If there’s one thing the equality state possesses in spades, it’s wind. Having sharp snow crystals driven stingingly into any exposed skin by 50-mile-an-hour gusts is something of a rite of passage at the University of Wyoming. That same biting wind, however, represents a huge amount of energy – each icy blast can be captured and transformed into electricity by wind turbines. One of the largest barriers to truly developing this energy resource has historically been the problem of storing the energy. A recent project at the Harvard School of Engineering and Applied Sciences has produced a new type of organic flow battery which might just provide a solution.
Renewable energy sources like solar and wind produce what University of Wyoming chemistry professor Dean Roddick calls “intermittent power.” Solar panels only produce electricity when the sun is out, and wind turbines only spin when there is sufficient wind to drive them. In order for these renewables to be a viable energy source, battery technology must develop to a point where their energy can be stored and then fed into the electrical grid during the hours of peak energy consumption.
Traditional batteries rely on chemical reactions between two different compounds which produce a consistent flow of electrons, also known as an electric current.
“You basically have to have two compounds, one of which has an unequal desire to attract electrons” explained Roddick. “A battery basically puts them apart from each other and exploits that.”
These two different chemical species are physically separated and forced to react slowly and predictably, swapping electrical charges.
“Instead of just letting them react together, which is what would happen if you put them in intimate contact, you force them to do some electrical work: to transfer electricity. “
In most modern batteries, the chemical species used are metallic ions. Anyone who owns a smartphone is likely familiar with the terms “lithium-ion” or “nickel-cadmium” in reference to high performance energy storage. The team at Harvard has rocked this paradigm by creating a battery that replaces metals with a class of naturally abundant organic compounds called quinones.
Quinones are small molecules which contain carbon. They are often used to store chemical energy in living organisms and have an ability to accept and donate electrons that rivals the capacity of metals like lithium and zinc.
“Quinones are very prevalent,” said Roddick. “Hydrogen peroxide, like you buy at the store – it’s made from basically the same compound [the Harvard Team] is using.”
According to the Harvard press release, their battery is a flow battery, which means that it consists of three distinct parts. There are two tanks containing the two chemical species, and “electrochemical conversion hardware,” where the chemicals come together to react and release their stored energy. The importance of this battery model is that it can be scaled-up, and thus has the potential to store tremendous energy.
“In general battery technology,” said Roddick “people strive for power density. They want to get everything in as small a space as possible. And that’s not really appropriate for the stated use of storing intermittent power.”
“Instead of power density, [The Harvard Team] wants power capacity,” he continued. “They want to be able to store large amounts of power and then get it back later. Their battery doesn’t have to be restricted by space.”
For Wyoming wind energy, this technology could be a huge boon. Energy created by a 4AM wind storm – when no one is awake and using electricity – can be stored in a few warehouse-sized organic flow batteries and released into the grid over the course of the day as needed.
Quinone-based batteries have other advantages as well, both economic and environmental. Metals like lithium and cadmium are highly reactive and even toxic. They have to be mined, and many of them are controlled almost completely by foreign economies like China and Russia. What’s more, they are expensive compared to quinones; scaling up a lithium battery to match the performance of a large organic battery would be nightmarishly expensive.
The Harvard team is in the ongoing process of testing and refining their battery, and it is unlikely that this energy advance will make its way west any time in the immediate future. As a proof-of-concept, however, it is startling in its potential. Perhaps a decade from now Wyoming can leave behind our coal economy and become a titan in the wind energy industry.
