Your usage of the phrase "watts per year" tells me you do not know what the term watt means. A watt is a unit of power not energy.
From Wikipedia:The watt, defined as one joule per second, measures the rate of energy conversion. Confusion of watts, watt-hours, and watts per hour
The terms power
are frequently confused. Power is the rate at which energy is generated or consumed.
For example, when a light bulb with a power rating of 100W is turned on for one hour, the energy used is 100 watt-hours
(W•h), 0.1 kilowatt-hour, or 360 kJ
. This same amount of energy would light a 40-watt bulb for 2.5 hours, or a 50-watt bulb for 2 hours. A power station would be rated in multiples of watts, but its annual energy sales would be in multiples of watt-hours. A kilowatt-hour is the amount of energy equivalent to a steady power of 1 kilowatt running for 1 hour, or 3.6 MJ
Terms such as watts per hour
are often misused.
Watts per hour properly refers to the change
of power per hour. Watts per hour (W/h) might be useful to characterize the ramp-up behavior of power plants
. For example, a power plant that reaches a power output of 1 MW from 0 MW in 15 minutes has a ramp-up rate of 4 MW/h. Hydroelectric
power plants have a very high ramp-up rate, which makes them particularly useful in peak load and emergency situations.
Major energy production or consumption is often expressed as terawatt-hours
for a given period that is often a calendar year or financial year. One terawatt-hour is equal to a sustained power of approximately 114 megawatts for a period of one year.
The watt second
is a unit of energy, equal to the joule
. One kilowatt-hour is 3,600,000 watt-seconds. The watt-second is used, for example, to rate the energy storage of flash lamps
used in photography.