Energy: Difference between revisions
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Energy is the ''work done'', or in the case of batteries the ability or capacity to do work | Energy is the ''work done'', (*or in the case of batteries the ability or capacity to do work*) | ||
The average household electricity | TSTA is concerned with this statement. While the definition of capacity regarding batteries here is not incorrect, term "capacity" is misplaced. For clarity, batteries (and impounded hydro, heated mass, capacitors, rotational inertia and other forms of energy storage, deserve no special reference in a basic definition of electrical energy. I suggest to address electricity de-conversion and re-conversion (storage and retrieval) and associated losses separately after defining power and energy. Begin by stating that alternating current electricity itself cannot be stored and must be consumed or lost at the moment it is produced i.e. JIT (just-in-time)). | ||
ENERGY is [[power]] × time. | |||
Electrical energy is power (most commonly stated in watts) times a unit of time, most commonly one hour) (watt-hours). 1,000 watt hours equals one kilowatt-hour (kWh), which is the average amount of power in watts transferred (or used) for 1 hour DIVIDED BY 1,000. A MWh is equal to 1,000 kWh or 1,000,000 watt-hours. All other metric prefixes can also be applied. Electrical energy could also be expressed in other units of power and time, such as gigapascals per year or calories per second, for instance. | |||
The US population in 2013 was about 316 million. | |||
The number of household dwellings in the US in 2013 was about 116,926,300. | |||
The average number of persons per household in the US in 2013 was about 2.64. | |||
Energy resource inputs to electricity generation in the US in 2013 were about 4,080,000,000,000,000 watt-hours (4.08 quadrillion watt-hours or 4.08 "Quads"). | |||
Therefore energy resource inputs to electricity generation in the US were about 12,900 kWh per capita in 2013, including all sectors (industrial, commercial, residential, transportation and including electric power system losses). | |||
Conversion and transmission losses (rejected energy) consumed 67.5% of energy resource inputs to the electricity generation sector: 32.5% were ultimately consumed by end users. | |||
Therefore electricity consumption in the US was about 4,190 kWh per capital in 2013. | |||
Per capita energy resource use for electricity consumption by sector breaks down as follows: | |||
Energy resources used in electricity generation: 38.2 Quads (100%) | |||
Conversion and transmission losses: 28.4 Quads (67.5%) | |||
Total electricity consumption: 12.4 Quads (32.5%) (system conversion efficiency) | |||
Of consumed electricity the breakdown is as follows: | |||
Residential: 4.75 Quads (35.7% of delivered electrical energy) | |||
Commercial: 4.57 Quads (36.8% of delivered electrical energy) | |||
Industrial: 3.26 Quads (26.3% of delivered electrical energy) | |||
Transportation: 0.02575 Quads (0.2% of delivered electrical energy) | |||
Per capita electricity use is more important than "household" (residential) electricity use when discussing electricity sources supplying all sectors of society. | |||
Another important metric is energy per unit of productivity (such as GDP), discussed next. | |||
Revision as of 13:12, 9 August 2017
Energy is the work done, (*or in the case of batteries the ability or capacity to do work*)
TSTA is concerned with this statement. While the definition of capacity regarding batteries here is not incorrect, term "capacity" is misplaced. For clarity, batteries (and impounded hydro, heated mass, capacitors, rotational inertia and other forms of energy storage, deserve no special reference in a basic definition of electrical energy. I suggest to address electricity de-conversion and re-conversion (storage and retrieval) and associated losses separately after defining power and energy. Begin by stating that alternating current electricity itself cannot be stored and must be consumed or lost at the moment it is produced i.e. JIT (just-in-time)).
ENERGY is power × time.
Electrical energy is power (most commonly stated in watts) times a unit of time, most commonly one hour) (watt-hours). 1,000 watt hours equals one kilowatt-hour (kWh), which is the average amount of power in watts transferred (or used) for 1 hour DIVIDED BY 1,000. A MWh is equal to 1,000 kWh or 1,000,000 watt-hours. All other metric prefixes can also be applied. Electrical energy could also be expressed in other units of power and time, such as gigapascals per year or calories per second, for instance.
The US population in 2013 was about 316 million.
The number of household dwellings in the US in 2013 was about 116,926,300. The average number of persons per household in the US in 2013 was about 2.64. Energy resource inputs to electricity generation in the US in 2013 were about 4,080,000,000,000,000 watt-hours (4.08 quadrillion watt-hours or 4.08 "Quads").
Therefore energy resource inputs to electricity generation in the US were about 12,900 kWh per capita in 2013, including all sectors (industrial, commercial, residential, transportation and including electric power system losses).
Conversion and transmission losses (rejected energy) consumed 67.5% of energy resource inputs to the electricity generation sector: 32.5% were ultimately consumed by end users.
Therefore electricity consumption in the US was about 4,190 kWh per capital in 2013.
Per capita energy resource use for electricity consumption by sector breaks down as follows: Energy resources used in electricity generation: 38.2 Quads (100%) Conversion and transmission losses: 28.4 Quads (67.5%) Total electricity consumption: 12.4 Quads (32.5%) (system conversion efficiency)
Of consumed electricity the breakdown is as follows:
Residential: 4.75 Quads (35.7% of delivered electrical energy) Commercial: 4.57 Quads (36.8% of delivered electrical energy) Industrial: 3.26 Quads (26.3% of delivered electrical energy) Transportation: 0.02575 Quads (0.2% of delivered electrical energy)
Per capita electricity use is more important than "household" (residential) electricity use when discussing electricity sources supplying all sectors of society.
Another important metric is energy per unit of productivity (such as GDP), discussed next.