Renewable Energy terms starting with H

74 terms

Habitat The natural environment where people, animals and plants live. In an aquatic environment, it includes the water, topography, structure and cover present…
Habitat alteration A change in the particular environment or place where an organism or species lives.
Habitat degradation Decline in habitat quality that accompanies non-natural forms of disturbance.
Habitat generalist (species) See Generalist
Habitat type An aggregation of all land areas potentially capable of producing similar plant communities at climax.
Half-graben A geological term that describes a sedimentary basin where one side is bounded by a normal (extensional) fault.
Hammermill A device consisting of a rotating head with free-swinging hammers which reduce chips or hogged fuel to a predetermined particle size through a perforated…
Hand pile A pile of slash constructed by a crew, not by machine. Hand piles are typically less than 10´ high and less than 12´ in diameter.
Harassment The intentional or unintentional disturbance of individual animals causing them to flee a site or avoid use of an area.
Hardpan A dense, often impermeable soil horizon cemented with silica, iron oxides, calcium carbonate, or organic matter.
hardwood One of the botanical groups of dicotyledonous trees that have broad leaves in contrast to the conifers or softwoods.
Hardwoods Usually broad-leaved and deciduous trees.
Hazardous air pollutant (HAP) Substances that have adverse impacts on human health when present in ambient air.
Hazardous material Any material that poses a threat to human health and/or the environment. Hazardous materials are typically toxic, corrosive, ignitable, explosive, or…
Hazardous waste By-products of society that can pose a substantial or potential hazard to human health or the environment when improperly managed.
Head The upper horizontal part of a window frame or window opening.
Header A masonry wall unit of brick which is laid so that its short end is exposed.
Headwater (1) The source and upper reaches of a stream; also the upper reaches of a reservoir; (2) the water upstream from a structure or point on a stream; (3) the…
Heat Exchanger A device used to transfer heat from a fluid (liquid or gas) to another fluid where the two fluids are physically separated.
Heat rate The ratio of fuel energy input as heat per unit of net work output; a measure of a power plant thermal efficiency, generally expressed as Btu per net…
Heat transfer efficiency The useful heat output released to a room divided by the actual heat produced in the firebox.
Heat transfer fluid (HTF) Fluids that transfer heat generated at the solar collectors to a heat exchanger where steam is produced to run a steam generator.
Heating Value The amount of heat produced from the complete combustion of a unit of fuel. The higher (or gross) heating value is that when all products of combustion…
Heavy metals Metallic elements with high atomic weights (e.g., mercury, chromium, cadmium, arsenic, and lead); can damage living things at low concentrations and tend…
Hectare An area equal to 2.47 acres. There are 100 hectares in 1 square kilometer.
Hedonic – (modeling approach) The hedonic method is a regression technique used to estimate the prices of qualities or models that are not available on the market in particular…
Hedonic statistical framework A method of assessing the impact of various structural (number of bedrooms, bathrooms, square footage, age, etc.
Heliostat A device that tracks the movement of the sun; used to orient solar concentrating systems.
hemicellulose Any cellulose-like carbohydrate, but excluding cellulose itself. Together with pectin and lignin, hemicelluloses form the cell wall matrix.
Herbaceous The plant strata that contain soft, not woody, stemmed plants that die to the ground in winter.
herbaceous energy crops Perennial non-woody crops that are harvested annually, though they may take two to three years to reach full productivity.
herbaceous plants Non-woody species of vegetation, usually of low lignin content such as grasses.
Herbicide A chemical that kills plants.
Herd Area (HA) Following passage of the Wild Free-Roaming Horses and Burros Act (WFRHBA) in 1971, the Bureau of Land Management was directed to identify areas where wild…
Herd Management Area (HMA) An area that has been designated for management of wild horses and/or burros.
Herpetofauna Amphibian and reptile species including frogs, toads, salamanders, turtles, lizards, and snakes.
