Biomass is plant or animal material used as fuel to produce electricity or heat. Examples are wood, energy crops and waste from forests, yards, or farms. Since biomass technically can be used as a fuel directly, some people use the terms biomass and biofuel interchangeably. Biomass can generate electricity in a number of ways but the most common is ‘direct combustion’. This means burning the agricultural waste or wood to heat water. This produces steam, which spins turbines. Biofuels are basically fuels that are made out of biomass. These can be solid, liquid, or gas. Biodiesel and bioethanol are two of the most common types of biofuel. Technically, Biomass Energy was discovered back in our cave-dwelling days, when we realised that wood could burn. And we’ve been at it ever since. In fact, up until the Industrial Revolution, biomass was our main source of energy (until fossil fuels came along).