The best replacement for natural gas is propane.

The best alternatives to natural gas are rated as following:
★★★★★  propane
★★★★  oil
★★★  gasoline
★★★  electric
★★★  propane grill
★★  coal
★★  oil heat
★  lp
★  electric heat
★  heating oil
★  propane cost
★  heat pump
★  diesel
★  electricity
★  electric water heater
★  lp gas
  coal emissions
  oil prices
  electric dryer
  oil for home heating
  electric cheaper
  propane prices
  diesel generators
  fuel oil prices
  electric heating
  propane cost calculator
  oil boiler
  propane stove
  coal prices
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  propane bbq
  coal co2 emissions
  oil cost
  propane grills
  propane home heating
  oil emissions
  propane cheaper
  wind power
  electric hot water heater
  diesel generator
  fossil fuels
  propane for home heating
  liquid propane
  propane generator
  nuclear power
  oil differences
  propane furnace
  propane fireplace
  fuel oil
  electric cost
  oil heating
  propane gas

Your alternative for natural gas is not listed? Suggest!
Speaking about natural gas, one probably shouldn't forget about fracking.

Other search terms related to natural gas and their ratings are:

★★★★★ fracking
★★★★★ diesel
★★★★ propane
propane grill
orange flame
You have in mind a companion for natural gas and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of natural gas in all years. Click on graph for more.
natural gas