Joshua trees in the Mojave Desert

Solar energy has been enjoying its day in the sun with massive federal subsidies, but the energy taken from sunlight also has a dark side. Building these plants in the American West destroys large swathes of the desert ecosystem. Cacti must be mowed down and local wildlife displaced to make room for the giant mirrors that will essentially carpet the desert. The LA Times has a great feature on the Ivanpah project in the Mojave that began construction in October 2010.

Far from an empty stretch of sand, the Mojave supports diverse wildlife. No one knows exactly how the new solar power plant will affect the tortoises, eagles, and Joshua trees that currently inhabit the area. Is it okay to sacrifice the desert in the fight against larger climate change? The situation has put environmental groups in a bind, as Times reporter Julie Cart explains:

The national office of the Sierra Club has had to quash local chapters’ opposition to some solar projects, sending out a 42-page directive making it clear that the club’s national policy goals superseded the objections of a local group. Animosity bubbled over after a local Southern California chapter was told to refrain from opposing solar projects.

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For years, solar energy researchers have tried to imitate the success of photosynthesis by building devices like an artificial leaf and a solar cell that hijacks chemistry of photosynthetic bacteria. Now researchers at MIT have come up with an innovative technique that also happens to be very cheap: all you need is some “stabilizing powder” and plant waste. Mowed your lawn lately?

The stabilizing powder is a mix of safe, easily attainable chemicals that preserves photosystem I, a protein complex that captures light energy in plant cells. (In contrast, the newest photovoltaic cells in solar panels require metals that are rare or toxic.) The powder is mixed with plant matter such as grass clippings and crushed, and the resulting green goo is spread onto glass or metal substrate. Hook up wires to capture the electric current and that’s your solar panel.

The efficiency of these solar panels is only 0.1%, compared to the 15 to 18% efficiency of solar panels out in the market right now. Lead researcher Andrew Mershin says the technology still needs to improve 10-fold to become practical. After all, being able to power only one lightbulb with a whole house covered in solar panels isn’t much help. But the great advantage of all this is that it’s easy and dirt grass cheap. Because the barrier to entry is so low, anyone would be able to order a bag of chemicals and make their own solar panel. Mershin hopes home tinkerers experiment with the cells and find new ways to make improvements.

Correction, February 6: We eliminated a reference to mulch in the headline: mulch is low in chlorophyll, so it wouldn’t actually work for these plant-powered solar cells.

What’s the News: In traditional solar cells, sunlight is absorbed by the cell (made from silicon or titanium dioxide), freeing electrons, which travel across the cell to an electron collector, or electrode. A problem with solar cells is that many electrons don’t find their way to the electrode; carbon nanotubes can be used as bridges between the loosened electrons and the electrode, but nanotubes tend to bunch up, decreasing the efficiency and causing short circuits. Researchers have now created genetically engineered viruses can be used to keep the nanotubes in place, increasing energy conversion by nearly one-third. “A little biology goes a long way,” research group leader Angela Belcher told MIT News, noting that the entire virus-nanotube bridging layer represents only 0.1% of the finished cell’s weight.

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Perhaps you’ve heard the saying, “We’re not running out of oil. We’re running out of easy oil.” One place where oil is hard (and heavy) is below the Californian ground, where extractors must blast the sludgy petroleum with steam to get it flowing. Most such operations use natural gas to make the steam, but one startup has turned to an unusual partner for oil mining—solar energy—to try to make the business more efficient.

How? Greenhouses full of mirrors.

GlassPoint, a company based in Fremont, California, wants to use solar thermal energy to cook up some steam. Unlike photovoltaic solar, which converts the sun’s radiation directly into electricity, solar thermal projects trap and focus the sun’s heat. Those projects typically involve using the heat to turn turbines and create electricity, but this design is simpler.

GlassPoint’s system is cheaper because it doesn’t need the turbines, and because it has redesigned its mirrors and pipes to pump out steam that’s 250 °C to 300 °C (whereas the steam required to drive turbines must be 350 °C to 400 °C). [Technology Review]

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It’s such a fertile time in the green technology sector, solar power plants may soon begin reproducing.

Using two resources that the Sahara has plenty of, sun and sand, the Sahara Solar Breeder Project hopes to build factories that will refine the sand’s silica into silicon. That silicon will be used to build solar panels, which will power more silica-refining and solar panel factories, which will be able to build more solar panels, and on and on and on.

The potential for exponential growth allows for some extreme optimism: The project’s leaders say they could build enough power stations to meet half of the world’s energy needs by 2050. Project leader Hideomi Koinuma believes the project is key to solving the world’s energy crisis, saying:

“If we can use desert sand to make a substance that provides energy, this will be the key to solving the energy problem. This is probably doable. Moreover, the energy we continually receive from the Sun is 10,000 times the energy currently used by mankind. So if we can utilize 0.01% of it skillfully, we won’t have a shortage of energy, but a surplus.” [DigInfo TV]

Hit the break for a video about the project.

