built or proposed.

The downdraft version requires less land, and it has the advantage of operating 24 hours a day. However, pumping water to the top eats up an estimated 50 percent of the turbine’s output, so it isn't an unmixed blessing. The concept has been promoted for 15 years or so by Prof. Dan Zaslavsky of Iowa State University. He estimates that — depending on construction costs and other variables — an energy tower should be able to offer power at a cost of between one and four cents per kilowatt which puts the price below other alternatives, except for hydroelectric. How well the San Luis facility will operate won't be known until it (maybe) begins operation in 2018, but it all sounds good. In the meantime, you can see a video on the company website ( www.solarwindenergytower.com) and even invest if you are so disposed. As of this writing, the stock is moving at $0.03 per share. ▲

ADVANCED TECHNOLOGY

Laser Deployment Imminent

The US Navy has been seriously interested in laser weapons since 2010, when it awarded $11 million to Kratos Defense & Security Solutions ( www.kratosdefense.com) to develop the Laser Weapon System (a.k.a., La WS). By the time you read this, the first prototype should be installed on the USS Ponce for a 12 month at-sea test. The Ponce — a half century old Austin-class amphibious transport dock — isn't the most glamorous ship in the Navy, but it has been used as a test bed for several new technologies, including service as a

"lilypad" for MH- 53 mine-clearing helicopters.

The Navy has made directed-energy weapons a major priority to counter "asymmetric threats," including unmanned and small aircraft, and small attack boats. In a 2011 demonstration, a destroyer-based laser made short work of multiple small boat threats, and in 2012 La WS downed several unmanned aircraft (You Tube videos are accessible by searching "navy laws laser”). As noted by Rear Adm. Matthew Klunder, "Spending about $1 per shot of a directed-energy source that never runs out gives us an alternative to firing costly munitions at inexpensive threats."

The news release from the Office of Naval Research was light on specifics, but it was revealed that "using a video game-like controller, a sailor will be able to manage the laser's power to accomplish a range of effects against a threat, from disabling to complete destruction." Its power level has been estimated at between 10 k W and 50 k W with an effective range of about a mile. More info is available at www.onr.navy.mil. ▲