Tag Archives: panel

New, ultrathin solar cell doubles the current efficiency record by reaching almost 50%

Researchers at the National Renewable Energy Laboratory (NREL) have created a record-shattering new solar cell. The device can convert sunlight to energy at nearly 50% efficiency, much better than present alternatives.

NREL scientists John Geisz (left) and Ryan France testing their prototype panel.
Image credits Dennis Schroeder / NREL.

Solar cells today typically run with between 15% and 23% efficiency, meaning they convert roughly 1/6th to 1/4th of incoming energy (in the form of sunlight) to electricity. But a new, “six-junction solar cell” designed at NREL boasts an efficiency of almost 50%, a huge increase.

More bang for your sun

“This device really demonstrates the extraordinary potential of multijunction solar cells,” said John Geisz, a principal scientist in the High-Efficiency Crystalline Photovoltaics Group at NREL and lead author of a new paper on the record-setting cell.

The cell has a measured efficiency of 47.1% under concentrated illumination, with one variant setting a new efficiency record under one-sun (natural) illumination of 39.2%.

The team used III-V materials — so called because of their position in the periodic table, also known as the boron group of semiconductors — to build their new cell; such materials have a wide range of light absorption properties that made them ideal for the task. Due to their highly efficient nature and the cost associated with making them, III-V solar cells are most often used to power satellites

The cell’s six junctions represent photoactive layers, and each is designed to capture light from a certain part of the solar light spectrum — in essence, each layer is specialized in absorbing as much as it can from certain parts of incoming light. The device also contains about 140 layers of various III-V materials to support these junctions, however, it’s only one-third the thickness of a human hair, the team explains.

“One way to reduce cost is to reduce the required area,” says Ryan France, co-author and a scientist in the III-V Multijunctions Group at NREL, “and you can do that by using a mirror to capture the light and focus the light down to a point. Then you can get away with a hundredth or even a thousandth of the material, compared to a flat-plate silicon cell. You use a lot less semiconductor material by concentrating the light. An additional advantage is that the efficiency goes up as you concentrate the light.”

France adds that exceeding the 50% efficiency mark is “actually very achievable”, but reaching 100% efficiency is impossible due to the fundamental limits of thermodynamics — then again, that stands true for all engines and devices used to generate or convert power.

Geisz explains that the current hurdle in exceeding 50% efficiency is presented by resistive barriers that form inside the cell which make it harder for electrical currents to flow. While the team is working on tackling this issue, NREL overall is working heavily towards making III-V solar cells more affordable, to give this technology a competitive edge on the market.

The paper “Six-junction III–V solar cells with 47.1% conversion efficiency under 143 Suns concentration” has been published in the journal Nature Energy.

DeepSolar.

Stanford designed software to spot every solar panel in the US (there’s a lot of them)

A new open-access tool developed at Stanford University reveals that, in certain U.S. states, solar panels now account over 10% of total energy generation.

DeepSolar.

The interactive map of the United States on the DeepSolar website.
Image credits DeepSolar / Stanford University

Policy-makers, utility companies, researchers, and engineers currently have a hard time estimating just how many solar panels installed throughout the country. Stanford University researchers have come to their aid, however, with a new algorithm that makes it easier than ever before to quantify them and analyze development. The tool (accompanied by an open-access website) draws on high-resolution satellite data and automated image analysis.

Sunnyside up

“With these methods, we can not only maintain and update a high-fidelity database of solar installations, but also correlate them at the census-tract level with the amount of incoming solar radiation as well as non-physical factors such as household income and education level,” says co-senior author Arun Majumdar, a mechanical engineering professor at Stanford and co-Director of the Precourt Institute for Energy.

The tool, dubbed DeepSolar, offers unprecedented insight into the trends that drive solar power adoption by society at large, the team says. The algorithm works by analyzing high-resolution images across the U.S., looking for solar panels. When it finds a match, the program records the location and calculates its size.

In stark contrast to its predecessors, DeepSolar isn’t painfully slow. “Previous algorithms were so slow that they would have needed at least a year of computational time” to identify most of the solar panels in the U.S., says co-senior author Ram Rajagopal, a civil engineering professor at Stanford. Meanwhile, DeepSolar only needs a “fraction” of that time.

The team reports using DeepSolar to locate roughly 1.47 million individual solar installations across the country. These included rooftop panels, solar farms, and utility-scale installations. The software should help optimize solar development at the aggregate level, the team explains, especially since decentralization of solar power made it hard to keep track of all the panels being installed.

DeepSolar city.

DeepSolar interactive map showing solar panel distribution by county in the region surrounding Chicago.
Image credits DeepSolar / Stanford University.

One area the team hopes to make an immediate impact with DeepSolar is in the U.S. power grid. The tool, they say, could be used to better integrate solar into the grid by accounting for daily and seasonal fluctuations in incoming sunlight.

