A Funnel For Sunlight
Solar panels convert the most light into electricity when the sun shines directly on them, but as soon as it wanes, so does efficiency. A new antireflective film coating could help panels collect sunshine at 96 percent efficiency from nearly any angle. Developed by scientists at Rensselaer Polytechnic Institute, the film consists of seven layers of nanoscopic silicon and titanium-oxide rods arranged in increasing densities, with the topmost nearly as porous as air.
This funnel-like setup captures light from almost every direction and focuses it onto the photovoltaic panel while also inhibiting reflection. The film, which is about one hundredth as thick as a human hair, could easily be applied to any solar panel, says lead researcher Shawn-Yu Lin, and would help collect 20 percent more light while eliminating the need for the expensive hardware usually used to rotate solar panels as the sun moves. Before Lin can sell the film, he must find a way to protect the outermost layers from the wind and heat, a process that he says may take another year.
Turning The Tide
Engineers at the University of Oxford recently tested a 1.5-foot-wide prototype turbine that generates energy by spinning in the tide like the blades of a push lawn mower. The cylindrical turbines could be roughly 10 percent less efficient than fan-shaped turbines, but each rotor's size—the full-size versions will be 33 feet in diameter and 200 feet long—and the ability to link multiple units means they can harness more energy for less money. Spanning an entire river with the six-megawatt turbines could save 40 percent per megawatt on manufacturing and 60 percent on maintenance. The engineers are lining up funding and plan to evaluate a full-scale device next year.
I love hearing about energy solutions!
Does anyone know how many of the new wave and tide driven power generators have actually been put into service?
One of the big complaints about renewable sources of energy is the old "what if the wind doesn't blow" argument, or "what if the wind is blowing when we don't need the power". Ultimately, what's needed is some kind of mega-battery to store the power, then release it when needed in a constant predictable (non fluctuating)way. So check out these concepts to that end: http://www.mpoweruk.com/alternatives.htm
I particularly like the flywheel idea, as I imagine it would be something DaVinci would have dreamed up.
Unfortunately, 96% efficiency at collecting sunlight does not equate to 96% efficiency at converting it to energy. But that could change, as other solar cell inventors are making big claims about improved energy production.
The deal with wave and tide driven power generators is going to be their life cycle costs. Seawater is inherently corrosive and the sea is a rough place. If every passing storm washes these things up on the beach that isn't good, nor will be the ease of maintenance on them if they stay anchored. Still, they are attractive ideas and not quite as intermittent in their power production as solar and wind.
I think the tidal harness mentioned here is more of a dam and turbine alternative than an ocean tide harness.
Fresh water is less corrosive and less prone to biotic buildup and clogging. Also, fresh water in rivers runs continually (no mid-tide lapses). Considering the cost of concrete and construction, these turbines would cause less ecological and aesthic damage to a river system than traditional damming and turbines. Of course, the energy creation will also be reduced, as you are more "grazing" on gravity than harnessing it.
Depending on rate of spin, I could also see migratory fish issues. Also, suspension hight would be important. Too close to the top makes the first log floating downstream very destructive. Too close to the bottom creates the same issue. Mid-floating objects are much rarer, but still would likely warrent some sort of screening, which will slightly reduce water current (and thus yield), as well as increase installation costs.
Still, on a large river like the Mississippi, signifigant electric generation could be achieved without signifigant ecological disturbace or eyesore.
Underwater maintainace in the ole' Muddy, however, would be a chore.
"Unfortunately, 96% efficiency at collecting sunlight does not equate to 96% efficiency at converting it to energy."- Mike Cook
I see what your point is Mike but when a conventional solar cell collects only around 66% of the sunlight to convert to energy, wouldn't 96% collection be a nice upgrade? But you're right, 96% sunlight absorption does not mean 96% energy output. but by having 30% more absorption you're going to get an increase in energy output as well. It's a nice upgrade don't you think?
I'm as fascinated as the next person by verious technologies that hold great promise to provide us alternative sources of energy, other than nuclear and coal, both of which make me queasy when I think about "just where do we bury the waste?" Further, in the case of nuclear, what about an accident?
Anyway, I tend to think of these technologies on mass scales more than on an individual home or business scale. But these technologies already deliver on that level.
Water wheels, anyone? --been around thousands of years. Solar? Heck, my favorite way to make tea is to put the water and tea into a sealable jar that is clear, and put it into the sun. Depending on weather and location, an hour or two later, I've got a jug of nice tea. Ditto cooking, if with limits. (There are DIY plans out there to convert a used pizza box into a cooker for under $10, for instance.) Wind? On the ranch where I grew up, we had an old-fashioned windmill, like you see in photos of the Great Plains decades ago, next to a livestock barn. That windmill not only pumped water from underground; it also provided enough electricity, when the wind was blowing, to power the water pump and a few light bulbs. (Yes, Dad did keep a fossil-fuel generator for when the wind was too weak or nonexistent. Still, it cut the electric bill.) That windmill was maybe 20-25 feet tall, so it wasn't an eyesore, either.
Will any one person, family or small business utilizing this stuff make a significant contribution? Of course not. But the power comes in numbers. Get several tens of millions of folks doing the same thing, and we're talking a significant contribution to reducing our use of fossil fuels, cutting pollutants, etc. And saving a coin or two as well.
Works for me -- and does.
You would still need to rotate the solar panels so that they are flat on to the sun in order to get the most energy. If you don't then as the sun gets more 'edge-on' to the solar panel then the energy that the panel can capture will progressively get smaller just due to the fact that 'width' of panel exposed to the sun will get smaller.
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