World’s Largest Wave Energy Site Now Installed in UK

by Timon Singh

The Wave Hub, a groundbreaking renewable energy project that is set to become the UK’s first offshore facility dedicated to wave energy, has been installed off the North Coast of Cornwall. Four wave energy generation devices will connect their arrays into the Hub, allowing developers to transmit and then sell their renewable energy to the UK’s electricity distribution grid. The total capacity of the hub will be 20 MWe (megawatt electrical).
The project that has cost £42 million ($64 million) will essentially be a ’socket’ sitting on the seabed for wave energy converters to be plugged into. It is hoped Wave Hub’s construction will make the South West of England a leading player in the global marine energy industry. Wave Hub will also see the construction 0f a sub-station built at Hayle 10 miles away.  It will be situated adjacent to a connection point on the distribution network. From there, a cable will be taken through a 200m duct beneath the sand dunes and then across the sea bed to an eight square kilometre area within which the devices will be moored.

The South West Regional Development Agency (RDA) has put £12.5 million into the project with £20 million coming from the European Regional Development Fund (ERDF) Convergence Programme. Another £9.5 million will come from the UK government. The scheme is expected to be operational next year and has already signed up its first wave device developer – Ocean Power Technologies Limited. Fred Olsen Limited, WestWave and Oceanlinx are said to be the other three companies.

Stephen Peacock, executive director of Enterprise and Innovation at the South West Regional Development Agency (RDA), said, “This milestone is the culmination of more than six years’ work by the RDA and its partners and will catapult south-west England and the UK to the forefront of wave energy development. Our aim is to create an entirely new low-carbon industry in the south west and hundreds of quality jobs.”
Energy and climate change minister, Lord Hunt, welcomed news of the construction and said that it demonstrated huge scope for wave and tidal energy around the UK’s shores. ”The south west is the UK’s first low-carbon economic area, building on its regional business opportunities and skills,” he said. “The combination of its wealth of natural marine resource and its high level of expertise in marine technology makes it an ideal location for the Wave Hub.”
However while Wave Hub may be a source of national pride as well as renewable power, no-one is more proud than the RDA’s Wave Hub General Manager Guy Lavender who said, “Seeing Wave Hub lowered into the water was the culmination of more than seven years’ hard work by hundreds of people and the fact that it was designed and built in this country is testimony to the skills and experience that the UK already has in the fledgling marine renewables industry.”

More Solar

MIT Creates Self-Assembling Solar Cells That Repair Themselves

by Jaymi Heimbuch

MIT's Test Cell Patrick Gillooly, MIT
Solar cells are intended to mimic the photosynthesis of plants -- converting light into energy in the most efficient manner possible. But what other characteristics of plants could be handy for the renewable energy sector to mimic? How about the self-assembly of chloroplast, the component of plants that do all the vital photosynthesis. Leaves repair themselves after sun damage again and again to keep up their ability to convert light into energy. Now, MIT researchers believe they've discovered how to use this self-assembly to restore solar cells damaged by the sun.

Popular Science writes, "To recreate this unique regenerative ability, the MIT team devised a novel set of self-assembling molecules that use photons to shake electrons loose in the form of electricity. The system contains seven different compounds, including carbon nanotubes that provide structure and a means to conduct the electricity away from the cells, synthetic phospholipids that form discs that also provide structural support, and other molecules that self-assemble into "reaction centers" that actually interact with the incoming photons to release electrons."
These compounds can assemble themselves into structures able to harvest solar energy at an efficiency of about 40%. As they loose efficiency from damage, a surfacant can be spread across them to break down the compounds, then when it is filtered out, the cells reassemble good as new. The researchers think they can eventually boost the efficiency even higher, and perhaps provide solar cells that are virtually indestructible.
MIT is constantly coming out with new possibilities for the solar industry, from solar concentrators that improve both efficiency and designs, to printing thin film solar cells on paper. And now, perhaps, solar cells that bring us even closer to completely mimicking leaves.

SkyFuel’s SkyTrough is World’s Most Efficient Solar Concentrator

by Timon Singh

When it comes to producing solar power, efficiency is the key – efficiency of the panels, efficiency of the system’s collectors and, according to SkyFuel, efficiency of the solar concentrator technology. Solar concentrators are increasingly being used in the industry, due to their efficiency in providing cheap solar energy. By harnessing the sun’s energy, a solar concentrator can provide the necessary heat for dozens of homes and thus save electricity. As such, the systems are more efficient than regular solar generators as captured power is not just converted into electricity. But according to SkyFuel, a U.S.-based company, their SkyTrough solar concentrator technology has a thermal efficiency of 73% at 350˚C (662˚F). More than just a shallow claim, their statement has been confirmed by the National Renewable Energy Laboratory (NREL), which has certified the SkyTrough solar concentrator technology to have the highest efficiency in its class!

