WHY THIS MATTERS IN BRIEF
Despite solar power’s increasing popularity until now customers it’s been difficult and expensive for customers to store the excess energy from their solar panels to use later, meaning they often still have to be attached to the energy grid.
Recently we passed the 1 TeraWatt mark for the amount of electricity being produced from renewable energy sources like geothermal, wind and solar, and with their relatively moderate impact on the environment, especially compared with the climate change catastrophe being caused by burning fossil fuels, it’s now wonder that the popularity of renewable energy soaring. Furthermore, as we break efficiency record after efficiency record, whether it’s because of the development of new bacterial solar cells, or graphene coated solar panels that also generate electricity from rain water as well as sunshine, we can now see a time on the horizon when the cost of energy is at, or very close to, zero.
All that said though there are a number of reasons why you’re still reliant on coal and gas fired power stations for your electricity, some of which, by the way, like the ones in California, are being replaced themselves by new blockchain based virtual power plants and grid scale battery storage systems. Today’s commercial solar panels have an efficiency of around 17 percent, compared with the record breaking 28 percent for the new tech that’s coming through, but what really puts the boot in is that any extra energy they produce goes to waste because you can’t store it until you need it. This precariousness also means that people who want to go solar have to stay connected to the electricity grid.
Fortunately, however, all that may be about to change. In a new paper published in Chem, scientists from the University of Wisconsin-Madison in the US and King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, revealed a promising method that could free solar consumers from needing to worry about the time of day or being off-grid.
Storing solar energy isn’t a new challenge, other past ideas have included turning the excess energy into hydrogen or molten salt, but the team details how they managed to break efficiency records by successfully marrying a solar cell and a battery to form what they call a Solar Flow Battery (SFB) – in short think of it as a thin solar powered battery, part solar panel, and part battery.
At 14 percent round trip efficiency, which is the trip from solar collection to electricity output, these new SFBs are eight times more efficient than the team’s last prototype and it’s the highest efficiency ratio in the burgeoning field of solar rechargeable batteries.
The batteries even approach the level of most commercially available solar panels at 15 to 17 percent — with portability to boot, but even while achieving this new efficiency record, lead author Song Jin says they can do even better.
“We believe we could eventually get to 25% efficiency using emerging solar materials and new electrochemistry,” Jin told Cell Press.
The battery also has multiple modes – like a typical battery you can charge it with electricity, and like a traditional solar cell, it can convert sunlight into electricity immediately. It’s the battery’s special “third mode” though that allows solar energy to be stored as energy for use at a later point.
“These integrated solar flow batteries will be especially suitable as distributed and stand-alone solar energy conversion and storage systems in remote locations and enable practical off-grid electrification,” Jin explained.
Think, for example, rural areas, disaster zones, blackouts, and so on. RFBs tackle both the accessibility problem and the need for green energy in the space of one battery.
For now, the cost of the batteries is still too high to be a viable consumer option but in time the team think they might be cheaper to make than today’s separate solar panels and battery systems. But before the team begin focusing on that issue more research is needed to make sure the battery can fulfil its promise and, while it’s hard to predict, the team hope to have the tech commercialised within the next 5 to 7 years.