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Toward a Non-Reflecting, Self-Cleaning Solar Panel

Continuing on yesterday's improving-solar-panels beat, today we learn of a new process that can quickly create a solar surface that barely reflects any light and can clean itself. And the innovation comes from sunny Finland, of course.

Researchers at Aalto University (a recently formed conglomeration of three older Universities) created a new method -- using deep reactive ion etching -- for fabricating a pyramid-shaped nanostructure on a silicon surface. The silicon wafer, once etched, can then be used to create a stamp, making further wafer fabrication an easy additional step.

Generally, the smooth silicon surfaces used in solar cells reflect a lot of the light that hits them, lowering their efficiency. The shaped surfaces, though, barely reflect any light at all.

Water and particle accumulation on solar cell surfaces also increase the reflectivity, so the researchers went a step further. They coated the surface with a "low surface energy fluoropolymer," which made it ultrahydrophobic. Water droplets that hit a solar cell with such a coating would quickly roll off, carrying dust and other particles with them. There are other strategies for dust removal on solar cells -- including one that was developed for use on Mars, of all places -- but no matter what the method it's clear that keeping a cell clean will boost its efficiency by an enormous amount.

According to the researchers' paper, which was published in the journal Advanced Materials: "High-throughput fabrication of low-cost self-cleaning surfaces, which suppress the reflection of light over a wide spectral range, is expected to have applications ranging from chemical analysis of drugs and biomolecules to photovoltaics."

(Image via Aalto University)

Semiconductors + Fullerenes = Power-Generating Windows

We've covered transparent solar cells here before, but when there's a cool new entry to the field it deserves some attention. Researchers at Brookhaven and Los Alamos National Laboratories have created thin films capable of generating power by combining a semiconducting polymer with carbon fullerenes.

From a press release: "Under carefully controlled conditions, the material self-assembles to form a reproducible pattern of micron-size hexagon-shaped cells over a relatively large area (up to several millimeters)."

The researchers noted that hexagonal transparent cells have been created before using other polymers, but never with the semiconductor-fullerene combination. By repeating the millimeter-scale patterning over a wider area, one of the researchers said the thin film could be used to create "energy-generating solar windows, transparent solar panels, and new kinds of optical displays."

The hexagons tend to let light through their centers and absorb it better at the edges, keeping an array of them largely transparent. And the edges also seem capable of conducting electricity.

Even the fabrication process seems predisposed to scale up toward commercial uses. Micrometer-scale water droplets were spread over a thin layer of the polymer-fullerenes combo, and the water then assembled itself into larger arrays. When it evaporated, the hexagonal structure of the arrays was left behind. The paper on the new technique and material was published in the journal Chemistry of Materials.

The list of solar cell innovations continues to grow, but most are slow to scale up toward actual market use. Still, it doesn't get any less exciting to picture the windows of one's house actually powering what's behind them.

(Image via Brookhaven National Laboratory)

Twin Setbacks for Tidal

PG&E has announced it's ditching, at least for now, a 5 MW tidal energy project that had been slated for the coast of Humboldt County in northern California. The utility cited excessively high investment costs--including $50 million just to cover transmission infrastructure--and absence of any potential for physical expansion. Pacific Gas & Electric cancelled another plan for a tidal project in northern California last year but is continuing to pursue one near Santa Barbara.

So far, the Federal Energy Regulatory Commission has issued just one license for a tidal project in the United States, and that one is dormant, the owner having surrendered it after failing to raise funds, according to Energy Central's Ucilia Wang.

The bad news on the U.S. side of the pond pales, however, with the recent news from the UK. The British government said two weeks ago it was giving up plans for a giant tidal plant to be built across the Severn estuary that cuts into southwestern England north of the Wales peninsula. The gigantic 8 GW facility consisting of 214 4o MW turbines would have been gigantically expensive to build: 20 billion pounds according to its promoters, more like 34 billion according to the British government--which said the project had turned out to be too risky and too expensive compared to other sources of low-carbon electricity.,

Scotland's 10 billion pound tidal challenge remains very much active, but England's decision does cast serious doubt on whether Scotland will ever generate 25 percent of the UK's electricity, as the Scots claim they could do.

