Wednesday, November 26, 2008

UMich VIVACE Hydropower System Makes Energy From Slow Currents [Hydropower]

UMich VIVACE Hydropower System Makes Energy From Slow Currents [Hydropower]

A new hydropower prototype from the University of Michigan could end up using even slower river and ocean currents to generate energy. VIVACE, which stands for Vortex Induced Vibrations for Aquatic Clean Energy, can generate power from as little as 2 knots, making it more useful than most turbine and water mill systems out there, which need an average of 5 to 6 knots to operate efficiently.

The system works by harnessing "vortex induced vibrations," the thrumming caused by the flow of liquid or air over rounded objects. A cylinder placed underwater is subject to the current and starts to vibrate as liquid sticks and creates eddies on the object's opposite side. It's the same scientific principle that caused the collapse of the Tacoma Narrows bridge in 1940.

"For the past 25 years, engineers—myself included—have been trying to suppress vortex induced vibrations. But now at Michigan we're doing the opposite. We enhance the vibrations and harness this powerful and destructive force in nature," said VIVACE developer Michael Bernitsas, a professor in the U-M Department of Naval Architecture and Marine Engineering.

Just a few cylinders could possibly power an anchored ship or a lighthouse. An array of VIVACE cylinders about the size of a running track could produce energy at 5.5 cents per kilowatt hour and power about 100,000 houses. U of M is now working on possibly deploying a pilot project in the Detroit River within the next 18 months. [UMich via Gizmag]


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Tuesday, November 25, 2008

Spanish Solar Power Tower Almost Ready

source: http://earth2tech.com/2008/11/25/spanish-solar-power-tower-almost-ready/

One of the world’s largest solar farms that uses “power tower” technology — Abengoa’s “PS20″ solar farm just outside of Seville Spain — will start generating clean power in January, and the company is making the final adjustments on the solar farm’s massive mirrors over the next few weeks, according to the Guardian. Solar power tower farms are a next generation solar thermal technology that use large mirrors to concentrate light and heat water at a massive centralized tower.

Abengoa’s PS20 solar power tower plant will initially generate 20MW of electricity, and will be a significant proving ground for the solar power tower technology. What the Guardian article doesn’t mention is that while this technology is being tested in Spain, Abengoa has actually decided to only tackle the more traditional solar trough technology in the U.S. As Abengoa’s senior adviser to the U.S., Fred Morse, says, that’s because the policy framework and utility contract needs of the U.S. market require that the solar thermal technology be “proven,” “bankable” and “reliable.”

abengoasolarpowertower

So solar power tower technology is still in the early stages. But one startup in the U.S. is aiming for this market: Oakland-based Brightsource Energy is looking to build solar power tower technology in the deserts of California. The BrightSource team worked on the original solar trough technology built in the ’80s and ’90s and says that solar power tower technology offers “higher concentrations,” “higher temperatures,” and “higher efficiencies” compared to solar trough. Update: Keely Wachs, BrightSource’s Senior Director of Corporate Communications says that BrightSource’s 900 MW deal with PG&E is an indicator that the US policy framework and U.S. utilities are supporting power tower technology.

Images courtesy of Abengoa.

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Thursday, November 20, 2008

New wind turbines at least 30% more efficient, Earth one step closer to salvation

New wind turbines at least 30% more efficient, Earth one step closer to salvation

Still addicted to oil like the rest of the world? You might reconsider wind power rehab now that a startup called ExRo has developed turbines that it says are consistently 30% -- and in some situations as much as 100% -- more efficient than the standard kind. The traditionally-used mechanical transmissions have been replaced with an inexpensive electric alternative that can adapt to changes in wind speed more efficiently. Also, many small generators are used instead of a large one, so the turbines can be customized in production to suit the intended installation site. If this is the real deal, it beats the 0.1% increase we saw in solar cell efficiency a few months ago, and those Maglev uber-turbines are still on the horizon. Hey Sun -- jealous yet?

[Via DailyTech]

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New wind turbines at least 30% more efficient, Earth one step closer to salvation originally appeared on Engadget on Thu, 20 Nov 2008 08:29:00 EST. Please see our terms for u! se of fe eds.

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Wednesday, November 5, 2008

Solar Panel Quantum Leap: Near-Perfect Light Absorption Possible [Solar Power]

Solar Panel Quantum Leap: Near-Perfect Light Absorption Possible [Solar Power]

Today's silicon solar panels absorb about two-thirds of the light that reaches them, but a new nanocoating developed by Rensselaer Polytechnic Institute gives most run-of-the-mill solar panels the ability to capture almost every drop of sunlight. Not only does it grab 96.2% of the sun's rays, but it can do it from any angle, so there's no need for panels to waste energy by mechanically tracking the sun in the sky. This is happy leap forward for solar technology, whose quest for cheapness has been long and hard.

I said it's one coating, but it's actually seven, each between 50 and 100 nanometers thick, made of silicon dioxide and titanium dioxide nanorods that can be vaporized and deposited on "nearly any photovoltaic materials." PhysOrg compares the tightly hugging nanorods to "a dense forest where sunlight is 'captured' between the trees." There's no word yet on the deployment of this process—it's barely a year since its chalkboard conception—but this efficiency means lower cost to acquire energy, which means solar power is more viable than ever as an alternative to fossil fuels.

I hate pigeonholing myself as one of those wide-eyed Trek fans who thinks that alt energy will radically change the way we live our lives and help us get on with impulse drives, synthehol and breathable spandex formalwear, but seriously, this is my kind of breakthrough. [PhysOrg via Kurzweil AI]


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