Wednesday, August 31, 2011

Latest from: CleanTechnica

Latest from: CleanTechnica

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Batteries that Charge Themselves with Mechanical Energy

Posted: 31 Aug 2011 03:05 PM PDT

Piezoelectric Buzzer. Image obtained with thanks from Gophi on the English Wikipedia. Click image to view larger version of it.

MicroGen Systems has been working on electricity-generating chips designed to power wireless sensors like those used to monitor tire pressure and environmental conditions.

These chips convert the mechanical energy of vibrations into electricity, which is then used to charge a small battery, which in turn powers the sensors.

If the chips are capable of generating adequate electrical energy, then they could mostly (or maybe even completely) eliminate the need to replace the batteries.

The core of MicroGen’s chips is a 1 cm2 array of silicon cantilevers that oscillate when the chip is jostled. At the base of the cantilevers is a bit of piezoelectric material: when it’s strained by vibrations, it produces a voltage that can be used to generate electrical current. Voltage is what causes current to flow. Voltage (potential difference) is the difference in electric charge between two points in a circuit. This difference causes electrons to flow until both charges become equal.

The array of cantilevers is mounted on top of a postage-stamp-sized, thin-film battery that it charges. The current passes from the piezoelectric array through an electrical device that converts the current to an appropriate DC current that is suitable for charging the battery. When the chip is shaken by the vibrations of a rotating tire, for example, it can produce about 200 microwatts of power.

An efficient vibration-energy-harvesting device has the potential to be very beneficial because there are so many vibrating devices, such as mechanical machines, in general, including automobiles, generators, engines in general, and fans, as well as humans walking, arm and hand movements, and much more.

David Culler, chair of computer science at the University of California, Berkeley said: ”If you can get it down to a small size, 200 microwatts is potentially quite useful.”

Robert Andosca, the founder and president of MicroGen Systems, said that what sets this technology apart from other piezoelectric generators is the fact that it is made of a non-toxic material known as PZT.

200 microwatts of power might not be much, but if it is small enough, it could be very beneficial to tiny sensors that need to be integrated into small places.

h/t Technology Review


New LED Lightbulb Under $15 Hits the Market, May Go Lower

Posted: 31 Aug 2011 02:49 PM PDT

Lighting Science launches new low cost LED lightbulb for less than $15The days of using lightbulbs as a political football may be drawing to a swift and un-melodramatic close, now that the company Lighting Science Group has announced the development of a new 60-watt equivalent LED lightbulb that will retail for under $15.00. The sub-$15 price point is critical, because given that the new bulb uses about 85% less electricity than a conventional incandescent bulb, the payback is a mere eight months. On top of that, the life expectancy of the new LED lightbulb is about 8 years compared to whatever for those pesky conventional bulbs that keep burning out, so there is the potential for a quick and widespread breakthrough into the mass market within the next few years.

Coal Power and High Efficiency LED Lightbulbs

The new bulb will be introduced globally, starting with India this year, and it was designed specifically for the Indian power grid’s variable quality. It may also prove to be a key factor in India’s management of greenhouse gas emissions from coal fired power plants. According to a press release from Lighting Science, India plans to build 80 new coal plants to keep up with energy demand over the next five years, but a full switch to LED lighting could reduce that load by up to 40 percent.  If that figure seems a bit high, check out this lightbulb infographic to get a picture of the impact that lightbulbs have on energy consumption in the U.S.

Even Cheaper LED Lighting

Meanwhile, over in the U.S.A researchers at the University of Florida are on to a new LED lightbulb design that could result in an even cheaper LED. The new approach is based on semiconductors composed of layers of different materials including quantum dots, which are tiny nanoscale crystals. Though this hybrid composition results in a more efficient LED, until now the catch has been that different processes are needed to apply the different kinds of layers, and that adds up to a more expensive LED lightbulb. The  Florida team has developed a way to design the structure so that only one process is needed. As an added bonus, the new design is more efficient and has a longer lifespan that conventional LED lightbulbs.

