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nsf.gov – National Science Foundation (NSF) News – Iceland Volcano’s Molten Rock Could Become Source of High-Grade Energy – US National Science Foundation (NSF).

Geologists drilling an exploratory geothermal well in 2009 in the Krafla volcano in Iceland met with a big surprise: underground lava, also called magma, flowed into the well at 2.1 kilometers (6,900 feet) depth.

It forced the scientists to stop drilling.

“To the best of our knowledge, only one previous instance has been documented of magma flowing into a geothermal well while drilling,” said Wilfred Elders, a geologist at the University of California, Riverside, who led the research team.

The scientists received $3.5 million from the National Science Foundation (NSF), and $1.5 million from the International Continental Scientific Drilling Program, to conduct their research.

Elders and his team studied the well within the Krafla caldera as part of the Iceland Deep Drilling Project, an industry-government consortium, to test whether geothermal fluids at supercritical pressures and temperatures could be exploited as sources of power, said Leonard Johnson, program director in NSF’s Division of Earth Sciences, which funded the research.

“We were drilling a well designed to search for very deep–4.5 kilometers (15,000 feet)–geothermal resources in the volcano,” said Elders.

“While the magma flow interrupted our project, it gave us a unique opportunity to test a very hot geothermal system as an energy source.”

Currently, a third of the electric power and 95 percent of home heating in Iceland is produced from steam and hot water that occurs naturally in volcanic rocks.

“The economics of generating electric power from such geothermal steam improves the higher its temperature and pressure,” Elders said.

“As you drill deeper into a hot zone, the temperature and pressure rise. It should be possible to reach an environment where a denser fluid with very high heat content–but also with unusually low viscosity occurs–so-called ‘supercritical water.’”

Although such supercritical water is used in large coal-fired electric power plants, he said, “no one had tried to use the supercritical water that should occur naturally in the deeper zones of geothermal areas.”

Elders and colleagues report in the March issue of the journalGEOLOGY, published by the Geological Society of America, that although the Krafla volcano, like other volcanoes in Iceland, is basaltic (a volcanic rock containing 45-50 percent silica), the magma they encountered is a rhyolite (a volcanic rock containing 65-70 percent silica).

“Our analyses show that this magma formed by partial melting of basalts within the Krafla volcano,” Elders said.

“The occurrence of minor amounts of rhyolite in some basalt volcanoes has always been something of a puzzle.

“It had been inferred that some unknown process in the source area of magmas, in the mantle deep below the crust of the Earth, allows a silica-rich rhyolite melt to form–in addition to the dominant silica-poor basalt magma.”

Elders said that in geothermal systems water reacts with and alters the composition of the rocks, a process termed “hydrothermal alteration.”

“Our research shows that the rhyolite formed when a mantle-derived basaltic magma encountered hydrothermally altered basalt, and partially melted and assimilated that rock,” he said.

In the spring of 2009, Elders and colleagues progressed normally with drilling the well to 2 kilometers (6,600 feet) depth.

In the next 100 meters (330 feet), however, multiple acute drilling problems occurred.

The drillers determined that at 2,104 meters (6,900 feet) depth, the rate of penetration suddenly increased and the torque on the drilling assembly increased, halting its rotation.

When the drill string was pulled up more than 10 meters (33 feet) and lowered again, the drill bit became stuck at 2,095 meters (6,875 feet).

An intrusion of magma had filled the lowest 9 meters (30 feet) of the open borehole. The team terminated the drilling and completed the hole as a production well.

“When the well was tested high pressure dry steam flowed to the surface with a temperature of 400 degrees Celsius or 750 degrees Fahrenheit, coming from a depth shallower than the magma,” Elders said.

He and colleagues estimated that this steam could generate 25 megawatts of electricity if passed through a suitable turbine–enough electricity to power 25,000 to 30,000 homes.

“What makes this well an attractive source of energy,” said Elders, “is that typical high-temperature geothermal wells produce only 5 to 8 megawatts of electricity from 300 degrees Celsius or 570 degrees Fahrenheit wet steam.”

