That used to be the case. However the price of solar panels have dropped 80% in the last 10 years, making the technology more affordable. Typically for the small schemes solar capital cost can be compared to diesel-generator ones. What is important however, it is to look at costs over the life of equipment. As good solar panels have a lifespan of 25 years and the running costs are so low, the cost advantages will become clear when looking at it over time. On average, Return on investment period ranges between 0 to 4 years and cost savings are of 40% to 90% when compared to equivalent diesel systems.