 

Performance of the optical elements of the SkyTrough was measured at the Optical Efficiency Test Loop in Golden, Colorado. The test facility was designed to allowed the study of the optical performance independent of the receiver’s heat loss characteristics. Optical efficiency is a direct gauge of the design elements unique to the SkyTrough’s mirror reflectance, parabolic accuracy, receiver alignment to the focal line of the trough, and the system’s tracking precision. ”The SkyTrough solar collector is a new, low-weight design that takes advantage of the patented reflector film jointly developed by SkyFuel and NREL,” said Chuck Kutscher, Principal Engineer and Manager of NREL’s Thermal Systems Group.
In a statement from SkyFuel, the company’s Chief Technology Officer Randy Gee said, “A lot of thoughtful engineering went into the SkyTrough, so we were confident our efficiency would be high, but NREL’s confirmation really validates our technology. We couldn’t be more pleased with NREL’s assessment.”
Parabolic trough solar concentrators, such as the SkyTrough, are designed to harness the sun’s energy to make steam for electricity generation. The more efficiently that a trough can harness the sun’s energy and convert it to steam, the more electricity it will be able to make. In the SkyTrough’s case, nearly three quarters of the solar radiation is thus converted into thermal energy, and then into electricity – a very high figure for solar power production. The fact that the thermal-to-electricity loss is only 27% is quite remarkable considering the large losses of efficiency that occur within the industry.

Global Solar rolls out stick-on solar panels

by Martin LaMonica

Glue may be the magic ingredient to making solar power cheaper.
Solar company Global Solar introduced a line of flexible solar modules which are designed for flat commercial rooftop buildings.
Rather than install racking systems to hold heavy glass-covered solar panels, the company's PowerFlex BIPV modules can be adhered onto a roof or built right into roofing materials. The modules are quicker to installer, lighter, and don't require any penetrations into the roof, according to the company.
The installed cost of Global Solar modules is about the same as traditional polycrystalline silicon panels with racks, said Jean-Noel Poirier, the vice president of marketing and business development. But because there is no need for spacing between racks, the flexible thin-film modules can cover more roof space and generate more power, he said.
The company plans to sell its solar modules--long strips of solar panels which almost 19 feet long and one and a half feet wide--through roof membrane manufacturers. The solar cells are made from a combination of copper, indium, selenium, and gallium (CIGS) and perform comparatively well in areas that don't have direct sun, Poirier said.
The company plans to get certification for the modules, which are being evaluated by roofing membrane companies now, by the end of the year and start production early next year.
Global Solar, one of many solar companies developing CIGS solar cells and modules, now has 75 megawatts worth of production capacity at two plants in Tucson, Arizona and Berlin, Germany. Until now, the company has supplied solar cells to panel manufacturers, but the company is now manufacturing its own modules for building-integrated photovoltaics, said CEO Jeff Britt.

New Black Silicon Solar Cells are Cheap and Absorb More Sun

by Brit Liggett

While the reflective and shiny solar panels that researchers have been making thus far look pretty, they’re no match for the National Renewable Energy Laboratory’s (NREL) recently discovered black silicon solar cell. The scientists at NREL discovered that etching thousands of tiny holes into a silicon wafer causes it to be almost black and thus able to absorb almost all of the sun’s rays, and more absorbent solar cells mean more efficient panels.

 

We recently reported on researchers that are using off the shelf dyes to help solar cells absorb a wider range of light but this experiment goes even further. No color can stand up to black when it comes to absorbing . Black doesn’t bounce anything back – it hoards all photons for itself. The researchers got the idea from a team in Munich that had carefully placed a thin layer of gold and some fancy chemicals on their silicon to turn it black.
By mixing gold and chemicals into a cocktail and spraying it on silicon, they were able to create a black silicon wafer in under 3 minutes at room temperature. At 100 degrees Fahrenheit they can do it in less than a minute — this bodes well for mass manufacturing. They call their black silicon wet-etched, because the chemical and gold mixture is wet when applied and etches holes into the substance. Their next effort — and its a big one — is engineering a workable solar panel around their etched silicon.

Eddy GT Wind Turbine Is Sleek, Silent and Designed for the City

by Cameron Scott

If you launch a clean energy business in Manhattan it’s almost a given you’ll be inspired to start designing products specifically for the urban environment. Urban Green Energy has just launched a new, one-kilowatt wind turbine designed specifically for city rooftop use! A machine certainly made for the modern dweller, the near silent Eddy GT turbine is a chic piece of wind technology that rotates on a vertical axis, optimizing wind capture, even as the air stream shifts within the dynamic city landscape.

The Eddy GT takes up just 40 square feet to generate its kilowatt — to get that much juice from a solar array, you would need up to 400 square feet, which is a tough sell in major cities like New York and San Francisco. While not a light investment at $7,000 per turbine, Urban Green Energy CEO Nick Blitterswyk estimates that in California, which offers a rebate, you could break even in 10 years, and without the $3,000 rebate, it could take 20 years.
If you’re in San Francisco, look for some turbines in action atop Blitterswyk’s company, amongst other products like the Sanya Solar- and Wind-Powered Streetlamp, in front of Civc Center come mid-October. The turbines have scored some other less predictable placements as well, including a position atop the National Guard building in Cleveland, Ohio, and just about every house in a new middle-class subdivision outside St. Louis!

