If you watch your propane tank gauge, you may have noticed that your propane supplier delivered your fuel, he didn’t fill your propane tank all the way up to the 100% level.

If you have a swimming pool in your backyard, count yourself as among the fortunate ones who have an outlet for the kids to find some respite from cabin fever. Even if the summer temperatures haven’t set it in, you can enjoy your pool sooner—and later into the fall—by heating your pool with propane.

So what is an alternative fuel? It’s anything that bypasses the two big traditional motor fuels: gasoline and diesel. According to the Alternative Fuels Data Center, 60% of alternative-fuel vehicles nationwide run on propane, from buses in metropolitan areas to fleet trucks, forklifts, lawnmowers and farm tractors.