First of all, hi, new kitty!
The problem, in part, is that the problem of energy storage is a really tricky one. It's a problem, and it's something that the industry is trying to get their butts off the ground and work on (mainly because of wind turbines and trying to store the energy from those since they are intermittent and that does not interface well with the electrical grid).
All the energy has to be stored as potential energy, and there's the option of mechanical, chemical, and electrical storage. With mechanical, you could have a wound up spring that slowly unwinds or bladder full of gas that slowly releases the gas (and many other possibilities that I can't think of right now). With chemical, you can have chemical reactions that take place over a period of time (like in a battery) or have a fuel, like in a car. With electrical...it's a bit harder. Electromagnetic waves kinda do whatever they want to do, so it's easier to store that energy as chemical or mechanical potential energy and then convert it in to electrical.
Take light for example. We can't (easily) tell the light where to go or where to stop, and we can't store light itself, but that light can be transform into a different form of energy with plants and solar panels and the like. It's an energy conversion game, and right now, batteries are the best we've come up with, unfortunately.
(And hopefully that all made sense).