Man has been harnessing the power of the wind to produce mechanical energy since the first century when Heron of Alexandria created his windwheel operating an organ. Things have come a long way since then. Giant wind turbines now generate over 3% of all the electricity in the United States, but a new technological advancement – wind lens technology – looks to triple that!
Traditional Turbine Limitation
Traditional turbines have always worked by placing blades around a centrally spinning axis that turns a magnetic coil electrical generator encased in the structure. This system was always believed to have a maximum efficiency of 59.3% – the Betz Limit. The Betz limit is calculated by assuming that to maintain air flow around the blades of the turbine, approximately 40% of all wind passing through the blade system will not by converted into electrical energy. In the real world, efficiencies are closer to 35% to 40%.
Wind Lens Potential
The wind lens takes the idea of the Betz limit and tweaks it by adding a focusing lens around the exterior circumference of the blades. This creates an area of low pressure around and behind the blades. This is exactly the same principal that creates lift in airplane wind design. The air that flows over the outside of the lens must travel faster than the wind that travels inside it. This creates a lower air pressure within the area directly behind the blades. Because air will tend to move toward equilibrium, the high pressure air in front of the blades will necessarily accelerate into the low pressure area. To see this in action view the video below.
In the video there is talk about the wind lens working at lower wind speeds than traditional turbines. It had been generally accepted that no turbine could produce viable, sustained electrical current at wind speeds below 10 mph. The Japanese wind lens model was shown to operate efficiently at wind speeds of 12 m/s (meters per second). 1 mph is equal to approx. .44704 m/s. Doing the math, that means that the wind lens operates at speeds as low as 26.8 mph.
Conquering the Need for Space
The biggest problem with wind turbine technology is the sheer amount of space it takes up. Even if the wind lens technology was added to every turbine in the U.S., we would still only reach 10% of our energy usage. To meet our total energy needs, an area of about 170,000 sq. mi. would need to be devoted to turbines. That’s roughly the size of California.
There are two solutions. The first is to utilize existing structures by placing turbines on top of them. The previous turbines wouldn’t work at the lower wind speeds in most urban areas. These new wind lens versions have removed that obstacle. But the most ambitious ad innovative solution has been proposed by the wind lens developers themselves – place the turbines on platforms in the ocean. Wind speeds are higher here, so the energy potential is greater. It also takes advantage of areas of the Earth’s surface that are not able to be developed in traditional ways.
Do you think that wind lens technology is a viable green technology? Are there downsides that you can see? Tell us what you think in the comment section.