“Now that we know where the solar panels are, or are likely to be in the future, we can feed that information into questions of modeling the electricity system and predicting where storage units and substations should go,” says Majumdar.

DeepSolar could also help in pinpointing new areas for solar deployment. The team used the program to establish correlations between solar installation density and variables such as population density or household income — which, when pooled together, allowed them to create a model predicting which areas are most likely to adopt solar in the future.

“Utilities, companies that install solar panels, even community planners that are thinking about sustainability, they all can benefit from this high-resolution spatial data and a website where they can explore and analyze the different trends involved,” Rajagopal says.

The team plans to expand the DeepSolar database to include solar installations in other countries with suitably high-resolution satellite images and to improve its ability to estimate energy output based on characteristics such as the angle of incoming light.

The paper “DeepSolar: A Machine Learning Framework to Efficiently Construct Solar Deployment Database in the United States” has been published in the journal Joule.

Opportunity dusty.

Rumors of Opportunity’s death “very premature”, despite three-weeks silence

NASA’s last contact with the Opportunity Rover took place over three weeks ago. Despite this, the agency believes it’s too early to assume the worst case scenario — the rover’s demise.

Opportunity dusty.

Opportunity covered in dust on Mars.
Image credits NASA / JPL.

We’ve been talking a lot about the huge dust storm that’s engulfed Mars of late, and of how NASA’s two rovers — Opportunity and Curiosity — are weathering the event. Out of the two, Curiosity has been served the much sweeter side of the dish: powered by a nuclear reactor and sitting out of the storm’s way, it’s been free to leisurely capture pics of the weather (and itself).

The older and solar-powered Opportunity, however, is stuck in the massive storm. Besides getting pelted by dust that may harm its scientific instruments, the rover is also unable to recharge. Dust blocks so much of the incoming sunlight that Opportunity’s solar panels just can’t create a spark. Bereft of battery charge, the rover stands a real chance of freezing to death on — fittingly– Mars’ Perseverance Valley.

Tough as old (ro)boots

Opportunity has been on duty for some 14 years now. It’s a veteran space explorer that relayed treasure troves of data for researchers back here on Earth. I’m rooting for the bot to weather the storm. By this point, however, it’s been three weeks since it last established contact with NASA — enough to make even the most resolute worry about its fate.

Dr. James Rice, co-investigator and geology team leader on NASA projects including Opportunity, says we shouldn’t assume the worst just yet.

Talking with Space Insider, Dr. Rice explains during its last contact with NASA, Opportunity also sent back a power reading. It showed the rover managed to scrape a meager 22 Wh of energy from its solar panels. For context, the rover managed to collect 645 Wh of energy from its panels just ten days before. This chokehold on energy is the NASA’s main concern at the moment.

However, he adds that the same storm which prevents Opportunity from recharging its batteries may ultimately also be its salvation.

One of the reasons NASA was caught offguard by the storm is that they simply don’t generally form around this time of the Martian Year. It’s currently spring on the Red Planet’s Southern Hemisphere, but dust storms usually form during summer. The only other dust event NASA recorded during the Martian Spring formed in 2001, and even that one came significantly later in the season than the current storm.

Mars storm.

The first indications of a dust storm appeared back on May 30. The team was notified, and put together a 3-day plan to get the rover through the weekend. After the weekend the storm was still going, with atmospheric opacity jumping dramatically from day to day.

Still, at least it’s not winter — so average temperatures aren’t that low on Mars right now. The dust further helps keep Opportunity warmer, as it traps heat around the rover.

“We went from generating a healthy 645 watt-hours on June 1 to an unheard of, life-threatening, low just about one week later. Our last power reading on June 10 was only 22 watt hours the lowest we have ever seen” Dr. Rice explained.

“Our thermal experts think that we will stay above those low critical temperatures because we have a Warm Electronics Box (WEB) that is well insulated. So we are not expecting any thermal damage to the batteries or computer systems. Fortunately for us it is also the Martian Spring and the dust, while hindering our solar power in the day, helps keep us warmer at night,” he added.

The storm has reached 15.8 million square miles (41 million square kilometers) in size this June. It poses a real risk to Opportunity’s wellbeing, but ground control remains optimistic. Mars Exploration Program director Jim Watzin believes that the massive storm may have already peaked — but, considering that it took roughly a month for it to build up, it could take a “substantial” amount of time before it dissipates completely.

“As of our latest Opportunity status report Saturday (June 30) this storm shows no sign of abating anytime soon. We had a chance to conduct an uplink last night at the potential low-power fault window. We sent a real-time activate of a beep as we have done over the past two weeks. We had a negative detection of the beep at the expected time,” Dr Rice added.

“A formal listening strategy is in development for the next several months.”

