by Emil Morhardt
Windpower, because it is intermittent, works best on the electrical grid if it has some energy-storage facility connected to it. Batteries are the simplest approach, and the low cost of lead-acid batteries makes them good candidates, but they resent being randomly charged and discharged (especially deeply discharged) at the will of the wind, and die prematurely. Enter the supercapacitor; it can be charged by wind turbines much faster than a battery, can deliver its stored energy to the grid much faster as well, and doesn’t resent it at all, even being deeply discharged at every cycle. Engineers at Kocaeli University connected a supercapacitor in parallel with a battery (see diagram above) so that it would buffer transient current surges, saving the battery to do what it does best. The system worked just like one might expect, but there are some graphs in the paper showing just how the current flowed, and I think it is a nice example of an experimental setup to look into these types of hybrid energy storage systems. (The diagram is from their paper. There’s a link to it below.)
Erhn, K., Aktas, A., Ozdemir, E., 2014. Analysis of a Hybrid Energy Storage System Composed from Battery and Ultra-capacitor, 7th International Ege Energy Symposium & Exhibition, June 18-20, 2014, Usak, Turkey http://bit.ly/1neZfey
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