The Science of Solar Comes Down to Earth Three Times Over

The Science of Solar Comes Down to Earth Three Times Over

1. A new type of solar cell which can convert liquid water into clean hydrogen fuel 10 times more effectively than any other technology has been discovered in The Netherlands. It uses 10,000 times less precious material in the process. 2. Halfway between a balloon and a kite, a flying solar device called Zephyr (from France) is assisting those deprived of electricity in disaster areas. 3. Imagine a tent with an outer solar-powered skin which absorbs solar energy that is then converted into usable electricity, while the inner skin provides pockets for storage – particularly at the lower half of the shelters. Plus a water storage tank on the top. It’s the work of Jordanian-Canadian architect and designer Abeer Seikaly. Read More

Scientists figure out how to make solar cells produce fuel AND electricity

How does powering our cars with solar fuel sound?

Science Alert (20 July 2015): 20 JUL 2015

A new type of solar cell can convert liquid water into clean hydrogen fuel 10 times more effectively than any other technology, and uses 10,000 times less precious material in the process.

Invented by researchers in the Netherlands, the secret to these new prototype solar cells are gallium phosphide nanowires, which can split water into its hydrogen and oxygen components far more cheaply and efficiently than the batteries and semiconductor materials that have been used in the past.

The efficiency of solar cell technology has improved dramatically over the past decade, and is now providing Germany with at least half its national energy requirements. And earlier this year in the Netherlands, it was announced that a tiny, 70-metre stretch of road covered in solar cells generated enough electricity to power a household for a year.

Over the past few years, scientists have been figuring out how to take things one step further by using solar cells to produce both fuel and electricity. The dream is one day we’ll be using nothing but the boundless energy of the Sun to not only power our homes, but our cars, trains, and buses too.

Previous studies have shown that connecting an existing silicon solar cell to a water-splitting battery can produce hydrogen fuel, but it’s certainly not a cheap enough process to be a realistic alternative. The most promising option is using some kind of semiconductor material that can convert sunlight into an electrical charge while splitting water into useable components, like an all-in-one solar fuel cell, but semiconductor materials aren’t cheap either.

A team Eindhoven University of Technology investigated the potential of gallium phosphide (GaP), which is a compound of gallium and phosphide that’s also used in the production of red, orange, and green-coloured LED lights, and has shown great potential in terms of its electrical properties. But gallium phosphide is expensive to produce, and when used in big, flat sheets, it’s not capable of absorbing sunlight as efficiently as needed for a viable solar cell system. So the researchers tried producing a grid of tiny gallium phosphide nanowires measuring 90 nanometres thick and 500 nanometers long, and integrated them with existing solar cell technology.

Not only did they end up using 10,000 less gallium phosphide than if they’d used it to build a flat surface, but they discovered a whole new way to make solar fuel. “This immediately boosted the yield of hydrogen by a factor of 10 to 2.9 percent,” the press release explains. “A record for GaP cells, even though this is still some way off the 15 percent achieved by silicon cells coupled to a battery.”

The team argues that it’s not just the yield we should be looking at when it comes to producing solar fuel, but the cost of the system, because if it’s not cheaper than what we already get from fossil fuels, no one’s going to use it no matter how much better for the environment it is. Their challenge now is to figure out how to increase the yield of their gallium phosphide grids so their solar cells can meet this 15 percent battery yield.

“For the nanowires we needed 10,000 less precious GaP material than in cells with a flat surface. That makes these kinds of cells potentially a great deal cheaper,” lead researcher Erik Bakkers says. “In addition, GaP is also able to extract oxygen from the water – so you then actually have a fuel cell in which you can temporarily store your solar energy. In short, for a solar fuels future we cannot ignore gallium phosphide any longer.”

The results have been published in Nature Communications.



From Straits Times (20 June 2015):

Solar balloon makes light work at disaster sites

HALFWAY between a balloon and a kite, a flying device called Zephyr is assisting those deprived of electricity in disaster areas.

Designed by students from the Ecole Nationale Superieure des Arts Decoratifs in Paris, the device can generate energy anywhere.

It is made up of a box with an electrical transformer and a lightweight sail. Measuring 3.8m in diameter, the sail is covered with 15 sq m of lightweight solar panels.

Mr Cedric Tomissi, one of the two designers behind the project, said: “All you need to do is unfurl the sail and allow it to inflate.

“The balloon collects solar energy and transports it to the ground via a cable, while the batteries store surplus energy and take over the power supply at night.”

The device can yield up to 3kwh of power, putting it on a par with a traditional generator.

It can supply lighting and heating to 50 people in, say, a refugee camp or an emergency hospital.

The designers have won several awards, including the 2014 James Dyson Award.

A technical feasibility study was carried out on the photovol-taic balloon in November last year.

The next stage is to build an initial prototype.

The team will need about €25,000 (S$38,000) to do that. It has received around €10,000 from various prizes. A fund-raising campaign is set to run from September to January.

The team hopes to move the project into an industrial phase and start selling the device in 2018. About €1 million will be needed at this stage.

In the long term, the aim is to sell an entire range of balloons for various uses, including non-humanitarian applications.

Said Ms Julie Dautel, the other designer: “The balloon can be used for homes in remote areas where the roof cannot take the weight of traditional solar panels, at campsites and in nomadic encampments like those found in Africa and Asia. It can even be used to support communications technology.”


A version of this article appeared in the print edition of The Straits Times on June 20, 2015, on Impact Journalism Day, with the headline ‘Solar balloon brings electricity to disaster sites’.


Collapsible woven refugee shelters powered by the sun

From Green Prophet:

More than 40 million people worldwide have been displaced from their homes and left to find shelter in strange lands. Maybe they find a tarp, or a tent, but their quality of life almost always remains dismal.

To close this gap in need, Jordanian-Canadian architect and designer Abeer Seikaly designed a new kind of shelter.  One that allows refugees to rebuild their lives with dignity.

Seikaly, now living in Amman, Jordan is well poised to design a dwelling for refugees given that her ancestors in Jordan probably toggled between nomadic and sheltered life in the desert for centuries.

“The movement of people across the earth led to the discovery of new territories as well as the creation of new communities among strangers forming towns, cities, and nations,” writes Seikaly in her design brief. “Navigating this duality between exploration and settlement, movement and stillness is a fundamental essence of what it means to be human.”

But today, a great deal of migration is no longer voluntary, as wars and climate change force people out of their homes – often with very little money. The collapsible woven shelters, which are conceptual but proven to work, would allow these people to carry their homes with them.

Comprised of a structural woven fabric that “blurs the distinction between structure and fabric,” the shelter expands to create a private enclosure and contracts “for mobility.” It also comes with some fundamental amenities required by modern people, including water and renewable electricity.

The outer solar-powered skin absorbs solar energy that is then converted into usable electricity, while the inner skin provides pockets for storage – particularly at the lower half of the shelters. And a water storage tank on the top of the tent allows people to take quick showers. Water rises to the storage tank via a thermosiphoning system and a drainage system ensures that the tent is not flooded.


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