Debut of the first practical artificial leaf


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Yet another new breakthrough in low cost solar energy just made its debut, and this one is a doozy: a solar cell the size of a typical leaf, that actually creates energy the same way a leaf does: with photosynthesis. No, for real. You just park it in a bucket of water and it generates enough electricity to power household devices… eventually (more on that below). The announcement was made by the lead researcher on the MIT-based project, Dr. Daniel Nocera, who said, “A practical artificial leaf has been one of the Holy Grails of science for decades.”

Solar Power from an Artificial Leaf

The new solar cell is about about the size of a poker card. It doesn’t produce usable electricity directly, like a photovoltaic cell does. Instead, it is used to split water molecules into hydrogen and oxygen gasses. These are stored in a fuel cell, which then produces the electricity for household use. The idea is to have the combination of solar “leaf” and fuel cell as an affordable onsite renewable energy appliance that practically anyone could afford, just like a furnace, hot water heater or emergency generator. One sticking point in the research was to find a low-cost catalyst to set off the reaction, and Nocera’s team came up with several alternatives made of nickel and cobalt.


Photosynthesis and Renewable Energy

Though Nocera is apparently the first to come up with a commercially viable, low-cost renewable energy system based on photosynthesis, other researchers are also following the trail. At the Department of Energy’s Oak Ridge laboratory, long-running research into a light-harvesting protein from spinach has resulted in a similar hydrogen-producing process.

Affordable Energy, Thank You Federal Government

With oil prices spiking up for the umpteenth time in the past few years, consumers are eager for a solution, and renewable energy is beginning to provide it. When Nocera’s solar leaf is ready for commercial production, we can all pat ourselves on the back: some of our tax dollars have supported his research, through the Department of Energy’s ARPA-E transformational energy program.
Source: Clean Technica
A lab at MIT, led by Dr. Daniel Nocera, have invented a new and novel form of storing energy that may prove to be an important milestone in the development of alternative energy. In fact, the obvious utility of the process has engendered a bit of excitement, but this excitement has also generated some misconceptions about the process that I would like to clear up, now that I have a more complete understanding of how it works.



Why This Technology is Important
What this technology represents is something even better than a mere power generation method; it’s a way to put the methods that we currently have to generate clean energy to work for us in a huge way! Many people complain that they always see wind generators standing still, but this is because there is too much power available, and the grid can’t handle the extra juice. Indeed, we wasted 25 TWh of potential electricity generation from windmills last year because we had no place to store the power. In the past, methods of storing this excess energy were terribly expensive (batteries), terribly inefficient (hydrolysis), or just terrible (complex and potentially dangerous spinning flywheels).


High-Efficiency Solar Cells Getting More Efficient, Cheaper


Solar Junction is a 4-year-old company spun out of Stanford University that designs high-efficiency, multi-junction solar cells for concentrating photovoltaic (CPV) solar collectors. The National Renewable Energy Laboratory recently certified that its solar cells can operate at 40.9% efficiency, a significantly higher efficiency than typical silicon solar cells that convert sunlight to electricity at an efficiency of about 15-20%.

Multi-Junction Solar Cells
How do these “multi-junction” solar cells convert sunlight into electricity so efficiently? They use “different materials than the traditional silicon cell and multiple semiconductors within a single package.”
“In essence, you have three basic subcell materials that take in some light and pass the rest to the next. They are connected serially inside the device just like battery cells,” Solar Junction co-founder Craig Stauffer explains.
The technology isn’t actually new, but it “hasn’t become as established or widely used for wholesale electricity production as regular flat solar panels” due to the cells’ complexity and price. However, Stauffer says the costs are coming down due to efficiency improvements and higher concentration levels. “CPV solar collectors can now concentrate light 1,000 times, compared to 500 times in the past year or two,” and Stauffer thinks Solar Junction’s solar cells will achieve efficiencies of over 50% in the next five years.