There are a couple of ways to make solar energy more economical. One way is to make the conversion of solar wnegy into electricity more efficient, for example, making more effecient solar panels. Another way that's important for large solar energy farms is to find efficient ways to store all the energy that's generated. Now, lots of the solar energy production occurs mid-day but the hightest demand for electricity is late in the day. Thus we need a way to store the energy cheaply and efficiently.