 

Sleek Solar and Wind Powered Hybrid Street Lamps

by Bridgette Meinhold

As designers strive to create a more sustainable future, we’re thrilled to see designs that integrate a variety of renewable energy technologies into objects we encounter in everyday life. This innovative hybrid wind and solar powered street lamp is just such a solution – not only does it use renewable energy to provide light, it’s a stylish update to an everyday object that is capable of operating completely off-grid. The hybrid streetlamps consist of a solar array topped with a wind turbine, and they are capable of generating up to 380 W of power.

 

Designed and manufactured by Urban Green Energy, these solar/wind powered street lamps are mounted to a standard galvanized steel pole that can be made locally and easily swapped with older street lamps. The turbine on top can be either a 300 W 2nd Generation vertical axis wind turbine (VAWT) or a horizontal axis wind turbine. Mounted on the side of the pole are 2 solar panels made by F3 Solar that are capable of generating up to 80 W of power.
The street lamp is capable of producing up to 380 W of power if the sun was shining and the wind were blowing, and the street lamps save excess energy generated in a battery that powers their high efficiency LEDs through the night. Since every location and project is different, Urban Green Energy is taking a component-focused approach to the street lamps’ design – the LED lights, solar panels, wind turbine, tower height, and battery storage are all easily scaled to best fit a particular project.
Decorations on the pole compliment the sweeping lines of the wind turbine and can be customized to whatever color the buyer wants. The hybrid LED lamps seem more like an commissioned art piece rather than a standard industrial looking street lamp.
Urban Green Energy’s Hybrid Wind/Solar Lamps are already gaining attention around the world – they just signed an agreement with an undisclosed city in China to outfit their streets with these street lamps. The company also offers wind turbines ranging from 300 W up to 10 kW, and we recently got a sneak peak at their new 2nd generation 4kW VAWT. We think this new company is on the right track, and we can’t wait to see their hybrid turbines hit the streets.

More Shipping Containers!!!!!!

Breathtaking Shipping Container Studio in San Antonio

We’re green with envy over this beautiful shipping container studio in San Antonio designed by Texas architect Jim Poteet. Painted a deep blue, the 40′ shipping container was transformed into a gorgeous backyard retreat, complete with a living green roof, composting toilet, rainwater collection and eco friendly finishes. The studio retreat also features floor-to-ceiling windows cut out of the container, blown-in insulation, and bamboo floors and walls. Dwell has the full scoop on the container as well as a ton of gorgeous pictures.

Fun PreFab Gym Built from Containers in Just Three Days!

by Andrew Michler

The students of the Dunraven School located in South London are enjoying a huge new prefab gym that took only three days to erect! Designed by architecture firm Scabal as the world’s first gym of its kind, the team of designers carefully chose materials that would provide for a fun and bright environment for the school children to enjoy. And best of all, the school reduced overall costs by a third opting to go prefab over a traditional facility built-on-site. But don’t think being budget conscious came at a cost to the overall program — this dynamic eco-friendly design easily provides for twice the engagement.

The bright building uses a wall of containers to hold changing rooms, storage and offices, while at the core of the box arrangement is a spacious gym floor for the kids to get some serious physical education done. While a stacked arrangement of containers could give way to a behemoth of a building, by using four primary colors, lots of light, and fun details like zigzag cutouts for observation deck, Sacbel easily broke the mass down to a more manageable level that also inspires fun.

The 8,200 square meter building uses a number of green materials, including reused shipping containers and walls of translucent polycarbonate (what is used in green houses) to allow light to pour into the space. The school has a tradition of green building, and the gym is no different, even employing a  rainwater collection system for the campus-wide reclaimed water system.

Recycled Dumpster Pools Unveiled in NYC this Weekend!

by Ariel Schwartz

Would you ever go dumpster diving? A whole lot of New York City residents did this weekend, as the city unveiled three unused dumpsters converted into small swimming pools as part of the third annual Summer Streets festival! The dumpster pools were laid out on Park Avenue this weekend for approximately 450 eager swimmers to enjoy.

 

Designed by Macro-Sea, each 50,000-pound pool features a layer of felt below 4,600 pounds of chlorinated water. The 8-by-22 pools are slightly on the small side — they only fit 10 people at a time and aren’t deep enough for diving — but they’re good for soaking.
We’d love to see more of these pop-up pools in places that don’t have the space or cash for full-sized versions. Because sometimes it’s just so hot that you’ll swim anywhere — even in a dumpster.