Concurrently with the Severn decision, the British government approved eight sites for construction of new nuclear power plants.

California's Climate Commitment

“[Climate change] creeps up on you. And then all of a sudden, it is too late to do something about it. ... We don’t want to go there.”

Thus spoke Schwarzenegger, California's body-building movie star governor, upon signing four years ago a California law committing the state to cut its greenhouse gas emissions an estimated 25-30 percent by 2020. Nationally, any directed governmental effort to reduce GHG died earlier this year when the White House gave up on getting a cap-and-trade bill through the Senate; with last yesterday's loss of the House, the idea of deliberately reducing U.S. carbon emission is dead as a doornail. But Californians, defying the national trend, voted to uphold Arnold Schwarzenegger's SB 32--and, in the same breath, chose Democrats Jerry Brown and Barbara Boxer over the former corporate CEOs Meg Whitfield and Carly Fiorina, for governor and senator.

The battle over Proposition 23, which would have suspended implementation of the state's Global Warming Solutions Act of 2006 until economic conditions improve, was seen as a national bellwether and pitted some big-name donors on both sides of the fight against each other: Supporters of the ballot initiative included a Kansas company owned by the Koch brothers ($1 million), the Missouri-based Adam Smith foundation (nearly $500,000), and Occidental Petroleum ($300,000); among the opponents were San Francisco Democratic Party donor Thomas Steyer ($2.5 million), the Natural Resources Defense Council (more than $1 million), and venture capitalist John Doerr ($500,000).

Evidently the state's voters bought arguments that California's future depends on a sustained commitment to advanced green tech, and elected leaders they can count on to stick with the program. Brown, a former governor known for his visionary attitudes toward technology, once wanted California to have its own space program. Boxer, as chairperson of the Senate environmental committee, is one of the most influential national players in climate and energy policy.

California's commitment to greenhouse gas reduction was striking four years ago, and its reaffirmation of that commitment is all the more striking today, because in many ways it's tougher for the golden state to cut carbon than it would be for the country as a whole. The state already has in place some of the strictest building and fuel efficiency standards in the world, and little of its in-state electricity generation depends on coal. So while the United States could easily cut its emissions sharply by imposing much tougher standards and by encouraging rapid replacement of coal-fired plants by cleaner technology, California does not have those options.

That said, the one thing the golden state does have in relative abundance is sun. This last week, Schwarzenegger and the U.S. interior secretary joined with BrightSource executives to hail the beginning of construction of  the 370 MW, utility-scale Ivanpah solar concentrating plant. "Today we are breaking ground on the largest solar project in the world, right here in California," boasted Schwarzenegger. To be built with help of a $1.37 billion loan guarantee from the Department of Energy on 347,000 acres of Federal land, Ivanpah will feature 347,000 large mirrors surrounding three generating towers.

Some kind of carbon trading plan is expected to be part of California's program to implement AB 32, and other regional trading plans are being put in place piecemeal in other parts of the country--exactly the uneven regulatory environment that big business has said it didn't want. With companies no longer much interested in trading carbon voluntarily to prepare for inauguration of a national system, the Chicago climate exchange (CCX) is on the verge of collapse, the Financial Times reported Monday.

Had President Obama proposed a revenue-neutral "sky tax" on carbon, as some economists and climatologists proposed, in which revenues would be used to generate green-tech jobs in the parts of the country most adversely effected by penalizing coal, the national picture might be different today. The president might have created employment in just those regions where he took the worst drubbing yesterday, without standing accused of driving up the Federal deficit. But--to recycle this week's favorite cliches--he failed to exhibit the audacity of hope, and the electorate said nope.

Without a national system that penalizes emission of greenhouse gases equally regardless of their source--a system that can be tuned to achieve just the reductions the nation desires--we are left with second-best solutions and a second-rate approach to policy making, in which each special interest lobbies to favor its cause and disadvantage its adversaries. The result is a hit-and-miss approach to greenhouse gas reduction, in which the end result cannot be accurately predicted and everything depends on who is picked as a winner or loser.

