Today’s world faces a large problem which is global warming. Glaciers melting see, and oceans water level rising, and droughts in Africa. According to  there are seven main sources of CO2 emissions from fossil fuels combustion: 1. Solid fuels (e.g. coal) – 35% of CO2 emission 2. Liquid fuels (e.g. gasoline, fuel oil) – 36% of CO2 emission 3. Gaseous fuels (e.g. natural gas) – 20% of CO2 emission 4. Flaring gas industrially and at wells: <1% of CO2 emission 5. Cement production: 3% of CO2 emission 6. Non-fuel hydrocarbons: < 1% of CO2 emission 7. The "international bunkers" of shipping and air transport not included in national inventories: 4% of CO2 emission As one can see from the list above, natural gas, which is mainly used for space heating in Europe, is responsible for 20% of total CO2 emission. Because of this fact limitation in using of this fossil fuel is an important issue.