Researchers have shown a new way to help solar cells track the sun as it moves across the sky, which could boost a panel’s energy generation by 40 percent.

By Mike Orcutt

Most of the solar panels in the world sit on rooftops at a fixed angle, so they miss out on capturing energy during parts of every day. Now researchers have shown that by cutting solar cells into specific designs using kirigami, a variation of origami which entails cutting in addition to folding, they can allow the cells to track the sun’s angle without having to tilt the whole panel. This could have a substantial payoff: solar panels with tracking mechanisms can generate 20 to 40 percent more energy per year than those without trackers.

As shown in the video here, applying a specific kirigami cut creates strips in a solar cell. Pulling the two ends in opposite directions causes the strips to tilt and assume a desired angle. Crucially, the structure morphs in such a way that prevents the individual strips from casting shadows on the others, and the “waviness” of the new form does not detract from performance, says Max Shtein, a professor of materials science and engineering at the University of Michigan. Shtein led the research along with Stephen Forrest, also a professor of materials science and engineering at the University of Michigan.

The kirigami-based approach makes it possible to generate more electricity while using the same amount of semiconducting material, and accomplishes this to nearly the same degree that conventional tracking systems do, says Shtein. Today’s tracking systems, featured in only a small portion of the world’s solar power installations, are cumbersome and can be costly. And they function by tilting the whole panel. That doesn’t work on most pitched rooftop systems, which account for more than 80 percent of all installations.

The newly demonstrated device, which features flexible solar cells made of gallium arsenide, is only a proof-of-principle. Developing a technology practical enough for commercial application will take a lot more work. The researchers will likely need to come up with a system for encasing the structures to protect them against the weather and provide mechanical support, and may add electric motors to pull the cells apart at specific times during the day. “It doesn’t take much force at all,” says Shtein. He says that although the approach is best suited for thin, flexible materials, in principle it could work with “almost any kind of solar cell.”


This transparent solar-powered battery looks like a futuristic Tony Stark invention

By: Chris Smith

Remember Iron Man’s transparent smartphones? They might become reality sooner than you think thanks to an unusual new type of battery that’s not only transparent, but it can also charge via solar power. The technology could also be used for other products in the future, such as smart office and home windows that would be able to let the sun’s light pass through them, but also recharge and store energy.

Developed by a team of researchers at the Kogakuin Univeristy, the lithium ion battery is not entirely transparent, as it contains the same chemical compounds that make any battery work. Furthermore, when exposed to sunlight, the battery becomes slightly tinted, transmitting 30% less light – but it’s still transparent. When fully discharged, the light transmittance rises to approximately 60 percent, TechXplore reports.

To pull these tricks off, the team of scientists shrunk down the electrodes, all the way down to around 80-90nm, to allow light to pass through.

The team has been working on it for about four years since a team of researchers at Stanford came up with the concept of a see-through battery that was also bendable. Two years ago, researchers unveiled a nearly transparent prototype that was charged with a separate solar panel, and then began work on integrating solar-charging powers into the battery.

The technology was demoed at Innovation Japan earlier this month, but it’s not clear how long it will take until it’ll be used in commercial products.

An image showing the new battery follows below.


The Dutch Railway Could Run Solely on Wind Power By 2018

By: Bryan Lufkin

Image: Netherlands Railways, via Shutterstock

The Netherlands has an ambitious new energy goal: The country wants its entire electric rail system to run on 100% wind power within three years.

Railway Technology reports that Dutch energy company Eneco and the VIVENS rail companies signed a deal to make Dutch electric trains within Netherlands Railways run entirely on energy produced by wind farms. Wind farms already supply half of the 1,800-mile, 1.5kV DC network’s energy—a network that carries 1.2 million passengers a day.

The wind power will come from within the Netherlands, as well as Belgium and some Scandinavian nations; part of the objective is to promote increased renewable energy adoption in other European countries.

In the last few years, wind power has seen rapid growth in adoption worldwide. According to the International Energy Council, the land-based wind power installation rate has gone up around 24% annually every year since 2000. The council predicts that if world governments stick to plan, wind power could account for 18% of all energy production globally.

Back in the Netherlands, Eneco says it also entered a 10-year deal with Google to make its data center in the northern part of the country totally powered by wind farm energy as well.


Light Shines on Shropshire Church Solar Panels

St Alkmund’s Cathedral is a building steeped in history. Part medieval, part Georgian, its 184ft spire has towered over Shrewsbury for half a millennium.

The Rev Tim Lomax at Christ Church, Bayston HIll, which has 126 solar panels installed on its roof

But while the church of St Alkmund can trace its roots back more than 1,100 years, its electricity supply comes from very much a 21st century source.

In 2008, the Rev Richard Hayes – the vicar at the time – was the driving force behind St Alkmund’s becoming the first church in Shropshire to install solar panels on its roof. The 22 photovoltaic panels cost £24,000 to install, with half of the money coming from a government grant, a quarter coming from energy company EDF, and with the Diocese of Lichfield paying the remainder.

It is one of a small but growing number of churches which are looking to the skies to source their energy.

“The planet is obviously suffering and we wanted to do our part and go green,” he says.

At the time, Mr Hayes hoped that St Alkmund’s would take the lead that other churches would follow, but installing panels on some of Shropshire’s most historic buildings was never going to be a simple affair.

Ruth Knight, environmental policy officer at Church Care, a division of the Archbishop’s Council, says there has been a slow but steady increase in the number of churches opting for solar power, but says it was a fine balance between preserving the fabric of historic buildings and developing a sustainable energy supply.

“It’s quite important to the church to reduce our carbon footprint,” she says. Read more »

Luminant inks deal with SunEdison to bring more solar power to Texas grid

By: Jordan Blum

(Jerry Lara/San Antonio Express News)

More solar power will enter Texas’ power market next year to compete “apples to apples” with coal and gas power now that Dallas-based Luminant has signed the largest such deal in the country with SunEdison.

Power generator Luminant will buy 116 megawatts — enough to power 58,000 homes during normal demand — from SunEdison’s new 800-acre Castle Gap facility in Upton County, just south of Midland. The complex will have 485,000 solar panels when it is completed next year.

The companies are touting the deal as the largest in the country in which solar power is being bought to compete in a competitive wholesale marketplace with all other power generation.

“That is a first and that is a big deal,” said Julie Blunden, SunEdison chief strategy officer. “Solar is ready to compete head to head.”

Unlike typical agreements in which the solar power is sold to a specific customer or in a regulated portion of Texas, Luminant will sell the electricity to the competitive market managed by the Electric Reliability Council of Texas. The companies are not revealing the financial terms of the deal.

Solar power currently makes up less than 1 percent of the Texas power grid’s generation capacity, while wind power represents 14 percent, but several solar projects in the state are being planned.

The costs for solar power have come down 15 percent in the last year, said Steve Muscato, Luminant chief commercial officer, in a video presentation.

“When our customers are running the most amounts of electricity is when solar is producing,” Muscato said about the hot summer days in Texas. “So it doesn’t necessarily replace coal or replace gas because coal and gas are sort of there 24 hours a day, seven days a week.”

Blunden said she expects a lot more solar growth in Texas through large solar farms, as well as a lot more solar panels on roofs. It will take time, she said, but solar will eventually catch up to wind power growth in Texas.

“As we evaluate our future generation needs, we focus on projects that are profitable and able to compete in the wholesale market. This agreement with SunEdison meets those goals since solar generation costs have become increasingly competitive,” Luminant CEO Mac McFarland said in the announcement.