Landfill gas: is about 40-60% methane, with the remainder being mostly carbon dioxide (CO2). Landfill gas also contains varying amounts of nitrogen, oxygen, water vapor, sulfur and a hundreds of other contaminants. see Syngas, Bio-syngas, Fuel gas, Natural gas, Producer gas.

Landing: A cleared working area on or near a timber harvest site at which processing steps are carried out.

Legume: Any plant belonging to the leguminous family. Characterized by pods as fruits and root nodules enabling the storage of nitrogen.

Levelized life-cycle cost: The present value of the cost of a resource, including capital, financing and operating costs, expressed as a stream of equal annual payments. This stream of payments can be converted to a unit cost of energy by dividing the annual payment amount by the annual kilowatt-hours produced or saved. By levelizing costs, resources with different lifetimes and generating capabilities can be compared.

Life Cycle Assessment (LCA also known as 'life cycle analysis', 'ecobalance', and 'cradle-to-grave analysis'): the investigation and evaluation of the environmental impacts of a given product or service caused or necessitated by its existence.

Lignin: The major non-carbohydrate, polypenolic structural constituent of wood and other native plant material that encrusts the cell walls and cements the cells together. It is a highly polymeric substance, with a complex, cross-linked, highly aromatic structure of molecular weight about 10,000 derived principally from coniferyl alcohol (C10H12O3) by extensive condensation polymerization. Higher heating value (oven dry basis): HHV=9111 BTU/LB (5062 CAL/G, 21178 J/G). (Source: Domalski, E.S.; Milne T.A., ed. Thermodynamic Data for Biomass Materials and Waste Components. The ASME Research Committee on Industrial and Municipal Wastes, New York: The American Society of Mechanical Engineers, 1987).

Lignin ratio of MeO to C9: Lignin empirical formulae are based on ratios of methoxy groups to phenylpropanoid groups (MeO:C9). The general empirical formula for lignin monomers is C9H10O2 (OCH3)n, where n is the ratio of MeO to C9 groups. Where no experimental ratios have been found, they are estimated as follows: 0.94 for softwoods; 1.18 for grasses; 1.4 for hardwoods. These are averages of the lignin ratios found in the literature. Paper products, which are produced primarily from softwoods, are estimated to have an MeO:C9 ratio of 0.94.

Lignin pseudo-molecule for modeling: The lignin ratio of methoxy groups to phenylpropanoid groups (MeO:C9) is used to calculate an ultimate analysis for the lignin pseudo-molecule. This ultimate analysis is used to estimate other properties of the molecule, such as its higher and lower heating values.

Lignocellulose: Refers to plant materials made up primarily of lignin, cellulose, and hemicellulose.

Lime stabilization: Lime treatment controls the environment needed for the growth of pathogens in bio-solids and converts sludge into a usable product.

Liquefaction is the conversion of biomass into a stable liquid hydrocarbon using low temperatures and high hydrogen pressures. One important subset of biomass liquefaction is the catalytic reforming of biomass in sub and supercritical water. Liquefaction is not foreseen as a future oriented technology due to the high operational cost.

Live-bottom trailer: A self-unloading tractor trailer with a hydraulically operated moving floor, which is used to push the biomass fuel load out the back of the trailer. Typically filled directly by the chipper in the mill or in the woods.

Live cull: A classification that includes live cull trees; when associated with volume, it is the net volume in live cull trees that are 5.0 in in diameter and larger.

Logging residues: The unused portion of growing-stock and non-growing-stock trees cut or killed logging and left in the woods.

Lower heating value (LHV) (or net calorific value, or net heat) is determined by subtracting the heat of vaporization of the water produced by combustion from the higher heating value. Specifically, it is the heat produced by combusting one unit of a substance, at atmospheric pressure under conditions such that all water in the products remains in the form of vapor. The net heat of combustion is calculated from the gross heat of combustion at 20°C by subtracting 572 cal/g (1030 Btu/lb) of water derived from one unit mass of sample, including both the water originally present as moisture and that formed by combustion. This subtracted amount is not equal to the latent heat of vaporization of water because the calculation also reduces the data from the gross value at constant volume to the net value at constant pressure. The appropriate factor for this reduction is 572 cal/g. (Source: Domalski, E.S.; Milne T.A., ed. Thermodynamic Data for Biomass Materials and Waste Components. The ASME Research Committee on Industrial and Municipal Wastes, New York: The American Society of Mechanical Engineers, 1987).

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