Re:watts per what unit of time? (Score 0)

Electricity is usually billed per kilowatt-hour. Therefore, if these panels are to be compared to buying power from the grid, one would need to know their electric production in watts per unit time. If they generate a watt of power, thats great - but is it a watt per minute (pretty good), a watt per hour (not very good), or a watt per day (almost worthless)?


Do you understand what a watt is? Watt is a unit of power. Power = Energy/time. You are billed in kWh since this represents the total amount of energy you used over the billing period. So take the number of kWh you were billed and the number of hours in the billing cycle to get the total power you used. We shall call this X.

This number, X, then represents the number of Joules/s you used on average. To figure out how much area you need in solar panels, take the W/m^2 factor and multiply by the number of square meters needed to obtain X watts.

Watts/minute = J/(smin).
Watts/hour = J(sh).
Watts/dat = J(sday).

Watt (ha) you really are concerend about is peak power, the maximum in the distibution of you power usage.
Like when you turn the oven on to heat your house.