He believes it should be possible to find reasonably shallow bodies of magma, elsewhere in Iceland and the world, wherever young volcanic rocks occur.

“In the future these could become attractive sources of high-grade energy,” said Elders.

The Iceland Deep Drilling Project has not abandoned the search for supercritical geothermal resources. The project plans to drill a second deep hole in southwest Iceland in 2013.

Elders was joined in the research project by scientists at HS Orka hf (HS Power Co.), Iceland; University of California, Davis; Stanford University; Iceland GeoSurvey; Landsvirkjun Power, Iceland; U.S. Geological Survey; New Mexico Institute of Mining and Technology; and the University of Oregon, Eugene

-NSF-

The folks over at ECOfriend put together an awesome blog-post explaining some of the most innovative wind turbine designs to come around well, …ever. Check it out.

As we know it:

The vitality of our very existence in the near future is preeminently defined by our optimum usage of renewable sources of energy. Essential among them is the wind energy, an all important energy source in itself as clearly shown by the statistics that affirms production of 58,982MW of power in 2005 through wind energy which was less than 1 percent of global energy. However, by 2008, eight percent of Europe’s electricity was derived from wind, and wind power generation in the United States has increased 13 fold from what it was in 2000. Globally 2 percent of electricity production now comes from wind-powered generators, with capacity increasing exponentially in recent years.

Need for a change:

Well, even clean energy producing wind turbines have their ‘bad days’. They are comparatively costly and can easily get damaged by natural calamities, like severe storms or extreme lightning. Moreover, they are susceptible to causing noise pollution, striking almost 50-60 decibels on an average. The horizontal axis ones are criticized for not being ‘bird friendly’ and at last but not the least – some people find wind turbines downright ugly!

What’s in the future?

Unconventional Turbine Designs:

1. Aerogenerator Wind Turbine:

What’s innovative?
Aerogenerator is made by the British firm Windpower. The gigantic V shaped structure of 144 meters is mounted offshore, and is capable of generating 9 megawatts of electricity – which is 3 times the conventional output. It can also generate power at more than 110mph wind speed.

The Impact:
The vertical axis of the Aerogenerator can make it possible to generate power from all directions, substantially cutting the expenses on building newer mechanism. Additionally it can also generate power in storms.

2. Helix Wind’s Savonious Turbine:

What’s innovative?
Helix Wind, a company known for designing efficient wind turbines, have introduced 2kW medium wind system and 5kW System and these turbines are claimed to generate much less noise and are safer for birds and bats than any other existing wind turbine. The noise that the turbine dubbed Savonius makes is similar to the noise generated when wind passes through a tree or a house.

See the rest of the ideas here: What’s Next In Wind Energy Harvesting Systems? – Ecofriend.

Image by Getty Images via @daylife

The folks over at eBay Green Team have some great, common sense tips that i wanted to share. Link to the story below.

In an ideal world, everyone would be able to ditch their cars, burn some extra calories, and bond with their community on electric subways, buses, and trains. However, since not all public transportation systems are created equal, it can be hard to give up your vehicle completely. So how about making those miles that you spend in the car as “green” as possible? The average US driver produces over 10,000 lbs of CO2 every year, contributing to the quarter of all US carbon dioxide emissions that come from the transportation sector. Therefore, the most direct way to ease your car’s impact on the environment is to bump up your gas mileage. Even if you can’t buy that new Prius, you can still reduce your gas consumption considerably just by changing the way you drive. Here are just a few places to start.

Buy a More Efficient Vehicle
If you are in the market for a new car, there are many options for a greener alternative – from Hybrid-electric cars, diesel cars, and alternative fuel vehicles (AVFs). Beyond the environmental benefits, Federal, State, and private companies add even more perks with tax incentives, access to HOV or carpool lanes, discounted parking, or even cash to their employees for purchasing a hybrid.

Share a car
If you commute on public transit and just need a car for the occasional grocery run or weekend escape, considerjoining a car co-op. One of the best ideas to come forward in the move toward collaborative consumerism, each shared car takes 15-20 cars off the road, and saves an average of $1300/year for those who drive around 5,000 miles annually (vs. car ownership). Not to mention relieving you from the headaches that come along with car registration, oil changes, car washes, daily parking fees, etc.