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Twenty miles outside of Abu Dhabi, in the scorching desert of the United Arab Emirates, the new planned city of Masdar is nearly ready for its close-up. This weekend The New York Times reported from the experimental zero-carbon closed community, funded by stacks of oil money, which is now prepared to take on its first inhabitants. The urban design is simultaneously sleek and unsettling, raising the questions: Is this what the city of the future will look like, and would that be a good thing?

Masdar’s main designer, Norman Foster, hits all the notes that make green ears perk up: excluding any carbon-based energy sources, using simplified “sustainable” architecture, and learning from the lessons of the past, even going back as far as centuries-old desert settlements.

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Faced with the sun’s damaging rays, new biological solar cells can repair themselves, regaining their maximum efficiency when some competitors might fade. In their current form these biological solar cells, made with a bacterium’s photosynthesis hub and carbon nanotubes, only reach a small fraction of the efficiency seen in the best traditional solar cells. But their ability to reinvent themselves by shedding damaged proteins and reassembling to regain their maximum efficiency could be a useful feature for future solar cells.

The researchers, who published their work in Nature Chemistry, used a bacterium’s natural light collection center to generate solar power, used proteins and lipids to make supporting disc forms, and employed conducting carbon nanotubes to channel away electric current. This set of materials chemically clumps together, making the cells self-assembling.

The spontaneous assembly occurs thanks to the chemical properties of the ingredients and their tendency to combine in the most energetically comfortable positions. The scaffolding protein wraps around the lipid, forming a little disc with the photosynthetic reaction center perched on top.  These discs line up along the carbon nanotube, which has pores that electrons from the reaction center can pass through. [Science News]

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California’s aggressive energy rules require its utilities to hit an ambitious target: 20 percent of their electricity should come from renewable sources by the end of this year. They’re not going to make it. But because of the drive for renewables, they are close to building some of the biggest solar power projects in the country—including one that would be the biggest ever.

The Beacon Solar Energy Project received the seal of approval from the California Energy Commission (CEC) this week. Beacon will be a 250-megawatt plant built north of Los Angeles near Mojave, California, and would cover more than 2,000 acres.

Beacon is solar thermal: Rather than converting sunlight to electricity through photovoltaic cells, solar thermal projects use mirrors to concentrate the heat of the sun, creating steam to turn turbines.

California hasn’t issued a license for this kind of big “solar thermal” power plant in about 20 years. But in the coming months, the energy commission will vote on eight other, large-scale solar projects that the state needs to meet its renewable energy goals. [San Francisco Chronicle]

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The goal: 80 days, 18,000 miles, no emissions.

Yesterday, the Zero Race electric car world tour began in front of the United Nations Palace in Geneva, Switzerland. Four teams–from Australia, Switzerland, Germany, and South Korea–won’t actually race one another to cross a finish line. Instead, spectators and experts will determine the winner based on reliability, energy efficiency, safety, design, and practicality, as the tour is meant to show the feasibility of electric vehicles.

The race organizer Louis Palmer won the European Solar Prize after driving a solar-powered vehicle around the world in 2008. He says in a press release that the “race” is against climate change and disappearing fuel.

“Petrol is running out, and the climate crisis is coming… and we are all running against time.” [Zero Race]

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Earlier this month, we described the successful flight of Solar Impulse, a manned solar plane that flew for over 26 hours before a safe landing in Switzerland. Now comes news of another feat of solar-powered derring-do. Currently circling above Arizona, a British-built unmanned solar plane dubbed the Zephyr has now flown for a record-breaking seven days straight. Zephyr’s developer, the defense company QinetiQ, hopes the plane can stay aloft and double its own record for a total of fourteen days.

With a 74-foot wingspan, this latest version of the  Zephyr is fifty percent bigger than its predecessors. Its designers hope that the plane will one day find use both for military reconnaissance and also for scientific research. Without a payload, it weights about 110 pounds. Says project manager Jon Saltmarsh:

“Zephyr is basically the first ‘eternal aircraft.’… The launch was absolutely beautiful; it was just so smooth,” said Mr Saltmarsh. “We had five people lift it above their heads, start running and it just lifted away into the sky.” [BBC]

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Success for Solar Impulse: This morning the solar-powered plane touched down in Switzerland after more than 26 hours in the sky—including flying overnight on battery power.

As we noted yesterday, this was by far the most ambitious test of adventurer Bertrand Piccard’s experimental aircraft, which is covered by 12,000 solar cells. Swiss pilot André Borschberg had to decide last night whether those cells had absorbed enough battery power during the day to coast through the night, and he managed to do it.