 

 

New Lessons From Old Buildings

Over the last 60 years, architects and engineers forgot how to make buildings work without cheap energy. But many are learning the lessons from the past and applying them to the new.

By Lloyd Alter

 Porches are cool and friendly.
National Archives

A hundred years ago, almost every house had a front porch; they served an important function in the world before air conditioning, when it provided a cooler place to sit. In the early 1980s, Andres Duany and Elizabeth Plater-Zyberk put front porches on the houses in Seaside, the iconic planned community that was the first big demonstration of New Urbanism (and where they filmed the Truman Show) They did it to reduce the need for air conditioning, but found other benefits as well, telling NPR:
"People would sit on the front porch instead of in the backyard because they could see people coming and going, say hello to their neighbors and have short conversations," says Plater-Zyberk. "The bonds of community were being formed through that brief interaction."

Credit: Steve Mouzon
Now front porches are almost common again, as New Urbanism spreads and people realize that they are nice, comfortable spaces. But that is only the most obvious of the lessons of the past that architects are learning, and applying to new buildings.

A hundred years ago, awnings were everywhere. It made sense; air conditioning did not exist, and awnings kept the heat from getting in. Now, we let the heat in and pay to use electricity to pump it out again. Dumb and expensive.

H&H Enterprises
But more and more, architects are installing louvres and sunscreens to take advantage of the way the sun is higher in the summer than in the winter. Have a look at this picture; the windows are almost completely in shade by the carefully designed and sized louvres. They make a dull facade look more interesting, too.
More on Awnings: Keep Cool with Awnings

A hundred years ago, buildings were shaped like letters of the alphabet. Es, Os, Us and Ls. Nobody could be too far from a window; that is where the natural light and air was. Then the fans and ducts and air conditioners came in and windows became almost irrelevant. Floor plates became huge and fresh air inside just a memory.

Weber Thompson Architects
But architects are learning , once again, that buildings with fresh air and natural light are not only cheaper to operate but more pleasant to work in. Weber Thompson's Terry Thomas Building in Seattle is an O building, with a big hole in the middle for air and light.
More on the Terry Thomas: Terry Thomas Building By Weber Thompson
Architects: Go Back To The ABCs and Design Buildings Like Letters Again

A hundred years ago if you had electricity it was expensive. People had all kinds of tricks to bring natural light deep into stores, my favourite being prism glass. When electric lighting came in, nobody needed it any more.

Parans
But as electricity becomes more expensive and people try to reduce their carbon footprint, and in Europe where building codes insist that workers have the benefit of natural light, all kinds of systems are being developed to bounce, pipe and reflect natural light deep into buildings. The Parans system shown here is based on fiber optics, but others are as simple as a skylight.
More: Daylighting Is Making a Comeback
Tubular Skylights for Ad Hoc Daylighting Are Totally Cool
DayRay: Flexible Daylighting

A hundred years ago, many buildings were covered in vines. They served a useful function; they can cut the heat gain on a wall by 50%, reduce temperatures and provide insect and bird habitats. They were really high tech, falling off as winter approached to let more warming sun in.

Today architects are once again integrating nature into their buildings. Edouard Francois clads his buildings in green facades, where plants grow to enclose and protect the buildings from the sun. They are also more lively; he says 'Watch a tree. It has a thousand branches, it moves, grows, changes colour!' and thinks buildings should too.
Those are just some of the ideas from old buildings that are being used in new ones.

10 Overlooked Low-Tech Ways of Keeping Your Home Cool

by Lloyd Alter

Ontario Archives
Summer is here and the air is full of the the sound of whining air conditioners, all seriously sucking kilowatts. Yet much of that air conditioning load could be reduced or the air conditioning season shortened if we did simple things, many of them common before air conditioning was common in North America. Here are some low-tech tips for keeping cool.
The best ideas are those that keep the heat out of your home in the first place, rather than paying to pump it out after it gets in.

1. Use awnings.

According to the Washington Post, The Department of Energy estimates that awnings can reduce solar heat gain—the amount temperature rises because of sunshine—by as much as 65 percent on windows with southern exposures and 77 percent on those with western exposures. Your furniture will last longer, too.
We noted in Planet Green last spring that this can translate into a saving of cooling energy of 26 percent in hot climates, and 33 percent in more temperate climates where it might even make air conditioning unneccessary.

Lloyd Alter

2. Plant A Tree.

I don't own an air conditioner. The house immediately to the south does it for us, completely shading the south side of our house. What it misses, a huge ancient maple in its front yard gets, so in winter I get a lot of sun in my window, and in summer I am always in shade. A tree is as sophisticated as any electronic device around; it lets the sun through in winter and grows leaves in summer to block it.
Geoffrey Donovan studied it in Sacramento, and calculated the savings.
"Everyone knows that shade trees cool a house. No one is going to get a Nobel Prize for that conclusion," says the study co-author, Geoffrey Donovan. "But this study gets at the details: Where should a tree be placed to get the most benefits? And how exactly do shade trees impact our carbon footprint?"