Easy on the Pedal
Driving aggressively is a guaranteed way to waste gas, lowering your mileage by up to 33% on highways and 5% around town. Every time you brake, you’re wasting the gas used to get going. Instead of accelerating quickly and slamming on the brakes, gain speed slowly and look ahead to anticipate when you can take your foot off the gas and begin stopping.

Turn it off
Contrary to conventional wisdom, starting your engine takes the same amount of energy as idling for 6 seconds. So, if you’re sitting for more than a minute, turn off the car and expend your own energy to turn that key one more time.

Navigate Smarter
Believe it or not, drivers that use GPS navigation systems are much more planet-friendly than those who don’t – just by virtue of the fact that they get lost less! Driving in circles is not only frustrating for you, it takes a significant toll on the environment. Smart car manufacturers like Ford have even taken it a step further and installed systems like Eco-Routes that let you choose the most fuel efficient path. So invest in a GPS system to give you peace of mind AND a clear green conscience; and don’t forget to trade it in using eBay Instant Sale when you are done with it!

Lighten your Load
As common sense would tell you, the lighter and sleeker the car, the better mileage you get. So, take off that luggage rack, roll your windows up, and empty out your trunk to lighten the load for your engine.

Be Cheap – Pass on Premium Gas
Unless your car specifically requires premium gas, most modern engines do not benefit from the higher grade of gas. Instead, it just costs you more and creates more pollution from higher octane levels.

Show some love
Give your car the attention it deserves and it will reward you by running more efficiently and lasting longer. Make sure you’re using the recommended grade of oil for your car, keep your tires inflated to the recommended pressure, and get your car serviced regularly to catch any problems that can drastically reduce gas mileage or cause extra pollution. Even better, find a green auto body shop to do the work.

Use a Commercial Car Wash
Put down the hose. A commercial car wash uses 60% less water than an at-home wash, and they are legally required to properly treat contaminated waste water so it doesn’t go through neighborhood storm drains and into local lakes and rivers. If you’re committed to DIY, at least follow these tips to make your car wash as green as possible.

Track your progress
Yes, there is an app for this too. Track your gas mileage with an iPhone app to monitor the results of your new driving behavior. You can even get extra fancy with apps that track oil change and other maintenance reminders to keep your car in top condition.

Drive Greener for the Planet (and your wallet) – eBay Green Team.

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China’s Coming Green Boom | The Diplomat.

For years now, China has been at the receiving end of stinging criticism from the West over its environmental policies, with critics describing it variously asone of the most polluted countries, an insatiable, consumer-driven energy guzzler, and the world’s worst emitter of greenhouse gases.

These labels have been prompted by China’s rapid industrialization and urbanization over the past 30 years, which has allowed it to achieve blistering economic growth, but at enormous cost to its environment. Given the widespread criticism, it’s understandable why many in the West might find it hard to imagine this ‘dirty’ giant ever getting clean.

Yet these difficulties shouldn’t overshadow an encouraging reality—China’s top decision makers are planning to take a more holistic approach to the quest for greener growth that could transform the country’s image.

China’s central government is currently thrashing out details of how best to steer towards greener growth as part of closed-door discussions aimed at finalizing the country’s 12^th Five Year Plan (2011-2015), which will be announced in March. The plan is expected to become China’s first national plan to shift the development agenda decisively toward a pattern of green growth, accelerating the country’s efforts at green modernization. Expect ‘establishing a low carbon society’ to be a key political slogan over the next five years.

With a limit to the amount of fossil fuel it can access, and with these fuels anyway creating significant environmental damage and associated socioeconomic problems, China’s top leadership seems to be realizing that the old ‘growth at all costs’ model that has previously been followed threatens not only the country’s energy security, but its very survival. A green development pathway based on low energy consumption and low carbon emissions is essential if China is to find a sustainable path to growth.

The environmental aspects of the plan are likely to be boiled down to five key points that will be presented to the public and used to measure China’s success in achieving its ambitious targets.