Lightbulb War Fizzles Out

At the beginning of this summer the majority party in Congress was still dead set on clinging to incandescent lightbulbs, but the hullabaloo seems to be dying quickly. Little wonder, because Lighting Science is not the only company introducing low-cost, high efficiency lighting alternatives.It’s not just the consumer market, either; LEDs are popping up all over the place, from modestly scaled designs for  U.S. Navy bunk lights to gigantic airport parking garages. Some legislators are still carrying a torch for incandescents, but the rest of the world is moving on.

Image: Cash register by seanmcmenemy on

Tina Casey on Twitter: @TinaMCasey

Changing the Climate Conversation to Conservation

Posted: 31 Aug 2011 12:10 PM PDT

Wind turbines currently supply seven percent of all electricity in Kansas

Polling data shows the percentage of Americans concerned about climate change is falling, down 12 percent over the past 10 years, according to a recent Gallup Poll, and in some parts of the country the term "global warming" is practically taboo. So why, then, are some of the states with the biggest populations of “global-warming skeptics” also some of the states making the biggest investments in renewable energy?

energyNOW! correspondent Lee Patrick Sullivan visited Kansas, where some clean energy advocates say they've figured out what it takes to convince climate-change skeptics to invest in renewables and energy efficiency. Their advice: stop talking about global warming and change the conversation to energy conservation. You can watch the full video below:

"Almost half of all Kansans don't really buy into the whole global warming idea," said Dorothy Barnett of the Climate and Energy Project, a group working to reduce fossil-fuel use in Kansas. "They don't buy the climate science." But Barnett's group is avoiding the climate change controversy by offering cash incentives for communities to reduce energy use.

The new approach seems to be working, says one town competing for the $100,000 top prize in the Climate and Energy Project's "Take Charge!" challenge to lower energy use. Goodland, a small town located in western Kansas, has reduced its energy use by five percent. "I would say primarily the motivation here is people who want to help their pocketbook, maybe earn the community some cash on the back end and also have a good competition with their neighbors," said city manager Douglas Gerber.

Saving money isn't the only motivator to cutting energy use in the state — religious faith is also playing a big role. The Kansas Interfaith Power and Light Initiative has signed up more than 10,000 congregations who pledge to incorporate creation stewardship and energy efficiency measures into their practices since 2008. But the effort has run into resistance because of its acceptance of the theory of global warming, says one of the initiative's founders.

"I did bring it (the IPL pledge) to my Pastoral Council, but we couldn't get it signed," said Father Kerry Ninemire, of St. Mary's Church in Salina, Kansas. His parishioners refused to sign it, he said, because of the climate change language contained in the pledge. Father Ninemire was able to convince his parish to take the Initiative's energy efficiency advice, and reduced energy use in the church and high school 10 percent by switching to efficient lighting and programmable thermostats.

This shift in thinking isn't limited to conservation, however. Wind energy is growing across the state, creating green jobs and emission-free electricity. Kansas currently gets seven percent of its electricity from wind, and the state has the second-highest wind energy potential in the U.S. behind Texas. To many Kansans, all those potential electrons from the near-constant wind look like dollar signs. "We don't need to produce wind energy, necessarily, for anything other than the economic side of it," said Mark Richardson of the Reno County Wind Energy Task Force.


Electricity Home Rule Could Save D.C. Billions, Create Over 14,000 Jobs

Posted: 31 Aug 2011 06:40 AM PDT

For many years the citizens of Washington, DC, struggled for the basic right to elect their own leaders.  In 2011, they should use their political home rule to maximize the economic benefits of local renewable energy with "electricity home rule."

Currently, residents and businesses in Washington spend over $1.5 billion dollars a year on electricity.  According to a study of DC's energy dollars by the Institute for Local Self-Reliance, 90% of that amount (largely unchanged since the 1979 study) – $1.4 billion – leaves the city.

With rooftop solar power, DC residents could keep more of those electricity dollars at home.

