The historic sources on fuel – Coal, Oil, natural gas were created hundreds of Million years ago, from decaying plant and animal matter that was buried and compressed. These are known as FOSSIL FUELS.

Humans have been using theses fuels so rapidly that they would start running out in 50-100 yrs time. BUT the bigger immediate problems is that they produce gases which trap heat in the atmosphere, warming the planet and Changing the Climate. They all produce CO2, carbon dioxide which is acting like an extra blanket around the earth

Renewable sources of energy don’t use anything up. These include solar, wind, wave and tidal power and some others. Hydroelectric power is considered clean but is short term. Dams slowly silt up and new ones are unlikely to be built because of environmental impacts.

COALmountain top mining is extremely destructivehas been cheap and plentifulburning produces CO2, particles, acid rain and mercury
OILThe root cause of a series of mid-east warsused for transport and energyusing it produces CO2 and smog making gases.
NAT GASnow produced by frackingclean burningExtraction by fracking pollutes water. Leakages of METHANE counter act all advantages. Still produces CO2 although less than coal.

NOTE – the “Clean Burning Natural Gas Powered” sign on many Santa Cruz buses is misleading. It’s true that what comes out of the tailpipe looks and smells relatively clean, but the modern production from Fracking is very damaging to water supplies where it’s extracted. AND the leakage from wells, condensers, pipes etc includes lots of METHANE which is 100x more effective than CO2 at trapping heat

Fracking aka Hydraulic Fracturing frequently poisons local water sources