There is another way to harness the sun without all the wires and batteries. You can utilize the energy as it is created with the help of a skylight or solar tube. These kinds of interior lighting are incredibly efficient as you are taking advantage of the light its self with no losses in power conversion or storage. 
The obvious drawback here is it only works for you when da sun is a-shinin. But that is no reason not to take advantage of its usefulness when it is. Houses, long ago, use to be designed with the sun in mind, southern exposures, big picture windows, (actually pretty poor at thermal insulating,) that are great for letting in light. 
We tend to build on smaller lots now with fewer options, in some cases, to take advantage of natural lighting. We also build with relatively energy efficient materials to help us hold in the heat or air conditioning to help make our lives a little more comfortable. Unfortunately with smaller more energy efficient windows further handicapping our capacity to use this valuable resource.
The good news though is we can actually "pipe in" sunlight. With products like the tubular skylight
we can enjoy the sun inside our temperature controlled environments. Not to mention save a little cash on the old power bill. There are actually other benefits to letting in a little UV. Ultra Violet light has been use for all kinds of sanitation purposes. They are using it to kill germs and bacteria, mold and mildew, apparently it also offsets some of the ill effects of less than friendly old magnetic ballasted florescent lighting.
This type of technology should definitely be remembered in the struggle to become a little more frugal and a lot more energy efficient. If its already there you may as well use it to your advantage.