Travelpod

3. Plant Vines.

Frank Lloyd Wright once said "a doctor can bury his mistakes, but an architect can only advise his clients to plant vines." It turns out he could have been a mechanical engineer, for it is surprising how effective vines are at keeping a house cool. With the new weatherization grants, the salesmen are out peddling ground source heat pumps to keep you cool for less, but really, free is better.
Vines such as ivy, russian-vine and virgina creeper grow quickly and have an immediate effect; according to Livingroofs.org.
Climbers can dramatically reduce the maximum temperatures of a building by shading walls from the sun, the daily temperature fluctuation being reduced by as much as 50%.Together with the insulation effect, temperature fluctuations at the wall surface can be reduced from between –10°/14°F to 60°C/140°F to between 5°C/41°F and 30°/86°F. Vines also cool your home through envirotranspiration, described in our post Be Cool and Plant A Tree.

4. Tune your Windows

The windows on your home are not just holes in the wall that you open or close, they are actually part of a sophisticated ventilation machine. It is another "Oldway"—People used to take it for granted that you tune them for the best ventilation, but in this thermostat age we seem to have forgotten how.
For instance, everyone knows that heat rises, so if you have high windows and open them when it hot inside, the hot air will vent out. But it can be a lot more sophisticated than that. When air passes over your home, it works the same way as it does over an airplane wing: the Bernoulli effect causes the air on top and on the downwind side of the house to be at a lower pressure than on the upwind side. So if you have double hung windows, you can open the bottom section of the upwind side of the house and the upper section of the downwind side, and the low pressure will suck the air through your house. Make the outlet openings larger than the inlet opening, it increases the draft. That is why I love double hung windows; they offer the most flexibility and options. Others say that casement windows are best because they can open up to 100%; double hungs can never be open more than 50%. However I have seen studies (which I cannot find) that show that double hung windows actually work better because of the many options in setting them.

5. Get a Ceiling Fan

It doesn't have to be like Collin's Batman fan; they come in all kinds of designs and work on the same principle, that moving air evaporates moisture from your skin and keeps you cooler.
Collin notes that using them is one of our 25 Ways to Save the Planet, and they can save you some cash since they operate at a fraction of central and window air-conditioning units (and they can work great in tandem with your A/C if global warming has you sweating it out). As Energy Star reminds us, ceiling fans help keep you cool, rather than cooling the entire room.

Cool Roof Contractor

6. Paint Your Roof

Kristen writes: In much the same way that more ice/snow reflects UV rays instead of absorbing the heat the way the oceans do (think: feedback loop that results from melting polar ice caps), cities are now giving white roofs a second look as a way to cool cities and fight climate change. The Los Angeles Times reports that the Climate Change Research Conference, held this week, advised that if buildings and road surfaces in 100 of the largest cities in the US were covered with lighter and heat-reflective surfaces the savings could be massive.

White Pine Handbook

7. Install Operable Shutters or External Blinds

The best way to deal with unwanted solar gain is to keep it out in the first place. One can do that with properly designed overhangs or bris soleil, which keep out the sun in summer but are designed to let it in during winter. However this is not very flexible. Another option is the exterior blind, quite common in Europe or Australia but expensive and hard to find in North America, where upfront cost always loses out to operating cost.
Shutters really are the most amazing overlooked technology. They provide ventilation, security, shading and storm protection in one simple device.

8. Get an Attic Fan

A lot of people run expensive air conditioning when it is actually pretty cool out- after the sun has been baking a California house all day it can be cool in the evening but the house is still holding a couple of hundred thousand BTUs of heat. In more temperate parts of the country, just moving the air and having good ventilation could eliminate the need for AC much of the time.

Culinary Historians of Ontario

9. Don't Cook Hot Food Inside

There is a reason our ancestors built summer kitchens; those stoves put out a lot of heat and you didn't want them in your house in summer. Outside summer kitchens are all the rage in the luxury house/ mcmansion set as well. It really makes no sense to run a stove inside, just to then spend money to run air conditioning to remove the heat again. So get a gas barbecue and grill your vegetables, take advantage of farmers markets to get fresh stuff, and eat lots of salad.

10. Be Smart Where You Put Your Money and Energy.

John's graph from the Florida Solar Energy Center says it all. When the weatherization contractors come to get you to insulate your house, (the most expensive thing you can do to save energy) you can show them that this makes no sense, only 7% of the cooling load is coming through the walls. A couple of hours with a caulking gun to reduce infiltration would do more.
When they tell you that you need to install expensive new low-e tinted windows, remember that an awning or a shutter is more sophisticated and flexible; you have the choice whether to let the sun in or not.
Tape up your ducts, turn off your computers and save your money. The simple, low-tech tried and true methods cost less, save more energy and work forever.

