Running Energy

Composite Power Corp., Las Vegas, plans to use composites as a key material in a wind turbine a quarter-mile across that will turn on air or magnetic bearings in breezes as mild as 3 mph. Composite towers cost more than steel, however, are cheaper to transport and easier to assemble on-site, making them cost-competitive, especially in remote areas. Since composite towers have small footprints, they can share rights of way with railroad tracks. The system is designed so even if a car jumps the track and takes out up to three towers, the fiber-reinforced cable will remain intact. Beginning with inexpensive coal fuel, the proposed Montana-Wisconsin line will deliver power for an estimated 3 cents a kilowatt, compared with the 4 to 9 cents a kilowatt it costs other state utilities. The heart of the technology consists of cables made of aluminum strengthened by a composite wrapping. Although aluminum has a generous current-carrying capacity, its poor mechanical strength has curbed its role in power transmission lines.