“I’ve been a pilot for 40 years now, but this flight has been the most incredible one of my flying career,” Mr. Borschberg said as he landed, according to a statement from the organizers of the project. “Just sitting there and watching the battery charge level rise and rise thanks to the sun. I have just flown more than 26 hours without using a drop of fuel and without causing any pollution” [The New York Times].

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As I write this, a plane powered by the sun is flying somewhere over Europe, undertaking its most ambitious test flight yet.

When we last left the Solar Impulse back in April, the experimental aircraft had flown a two-hour test to prove it was flight-worthy. Today, the pilot in the plane, which weighs about as much as a car and is covered in 12,000 solar cells, will try to stay aloft for 24 hours, even cruising along during the nighttime hours.

“The goal of the project is to have a solar-powered plane flying day and night without fuel,” said team co-founder Bertrand Piccard, adding that this test flight – the third major step after its first ‘flea hop’ and an extended flight earlier this year – will demonstrate whether the ultimate plan is feasible: to fly the plane around the world. “This flight is crucial for the credibility of the project” [AP].

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A new type of solar cell using “quantum dots” may double the theoretical efficiency of current solar cells–allowing a panel to convert around 60 percent of the sun’s energy that it laps up into electricity. The research on these new cells appeared Friday in Science.

Current silicon-based solar cells lose about 80 percent of the sun’s energy they take in. It’s an inherent flaw: even working at their theoretical ideal, these cells would still lose 70 percent.

We can blame the sun’s diversely energized photons for this inefficiency. Silicon cells can only purposefully harvest photons with just the right amount energy. When they strike the cell, photons with just enough juice will prod an electron into motion (and create an electric current). An overly energized photon will excite the electrons to no purpose; the electrons will just quickly give off that photon’s energy as heat.

In two steps, this project, funded in part by the Department of Energy, salvages these “hot electrons.”

“There are a few steps needed to create what I call this ‘ultimate solar cell,’” says [Xiaoyang] Zhu, professor of chemistry and director of the Center for Materials Chemistry. “First, the cooling rate of hot electrons needs to be slowed down. Second, we need to be able to grab those hot electrons and use them quickly before they lose all of their energy.” [University of Texas at Austin]

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Who needs big silicon panels? MIT scientists just coated paper with solar cells, reportedly the first team to ever do that. Vladimir Bulovic, director of the Eni-MIT Solar Frontiers Research Center, unveiled them this week, and said the design was being submitted for peer review.

The printed solar cells, which Bulovic showed at a press conference Tuesday, are still in the research phase and are years from being commercialized. However, the technique, in which paper is coated with organic semiconductor material using a process similar to an inkjet printer, is a promising way to lower the weight of solar panels. “If you could use a staple gun to install a solar panel, there could be a lot of value,” Bulovic said [CNN].

Right now the solar cells on paper get just 1 to 2 percent efficiency at converting sunlight to electricity (some cells have achieved 40 percent or more in lab trials). But they carry the advantages of being flexible, and Bulovic says he could potentially use a number of different materials, not just the carbon-based dye used in these first attempts. And they’re tunable:

MIT is focusing much of its effort on quantum dots, or tiny crystals that are only a few nanometers in size. A human hair is about 50,000 to 100,000 nanometers thick. By using different materials and sizes, researchers can fine-tune the colors of light that quantum dots can absorb, a way of isolating good candidates for quantum dot solar cells [CNN].

Bulovic gives the standard warning about new technologies—it could be a decade before it’s ready for commercial development.

And once it is? There’s no telling how it could revolutionize the home solar industry, which currently relies on pricey professional installers to set up panels [Inhabitat].

Related Content:
DISCOVER: Sun Catcher Promises Cheaper Solar Power
80beats: Glitter-Sized Solar Cells Could Be Woven into Your Power Tie
80beats: Self-Assembling Solar Panels Use the Vinaigrette Principle

Image: Martin LaMonica at CNET

In the hot desert kingdom of Saudi Arabia, finding fresh drinking water has always been a great challenge. For decades now, the state has been providing clean water by converting millions of gallons of seawater via desalination plants that remove salts and minerals from the water. Now the country plans to use one of its most abundant resources to counter its fresh-water shortage: sunshine [Technology Review].

Working on a joint project with IBM, Saudi Arabia’s national research group King Abdulaziz City for Science and Technology (KACST) has announced that it will open the world’s largest solar-powered desalination plant by 2012 in the city of Al-Khafji. The pilot plant will not just supply 30,000 cubic meters of clean water per day to 100,000 people, but will also reduce operating costs in the long run by harvesting energy from sunshine. Saudi Arabia, the top desalinated water producer in the world, uses 1.5 million barrels of oil per day at its plants, according to Arab News [Technology Review].

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