Quick to get a jump on the new realities,however distasteful they may be, the American Wind Energy Association issued a press release this week pointing out that while wind far outdid coal last year in new electricity generation installation, this year the pattern has reversed, with coal coming out far ahead. To redress that, AWEA would like to see the government enact a national renewable energy standard and extend 2009 wind tax credits. Good luck.

Trains Need Greening Too: Amtrak to Add New Efficient Locomotives

Amtrak has agreed to buy 70 electric locomotives from Siemens as part of an ambitious $11 billion, 14-year plan to upgrade its rail service. The trains, called Cities Sprinters, will drastically upgrade the energy efficiency of their predecessors.

Among the energy-saving features on the Siemens design - which will be based on the Euro Sprinter design (pictured) - is regenerative braking.

“This isn’t your grandfather’s locomotive,” said Oliver Hauck, president of  Siemens Industry’s Mobility Division, in a press release. “Not only will we use renewable energy to build them, the locomotives will also include energy efficient features, such as regenerative braking that can feed up to 100 percent of the energy generated during braking back to the power grid."

Moreover, the $466 million contract with Siemens will be filled largely by manufacturing at a Sacramento plant powered (mostly) by solar energy. So if anyone starts doing lifecycle emissions calculations for these trains, that will help as well. (The project will also create more than 200 jobs, mostly in California).

I'm an unabashed trains lover, but I'm the first to admit they're far from perfect when it comes to energy use and efficiency. So it's nice to see Amtrak, in spite of seemingly constant financial problems, following through on promises to upgrade its fleet.

(Image via Siemens)

Smart Traffic Lights Could Help Cars Save Gas

 
Smart intersection diagram from Denso Corp.
 
 
We've all driven through--or waited a long time at--intersections that have car-sensing traffic lights.
 
Now Denso has modeled the next iterations of a "smart traffic light" system. It would use messaging between vehicles and the traffic-light controller to let the light make better decisions about when to change, to maximize overall vehicle throughput.
 
And that, in turn would reduce the number of minutes cars spent idling at traffic lights, cutting their emissions and their fuel usage.
 
In other words, cutting red-light time helps you go green.
 
Today's car-sensing lights stay green in one direction until a car wants to enter the intersection from the cross street, when the light is directed to change based on sensor data from a loop of wire in the roadway.
 
Denso's proposed system uses short-range wireless transmitters (think your WiFi router) in cars and elements of the road infrastructure. The field is broadly known as V2V (for vehicle to vehicle) communications.
 
Traffic lights that "knew" more about upcoming vehicles could change dynamically based on their approach speeds, the mix of vehicle types (e.g. compact car, tractor-trailer truck), and the relative volumes of cars approaching from any direction.
 
This would let a stoplight "know" that one single vehicle was approaching from a given direction, and delay a regularly scheduled change long enough to let it pass through.
Two tractor-trailers traveling one after the other could signal their presence to the light, allowing it to stay green in one direction long enough to let the pair (which together extend the length of five or six cars) pass through.
 
Data on whether a car was accelerating, braking, or flashing a turn signal would all factor into signal timing--including the duration of optional features like turning-lane arrows.
 
Some express city transit buses already carry equipment that lets them pre-empt changing traffic signals, to reduce time lost waiting at red lights. The theory is that a bus with 50 passengers can and should take priority over 20 single-occupant cars.
 
Denso's model, however, goes well beyond the current signal-control algorithms--which use averages of traffic flow--to adjust cycle times and light extensions to get to the "state optimum" for any given set of upcoming vehicles.
 
The company has been testing both pre-empting red lights and extending green lights via transmitters onboard the vehicle and receivers in stoplights at its Vista, California, research facility.
 
Ultimately, not only vehicles but motorcycles and perhaps even bicycles might carry signaling transmitters to take their place in the data flow.
 
Since engine idling at stoplights produces gas mileage of 0 mpg, and accelerating up to speed uses far more fuel than maintaining a steady speed, the savings come not only in time but also in reduced fuel usage and lower emissions.
 
