Biomass heating systems generate heat from biomass. The systems fall under the categories of direct combustion, gasification, combined heat and power (CHP), anaerobic digestion, aerobic digestion. The types of biomass heating are fully automated, semi-automated, pellet-fired, and combined heat and power. Types The use of biomass in heating systems has a use in many different types of buildings, and all have different uses. There are four main types of heating systems that use biomass to heat a boiler. The types of biomass heating are fully automated, semi-automated, pellet-fired, and combined heat and power. Fully automated In fully automated systems chipped or ground up waste wood is brought to the site by delivery trucks and dropped into a holding tank. A system of conveyors then transports the wood from the holding tank to the boiler at a certain managed rate. This rate is managed by computer controls and a laser that measures the load of fuel the conveyor is bringing in. The system automatically goes on and off to maintain the pressure and temperature within the boiler. Fully automated systems offer a great deal of ease in their operation because they only require the operator of the system to control the computer, and not the transport of wood while offering comprehensive and cost effective solutions to complex industrial challenges. Semi-automated or "surge bin" Semi-automated or "Surge Bin" systems are very similar to fully automated systems except they require more manpower to keep operational. They have smaller holding tanks, and a much simpler conveyor systems which will require personnel to maintain the systems operation. The reasoning for the changes from the fully automated system is the efficiency of the system. The heat created by the combustor can be used to directly heat the air or it can be used to heat water in a boiler system which acts as the medium by which the heat is delivered. Wood fire fueled boilers are most efficient when they are running at their highest capacity, and the heat required most days of the year will not be the peak heat requirement for the year. Considering that the system will only need to run at a high capacity a few days of the year, it is made to meet the requirements for the majority of the year to maintain its high efficiency. Pellet-fired The third main type of biomass heating systems are pellet-fired systems. Pellets are