There has been many talks and articles about ultracapacitors and its potential use for renewable energy. Let me first start by answering the question What is an Ultracapacitor?
An Ultracapacitor, sometimes called electric double-layer capacitors or supercapacitors are just just like any other capacitor but have a very high energy density. It can store huge amounts of energy for its size. If you are familiar with the usual electrolytic capacitor, think about a device than can store a thousand times more energy. Most electrolytic capacitors have a value in micro farads, but a typical ultracapacitor has a value in 10, 100, or sometimes thousands of farads.
One may also think of ultracapacitors as a super battery. Normal rechargeable batteries such as Nicd and NiMH have very slow charging times. What’s great about an ultracapacitor is that it charges very quickly just as an ordinary electrolytic capacitor does. It can also discharge high amounts of power very quickly unlike normal batteries.
Such properties of Ultracapacitors made it a very suitable for applications such as for motor startup, and regenerative braking. Someday, I won’t be surprised to see Ultracapacitors replace batteries in all-electric cars (EV) and plugin hybrids.