80% Cheaper Solar Cells Switch Gold For Nickel

by Brit Liggett

One of the major drawbacks of most renewable energy sources is high cost. In order to see a huge rise in the use of renewable energy sources, prices must come down. In the world of solar there have recently been some major breakthroughs in cost advantages and efficiency increases. Scientists at the University of Toronto in Canada have come up with a way to reduce colloidal quantum dot solar cell prices by up to 80%, by swapping out costly conductive gold for cheap nickel.



Quantum dot solar cells consist of a silicon substrate that has a thin film coating of nanocrystals — or quantum dots. Gold was previously used as the conductive material in the cells and when scientists tried to switch the gold out for nickel the nickel formed new particles with the quantum dots that weren’t able to capture energy. Scientists at the University of Toronto led by Dr. Ratan Debnath found that increasing the layer of silicon substrate created a big enough barrier between the dots and the nickel that the solar cells became effective at the expected efficiency levels.
The team at University of Toronto published their findings in a paper in the July 12, 2010 issue of Applied Physics Letters and noted that with further research they believe that they will be able to increase the efficiency of their extremely inexpensive quantum dot solar panels and make them look attractive to consumers when they eventually hit the market. Unlike conventional solar panels, the quantum dot solar cells that the University of Toronto invented capture visible and infrared light. Though a mode for large scale production still hasn’t been found the impacts of these super-cheap cells could be huge.

 

 

New solar energy conversion process could revamp solar power production

New solar energy conversion process could revamp solar power production

A small PETE device made with cesium-coated gallium nitride glows while being tested inside an ultra-high vacuum chamber. The tests proved that the process simultaneously converted light and heat energy into electrical current. Credit: Photo courtesy of Nick Melosh, Stanford University

Stanford engineers have figured out how to simultaneously use the light and heat of the sun to generate electricity in a way that could make solar power production more than twice as efficient as existing methods and potentially cheap enough to compete with oil.

Unlike photovoltaic technology currently used in solar panels - which becomes less efficient as the temperature rises - the new process excels at higher temperatures.

Called 'photon enhanced thermionic emission,' or PETE, the process promises to surpass the efficiency of existing photovoltaic and thermal conversion technologies.
"This is really a conceptual breakthrough, a new energy conversion process, not just a new material or a slightly different tweak," said Nick Melosh, an assistant professor of materials science and engineering, who led the research group. "It is actually something fundamentally different about how you can harvest energy."
And the materials needed to build a device to make the process work are cheap and easily available, meaning the power that comes from it will be affordable.
Melosh is an assistant professor of materials science and engineering, and is senior author of a paper describing the tests the researchers conducted. It was published online August 1, in Nature Materials.
"Just demonstrating that the process worked was a big deal," Melosh said. "And we showed this physical mechanism does exist, it works as advertised."
Most photovoltaic cells, such as those used in rooftop solar panels, use the semiconducting material silicon to convert the energy from photons of light to electricity. But the cells can only use a portion of the light spectrum, with the rest just generating heat.
This heat from unused sunlight and inefficiencies in the cells themselves account for a loss of more than 50 percent of the initial solar energy reaching the cell.
If this wasted heat energy could somehow be harvested, solar cells could be much more efficient. The problem has been that high temperatures are necessary to power heat-based conversion systems, yet solar cell efficiency rapidly decreases at higher temperatures.
Until now, no one had come up with a way to wed thermal and solar cell conversion technologies.
Melosh's group figured out that by coating a piece of semiconducting material with a thin layer of the metal cesium, it made the material able to use both light and heat to generate electricity.
"What we've demonstrated is a new physical process that is not based on standard photovoltaic mechanisms, but can give you a photovoltaic-like response at very high temperatures," Melosh said. "In fact, it works better at higher temperatures. The higher the better."
While most silicon solar cells have been rendered inert by the time the temperature reaches 100 degrees Celsius, the PETE device doesn't hit peak efficiency until it is well over 200 degrees C.
Because PETE performs best at temperatures well in excess of what a rooftop solar panel would reach, the devices will work best in solar concentrators such as parabolic dishes, which can get as hot as 800 degrees C. Dishes are used in large solar farms similar to those proposed for the Mojave Desert in southern California and usually include a thermal conversion mechanism as part of their design, which offers another opportunity for PETE to help generate electricity, as well as minimizing costs by meshing with existing technology.
"The light would come in and hit our PETE device first, where we would take advantage of both the incident light and the heat that it produces, and then we would dump the waste heat to their existing thermal conversion systems," Melosh said. "So the PETE process has two really big benefits in energy production over normal technology."
Photovoltaic systems never get hot enough for their waste heat to be useful in thermal energy conversion, but the high temperatures at which PETE performs are perfect for generating usable high temperature waste heat. Melosh calculates the PETE process can get to 50 percent efficiency or more under solar concentration, but if combined with a thermal conversion cycle, could reach 55 or even 60 percent - almost triple the efficiency of existing systems.
The team would like to design the devices so they could be easily bolted on to existing systems, making conversion relatively inexpensive.
The researchers used a gallium nitride semiconductor in the 'proof of concept' tests. The efficiency they achieved in their testing was well below what they have calculated PETE's potential efficiency to be, which they had anticipated. But they used gallium nitride because it was the only material that had shown indications of being able to withstand the high temperature range they were interested in and still have the PETE process occur.
With the right material - most likely a semiconductor such as gallium arsenide, which is used in a host of common household electronics - the actual efficiency of the process could reach up to the 50 or 60 percent the researchers have calculated. They are already exploring other materials that might work.
Another advantage of the PETE system is that by using it in solar concentrators, the amount of semiconductor material needed for a device is quite small.
"For each device, we are figuring something like a six-inch wafer of actual material is all that is needed," Melosh said. "So the material cost in this is not really an issue for us, unlike the way it is for large solar panels of silicon."
The cost of materials has been one of the limiting factors in the development of the solar power industry, so reducing the amount of investment capital needed to build a solar farm is a big advance.
"The PETE process could really give the feasibility of solar power a big boost," Melosh said. "Even if we don't achieve perfect efficiency, let's say we give a 10 percent boost to the efficiency of solar conversion, going from 20 percent efficiency to 30 percent, that is still a 50 percent increase overall."
And that is still a big enough increase that it could make solar energy competitive with oil.
Provided by Stanford University

