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  2. Kilowatt-hour - Wikipedia

    en.wikipedia.org/wiki/Kilowatt-hour

    A kilowatt-hour is a unit of energy. Kilowatt per hour would be a rate of change of power flow with time. Work is the amount of energy transferred to a system; power is the rate of delivery of energy. Energy is measured in joules, or watt-seconds. Power is measured in watts, or joules per second. For example, a battery stores energy.

  3. Units of energy - Wikipedia

    en.wikipedia.org/wiki/Units_of_energy

    A unit of electrical energy, particularly for utility bills, is the kilowatt-hour (kWh); [3] one kilowatt-hour is equivalent to 3.6 megajoules. Electricity usage is often given in units of kilowatt-hours per year or other periods. [4] This is a measurement of average power consumption, meaning the average rate at which energy is transferred ...

  4. Specific energy - Wikipedia

    en.wikipedia.org/wiki/Specific_energy

    The SI unit for specific energy is the joule per kilogram (J/kg). Other units still in use worldwide in some contexts are the kilocalorie per gram (Cal/g or kcal/g), mostly in food-related topics, and watt-hours per kilogram (W⋅h/kg) in the field of batteries.

  5. Electric power - Wikipedia

    en.wikipedia.org/wiki/Electric_power

    Electric power is the rate of transfer of electrical energy within a circuit.Its SI unit is the watt, the general unit of power, defined as one joule per second.Standard prefixes apply to watts as with other SI units: thousands, millions and billions of watts are called kilowatts, megawatts and gigawatts respectively.

  6. Energy density - Wikipedia

    en.wikipedia.org/wiki/Energy_density

    The following unit conversions may be helpful when considering the data in the tables: 3.6 MJ = 1 kW⋅h ≈ 1.34 hp⋅h. Since 1 J = 10 −6 MJ and 1 m 3 = 10 3 L, divide joule/m 3 by 10 9 to get MJ/L = GJ/m 3. Divide MJ/L by 3.6 to get kW⋅h/L.

  7. Joule - Wikipedia

    en.wikipedia.org/wiki/Joule

    The joule (/ dʒ uː l / JOOL, or / dʒ aʊ l / JOWL; symbol: J) is the unit of energy in the International System of Units (SI). [1] In terms of SI base units , one joule corresponds to one kilogram - square metre per square second (1 J = 1 kg⋅m 2 ⋅s −2 ).

  8. Watt - Wikipedia

    en.wikipedia.org/wiki/Watt

    In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical circuit).

  9. Energy conversion efficiency - Wikipedia

    en.wikipedia.org/wiki/Energy_conversion_efficiency

    It would operate at a cell voltage of 1.24 V. For a water electrolysis unit operating at a constant temperature of 25 °C without the input of any additional heat energy, electrical energy would have to be supplied at a rate equivalent of the enthalpy (heat) of reaction or 285.830 kJ (0.07940 kWh) per gram mol of water consumed. [6]