First, the government is believed to be considering using green indices as a yardstick for evaluating the performance of local officials. Water consumption per unit of GDP, proportion of clean coal consumption utilized, and the proportion of GDP invested in environmental protection will all be integrated into the indices. The idea is that this will force local governments to strengthen resource efficiency and improve ecofriendliness in key sectors such as heavy industry, construction, and transportation. Gone will be the days when the rate of GDP growth is the sole determinant of success.

Second, China aims to gradually establish a carbon trading system to help it meet its 2020 carbon intensity target of reducing CO2 emissions as a proportion of each unit of GDP by 40 to 45 percent of 2005 levels. Policymakers are expected to view carbon trading as a market-oriented, cost-effective way of supplementing current administrative measures to reduce emissions and genuinely shift the country’s ‘brown’ economy to a ‘green’ one. A cap-and-trade market is also expected to be up and running by 2014, while over the next couple of years, carbon trading programmes will most likely focus on pilot schemes in economic zones and/or industrial sectors such as the coal-fire power generation sector.

Third, China will continue to support the research, development, and deployment of clean energy technologies. China was reported in December to be seriously considering, for example, investments of up to $1.5 trillion in seven strategic industries including renewable energy, clean energy vehicles,and low carbon technologies. In this regard, keep an eye out for two Chinese companies—Yingli Solar and Wanxiang Group—that will play a more proactive role in producing state-of-the-art clean energy technologies to help create more ‘green collar’ jobs domestically and overseas. With robust government support and private sector innovation, China’s pledge to have 15 percent of its energy come from non-fossil fuels by 2020 could be achieved more smoothly and quickly with smart investment. If it can follow through on these ambitious plans—admittedly a big if—there’s little doubt China will be able to join world leaders in the development of wind, solar, and electric vehicle technologies.

Fourth, with the country’s total power capacity expected to climb to more than 1,430 GW by 2015, compared with 874 GW at the beginning of last year, China has been trying to figure out how to bring trillions of kilowatts of power to more than a billion consumers, sometimes over extremely long distances. With this in mind, the government is said to be planning to invest about $300 billion in a smart grid over the next five years that allows potential problems to be detected early. So far, local governments including the Jiangsu Provincial Government and the Shanghai Municipal Government have taken the lead in publishing plans for smart grid development.

Last but not least, China is expected to begin efforts to restore marine ecologies for the first time, focusing not only on supervising chemical oxygen demand, which measures the amount of organic pollutants found in surface water, but also limiting emissions of nitrogen and phosphorus, which causes eutrophication. In addition, constructions such as dams and sea walls will be strictly examined to ensure that they aren’t adversely impacting the environment.

If China’s policymakers can follow up on this promising list, then it could produce some genuinely spectacular policies that will help the country dramatically increase its chances of sustaining its strong growth, expand its clean technology market, and achieve green job creation.

None of this will be easy, not least because rapidly rising energy demand will mean coal and oil inevitably remain a foundation of China’s economy for years to come. In addition, China’s efforts at developing a green economy so far look like a top-down initiative, meaning much of the public doesn’t really understand what a green economy entails, its importance, or how they can contribute to creating one. As a result, there’s a clear need for proper public outreach to encourage people to become engaged.

Still, the talk around the upcoming five-year plan offers some cause for optimism that with the central government genuinely behind it, and if market-driven mechanisms can be properly utilized, China can launch itself on the path to a greener future.

Related articles

• Asia Challenges the U.S. for Green-Tech Supremacy (time.com)
• China committed to more open market- vice premier (reuters.com)

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BBC News – Forest loss slows as Asian nations plant.

Forest loss across the world has slowed, largely due to a switch from felling to planting in Asia.

China, Vietnam, the Philippines and India have all seen their forested areas increase in size.

There are also gains in Europe and North America, but forests are being lost in Africa and Latin America driven by rising demand for food and firewood.

The findings come in the UN Food and Agriculture Organization’s (FAO)State of the World’s Forests report.

Environmental groups are warning that priority needs to be given to old forests and the biodiversity they maintain in the face of climate change and growing demand for resources.

