Magnetic levitation promises huge efficiency gains in wind power generation
By Loz Blain
July 30, 2007
July 31, 2007 Sustainable generation of electric power is the key to realizing the vision of a world free from dependency on fossil fuels - the challenge is to ramp up the production of electricity to a level that can begin to approach the energy we get from burning coal and oil, without the perceived dangers of going nuclear. The combined threats of Peak Oil and global warming are spurring science into a furious new age of innovation. With almost daily breakthroughs in solar energy capture, battery technology and tidal energy harvesting, but the biggest contribution to green power thus far is coming from wind farming. The common windmill design used to capitalize on air currents, while centuries old, operates at around 1% efficiency in terms of the power it harvests from the wind, due to the deflective blade design and friction losses. But a new technology unveiled last year in China seeks to dramatically boost the output of wind-driven generators by using the virtually frictionless advantages of magnetically levitated turbines. Since there's virtually no touching of moving parts, the Maglev wind turbine requires far less servicing than a traditional windmill - which dramatically lowers the operating costs to under five U.S. cents per kilowatt-hour. If projections are accurate, giant 1-gigawatt versions of these machines could have a 12-month ROI - a scenario sure to catch the eye of investors worldwide.
Magnetic levitation uses the repelling properties of magnets to lift an object off the ground. In this case, the object is a wind-harvesting fan. The benefit of having it floating in midair is that it cuts down on the friction that causes so much inefficiency in the traditional windmill-style wind energy harvester we see dotting our coastlines. Friction is also the key factor necessitating frequent maintenance of windmill turbines, adding considerably to the cost of running them.
Without rotational friction to overcome, a wind turbine generator can begin to harvest power from air speeds as low as 1.5 meters per second.
Chinese researchers unveiled a prototype Maglev wind generator device at the Wind Power Asia exhibition in June 2006. The devices were hailed as a huge breakthrough in a vast and spread-out country that has more than 70 million households with no electricity. One innovative possible use could be to harvest wind energy from passing cars on freeways to power the roadside lighting.
American company Maglev Wind Turbine Technologies believes that scale is the answer and has released plans for a massive-scale installation. Pointing out that the low power outputs of current windmill units render them cost-ineffective to install and repair, the company proposes the building of giant 1-gigawatt units, each the size of an office building.
The company proposes that a one-unit wind farm of such scale would be less than half the price of windmill generators of equivalent output - it would last longer, be cheaper to build and run and therefore result in higher profits. In ideal conditions such a plant could have a power output similar to a nuclear power station and a 12-month return on investment.
It's certainly a promising technology - we look forward with great interest to seeing how it operates in practice.