Producing Methane Gas from domestic & sewage water will effect the natural gas world wide prices?

Natural gas is limited and bound to end some day, however, as long as there are human beings on this earth Methane gas will never end. Currently the following are generated from Methane Gas;

Electricity, Bio Deisel, gas for domestic house hold etc. 

NOT REALLY

Really not, day to day life we require more natural gases and other form of energy. It will not leads to major problem.