Saturday 4 August 2007
Buoys flex artificial muscles for renewable energy
Artificial muscles are being used to turn the ocean's waves into electrical power in a novel pilot project off the coast of Florida, US.
The "muscles" produce electricity as they bob up and down attached to buoys. Although they only generate enough power to light a small light bulb currently, the scientists involved see it as a first step to implementing a new, cheap technology for harvesting renewable energy from the ocean.
The artificial muscles are made from electroactive polymers, a material that can be physically activated with a jolt of electricity.
Electroactive polymer artificial muscles (EPAMs) are heralded as a key technology for powering future robots and other machinery. The design is remarkably simple – essentially several sheets of specialised rubber sandwiched between two elastic, oppositely-charged electrodes. When an electric charge is applied the electrodes squeeze the rubber. When the charge is dropped, the rubber relaxes.
Crowded fieldRoy Kornbluh of Stanford Research Institute International in California, US, and colleagues simply reversed the process. They rolled a sheet of EPAM into a cylindrical shape, and attached a weight to one end. They then fixed it to a weather and navigation buoy inside a watertight capsule.
As the buoy floats on the ocean surface, the force generated by the wave action stretches and relaxes the rubber, oscillating the distance between electrodes and generating electricity .ANIMATION
With an average 0.8-meter wave, each stretch of the muscle can generate as much as 20 watts of power. Since waves tend to come about every 4 seconds, though, the sustained energy output is closer to 5 watts.
"Right now we're just powering lighting systems on a buoy," Kornbluh admits, "but we want to scale up by orders of magnitude, and you can imagine hundreds or thousands of these thing scattered in the ocean."
In the last year, nearly 40 applications were filed with the US Federal Energy Regulation Commission for installing the ocean energy systems along the US coastline. It is a crowded field, but Kornbluh believes the simplicity and low cost of his design could give it advantages over competitors.
No adverse affects"Most wave systems are more complicated, they use flowing hydraulic fluid to turn a transmission, which then spins a turbine," Kornbluh says. "We're just stretching our generator. It's hard to imagine anything more simple."
The US energy market could welcome ocean energy technology with open arms. A recent report issued by the Electric Power Research Institute suggested that ocean energy could expand to meet 10% of the total electricity demands of the US without any measurable adverse effects on the environment.
"Either way it's encouraging that someone is working with artificial muscles and moving in a direction that is really our problem now – energy," says Yoseph Bar-Cohen of Jet Propulsion Laboratory in Pasadena, California.
full article
The "muscles" produce electricity as they bob up and down attached to buoys. Although they only generate enough power to light a small light bulb currently, the scientists involved see it as a first step to implementing a new, cheap technology for harvesting renewable energy from the ocean.
The artificial muscles are made from electroactive polymers, a material that can be physically activated with a jolt of electricity.
Electroactive polymer artificial muscles (EPAMs) are heralded as a key technology for powering future robots and other machinery. The design is remarkably simple – essentially several sheets of specialised rubber sandwiched between two elastic, oppositely-charged electrodes. When an electric charge is applied the electrodes squeeze the rubber. When the charge is dropped, the rubber relaxes.
Crowded fieldRoy Kornbluh of Stanford Research Institute International in California, US, and colleagues simply reversed the process. They rolled a sheet of EPAM into a cylindrical shape, and attached a weight to one end. They then fixed it to a weather and navigation buoy inside a watertight capsule.
As the buoy floats on the ocean surface, the force generated by the wave action stretches and relaxes the rubber, oscillating the distance between electrodes and generating electricity .ANIMATION
With an average 0.8-meter wave, each stretch of the muscle can generate as much as 20 watts of power. Since waves tend to come about every 4 seconds, though, the sustained energy output is closer to 5 watts.
"Right now we're just powering lighting systems on a buoy," Kornbluh admits, "but we want to scale up by orders of magnitude, and you can imagine hundreds or thousands of these thing scattered in the ocean."
In the last year, nearly 40 applications were filed with the US Federal Energy Regulation Commission for installing the ocean energy systems along the US coastline. It is a crowded field, but Kornbluh believes the simplicity and low cost of his design could give it advantages over competitors.
No adverse affects"Most wave systems are more complicated, they use flowing hydraulic fluid to turn a transmission, which then spins a turbine," Kornbluh says. "We're just stretching our generator. It's hard to imagine anything more simple."
The US energy market could welcome ocean energy technology with open arms. A recent report issued by the Electric Power Research Institute suggested that ocean energy could expand to meet 10% of the total electricity demands of the US without any measurable adverse effects on the environment.
"Either way it's encouraging that someone is working with artificial muscles and moving in a direction that is really our problem now – energy," says Yoseph Bar-Cohen of Jet Propulsion Laboratory in Pasadena, California.
full article
Friday 3 August 2007
Flying windmills could harness the jet stream
Flying windmills tapping jet stream wind currents may sound far fetched, but groups in the US, Netherlands and Canada say such devices may soon be within reach. If successfully developed, they could harness an enormous amount of reliable, renewable energy.
"If we were able to tap 1% of the wind energy at high altitude, that would be enough to supply all the world's energy needs," says David Shepard, president of renewable energy startup Sky WindPower, in Coronado, California.
Shepard says he plans to begin building a 220kw Flying Electric Generator (FEG) prototype later in 2007, and hopes to have it flying at 4500 metres by the summer of 2009. Sketches of the contraption show four rotary blades connected to an H-shaped aluminum frame, which is tethered to the ground by a high-voltage power line.
