What is Biomass?
Biomass energy generation is the creation of heat and/or power from carbonaceous substances such as wood or wood residues, agricultural crop residues, aquatic plants, animal waste, and dedicated energy crops.
Biomass energy can be standalone heat generation such as the lumber dry kilns associated with sawmills or can be standalone power generation such as Atlantic Power’s Williams Lake facility. It can also be cogeneration of both heat and electricity such as the configuration at many British Columbian pulp mills. When configured as cogeneration, energy efficiencies often exceed 80%.
The processes utilized to create bioenergy include direct combustion, gasification, fast pyrolysis, fermentation and gas collection. Biomass technologies are generally considered to be renewable and carbon neutral. This is due to the short processing cycle combined with the regeneration of carbon through replanting, referred to as “biogenic carbon”. The most common technology used today is conventional boilers in combination with steam turbines. The boiler vaporizes water into steam, which is used to produce electricity through a back-pressure, condensing, or extraction turbines.
Emerging technology in Canada is focused on gasification, wherein woody material is gasified in an oxygen-starved vessel to make synthetic gas, or “syngas”. The syngas can be transported via a pipeline or oxidized in an adjacent vessel, which can then be utilized directly as heat or converted into steam in a heat exchanger. Syngas can also be cleaned to the point that it can directly fire a gas turbine or reciprocating engine.
Biomass gasification has various benefits including simple processes, low emissions, high fuel flexibility, and low operating and maintenance costs.
Biomass generation will replace beehive burners and greatly reduce particulate emissions discharged into the atmosphere. Biomass power is also considered firm power by utilities meaning typical Biomass facilities operate with a capacity factor that often exceeds 92% (wind averages 30%; Run-of-River 40%).
Environmental & Regulatory Considerations
Biomass facilities are heavily regulated and monitored by the BC Ministry of Environment and Climate Change Strategy for fine particulate emissions, amongst other criteria. Installations require provincial government authorization for solid wastes and air emissions.
Many local governments strongly endorse biomass generation. Proposed legislation may cap particulate emissions for all new biomass facilities in urban areas and rural areas. The proposed cap is less than 2.5% of the emissions from beehive burners, based on historical data.
The fuel input, such as mill residues and roadside debris, is independently owned and generated from private sector milling operations. Forestry companies pay for the timber and waste by-product through a complex stumpage formula, so the ‘waste’ used in biomass generation is at market prices. Further fuel is provided from harvesting residues and nearby standing timber not suitable for lumber manufacture. To encourage utilization of Mountain Pine Beetle timber, the Ministry of Forests has created a new form of forest tenure known as a “Bioenergy License”. Such Licenses potentially give biomass power developers long term access to fuel.