Among all this, or rather also because of all that’s happening to Opportunity, I can’t help but feel genuine admiration for it as well as the people who helped put it together. Opportunity was first launched in 2004 and along its sister craft Spirit, was supposed to perform a 90-day mission. Spirit kept going until 2010, and Opportunity is still going strong today (and hopefully for longer). That’s a level of dedication I can only dream of.

Based in part on the rover’s rugged track record, Dr. Rice believes that “rumors of Opportunity’s death are very premature at this point.”

France announces plans to pave 1,000 kilometers of road with solar panels

The French government announced its plan to build a 1,000 kilometer (621 mile) long stretch of solar panel-paved roads over the next five years. The locations for deployments have yet to be revealed. The fossil fuel tax is expected to bring in between 200 to 300 million euros ($220 to 440 million) of funding for the project coined “Positive Energy” .

Test laying of the Wattway panels.
Image via GCR

Paving roads with photovoltaic solar panels is an idea first put in practice in the Netherlands in 2014. The French government has announced plans to take that concept one step further and build a total of 1,000 kilometers of power-generating roads over the next five years. Their goal is to provide enough clean energy for 5 million people — about 8 percent of the current French population.

The roads will be built using Wattway panels, a photovoltaic technology unveiled last October by the major French civil engineering firm Colas. It took the firm five years to develop the panels that can be glued directly on top of existing pavement. These seven millimeter-thick strips harvest solar energy using a thin film of polycrystalline silicon, provide enough traction and are solid enough to withstand all types of traffic — Colas tested them under the weight of a 6-axle truck and they worked just fine.

“[The panels were tested on a] cycle of one million vehicles, or 20 years of normal traffic a road, and the surface does not move,” said Colas CEO Hervé Le Bouc.

The solar pavement also withstood the snowplow test, but the company recommends operating the machines with “a bit more care” than on pavement.

Colas CEO Hervé Le Bouc holding a Wattway panel.
Image via inhabitat

France’s Agency of Environment and Energy management states that four meters (13 feet) of solarized road is enough to power one household’s energy needs, not including heating, while one kilometer (3,281 feet) can supply enough electricity for 5,000 inhabitants.

According to Ségolène Royal, France’s minister of ecology and energy, the “Positive Energy” project will be funded by raising taxes on fossil fuels, a decision Royal says is “natural” given the low prices of oil. This is expected to cash in some 200 to 300 million euros ($220 to 440 million) in funding for the project.

Tenders for the “Positive Energy” initiative have been issued and tests on the solar panels will begin this spring. The government has yet to reveal the locations of the new roads.

Highest Silicon Solar Cell Efficiency Ever Reached

solar panel

Professor Martin Green and Dr. Anita Ho-Baillie

The efficiency of the solar cells is the first thing needed to be improved in order to improve the quality of the solar panels, and it is the aim of more and more scientists as time passes. Still, very few manage to obtain a breakthrough, and that’s exactly what researchers at University of New South Wales’ ARC Photovoltaic Centre of Excellence did; they created the first silicon solar cell that achieved the 25 percent milestone efficiency.

That’s not exactly a big milestone itself, because the previous record held by UNSW ARC Photovoltaic Centre of Excellence was 24.7, but the way they did it paved the way for future developments in the technology. Centre Executive Research Director, Scientia Professor Martin Green says they made a big step forward in expanding their knowledge about the composition of light.

“Since the weights of the colours in sunlight change during the day, solar cells are measured under a standard colour spectrum defined under typical operational meteorological conditions,” he said.
“Improvements in understanding atmospheric effects upon the colour content of sunlight led to a revision of the standard spectrum in April. The new spectrum has a higher energy content both down the blue end of the spectrum and at the opposite red end with, dare I say it, relatively less green.”

They also have an eye out to get these developments out in the open, and getting them to the mainstream consumption field.

Professor Stuart Wenham said the focus of the Centre is now improving mainstream production. “Our main efforts now are focussed on getting these efficiency improvements into commercial production,” he said. “Production compatible versions of our high efficiency technology are being introduced into production as we speak.”

Cost Effective Solar Energy Devices from MIT to hit Markets in 3 years

solar panelThe two major problems of green energy are actually developing the technology and making it cost productive. Both of them are yet to be solved, but scientists are making progress everyday to solve those matters.

Now, MIT engineers say they’ve created a new approach to harnessing the sun’s energy that provide windows with a clear view and illuminate rooms at the same time at low costs which promise to make it highly usable. This solar concentrator collects light from the edges, and dye molecules coated on the glass absorb that light, and then re-emits it at a different wave length.

The light is thus trapped and creates energy while allowing light into the room as well, thanks to this new mixture. Marc A Baldo, leader of the work claims that “the focused light increases the electrical power obtained from each solar cell by a factor of over 40″.

This technology will be developed and commercialized by a new company formed by members of the team who created it, and the system has every chance of being available for purchase in less then three years.