The race is on to find cheap renewable fuel sources, but there’s a problem: how do we store renewable power like solar and wind energy? Right now, battery storage devices are costly and potentially hazardous. Yet, could simple plants like rhubarb provide the materials for large-scale power storage devices of the future?
Yes, say scientists at Harvard university who this month reveal in the scientific journal Nature that they have been able to harness the composition of simple plants to create a revised “flow battery.”
The technology is a type of rechargeable fuel cell that utilizes chemical compounds dissolved in liquids. Flow batteries replace solid electrodes with two liquid electrolytes. These kinds of batteries can be scaled up to increase the duration of wattage they’re able to deliver without changing the power capacity, unlike lithium batteries which have to be scaled up in every sense in order to increase battery storage.
Flow batteries, which have been around for more than three decades, have long been seen as a promising technology but, until now, flow batteries have relied on compounds from high cost metals like vanadium, and this has made them unsuitable for mass market application and production.
Now, Harvard researchers have managed to adapt the technology to use quinones, organic molecular compounds which in this case were from crude oil but are virtually identical to those found in rhubarb and many other simple plants. As such, the process could cut the cost of creating flow batteries by over a third or even more.
“We’ve introduced the world of organic chemicals to flow batteries,” Professor Michael Aziz of Harvard University is quoted as saying. ”The ones we have used are very inexpensive, very abundant, they work really well and they’re safe.”
Why is this technology so interesting? Well, it could in the future change batteries in a big way. Currently, other than the expense of battery technology, there are a number of safety issues. For instance, market leading lithium batteries all come with one very big downside: they can catch fire. The newly engineered organic flow batteries on the other hand use molecules that are dissolved in water and so the batteries are unlikely to pose a fire hazard risk.
What’s more, the batteries could potentially be engineered very specifically so that they could meet the specific challenges of industry while remaining low cost and still relatively kind to the environment.
Roy Gordon, another researcher who worked on this technology, puts into perspective the exciting potential of this technology:
“The whole world of electricity storage has been using metal ions in various charge states but there is a limited number that you can put into solution and use to store energy, and none of them can economically store massive amounts of renewable energy. With organic molecules, we introduce a vast new set of possibilities. Some of them will be terrible and some will be really good. With these quinones we have the first ones that look really good.”
At the moment the technology remains in the testing phase. The researchers have said that the testing cycles on their small prototype have yielded good results with little energy loss and they believe that, based on these results, there is no reason why the battery couldn’t be scaled up to the size of a heating tank. This would enable a household to store about a day’s worth of solar-generated energy. Eventually, they hope to build batteries on a larger scale that could then be connected to solar arrays that are seen on commercial buildings, thus creating the potential for greater stores of power.
So, how far are we from seeing this kind of technology on the market? Currently, the test cycles have only lasted into the hundreds. The batteries will need to be capable of thousands of cycles of output before they could be commercially viable, but the aim to produce a battery that can provide eight or more hours of energy does appear within reach.
What’s more, now that this energy storage technology appears more than just theoretically viable it could increase the funding for renewable energy sources. This in turn will feed back into innovating storage — that is, assuming that those opposed to renewable energy don’t see fit to delay development like they have in the past.
While we must be cautious and say that at the moment this is all possibility and not fact, the organic flow battery is an exciting breakthrough that could at last answer part of the renewable energy problem that clouds our future.
Photo credit: Thinkstock.