Solar equipment, everywhere

©Tesla

Two pieces of news these last days. On the one hand, the biggest brown coal plant of Victoria State in Australia, located close to Melbourne and operated by French energy company Engie, will shut down in 2017. This is positive on an environmental point of view since brown coal is the biggest emitter of CO2 among all the energy sources. On the other hand, the Californian company Tesla has presented an unexpected new product: solar roof tiles. The roof tiles themselves integrate solar cells and produce electricity. This is not what one imagines when thinking of solar energy. One would represent the technology by large plane panels with metallic structure. Well, there is an alternative solution, called… organic solar!

ANOTHER CLASS OF SOLAR CELLS

We met David in BIO21
offices in Melbourne.
More here.

Tesla did not share any information about the technology behind the nice tiles. The solar tiles may carry organic solar cells. The most popular solar cells today are the silicon solar cells (silicium in French). It is what we find in the solar panels of solar farms or on roofs. Like the silicon ones, the organic cells convert solar energy into electricity. But organic solar cells are different; they use organic materials. They are made from carbon-based molecules or polymers and they have lots of advantages.

In Melbourne, a consortium of organisations has been working on the development of organic solar for several years. David Jones is the Project Manager representing the BIO21 Institute of the University of Melbourne. The Institute specializes in molecular science and biotechnology. Gerry Wilson is the Program Director from CSIRO, the federal government agency for scientific research in Australia.
 

We had the chance to visit labs at CSIRO together with Gerry.

“For years already, organic solar cells have demonstrated a great potential. Today the main drawback of the technology remains their efficiency,” says David. A simple definition of the efficiency is the portion of energy from sunlight that manages to be converted into electricity. Gerry says: “The silicon technology has reached 25% efficiency whereas the current best organic solar is 13% efficient. However the silicon solar has plateaued out while the organic is improving every year. This is why there will be more and more commercialization of organic solar.” Indeed, besides a lower efficiency, the numerous advantages of the organic technology are exciting!

THIN, SEMI-TRANSPARENT AND EVEN FLEXIBLE: LET’S UNROLL IT!

“We print the organic cells!” David explains. “We can print them on plastic, on glass or on metal or on textile. You can get thin, light and even flexible products.” Whereas the silicon panels are fragile, the organic solar items “can be rolled and transported easily. Camping tent can be covered with it. The Danish company infinityPV sells fine small phone chargers,” David says. “The solar panels we know go with heavy metallic structures. In India or in Africa for instance, they are very interested in lighter equipment.  

"Solar curtains" for the office? This tree with "solar leafs" should be installed next year.

Additionally we can make nicer equipment from an esthetic point of view. It is possible to alter the colors of the cells. There are even semi-transparent ones, which can be applied to windows for instance.” Gerry adds: “Also what is interesting with the technology is that the printing is not complicated; you can slightly modify a printer from the shelf and start to use it! It is one of the reasons organic solar equipment is simple to produce.”

The infinityPV phone charger. (©infinityPV)

PRODUCTION IS MORE SIMPLE AND LESS ENERGY CONSUMING

“Compared to traditional solar panels made of silicon, the organic cells require much less energy during manufacturing,” says Gerry. “Indeed there are purification and heating processes for the silicon cells. Organic is much less intensive, basically it is much about printing only. And costs for input materials are lower. The chemicals industry already manufactures the organic molecules.” In the end production costs are significantly lower.

Printers of the CSIRO Flexible Electronics Laboratory.

David concludes: “The technology is quite exciting. There is lot of enthusiasm among us working on it. There is plenty of room for improvement and innovation. We cannot imagine all the commercial applications behind organic solar!” Like the Tesla tiles, plenty of unexpected innovations will allow building the low-carbon society faster than we think.

On the left: SolarWindow designs windows which integrate organic solar cells. "Importantly, our liquid coatings are primarily made of hydrogen and carbon – two of the most abundant materials found in nature," says SolarWindow. (©SolarWindow)

On the right: Windows of this building in Yokohama, Japan, are covered with solar organic cells… (©Tasei)

In France, the construction of a “solar road” has recently started. Silicon solar is used among several layers and 15% efficiency is claimed by the designer WattWay. The future will tell us if it works! One important parameter to assess is how long the energy payback is.
(©Colas)

David gave an inspiring TEDx Talk in 2013.

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According to the International Energy Agency, in 2015 renewable sources of energy have surpassed coal in terms of cumulative installed power capacity, with photovoltaic solar adding 49GW. These 49GW represents nearly a third of all renewable energies added in 2015. When it comes to solar, the electricity generation depends on the weather, but the increase in the installed power capacity is putting this energy source rapidly as a key and cheap solution.

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