Bio-Energy is a broad category which includes all energy generated from burning materials produced (recently) by the biosphere. While humans have obtained energy from such sources throughout their history, the amounts of energy that industrial society now demands cannot possibly be sourced in a sustainable way. Every year we burn a quantity of fossl fuels which it would take the biosphere 400 years to produce. Bio-Energy includes liquid biofuels (or agrofuels) such as palm oil as well as biomass such as wood pellets. The growth in Bio-Energy is devastating large areas of the globe and leading to hunger and poverty for many. Bio-Energy requires a colossal quantity of feedstock and huge areas of growing land. This land must either be land that was previously used to grow food or land that was previously forests etc. Either way the results are not good.
Bio-Energy is driving a wave of land grabs and human rights abuses in the third world. This is concentrating land ownership in the hands of large producers, and encouraging farmers to grow cash crops for this new energy market instead of growing food for their own population. It is also leading to increased deforestation even in developed countries. Small scale biofuel power stations have been increasing in number, usually built near ports to import their fuel, but a recent trend has seen existing coal-fired power stations converting to run partly or wholly on biomass. Power stations burning wood emit up to 50% more carbon than ones burning coal. When forests are destroyed and turned into monoculture plantations, much of that carbon will simply stay in the atmosphere.