Rise of Asia

The FAO report’s formal launch at UN headquarters in New York co-incides with the start of the UN’s International Year of Forests.

The initiative aims to raise awareness of conservation among governments and other stakeholders.

The FAO is urging governments to explore ways of generating income from forests that do not depend on chopping trees down.

Forests now cover about 40 million sq km – just less than one-third of the Earth’s land surface.

Although 52,000 sq km were lost per year between 2000 and 2010, that was a marked improvement on the 83,000 sq km annual figure seen during the previous decade.

Europe traditionally has been the region with the biggest increase; but now, Asia has overtaken it.

A net loss of forest in Asia during the period 1990-2000 has been transformed into a net gain in the decade since.

“China has increased its forest by three million hectares (30,000 sq km) per year – no country has ever done anything like this before, it’s an enormous contribution,” said Eduardo Rojas-Briales, assistant director-general of the FAO’s forestry department.

Madagascar’s forests have been hit hard by illegal logging following political unrest

“But we can also highlight the case of Vietnam, a small and densely populated country that’s implemented very smart and comprehensive forest reform – or India, which has not controlled its population as China has and where standards of living are even lower.

“Nevertheless India has achieved a modest growth of its forest area, and the Philippines has turned things around as well – so we’re seeing improvement across Asia except in the weakest states,” he told BBC News.

Dr Rojas-Briales suggested Latin American countries where forest loss continues could learn from East Asian policies, in particular the adoption of land use planning.

The report cites agriculture as the leading cause of deforestation in South and Central America and the Caribbean.

In Africa, the need for firewood is the key factor.

Conservation call

In Asia, South America and Africa, the area covered by deliberately planted forests is increasing, which could mean that old-growth forests continue to disappear while plantations spread.

The report does not distinguish between the two kinds; but Dr Rojas-Briales said plantations overall were not expanding at the expense of old-growth forests, at least not in Asia.

This is supported by the report’s conclusion that in the Asia-Pacific region, the area of forest designated for production has fallen since 2000, with an increase in lands set aside for conservation of biodiversity and ecosystem services.

However, as old-growth forest continues to disappear in some parts of the world, Conservation International is one of several environment groups pressing for increased attention on these areas and their special importance for nature.

“Forests must be seen as more than just a group of trees,” said Olivier Langrand, the organisation’s head of international policy.

“Forests already play an enormous economic role in the development of many countries as a source of timber, food, shelter and recreation, and have an even greater potential that needs to be realised in terms of water provision, erosion prevention and carbon sequestration.”

Conservation International is highlighting 10 places in the worldwhere forests of iconic importance are under threat, including the banks of the Mekong River and the wildlife it supports, the lemur-rich jungles of Madagascarm and the Californian Floristic Province, home of the giant sequoia.

All currently cover less than 10% of their original range.

There are concerns in some quarters that the UN scheme on Reducing Emissions from Deforestation and forest Degradation (Redd) may lead to forests being conserved simply because they store carbon, without taking account of their immediate benefits to wildlife and local people.

Related articles

• Asia drives forest growth trend (bbc.co.uk)

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Repurpose an old laptop as a digital picture frame |.

I love this idea. Many of us do indeed have old laptops gathering dust and the folks over at Maker.com have come up with a great how-to on getting a project like this on your wall.

Erik Pettersson couldn’t find a digital picture frame he liked, so he rolled his own using an old laptop and a frame from Ikea. With Ubuntu running on the laptop, he created a few scripts for changing the picture at a determined interval and for turning the display on and off at different times of day.

After disassembling the laptop and removing the unnecesary components, he mounted the screen in the frame and the CPU behind it. Using VNC over WiFi, Erik can easily make adjustments to the settings of his newly-hacked digital picture frame. And just in case that doesn’t work, he also left the keyboard and a USB port accessible on the back. Nice work, Erik! [via Ikea Hacker]
More:

• Digital picture frame
• Flickr Enabled LCD Frame
• Juicebox picture frame…
• Cheap ‘n easy digital picture frame under $100
• DIY digital picture frame
• The $11 LCD Photo Frame?