Hertz (Hz) The unit of measurement of frequency, equivalent to one cycle per second.
Heterogeneity See: genetic heterogeneity.
hexose Any of various simple sugars that have six carbon atoms per molecule (e.g. glucose, mannose, and galactose.)
Hibernacula Caves or other structures used by bats for hibernation.
High liquefaction potential Refers to the susceptibility of soils to liquefy when subjected to sudden loading, such as intense ground shaking from an earthquake.
Higher Heating Value (HHV) The maximum heating value of a fuel sample, which includes the calorific value of the fuel (bone dry) and the latent heat of vaporization of the water in…
Highly discordant land use Refers to development that is at variance with the existing condition of the land. It might also be described as incongruous.
Historic The time period after the appearance of written records. In the New World, this generally refers to the time period after the beginning of European…
Historic floodplain An area larger than the 100-year floodplain.
Historic properties Any prehistoric or historic districts, sites, buildings, structures, or objects included in, or eligible for inclusion in, the National Register of…
Historic resources Material remains and the landscape alterations that have occurred since the arrival of Euro-Americans.
Hog fuel or hogged fuel Wood residues processed through a chipper or mill to produce coarse chips normally used for fuel.
Hogbacks An eroded steep ridge of resistant rocks produced by erosion of the broken edges of highly tilted strata.
holocellulose The total carbohydrate fraction of wood; cellulose plus hemicellulose.
Holocene The past 10,000 years of geologic time. The most recent epoch of the Quaternary period.
Horizon line The apparent line in the landscape formed by the meeting of the visible land surface and the sky.
Horizontal angle of view The angle of landscape viewed in sharp focus, measured along the horizon, without turning the head. See also Vertical angle of view; Angle of view
Horizontal field of view See Horizontal angle of view
Horsepower (hp) A unit of rate of operation. Electrical hp: a measure of time rate of mechanical energy output; usually applied to electric motors as the maximum output…
Horst An elongated crustal block that is relatively raised between two parallel normal faults or grabens. See also Half-graben
Hunter gatherers A term applied to people whose diet is based on hunting, fishing, and gathering, as opposed to domesticating animals or plants.
Hunting Includes big- and small-game hunting, waterfowl hunting, and trapping.
Hybrid A class that is a mixture or combination of 2 or more classes. For example, a Druid can be viewed as a Warrior/Rogue/Priest hybrid.
Hybrid (wet-dry cooling) systems A variation on a dry cooling system. In this hybrid system, small amounts of water are sprayed as a fine mist into the flow of ambient air being directed…
Hybrid electric vehicle A vehicle that is powered by two or more energy sources, one of which is electricity.
Hydraulic gradient In an aquifer, the rate of change of total head per unit of distance of flow at a given point and in a given direction.
Hydraulic load Amount of liquid going into a system.
Hydro-compactable, collapsible soil (settlement) Low-density soils that undergo appreciable loss of volume when wetted or subjected to increased load (or both).
Hydrocarbon Any chemical compound containing hydrogen, oxygen, and carbon.
hydrocracking A process in which hydrogen is added to organic molecules at high pressures and moderate temperatures; usually used as an adjunct to catalytic cracking.
Hydroelectric power The generation of electricity using falling water.
Hydrofluorocarbon (HFC) Man-made chemicals, many of which have been developed as alternatives to ozone-depleting substances (ODSs) for industrial, commercial, and consumer…
hydrogenation Treatment of substances with hydrogen and suitable catalysts at high temperature and pressure to saturate double bonds.
Hydrology The science dealing with the distribution, properties and circulation of water on land, in the soil, and in the atmosphere.
Hydrolysis A chemical reaction that uses water to break down a compound.
Hydrostratigraphic Grouping of rock and sedimentary units based on the capacity of the rock, sediment, or soil to transmit water.
Hypothesis A tentative proposal made to explain certain observations or facts that requires further investigation to be verified.
Hz See Hertz