In its recently published atlas of state renewable energy potential, the Institute for Local Self-Reliance (ILSR) found that the District of Columbia could generate 19% of its electricity from rooftop solar PV systems.  That's $267 million spent on electricity bills that could be kept locally.

But maximizing local electricity generation with rooftop solar has enormous additional economic benefits.  To fill District roofs with solar panels, residents would need to install just over 1,800 megawatts (MW) of rooftop solar.  The National Renewable Energy Laboratory (NREL) estimates that every megawatt of solar generates $240,000 in additional economic activity, making the economic value of maximizing solar energy self-reliance close to $432 million.

It could go even higher.

A previous NREL study of the value of local ownership of renewable (wind) energy found that it multiplied the economic benefits from 1.5 to 3.4 times.  If D.C. residents maximized local ownership of solar, it could have an economic value as high as $1.5 billion, equivalent to the District's total electricity bill.

The 1,800 MW of solar would also generate jobs.  With a rule of thumb of 8 jobs per MW, according to a University of California, Berkeley, study of the jobs created from renewable energy development, the District could get as many as 14,500 jobs from maximizing its solar energy self-reliance.

The cost of going solar is minimal.  At current best prices for solar PV (around $3.50 per Watt installed) and with the benefit of the 30% federal Investment Tax Credit, solar PV can deliver electricity to the District for 16.1 cents per kilowatt-hour.  After seven years at current electricity inflation rates (3% per year), solar PV — with zero fuel cost or inflation — would be less expensive than retail grid electricity (currently 13.3 cents per kWh).  Over 25 years, a switch to sunlight from grid electricity could save District ratepayers $1.6 billion.

The solar power offers much more than just affordable electricity.  Recent studies have suggested that the actual value of solar power to the grid and environment far exceeds the value of the sun-powered electricity.  And ILSR’s recent report on Democratizing the Electricity System illustrates how solar power and other distributed renewable energy sources are the cornerstone of a transformation to a decentralized, more democratic energy system.

Citizens of DC should take the opportunity presented by their solar resource and pursue electricity home rule.

An Aeroponic Green Thumb: Click and Grow

Posted: 31 Aug 2011 03:00 AM PDT

If the complexity of your life has not admitted the capacity to grow a plant, and you long to, then Click and Grow aeroponics can be your secret green thumb. These special flowerpots are equipped with sensors, microprocessors and software that provide food and water. You’ll just need to provide “a spot with good light conditions, but away from direct mid-day sunlight.” The name “Click and Grow” seems to be a hold-over from prototypes of this system where the pot had a USB connection and the software was transferred from your computer.

This system requires 4 AA batteries to operate a small pump and the essential electronics. Each plant has ideal growing conditions. The Click and Grow cartridge contains the seeds, nutrients and now the software needed for the specific plant.

Aeroponics is different from hydroponics, where the roots are suspended in a mineral solution (and completely different from aquaponics). Hydroponics tends to a more humid environment, has more possibility of disease, and does not require as elaborate a kit. Aeroponics use small containers that hold seeds, usually in sponges. These are, in turn, held in a closed container with only enough opening to allow the plant to grow above. Water containing nutrients is pumped over the sponges and later roots that hang in the air. Some systems will use a mist or bubbles, but each is timed to keep the roots moist without decay. The plant grows above, held by the sponge and the former seed cartridge. Commercial systems are used where soil is not available, water is limited, and greater yields than hydroponics are wanted.

A seed starter system is possible with aeroponics, but is not suggested with the Click and Grow system. The full-grown plants are not easily transplanted to another medium. Similarly, if your home doesn’t have sufficient sunlight, other more costly systems with artificial lighting are going to be more suited to your circumstances.

My thumb may show a little green around the edges. I have experimented with using compost to heat my greenhouse during the winter, but it is the energy and mechanics of green culture rather than the proximity of plants that fascinates. To the “plant-whisperers” among us, the suggestion of growing green without attention may be a bit of a shocker. It is a big world, thuogh, and for those just starting their appreciation and connection with plants. the Click and Grow system may be a very good beginning.

Primary source and photo credit: Click and Grow via Gizmag