How would you feel about a transmitter on your car that "talked to traffic lights"? After all, on this one there's a clear payback: Without such a transmitter, the stoplight couldn't stay green to let you through because it wouldn't know you're approaching.
 
This article, written by John Voelcker, originally appeared on GreenCarReports.com, a content partner of IEEE Spectrum.
 

Get Excited: Tempering the Tempered Enthusiasm For Offshore Wind

Sometimes it seems like the offshore wind industry in the United States consists entirely of reports. Resource estimates, predictions, warnings... but still, nary a turbine to be found. This research is needed, of course, but one can only hope that the researchers make sure their central messages point a way forward rather than simply make excuses for the lack of progress.

A new contribution to the offshore wind report genre does contain some enthusiasm, but also falls back on some old - and largely answered - questions regarding the energy source's potential. The University of Maryland's Center for Integrative Environmental Research released a report [PDF] on Maryland's offshore wind potential, and put two major concerns front and center: expensive transmission issues and potential interference with nearby radar systems.

Now, to their credit, a press release from the University does allow the report's authors to tout offshore wind as "economically feasible and environmentally advantageous." Also, they at least partially answer their own transmission questions with the recent announcement of the Google-backed transmission backbone plan for the Atlantic coast (some of the issues with which fellow Spectrum blogger Bill Sweet discussed well here).

The radar problem, though, shouldn't be considered such an important issue. I've discussed it here and elsewhere, but generally speaking wind turbine interference with radar is a somewhat archaic issue. Newer radar systems don't really have a problem with turbines at all, and even older ones can be upgraded to see through the windmill's interference without a ton of trouble. Perhaps the most publicized radar-wind confrontation, the Shepherd's Flat wind project in Oregon (the biggest in the US, when completed), was settled quietly soon after the issue was raised; the government is comfortable enough with the radar issues to offer a $1.3 billion loan guarantee to the project.

So some tired and answerable questions prompted a tempered "mixed bag" take-home from the Maryland report's authors, and they buried the good stuff: that offshore wind could significantly contribute to Maryland's renewable portfolio standard requiring 20 percent of electricity from renewables by 2022, and that the costs of siting turbines in deeper water - where the transmission backbone project will likely be built - are roughly similar to shallow water.

I'm all for realism when it comes to renewable energy, but a little enthusiasm for planet-saving technologies wouldn't hurt either.

The Spill

Anybody even casually interested in the corporate environment that produced the Deepwater Horizon catastrophe will want to watch The Spill, a PBS Frontline investigative report that aired Tuesday evening in many markets and can be viewed any time online, along with supplementary interviews and supporting material. A joint production of PBS and ProPublica, it is mainly the work of PBS's excellent Martin Smith and ProPublica's Abrahm Lustgarten, who has done the best reporting to date on the environmental downsides to natural gas fracking.

To be sure, the show has much less to say about the details of the Gulf tragedy than the best initial post-mortems, flagged in an earlier post here. I am not the first reviewer to observe that the program could have been twice as long without straining patience or losing impact. Every major precursor--the Texas oil refinery fire, the Alaskan oil pipeline spills, the flamboyant PR-oriented culture that Lord John Browne introduced with his "beyond petroleum" campaign--could have been a program in itself.

One obvious issue left unexplored and barely alluded to in The Spill is whether BP escaped critical scrutiny from the environmental community precisely because of John Browne's campaign, the company's supposedly pioneering internal introduction of carbon trading, and arrangements it entered into with organizations like the Environmental Defense Fund to advance cap-and-trade. Carol Browner, Obama's so-called climate czar, acquits herself poorly in the show. (A recent New Yorker article also lays the White House decision to promote deep offshore drilling at Browner's doorstep.) But that's as far as it goes.

Perhaps it would be unfair to expect a young, relatively inexperienced president to be an expert on offshore drilling, among so many important things. But environmental specialists and activists should have known better.

First-ever Fuel Efficiency Standards for Heavy Trucks and Buses

The U.S. Department of Transportation and the Environmental Protection Agency announced yesterday fuel-efficiency standards for cars and trucks, having last year sharply tightened CAFE limits for light vehicles.  Covering new vehicles made between 2014 and 2018, DOT and EPA says the heavy-vehicle measures will "reduce greenhouse gas emissions by nearly 250 million metric tons and save 500 million barrels of oil over the lives of the vehicles produced within the program’s first five years."

