In the long run, solar power is economical. Even though solar panels and installation involve some expenses, this cost is soon offset by savings on energy bills. Eventually, you will produce a profit on your use. . The average solar unit in Sri Lanka is about 5–6 KWs. How much you will save depends on how big your array is, the capacity of your storage system, and the weather—and, of course, where you live and the sunlight available to you.