Question

What do we mean when we say that 50 million tons of coal could replace the use of 0.6 MBPD (million barrels per day) of oil used over a year?

Answer 1

This statement simply implies that the 50 million tons of coal will produce the same energy output in one year as the 0.6 million barrels per day of oil. Assuming coal is more plentiful than oil, this is significant as 50 million tons is much smaller than 219 million barrels of oil.