| Jack Pump | A submerged pump mechanically activated by a rod extending above the well head to a reciprocating engine, motor or any other rotating device. |
| Jet Stream | A meandering and relatively narrow belt of strong winds embedded in the normal wind flow, generally found at high altitudes. |
| Joule | A metric measurement of force equal to one Newton operating through the distance or one metre. |
| Joule (J) | A metric unit of energy or work. One joule per second equals 1 watt. |
| Junction | A region of transition between semiconductor layers, such as a p/n junction, which goes from a region that has a high concentration of acceptors (p-type) to one that has a high concentration of donors (n-type). |
| Junction Box | A photovoltaic (PV) generator junction box is an enclosure on the module where PV strings are electrically connected and where protection devices can be located, if necessary. |
| Junction Diode | A semiconductor device with a junction and a built-in potential that passes current better in one direction than the other. All solar cells are junction diodes. |
| Kaplan Turbine | A type of turbine that has two blades whose pitch is adjustable. |
| Kbtu | One-thousand (1,000) Btus. |
| Kerosene | Certain colorless, low-sulfur oil products that burn without producing much smoke. |
| Khamsin | A hot, dry wind that blows from the Sahara Desert to Egypt for about fifty days each spring. Egyptians call it “rih al khamsin,” which means “the wind of fifty days.” |
| Kilovolt (Kv) | One-thousand volts (1,000). Distribution lines in residential areas usually are 12 kv (12,000 volts). |
| Kilowatt | 1000 Watts = 1Kw or 1 Kilowatt |
| Kilowatt (Kw) | A standard unit of electrical power equal to 1000 watts, or to the energy consumption at a rate of 1000 joules per second. 1 kWh = ten 100 watt bulbs all burning at the same time for one hour. 10 bulbs x 100 watts each x 1 hour = 1,000 watts hours or 1kWh. |
| Kilowatt-Hour (Kwh) | One thousand watt-hours. Unit of energy used to perform work (energy and work are equivalent in units, energy being the potential value and work the achieved value). Fuel equivalents One barrel of crude oil contains roughly 1,700 KWH One ton of coal contains roughly 7,500 KWH One gallon of gasoline contains roughly 37 KWH One cubic foot of natural gas contains 0.3 KWH One ton of uranium ore contains 164 million KWH 1.34 horsepower-hours. 1 KWH = 3,400 BTU. Can be compared to 860 calories (food energy value). |
| Kinetic Energy | Energy available as a result of motion. (Kinetic energy is equal to one half the mass of the body in motion multiplied by the square of its speed.) |
| Knot | One nautical mile per hour (1.15 MPH). |
| Kona | A stormy, rain-bearing wind from the Southwest or SSW in Hawaii. Kona is a Polynesian word meaning “leeward.” |
