Wind is a clean, renewable source of energy with little to fault it except its inconstancy.
Photo:camTrails, Creative Commons, Flickr
The same can be said for solar energy. With both, this fickle supply vs demand equation is what keeps these alternative energy sources from replacing fossil fuel energy to any extent.
Wind can be relied on if you’re having a picnic or a wedding, but rely on it to light your home and wind speeds are either too great, too little, or nonexistent. Even when energy is generated (and not immediately used), the means to store it are cumbersome, chemical-laden, and subject to their own drawbacks and failures.
Some wind turbine manufacturers have improved their designs to capture weak wind, and have engineered turbines and blades that can safely operate even in high winds. The Albany wind farm in Australia is a prime example. Twelve 1800-kilowatt ENERCON E66 wind turbines from Germany feed into the grid and produce about 77,000,000 units of electricity, or enough to power about 60 percent of the area’s 25,000 homes. The wind turbines do not have gearboxes, which helps keep maintenance costs low.
The turbines operate at variable speed and the blades move very slowly, reaching a top speed of 22 RPM, or one revolution every three seconds, even in the strongest of winds. The three long blades cut in at 4 miles per hour, reach peak production at 31 miles per hour, and cut out at wind speeds of 80 miles per hour.
Clearly, variable wind speed is not the problem. Designs which allow homeowners to capture wind blowing as little as 2 miles per second also exist. One such manufacturer is Motorwind. Another potentially promising development is called the MagWind (Magnetically-Levitated Axial Flux Alternator with Programmable Variable Coil Resistance, Vertical Axis Wind Turbine – Whew!) But unfortunately the website isn’t up and people who have ordered the product haven’t yet received delivery. No one, then, can confirm quoted production figures, which state the MagWind produces 1100 kilowatt-hours of electricity a month at an average wind speed of 13 miles per hour, cuts in at about 3 miles per hour and runs until the wind gets to 100 miles per hour. Neither company trades as pink sheets or on the big board.
The problem is, once the energy is generated but not immediately used, where does one store it? Batteries are the obvious choice, but any battery is really only a tin can filled with sulfuric acid, to which lead plates and terminals are attached. Lead is a biological and reproductive toxin and I won’t even go into sulfuric acid.
Deep-cycle batteries, recommended for storing wind (or solar) power, are more of the same, and a typical battery array – enough to store the needed 50 kilowatts per day – takes up to 20 batteries in a 4 x 6-foot area. You can imagine costs for yourself, but it is worth noting that deep cycle batteries are the “prima donnas” of the battery world, requiring immense amounts of care and supervision.
Battery manufacture is another environmentally sensitive topic, creating soil, air and water contaminants that lead to cancers, cognitive difficulties and reproductive failure in humans and animals.
Technology may eventually solve the storage problem for residential wind turbines, but in the meantime a UK professor, Seamus Garvey, has hit on a splendid way to store commercial wind power. Namely, in flexible, plastic containers deep in the ocean, where water pressure increases their viability. Compressed Air Energy Storage (CAES) isn’t new, but Garvey’s methodology – which combines plastics, the pressurization that naturally occurs when air is drawn down the piston shaft of the turbine, and the use of the sea’s own pressurization – is.
According to Garvey, the plastic-reinforced bags will be able to store 25 megajoules of energy for every meter (cubed) at a depth of about 2,000 feet. The depth is essential, Garvey maintains, because only at sufficient depth and pressure do the bags deliver enough energy to make fabrication economically viable.
We’ve already contaminated our oceans with enough plastic to last until the next millennium; why not put it to good use?
Disclosure: I don’t own stock in any alternative energy venture.