The current prototype (see video, above) is based on an earlier model that was first flown in the 1980s by Sky WindPower's chief engineer, Bryan Roberts of the University of Technology in Sydney, Australia (See Reach for the sky).
Both models take off like helicopters powered by their electric tether. Then, once their rotors catch the jet-stream wind, they feed electricity back to the ground like traditional wind turbines with their rotors rotated to the horizontal.
Wing-shaped kites
Roberts, Shepard and others recently wrote a journal paper that sets out the details of their idea.
Shepard expresses great confidence in his projections, saying clusters of the devices will soon be flying at heights up to 9000 metres, providing renewable energy that out-competes all other fuels. "It's going to beat fossil fuels and nuclear power economically within 10 years," he claims.
Researchers at Delft University of Technology in the Netherlands are working on a slightly different high-flying generator called a Laddermill. The mill is made up of a series of wing-shaped kites that generate energy by rotating a large loop to which they are connected.
Curved fins
But a third group pursuing airborne wind generation says high-altitude jet stream currents are not worth the trouble. "When you go that high, there is this massive cable that you have to deal with," says Mac Brown, CEO of renewable energy start-up Magenn Power, of the electric tether connecting the generator to the ground.
"We've looked at all kinds of wind maps, and there is loads of wind in the 180 to 300 metre range," he says.
Brown's company uses a helium-filled blimp with curved fins that harness this lower altitude wind (see video, below). This causes the aircraft's midsection to spin, rotating power generators at each end.
The company flew a 3 x 7 metre prototype in 2006 that was too small to carry the weight of these generators. Brown says he now hopes to build a larger balloon "the size of a three-story house" and capable of lifting 1100kg.
full article
Thursday 2 August 2007
Rising support for homeowners getting green grants
To accompany the new Home Information Packs that came into force yesterday, a new system was also announced that will help homeowners to save energy and money by modifying their homes with ‘green grants’.
Communities and Local Government say that most people are unaware that they could be entitled to a typical grant of £100-£300 towards the price of loft and cavity wall insulation to reduce energy consumption.
The new system is also linked to the new Energy Performance Certificates (EPCs), which will give homeowners a ‘home energy rating’ – the combined systems will make it easier for consumers to get access to the grants in order to make the eco-friendly improvements recommended in the certificates.
Measures recommended by EPCs could save consumers as much as £300 a year off their energy bills, in addition to cutting the amount of non-renewable resources used in British homes, which could amount to a saving of one million tonnes of carbon a year by 2020, according to the Energy Saving Trust.
Housing Minister Yvette Cooper said: “Energy certificates have the potential to cut family fuel bills by hundreds of pounds. But it can still be a real hassle getting the work done. Most people don’t know these grants are available or don’t know how to apply for them. This means it should be much easier for homebuyers to get help to cut their fuel bills and carbon emissions too. It could save hundreds of pounds on insulation and hundreds off pounds on their fuel bills too.”
To encourage more environmentally-friendly homes and cut fuel bills, the eight major fuel companies have agreed that home-buyers will have immediate access to information about green grants and the measures they can take to improve the efficiency of their homes. This will include a new function on the Energy Saving Trust’s website, whereby consumers can gain easy access to the help available in their area by entering their postcode.
Paul King, Chief Executive of the UK-BC (Green Building Council), has said:
“It’s really very simple. We will fail to prevent the worst effects of climate change unless we make huge improvements to the energy efficiency of our existing homes. The new Energy Performance Certificates provide an essential tool for doing this.
"By showing people, for the first time, how their homes rate in terms of energy consumption, and giving them user-friendly advice about the most cost-effective ways of improving their performance, we can all be equipped to do something meaningful to tackle climate change.”
full article
Communities and Local Government say that most people are unaware that they could be entitled to a typical grant of £100-£300 towards the price of loft and cavity wall insulation to reduce energy consumption.
The new system is also linked to the new Energy Performance Certificates (EPCs), which will give homeowners a ‘home energy rating’ – the combined systems will make it easier for consumers to get access to the grants in order to make the eco-friendly improvements recommended in the certificates.
Measures recommended by EPCs could save consumers as much as £300 a year off their energy bills, in addition to cutting the amount of non-renewable resources used in British homes, which could amount to a saving of one million tonnes of carbon a year by 2020, according to the Energy Saving Trust.
Housing Minister Yvette Cooper said: “Energy certificates have the potential to cut family fuel bills by hundreds of pounds. But it can still be a real hassle getting the work done. Most people don’t know these grants are available or don’t know how to apply for them. This means it should be much easier for homebuyers to get help to cut their fuel bills and carbon emissions too. It could save hundreds of pounds on insulation and hundreds off pounds on their fuel bills too.”
To encourage more environmentally-friendly homes and cut fuel bills, the eight major fuel companies have agreed that home-buyers will have immediate access to information about green grants and the measures they can take to improve the efficiency of their homes. This will include a new function on the Energy Saving Trust’s website, whereby consumers can gain easy access to the help available in their area by entering their postcode.
Paul King, Chief Executive of the UK-BC (Green Building Council), has said:
“It’s really very simple. We will fail to prevent the worst effects of climate change unless we make huge improvements to the energy efficiency of our existing homes. The new Energy Performance Certificates provide an essential tool for doing this.
"By showing people, for the first time, how their homes rate in terms of energy consumption, and giving them user-friendly advice about the most cost-effective ways of improving their performance, we can all be equipped to do something meaningful to tackle climate change.”
full article
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