The number of designs for vertical wind-power turbines is growing because they’re efficient, small, and cheaper to build than regular windmills. Sound familiar? One of the companies that seem to be making real headway in this market is Mariah Power, with a propeller-free vertical axis windmill called the WindSpire. Rotorweb_2 At a height of 30 ft. tall and only 2 feet wide, the WindSpire converts wind energy into measurable electricity through a vertical design, a rotor/generator system (with a low speed giromill and rotating ‘air core’ motors), and a wireless modem that an owner can track on a computer. It produces about 1900 kilowatt hours per year in 12 mile per hour average winds, which is about a quarter of the total energy used by a regular U.S. house. But the key promise is that if the spire was twice as thick, it could likely produce 100% of the energy needs of a household. There is one thing about this windmill that I’m not entirely sold on, however. That the faster speed of the windmill’s revolutions will prevent collisions with birds. I’m not well versed in aviary predilections, but this just seems like rubbish to me. […]