Stanford Unveils Solar Tech That Harnesses Light and Heat

by Cameron Scott

Photo by Nick Melosh
We currently have two types of solar energy: energy generated from light, using silicon-based photovoltaic cells, and energy generated from heat, using solar concentrators and heat-conversion systems. What if we could collect both types of energy at once? Stanford researchers recently unveiled a new solar tech that can do exactly that — their PETE devices utilize a semiconducting material coated with cesium to boost efficiency levels up to 60 percent — three times that of existing systems.

Rooftop solar panels use silicon to convert light into electricity. But their efficiency declines rapidly at higher temperatures (like those needed to power heat-conversion systems). An either/or choice presents itself — but Stanford researchers found that a cesium coating allowed semiconducting materials to convert both light and heat into energy.
They dubbed the process PETE, for photon enhanced thermionic emission. Best of all, PETE devices could be cheaply and easily incorporated into existing solar collection systems. (Because the system hits peak efficiency at over 200 degrees Celsius, it’s not a good fit for rooftop arrays.) “The light would come in and hit our PETE device first,” explained lead researcher Nick Melosh. “We would take advantage of both the incident light and the heat that it produces, and then we would dump the waste heat to existing thermal conversion systems.”
PETE devices require only a small amount of semiconducting material, making them cheap. Melosh’s team also hopes to design devices that can easily be bolted on to existing solar collection systems, so that conversion would also be low-cost.
When used with the heat-conversion process, PETE devices could reach 60 percent efficiency. But even if they boost efficiency just to 30 percent, they will bring solar power down to the price point of oil. And that’s a good thing.

 

“Wind Lens” Turbines Could Boost Energy Generation 3X

by Ariel Schwartz

Forget about traditional tri-blade wind turbines — the ultra-efficient turbine of the future might look completely different if Kyushu University professor Yuji Ohya has anything to say about it. Ohya and his team recently unveiled the Wind Lens, a honeycomb-like structure that purportedly triples the amount of wind energy that can be produced by offshore turbines.

The Wind Lens was unveiled at this month’s Yokohama Renewable Energy International Exhibition 2010. The structure works similarly to a magnifying glass that intensifies light from the sun — except in this case, the lens intensifies wind flow. Ohya’s design doesn’t have too many moving parts — just a hoop (AKA a brimmed diffuser) that “magnifies” wind power, and a turbine that is rotated by wind captured from the hoop. Each Lens, which measures 112 meters in diameter, can provide enough energy for an average household.
Ohya doesn’t know if the Lens will go into commercial production, but if nothing else, it could provide a more aesthetically appealing alternative to traditional offshore turbines.

 

Artificial Photosynthesis Research Gets $122 Million DOE Funding

by Philip Proefrock

The US Department of Energy recently announced a five-year, $122 million grant to establish a new research facility in California with the goal of developing artificial photosynthesis. The Joint Center for Artificial Photosynthesis (JCAP) will seek to develop methods to create fuels directly from sunlight, water, and carbon dioxide. Key targets for this research will be catalysts and light absorbing materials needed in order to break down water and carbon dioxide in order to directly create usable fuels such as hydrogen, methanol, and methane.

 

Other technologies, such as algae biofuels retain the use of natural organisms in the process, and require refinement of the fuel, which makes them expensive. With artificial photosynthesis, the goal is to have the direct production of a usable fuel that requires little, if any, further processing.
Basic research in this field has already been carried out, but this new facility will expand on that knowledge and move toward larger scale implementations with commercial potential. The new research center will be operated by a group of research universities in California led by the California Institute of Technology along with Lawrence Berkeley National Lab, Stanford, and the Universities of California at Berkeley, Irvine, San Diego and Santa Barbara. The DOE grant will provide $22 million in the first year and $25 million for each of the remaining four years of the five-year grant to support these research programs.

