Why do people shift to petroleum as an energy source from coal?

Question

For a long time we've been using coal to make energy. Why suddenly we changed to petroleum?

Answer 1

petroleum is in the liquid form

utilization is much easier

combustion with air is easier

operational efficiency

transport easiness, wastage minimimum,

engine design compactness, availability

environmental protection, cost concern

Answer 2

Higher calorific value,easy to transport,available in different form and grades,less atmospheric pollutions.