Energy — page 16 of 33

Energy terms

1501. herbaceous energy crops Perennial non-woody crops that are harvested annually, though they may take two to three years to reach full productivity.
1502. herbaceous plants Non-woody species of vegetation, usually of low lignin content such as grasses.
1503. Herbicide A chemical that kills plants.
1504. Herd Area (HA) (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…
1505. Herd Management Area (HMA) (HMA) An area that has been designated for management of wild horses and/or burros.
1506. Herpetofauna Amphibian and reptile species including frogs, toads, salamanders, turtles, lizards, and snakes.
1507. Hertz A measure of the number of cycles or wavelengths of electrical energy per second; U.S. electricity supply has a standard frequency of 60 hertz.
1508. Hertz (Hz) (Hz) The unit of measurement of frequency, equivalent to one cycle per second.
1509. Heterogeneity See: genetic heterogeneity.
1510. Heterojunction A region of electrical contact between two different materials.
1511. hexose Any of various simple sugars that have six carbon atoms per molecule (e.g. glucose, mannose, and galactose.)
1512. Hibernacula Caves or other structures used by bats for hibernation.
1513. High liquefaction potential Refers to the susceptibility of soils to liquefy when subjected to sudden loading, such as intense ground shaking from an earthquake.
1514. High-Intensity Discharge Lamp A lamp that consists of a sealed arc tube inside a glass envelope, or outer jacket.
1515. High-Pressure Sodium Lamp A type of High-Intensity Discharge (HID) lamp that uses sodium under high pressure as the primary light-producing element.
1516. Higher Heating Value (HHV) (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…
1517. Higher Lubricity The ability to reduce friction—usually in fuel pumps and fuel injectors.
1518. 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.
1519. Hirschman-Herfindahl Index (HHI) Market share analysis (HHI) The sum of the squares of the market shares of firms competing in a market. HHI is a commonly accepted measure of market concentration.
1520. 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…
1521. Historic Area An area or building in which historic events occurred, or one which has special value due to architectural or cultural features relating to the heritage…
1522. Historic floodplain An area larger than the 100-year floodplain.
1523. Historic properties Any prehistoric or historic districts, sites, buildings, structures, or objects included in, or eligible for inclusion in, the National Register of…
1524. Historic resources Material remains and the landscape alterations that have occurred since the arrival of Euro-Americans.
1525. Hog fuel or hogged fuel Wood residues processed through a chipper or mill to produce coarse chips normally used for fuel.
1526. Hogbacks An eroded steep ridge of resistant rocks produced by erosion of the broken edges of highly tilted strata.
1527. Hole The vacancy where an electron would normally exist in a solid; behaves like a positively charged particle.
1528. holocellulose The total carbohydrate fraction of wood; cellulose plus hemicellulose.
1529. Holocene The past 10,000 years of geologic time. The most recent epoch of the Quaternary period.
1530. Home Energy Rating Systems (HERS) (HERS) A nationally recognized energy rating program that gives builders, mortgage lenders, secondary lending markets, homeowners, sellers, and buyers a precise…
1531. Homojunction The region between an n-layer and a p-layer in a single material, photovoltaic cell.
1532. Horizon line The apparent line in the landscape formed by the meeting of the visible land surface and the sky.
1533. 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
1534. Horizontal field of view See Horizontal angle of view
1535. Horizontal Ground Loop In this type of closed-loop geothermal heat pump installation, the fluid-filled plastic heat exchanger pipes are laid out in a plane parallel to the…
1536. Horizontal-Axis Wind Turbines Turbines in which the axis of the rotor's rotation is parallel to the wind stream and the ground.
1537. Horsepower (hp) (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…
1538. Horsepower Hour (hph) One horsepower provided over one hour; equal to 0.745 kilowatt-hour or 2,545 Btu.
1539. Horst An elongated crustal block that is relatively raised between two parallel normal faults or grabens. See also Half-graben
1540. Hot Air Furnace A heating unit where heat is distributed by means of convection or fans.
1541. Hot Dry Rock A geothermal energy resource that consists of high temperature rocks above 300 F (150 C) that may be fractured and have little or no water.
1542. Hot Water Heating Systems (See Hydronic)
1543. Housing Element A comprehensive assessment of current and projected housing needs for all economic segments of the community.
1544. Hub A network device that connects multiple computers/peripherals together and allows them to share data.
1545. Hub Height The height above the ground that a horizontal axis wind turbine's hub is located.
1546. Humidifier (hyoo-MID-ih-fye-er) A machine that puts moisture in the air.
1547. Humidity A measure of the moisture content of air; may be expressed as absolute, mixing ratio, saturation deficit, relative, or specific.
1548. Hunter gatherers A term applied to people whose diet is based on hunting, fishing, and gathering, as opposed to domesticating animals or plants.
1549. Hunting Includes big- and small-game hunting, waterfowl hunting, and trapping.
1550. HVAC Heating, Ventilation and Air Conditioning; a home's heating and cooling system.
1551. 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.
1552. 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…
1553. Hybrid electric vehicle A vehicle that is powered by two or more energy sources, one of which is electricity.
1554. hybrid system A renewable energy system that includes two different types of technologies that produce the same type of energy; for e.g.