Related articles

• Repurpose an old laptop as a digital picture frame (makezine.com)

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Nearly half the states are offering or considering incentives to consumers who buy electric cars in a bid to jump-start the fledgling market.

Experts say the sweeteners, including rebates and access to less-congestedcarpool lanes, are key to making the vehicles more affordable and convenient as automakers roll out the first mainstream electric cars in nearly a century.

The benefits, combined with a federal tax credit up to $7,500, often put the vehicles in the price range of standard cars, says Brian Wynne of the Electric Drive Transportation Association.

Last month, Nissan rolled out its $33,630 Leaf, a fully electric vehicle (EV), and Chevrolet launched its $41,000 Volt, a plug-in that also has an onboard generator powered by an auxiliary gas engine. They’re initially available in a handful of markets.

Tom Franklin of San Diego says a $5,000 state rebate plus the federal credit reduced the price of his Leaf from $35,000 to $22,500, less than his 2006 Toyota Prius. “It really made it a no-brainer.”

Seventeen states already offer inducements for EVs, while five — Connecticut, Massachusetts, New York, Pennsylvania and Texas — are considering legislation, advocacy group Plug In America says.

“You want to create an environment that’s conducive to the marketplace,” says Jorge Santana, chief of staff for Pennsylvania state Rep. Tony Payton, who’s introducing an EV incentive bill.

Automakers are responding. Nissan launched the Leaf in California, Arizona, Oregon, Washington and Tennessee, all states with incentives. Other lures:

•Seven states — Arizona, California, Florida, Georgia, Maryland, New Jersey and Utah — let EV drivers use carpool lanes even with no passengers. In California, up to 75,000 hybrid drivers who are losing special carpool lane privileges this year may upgrade to EVs to retain them, says Plug In America’s Jay Friedland. “It’s hours a day you’re saving.”

•Nine states offer EV buyers tax credits or cash rebates of $1,500 to $6,000. “We’re trying to get to zero emissions coming out of the tailpipe,” says William Cook, a Georgia environmental manager.

•Louisiana, Hawaii and Washington provide tax credits or other discounts to cut the price of home charging stations, which can cost at least $1,200.

•Maryland, New Jersey and Washington waive sales tax for EV buyers. Washington, with a 6.5% sales tax, hopes to “send the right signals” to car and part makers so they’ll locate plants in the state, says Gustavo Collantes, state energy policy adviser.

Some states offer electric car incentives – USATODAY.com.

Related articles

• Some states offer electric car incentives (usatoday.com)

Solar combo generator heats and powers | Green Tech – CNET News.

A new type of solar thermal system for homes that can provide heat, hot water, and electricity is being tested in Boulder, Colo., over the next few months.

Cool Energy says its SlowFlow system could provide the average U.S. home with 80 percent of its heat, 100 of its hot water, and 60 percent of its electricity needs.

It’s being developed with help from the National Science Foundation, the Department of Energy, and electricity and natural gas giant Xcel Energy.

The system consists of solar collectors, a Stirling engine, a hot water heater, a space heater, an insulated storage tank, and the SolarSmart Controller, a computer with networked communications

The SolarSmart Controller uses weather, ambient temperature, building temperature, and sunlight data to determine the device’s most effective usefulness for a given day. If, for example, it’s cold and overcast outside and its building’s internal temperature is below a given desired temperature, the device would generate its effort to heating the building. On warm and sunny days, it would direct itself to generate electricity instead.

But the centerpiece tech of the system, which won the 2009 Cleantech Open Sustainability Award for the Rocky Mountain region, is Cool Energy’s SolarHeart engine. The proprietary Stirling engine was developed by Cool Energy to efficiently convert solar thermal energy or waste heat into electricity. When tested in the lab over a wide array of temperature and solar conditions, the device’s SolarHeart engine was able to generate more than 2,000 watts of electricity, and achieve more than 16 percent efficiency for thermal-to-electrical conversion, according to Cool Energy statistics.

The complete Slow Flow system minus its solar collectors, which are located on the roof of the building.

