What is the energy crisis?

Most of the world’s electricity is generated by oil, gas and coal in power stations. These fossils fuels are being used up quickly, and some experts have predicated that an energy crisis will occur before long. At the present rates at which we are using oil and natural gas, the known reserves will run out in the early 21st century. Coal reserves are expected to last 300 to 400 years, but even they will be used up one day.