1555. 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.
1556. Hydraulic load Amount of liquid going into a system.
1557. Hydro-compactable, collapsible soil (settlement) Low-density soils that undergo appreciable loss of volume when wetted or subjected to increased load (or both).
1558. Hydrocarbon Any chemical compound containing hydrogen, oxygen, and carbon.
1559. 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.
1560. Hydroelectric power The generation of electricity using falling water.
1561. Hydroelectric Power Plant A power plant that produces electricity by the force of water falling through a hydro turbine that spins a generator.
1562. Hydrofluorocarbon (HFC) (HFC) Man-made chemicals, many of which have been developed as alternatives to ozone-depleting substances (ODSs) for industrial, commercial, and consumer…
1563. Hydrogen A chemical element that can be used as a fuel since it has a very high energy content.
1564. Hydrogenated Amorphous Silicon Amorphous silicon with a small amount of incorporated hydrogen. The hydrogen neutralizes dangling bonds in the amorphous silicon, allowing charge carriers…
1565. hydrogenation Treatment of substances with hydrogen and suitable catalysts at high temperature and pressure to saturate double bonds.
1566. Hydrology The science dealing with the distribution, properties and circulation of water on land, in the soil, and in the atmosphere.
1567. Hydrolysis A chemical reaction that uses water to break down a compound.
1568. Hydronic Heating Systems A type of heating system where water is heated in a boiler and either moves by natural convection or is pumped to heat exchangers or radiators in rooms…
1569. Hydropower The force of flowing water moving downstream creates energy that can be harnessed and turned into electricity.
1570. Hydrostratigraphic Grouping of rock and sedimentary units based on the capacity of the rock, sediment, or soil to transmit water.
1571. Hydrothermal fluids These fluids can be either water or steam trapped in fractured or porous rocks; they are found from several hundred feet to several miles below the…
1572. Hypothesis A tentative proposal made to explain certain observations or facts that requires further investigation to be verified.
1573. Hz See Hertz
1574. I-Type Semiconductor A semiconductor material that is left intrinsic, or undoped so that the concentration of charge carriers is characteristic of the material itself rather…
1575. I-V Curve A graphical plot or representation the current and voltage output of a solar photovoltaic cell or module as a load on the device is increased from short…
1576. Igneous rock A crystalline rock formed by the cooling and solidification of molten or partly molten material (magma).
1577. Ignite To heat a gaseous mixture to the temperature at which combustion takes place.
1578. Ignition Point The minimum temperature at which combustion of a solid or fluid can occur.
1579. Illuminance A measure of the amount of light incident on a surface; measured in foot-candles or Lux.
1580. Illumination The distribution of light on a horizontal surface. The purpose of all lighting is to produce illumination.
1581. Imbalance energy Discrepancy between the amount that a seller contracted to deliver and the actual volume of power delivered.
1582. Imhoff treatment system In wastewater treatment, a tank without aeration or oxygenation where solids settle out. The solids are digested in a separate compartment in the bottom.
1583. Impact The effect, influence, alteration, or imprint caused by an action.
1584. Impact Fees Costs imposed on new development to fund public facility improvements required by new development and ease fiscal burdens on localities.
1585. Impermeable Refers to a rock matrix that water cannot infiltrate.
1586. Impervious Surface Any surface through which rainfall cannot pass or be effectively absorbed. (Roads, buildings, paved parking lots, sidewalks etc.)
1587. Imperviousness Overlay Zoning One form of the overlay zoning process. Environmental aspects of future imperviousness are estimated based on the future zoning build-out conditions.
1588. Impingement The entrapment of aquatic organisms on the outer part of an intake structure or against a screening device during periods of intake water withdrawal.
1589. IMPLAN Input-output economic model based on economic accounts showing the flow of commodities to industries from producers and institutional consumers.
1590. Impoundment A body of water confined by a dam, dike, floodgate or other artificial barrier.
1591. Impoundment (surface) A body of water or sludge confined by a dam, dike, floodgate, or other barrier.
1592. Impulse Turbine A turbine that is driven by high velocity jets of water or steam from a nozzle directed to vanes or buckets attached to a wheel.
1593. Impulsive noise Noise from impacts or explosions (e.g., from a pile driver, forging hammer, punch press, or gunshot), which is brief and abrupt, and its startling effects…
1594. In attainment In compliance with air-quality standards. Areas that are in attainment have air quality that is as good as or better than specified in the National…
1595. In situ (in si'too) the natural or normal place; confined to the site of origin without invasion or spread to neighboring tissues.
1596. In-migration People moving into an area.
1597. Incandescent These lights use an electrically heated filament to produce light in a vacuum or inert gas-filled bulb.
1598. Incentive Zoning Provides for give and take compromise on zoning restrictions, allowing for more flexibility to provide environmental protection.
1599. Incident Solar Radiation The amount of solar radiation striking a surface per unit of time and area.
1600. Incidental take permit A permit issued under Section 10 of the Federal Endangered Species Act to private parties undertaking otherwise lawful projects that might result in the…