How much of the world’s energy consumption could be produced from agricultural biomass?

Currently about 14 million square kilometres of land is being cultivated. There is about another 4 million square kilometres of crop and pasture land which is not being used. If energy crops were planted on the abandoned land they could produce about 27 exajoules of energy a year – equivalent to 172 million barrels of oil or 5% of the world’s current energy use of around 500 exajoules a year. Even if all of the current agricultural land was user for energy crops, the total energy production would be only about a quarter of our total energy consumption.

While growing energy crops may make a contribution to our energy needs, it is obviously not the whole answer!