In a general outlook, fossils i.e. coal, oil, natural gas is a gift by nature, absolutely free, inasmuch that they are just lying in the ground, patiently waiting to be picked up. However, the cost of extracting them from the ground, processing costs, transmitting costs is what adds up to the cost and leads to them not being free to the consumer.
In this respect, renewables i.e. solar energy, wind energy, hydroelectric power, tidal energy, and the rest are no different to fossils.
Unfortunately, we are still cling to fossil fuels for a number of reasons. One reason is that in some cases fossil fuel is cheaper. Its exactly like e-books replacing hard-bind books and e-mail/sms replacing letters, there has to be some advantage that isn’t abstract, that can be easily felt that will make people change.