According to the New York Times, the standards draw heavily on a National Academy study issued earlier this year, which said that big fuel savings could be achieved by means of current technologies such as low-rolling-resistance tires, improved aerodynamics, better engines, hybrid-electric drive systems, and idling controls. The standards do not seem to owe much, however, to T. Boone Pickens' proposal to switch trucks to natural gas--in his revised "Pickens plan"--or to the long one-on-one conversation he boasted of having with Candidate Obama during the last presidential campaign.

In the new rules, if they take effect largely intact after a public comment period, tractor trailers including 18-wheelers will be required to show improved fuel efficiency of 20 percent, the heavier pickup trucks and vans of 10-15 percent, and specialized vehicles like fire engines and cement mixers of 10 percent. Though heavy vehicles are a relatively small proportion of all vehicles on the road, they account for a relatively large fraction of fuel consumption and emissions in the transportation sector. Enforcement of the new standards thus will go some way toward meeting Obama's 2020 greenhouse gas reduction pledge.

Clean Tech Patent Survey finds Asia in the Lead, Europe lagging

This year for the first time, IEEE Spectrum magazine has published a patent survey that focuses specifically on intellectual property bearing on the future of clean tech. The findings are rather dramatic: Of the 50 companies identified as clean-tech leaders by Spectrum and its partner 1790 Analytics, 24 are based in Asia and 22 in the United States; just three are European, and one Canadian.

That's a startling finding, considering that in the last two decades of the twentieth century and well into this one, Germany--together with several other European countries--clearly led the way in alternative energy technology, the United States having pretty much forfeited the field, after some pioneering first efforts during the Carter administration. The current survey covers just 2009, so it does not take into account accumulated patent power from decades of clean tech R&D. But even so, it points to a dramatic shift in prowess--when it comes to the technologies that will shape the world's future economies--from Europe to Asia.

What qualified as clean tech in the Spectrum-1790 analysis? "After scouring Spectrum’s news archives for the most talked-about technologies with potential for generating power without polluting the environment, we selected eight candidates: batteries, clean coal, fuel cells, geothermal energy, hybrid vehicles, hydropower, solar energy, and wind energy," report the authors, Patrick Thomas and Anthony Breitzman.

That's a good list, but everybody will have their reservations, myself included. In the spirit of airchair generalmanship, had I made the list, I would have skipped geothermal and hydro, in favor of mass transportation, on the one hand, and manufacturing equipment and industrial process technology, on the other.

As I see it, geothermal is simply too niche and too far off to be of much pressing interest. Mass, transit, however, is the greenest of transportation technologies. Experts may quibble about whether electric and hybrid-electric vehicles yield net energy and carbon savings, but there's no doubt that to the extent travelers can be lured from cars onto trains, substantial efficiencies result.

Hydroelectricity generally is classified as carbon-free, like nuclear power, but hydro's alleged carbon neutrality is more seriously open to question: Plants thrive in the huge lakes behind big dams, and when they rot, they release methane, a much more potent greenhouse gas than carbon dioxide. Still more to point, perhaps: How much really innovative technology can there be in dams, really?

Improving the energy efficiency of manufacturing equipment and processes, however, is perhaps the single most important way to green advanced industrial and fast-industrializing economies. And these technologies, as it happens, are just those in which the most technically advanced European countries--Germany and France, especially--excel. So if this category had been included, however amorphous and unwieldy it might appear, the effect surely would have been to boost Europe in the CleanTech50 rankings.

But this is a quibble. It's true that Germany and France are not much concerned about their trade balance with China today because they're busily providing its infrastructure. For them, China is as much an opportunity as a problem. But this situation is not going to last for ever. Not long from now China's basic infrastructure will be complete, it will have acquired key technology as part of the hard bargains its always strikes with companies like Siemens and Alstom--and then, if the Spectrum-1790 assessment of clean tech patent power is right, China's going to be a big problem for Europe too.

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