With the generation of energy at the top of everyone’s minds, it might be easy to forget how and where all that energy is stored and transported to the populations that need it. Even in a world bereft of renewable energy sources (I am not advocating this in any shape or form), energy storage can be so important as to completely affect the potential of a resource – think about the slow gains we’re making with battery technology and how that has translated to hybrid cars’ travelling distances and your cell phone’s computing capabilities.
Fun Fact: The term “battery” (in the electrical sense) came about when Benjamin Franklin described an array of capacitors as a “battery” of cannon artillery. Note that it then becomes quite incorrect to describe a single button cell in such a way.
In any case, the storage of electricity only increases in importance when we start talking about energy generation from intermittent sources. Energy gleaned from the sun, tides, and wind can be at best predictably sporadic, and at worst non-existent for weeks at a time. A question arises: without a SMART grid to distribute electricity in the most efficient way possible, how can we preserve excess electricity in times of surplus for use in the future when the resource is less than favorable? Like I said above, we continue to make incremental gains in traditional battery technology, but it’s slow. (If you’re interested in this, chat me up – I spent a summer researching increasing efficiency of Li-ion batteries as well as another investigating this neat-o idea of storing energy utilizing a reversible redox reaction of Vanadium ions with the clever moniker: All-Vanadium Redox Flow Batteries) You might also notice that these ideas strictly involve storing the electricity in the form of chemical potential energy.
I think this is an old idea, and while it’s not necessarily outdated, there are definitely other methods of energy storage that don’t get their day in court. One idea I find particularly interesting as well as a nice example of coming up with a solution that best solves multiple problems at once, is the idea of compressed air storage. If we want to get technical this concept is probably just as old as the battery, with salt domes used as the large container in which the air was compressed, but…not important.
Compressed air energy storage (CAES, I know, the creative names just keep coming) systems look particularly promising for ocean energy storage. There are a few different types of similar concepts, some involving actual compressed air, and others pumping water out to leave a pressurized space. For ocean energy uses, rather than rely on the locations of salt mines, like we currently do for natural gas storage, we can instead use the high pressure differential available as you travel down the water column. In short, a man-made cavity (in the form of a concrete structure, or even a hot-air balloon) can be moored to the ocean floor near an ocean energy farm. If there is too much energy being generated at once, the extra will be used to pump water out of the cavity or compress the air already present. It will then be available for release if more energy is needed at another point in time.
These solutions offer several benefits: by abandoning the traditional chemical energy storage, we avoid using materials that can be poisonous to our environment. Regardless of the technological advances we have made with Lithium-ion batteries in using environmentally safe binders in the slurry, the fact remains that disposal of these systems is problematic. A localized energy storage method is also arguably better long term – in my opinion a distributed energy model (like the local food and business movements) is our best bet in terms of tailoring energy solutions to the needs and resources of a particular location. Storage on site would provide options for communities instead of relying on an expensive, integrated grid infrastructure to distribute their locally produced power to other places.
Time to get off my soapbox. A quotable man once said, “Science never solves a problem without creating ten more.” This has become obviously apparent with the ‘solutions’ to the climate crisis, but it’s remarkably salient in other avenues as well. Being an engineer at heart, I tend to gravitate toward applications of science – designing and implementing solutions to tangible problems. There are a million answers to any one question, and we often remain entrenched in our historical ways of thinking or doing in order to minimize conflict. But I challenge you to find your inner engineer, and do more thinking outside the battery.