| abstract
| - The kilowatt•hour (kWh) is a unit of energy. It is equivalent to 3,600,000 joules (3.6 MJ) or 3412 British Thermal Units (BTU). Human forms 1.
* About the amount of energy expended by a strong cyclist riding for 5 hours solid. 2.
* The amount of energy needed for a 100 kg (220 lb) man to climb 3.7 km straight up against gravity. 3.
* Approximately the amount of energy your body can derive from one large meal, about 860 kcal (often called just "Calories") Fossil fuel forms 1.
* 113 mL of gasoline 2.
* 0.11 m³ of natural gas 3.
* 1.23 kg of high quality coal [1] Electrical energy forms 1.
* About 200 typical 9V alkaline batteries 2.
* About the total amount of energy stored in a fully charged 12V car battery 3.
* About 1/30th the typical daily consumption of power in a home in Canada and the US. 4.
* About enough energy to drive a modern electric car 4 miles / 6.4 kilometers. Billing of household electricity by utility companies is typically based on the kWh. The price for this much electricity varies widely, from perhaps USD $0.08 in West Virginia, USA, to perhaps USD $0.30 in Germany or California, USA. The price may also vary widely within a day, either because of planned time-of-use pricing or according to the spot (instantaneous) market [1]. As with other energy units, there is no time component in kWh. This is confusing because "hour" is right there. It's made even harder to understand when people mistakenly say "kilowatts per hour". Confusion is also likely to result when journalists or marketing people refer to the amount of energy that a solar installation is likely to produce in a year. Often they will say that a solar panel array will yield 1200 kWh of electricity per year. [2] (Adding time back in makes this a unit of power, but an unfamiliar one.) Unless the reader is also told the "name plate" capacity of the array (e.g. 1 kW in this case) this information is difficult to use -- for instance, it assumes a certain amount of sunlight per year but does not tell you how much. Sometimes it's difficult to avoid describing energy usage in these mixed terms. For example, the average house in Ontario, Canada consumes about 30 kWh of electricity each day. This might be better expressed as MATH: 30 kWh / 24 hours = 1.25 kW average all day. Or conversely, if a solar array produces 1200 kWh of electricity per year, and a year has 8766 hours, it is putting out MATH: 1200 kWh / y × 8766 h/Y = 0.14 kW (an average that includes night time, cloudy days, etc.) This last number matches up with a 1 kW array in Toronto, Canada, where solar has a capacity factor[2] of about 0.14.
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