(Credit: Cool Energy)

A successful solar multi-use generator might allow customers to recoup their investment in the device more quickly compared to solar panels that provide electricity only. It might be especially effective in climates where homeowners need home heating oil or propane to heat their homes in winter, and electricity-guzzling air conditioners to cool their homes in summer.

Of course, the field test will offer more insight on this system’s true real-world capabilities. And while this is certainly an innovative green tech product idea, Cool Energy is not the first to use a solar-driven Stirling engine.

Tessera Solar and Stirling Engine Systems have been testing a large-scale solar system that uses mirrored parabolic dishes that track the sun and heat hydrogen gas-filled pistons in a Stirling engine to generate electricity.

Read more: http://news.cnet.com/8301-11128_3-20029034-54.html#ixzz1Bc0lDl4H++

Related articles

• Solar combo generator heats and powers (news.cnet.com)

How Starbucks Saves Millions per Year in Energy from LED Lighting | Business | GreenBiz.com.

Small Vibration-driven Generator Developed for Replacing Button Batteries — Tech-On!.

A Japanese university researcher developed a small-size vibration-driven generator that measures approximately 2 x 3 x 12mm and can output a power of 1.56mW with a vibration of 357Hz.

The energy density of the generator, which was developed by Toshiyuki Ueno, associate professor at Kanazawa University, is about 22mW/cm³. It is about 20 times higher than the energy density of normal small-size vibration-driven generators, which is about 1mW/cm³.

“The energy density is high enough to replace a button battery,” Ueno said.

He is planning to apply the generator to tire pressure monitoring systems (TPMSes) for automobiles and mobile devices.

As a power generating element, Ueno used a magnetostrictive material called “Galfenol” (Fe_81.4Ga_18.6), which is an alloy of iron (Fe) and gallium (Ga) and has a large magnetostriction effect. Magnetostriction effect is a phenomenon in which the shape of an object changes due to magnetization. In the case of Galfenol, its magnetostriction effect is about 300ppm (a 1km-long bar would extend by about 300mm).

To generate electricity, Ueno used inverse magnetostriction effect, which is the converse phenomenon of magnetostriction effect. Inverse magnetostriction effect is a phenomenon in which the application of stress changes magnetization. In the case of Galfenol, its magnetic flux density decreases by up to more than 1T when compressional stress is applied. And the change in magnetic flux generates an induced voltage.

Galfenol was developed by the US Naval Research Laboratory (NRL) in 1998. But this is the first time that it has been used for a vibration-driven generator, Ueno said.

Galfenol is a ductile material. Therefore, it can be easily processed by machines, and it does not easily break when warped. Piezoelectric elements, which are normally used for vibration induced power generation, are made of a ceramic, which is a brittle material.

Terbium (Tb), dysprosium (Dy) and Terfenol-D, which is an iron-based super-magnetostrictive material with a magnetostriction effect of about 1,000ppm, have large magnetostriction effects. But they are also brittle materials.

This time, Ueno created a structure that is small but can generate a large amount of electricity by taking advantage of the ductility of Galfenol. Specifically, one ends of two long and thin magnetostrictive elements are fixed, and weights are added to the other ends (parallel beam structure). To output electricity, coils are made by winding thin electric wires around the magnetostrictive elements.

When the weights vibrate up and down, bending deformation occurs to the two magnetostrictive elements. At this point, a compressive force is applied to one element, and a tensile force is applied to the other element.

When the weights are moving up and down, the compressive force and the tensile force are alternately applied to each of the two elements, periodically changing the magnetic flux. This time variation generates induced voltage on the coils, and electric power can be efficiently output.

“Because Galfenol is a ductile material, even the thin rod-shaped structure does not easily break,” Ueno said.

The dimensions of the magnetostrictive element are 1.0 x 0.5 x 10mm, and it is equipped with a magnet that is 2mm in diameter and 2mm in length for bias magnetization.

Moreover, Galfenol features an excellent thermal property. Its Curie temperature is as high as 700°C, and its performance does not change much within the temperature range of -200 to 200°C, Ueno said. Therefore, Galfenol is suited for use in places where change in environment is fast and violent.