How to calculate how much PV you need to cover your electrical needs
Steps[edit | edit source]
- Safety first.
- Determine your energy use - you can do this by collecting a year's worth of electric bills and adding up the energy (measured in kilo watt hours kW-hrs) used. Another way to do this is to do a plug load analysis of all of your electric devices.
- Determine the solar insolation in your region and more specifically location of the pv panel to determine kW-hrs/kW installed of PV. This is done with your latitude or distance from the equator.
- Divide your energy use by the available solar insolation found from step 3 to get your number of maximum installed Watts.
- Design a pv system that meets your electrical power needs given the parameters of the available insolation. Keep in mind that solar insolation varies seasonally and daily.
Example[edit | edit source]
- Lets say you are average. The average annual electricity use per household is 10,654 kW-hrs/year (Energy Information Administration, 2005).
- From the solar resource map go here or here. If we assume you live in Kingston you can expect at least 1200 kW-hrs/kW (more if you are using thin film PV).
- 10,654/1200 = 8.9 kW. This is actually a pretty big system -- which shows you just how wasteful most people are with energy.
Warnings[edit | edit source]
Before you consider installing any type of photovoltaic you should first work to optimize your home's energy efficiency.
Things You will Need[edit | edit source]
For a plug load analysis you will need a watt meter.
Related How-Tos[edit | edit source]
Sources and Citations[edit | edit source]
Energy Information Administration (EIA). 2005. U.S. Household Electricity Report. Release date: July 14, 2005 at