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GSR 2015 - Glossary

245RENEWABLES 2015 GLOBAL STATUS REPORT G GLOSSARY ABSORPTION CHILLERS. Chillers that use heat energy from any source (solar, biomass, waste heat, etc.) to drive air conditioning or refrigeration systems. The heat source replaces the electric power consumption of a mechanical compressor. Absorption chillers differ from conventional (vapour compression) cooling systems in two ways: 1) the absorption process is thermo-chemical in nature rather than mechanical, and 2) the substance that is circulated as a refrigerant is water rather than chlorofluorocarbons (CFCs) or hydro chlorofluorocarbons (HCFCs), also called Freon. The chillers generally are supplied with district heat, waste heat, or heat from co-generation, and they can operate with heat from geothermal, solar, or biomass resources. ADSORPTION CHILLERS. Chillers that use heat energy from any source to drive air conditioning or refrigeration systems. They differ from absorption chillers in that the adsorption process is based on the interaction between gases and solids. A solid material in the chiller’s adsorption chamber releases refrigerant vapour when heated; subsequently, the vapour is cooled and liquefied, providing a cooling effect at the evaporator by absorbing external heat and turning back into a vapour, which is then readsorbed into the solid. AUCTION. (See Tendering.) BIODIESEL. A fuel produced from oilseed crops such as soy, rapeseed (canola), and palm oil, and from other oil sources such as waste cooking oil and animal fats. Biodiesel is used in diesel engines installed in cars, trucks, buses, and other vehicles, as well as in stationary heat and power applications. (Also see Hydrotreated vegetable oil.) BIOENERGY. Energy derived from any form of biomass (solid, liquid, or gaseous) for heat, power, and transport. (See Biofuels.) BIOFUELS. A fuel derived from biomass that may include liquid fuel ethanol and biodiesel, as well as biogas. Biofuels can be combusted in vehicle engines as transport fuels and in stationary engines for heat and electricity generation. They also can be used for domestic heating and cooking (for example, as ethanol gels). Advanced biofuels are made from feedstocks derived from the lignocellulosic fractions of biomass sources or from algae. They are made using non-traditional biochemical and thermochemical conversion processes. BIOGAS/BIOMETHANE. Biogas is a gaseous mixture consisting mainly of methane and carbon dioxide produced by the anaerobic digestion of organic matter (broken down by micro- organisms in the absence of oxygen). Organic material and/or waste is converted into biogas in a digester. Suitable feedstocks include agricultural residues, animal wastes, food industry wastes, sewage sludge, purpose-grown green crops, and the organic components of municipal solid wastes. Raw biogas can be combusted to produce heat and/or power; it also can be transformed into biomethane through a simple process known as scrubbing that removes impurities including carbon dioxide, siloxanes, and hydrogen sulphides. Biomethane can be injected directly into natural gas networks and used as a substitute for natural gas in internal combustion engines without fear of corrosion. BIOMASS. Any material of biological origin, excluding fossil fuels or peat, that contains a chemical store of energy (originally received from the sun) and that is available for conversion to a wide range of convenient energy carriers. BIOMASS ENERGY, MODERN. Energy derived from combustion of solid, liquid, and gaseous biomass fuels in high-efficiency conversion systems, which range from small domestic appliances to large-scale industrial conversion plants. Modern applications include heat and electricity generation, combined heat and power (CHP), and transport. BIOMASS ENERGY, TRADITIONAL. Solid biomass including fuel wood, charcoal, agricultural and forest residues, and animal dung, that is typically used in rural areas of developing countries with traditional technologies such as open fires for cooking, kilns, and ovens for small-scale agricultural and industrial processing. Often the use of traditional biomass leads to high pollution levels, forest degradation, and deforestation. BIOMASS ENERGY PELLETS. Solid biomass fuel produced by compressing pulverised dry biomass, such as waste wood and agricultural residues. Pellets typically are cylindrical in shape with a diameter of around 10 millimetres and a length of 30–50 millimetres. Pellets are easy to handle, store, and transport and are used as fuel for heating and cooking applications, as well as for electricity generation and combined heat and power. (Also see Torrefied wood.) CAPACITY. The rated capacity of a heat or power generating plant, which refers to the potential instantaneous heat or electricity output, or the aggregate potential output of a collection of such units(suchasawindfarmorsetofsolarpanels).Installedcapacity describes equipment that has been constructed, although it may or may not be operational (e.g., delivering electricity to the grid, providing useful heat, or producing biofuels). CAPACITY FACTOR. The ratio of the actual output of a unit of electricity or heat generation over a period of time (typically one year) to the theoretical output that would be produced if the unit were operating without interruption at its rated capacity during the same period of time. CAPITAL SUBSIDY. A subsidy that covers a share of the upfront capital cost of an asset (such as a solar water heater). These include, for example, consumer grants, rebates, or one-time payments by a utility, government agency, or government- owned bank. COMBINED HEAT AND POWER (CHP).(also called co-generation). CHP facilities produce both heat and power from the combustion of fossil and/or biomass fuels, as well as from geothermal and solar thermal resources. The term is also applied to plants that recover “waste heat” from thermal power generation processes. COMPETITIVE BIDDING. (See Tendering.) CONCENTRATING PHOTOVOLTAICS (CPV). Technology that uses mirrors or lenses to focus and concentrate sunlight onto a relatively small area of photovoltaic cells that generate electricity (see Solar photovoltaics). Low-, medium-, and high-concentration CPV systems (depending on the design of reflectors or lenses used) operate most efficiently in locations with high normal direct insolation and low moisture. CONCENTRATING SOLAR THERMAL POWER (CSP). (also called concentrating solar power or solar thermal electricity, STE). Technology that uses mirrors to focus sunlight into an intense solar beam that heats a working fluid in a solar receiver, which then drives a turbine or heat engine/generator to produce electricity. The mirrors can be arranged in a variety of ways, but theyalldeliverthesolarbeamtothereceiver.Therearefourtypes of commercial CSP systems: parabolic troughs, linear Fresnel, power towers, and dish/engines. The first two technologies are line-focus systems, capable of concentrating the sun’s energy to produce temperatures of 400 °C, while the latter two are point-focus systems that can produce temperatures of 800 °C or higher. CONVERSION EFFICIENCY. The ratio between the useful energy output from an energy conversion device and the energy input BACK

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