 

 

Incredible Edible: How To Make Your Town Self-sufficient

by Christine Lepisto, Berlin 

Image: Incredible Edible Blog
While citizens of the world turn their eyes to Copenhagen, awaiting leadership with dwindling hope, one town has taken matters into the hands of the people. An idea that started around a kitchen table has grown into a reality demonstrating wisdom not seen since Gandhi. Starting from just a few herb gardens, the "Incredible Edible" project grew organically, out of the energy of local people who sought no public funds because they wanted to do it their way. Now "their way" shows the way. Prepare to be inspired.

In Todmorden in West Yorkshire, Great Britain, a grass-roots effort to put the land to work has grown into a project drawing national media attention, Incredible Edible. The brains and energy behind Incredible Edible is Pam Warhurst, who combines insight gained as a former leader of Calderdale Council with the commitment that comes from being involved in a just cause. The principle is simple: food unites us, all peoples regardless of social rank or means, can communicate in the language of food.
It is not a new idea. The local food movement is growing. Some are driven by dire predictions of global economic disarray in the wake of peak oil, climate change, terrorism, or another dreadful threat. Others want a simpler way of life, food grown for nutrients rather than products of an antibiotic- and pesticide-dependent industrial farming.
But even more people watch from the edges, not daring to step into the ring. Many people own no land on which a few vegetables could be grown. The skills of planting, tending and harvesting have atrophied. And who has the time?
Incredible Edible answers those questions, overcoming bureaucracy and uniting people with the common denominator, food. Following 17(ish) tips for getting things done in spite of red tape, Incredible Edible has spread food farming to public lands, gotten the local housing authority support, and spread the campaign to schools.

You just need land and the will to grow stuff on it.

Incredible Edible has planted two orchards and many veggie gardens. They work with authorities to use public space, like the fire stations and railway lands, for common gardens. Getting the social housing landlords involved reaches out to those who live in apartments without access to their own land.
School children in Todmorden eat locally grown meat and produce at every meal. Children learn from agricultural projects and participate in farms run by the schools. The Todmorden High School is now seeking funding for an aquaponics installation, which will grow fish and recycle the nutrient rich water for growing water-intensive plants, for scientific study of the environmentally-friendly food production options for the future.
It does not stop at growing food. Incredible Edible holds workshops, like how to kill and prep a chicken, how to forage for edible plants, and skills for canning and preserving. Blogs and a Twitter presence tell the ongoing story.
The Incredible Edible project is on track to meet their goal to make the town self-sufficient by 2018. A third more people grow their own vegetables, seventy percent buy locally grown produce at least once a week and 15 times more citizens tend their own chickens, compared with a year and a half ago.

World’s First Molten Salt Solar Plant Produces Power at Night

by Philip Proefrock

Sicily has just announced the opening of the world’s first concentrated solar power (CSP) facility that uses molten salt as a heat collection medium. Since molten salt is able to reach very high temperatures (over 1000 degrees Fahrenheit) and can hold more heat than the synthetic oil used in other CSP plants, the plant is able to continue to produce electricity even after the sun has gone down.

While photovoltaic solar panels work by directly producing electricity from sunlight, CSP plants use mirrors to concentrate sunlight and produce high temperatures in order to drive a turbine to generate electricity. CSP plants have been in existence for many years, but the Archimede plant is the first instance of a facility that uses molten salt as the collection medium.
Heat from the molten salt is used to boil water and drive the turbines, just like other fossil fuel plants. CSP plants use the same kind of steam turbines as typical fossil fueled power plants. This makes it possible to supplement existing power plants with CSP or even to retrofit plants to change over to clean energy producing technology. Some existing CSP plants have used molten salt storage in order to extend their operation, but the collectors have relied on oil as the heat collection medium. This has necessitated two heat transfer systems (one for oil-to-molten-salt, and the other for molten-salt-to-steam) which increases the complexity and decreases the efficiency of the system. The salts used in the system are also environmentally benign, unlike the synthetic oils used in other CSP systems.

Since molten salts solidify at around 425 degrees F, the system needs to maintain sufficient heat to keep from seizing up during periods of reduced sunlight. The receiver tubes in the Archimede facility are designed to maximize energy collection and minimize emissions with a vacuum casing that enables the system to work at very high temperatures required with molten salts. By using the higher temperatures of molten salts, instead of oil, which has been used in other CSP plants until this point, the plant is able to maintain capacity well after the sun sets, allowing it to continue generating power through the night.
The Archimede plant has a capacity of 5 megawatts with a field of 30,000 square meters of mirrors and more than 3 miles of heat collecting piping for the molten salt. The cost for this initial plant was around 60 million Euros.