a cost of fossil fuel energy vs. wind power is that fossil fuels are non-renewable resources (it takes millions of years to form them) compared to wind power which is renewable (there's pretty much a non-stop flow of wind). another cost of fossil fuel energy is that CO2 is a byproduct of it's use and what it takes to GET the fossil fuel. a huge increase in CO2 is thought to be bad for the environment as well. one benefit of fossil fuel: they can be burned and produce great amounts of energy that we can harness (use).