How are fossil fuels different from renewable energy sources?

The difference between the two isn’t as complicated as you may think. Renewable energy comes from natural resources that can be replenished during an average human lifetime and includes the following types of power:
Solar
Wind
Hydro
Geothermal
Biomass
Fossil fuels, on the other hand, can take thousands—or even millions—of years to naturally replenish:
Natural gas
Coal
Oil
These distinctions may seem cut-and-dried, but there are some gray areas. Natural gas is often labeled as “clean power” because it burns cleaner than coal. Folks may even believe that natural gas is a sustainable resource. Don’t be fooled. natural gas is a fossil fuel that emits CO2 when burned. In the case of biomass, things also get a bit more complicated. Burning wood—the most common method of biomass energy generation—sometimes emits more CO2 than burning coal. That said, wood is classified as a renewable resource by a lot of scientists because trees can be replenished.