Sizing a Solar [Photovoltaic (PV)] Electric Array Renewable Energy System to Fit Your Needs

First, you determine how much energy you need on a daily basis in kilo-watt hours (kWh). This data can be found on your electric bill on a monthly basis if you have one for your location. Otherwise you will need to go through the process of estimating your energy consumption.

We offer an interactive "Load Analysis Spreadsheet"  solution where you determine your average daily usage.

Second, you need to determine the Solar insolation value for your site. If you are going to be totally disconnected from the electric grid/utility company then you will need to use the minimum (worst case) solar insolation value for your location.

Lastly, you need to divide your estimated daily energy usage (kilo-watt hours) by the solar insolation value and multiply by a system inefficiency factor.

Total Watts of Solar Electric Panels needed = [(Daily kilo-watt hours / solar insolation)] x inefficiency factor

The inefficiency factor for systems that are disconnected from the electric grid (off-grid) is 1.3. For systems that are connected to the grid (also called on-grid, grid-tied, grid inter-tied or grid connected) that value is usually assumed to be 1.2. The reason that it is higher for off-grid systems is that these systems have to store the energy in battery banks which are not perfectly efficient. Most on-grid systems either don't use batteries at all or use them in such a way that their inefficiencies are minimized.

We provide you with the comprehensive"Array sizing calculations"solutions to fit your preferences (grid connected or off-grid networks).

   Sizing a Renewable Energy Battery Bank System to Fit Your Needs

Many Renewable Energy (RE) systems incorporate batteries. Deep cycle batteries can be used in all types of systems. The energy stored in the deep cycle batteries can then be used to directly power DC loads or it can be inverted to power loads. To ensure you have enough reserve capacity to provide the electricity  you need (without running additional generators), invest the time to size your deep cycle battery bank properly. Because of the various conditions affecting battery bank sizing, this process may be one of the more challenging calculations you'll have to do when planning your RE system.

Before tackling the calculations, start by identifying a few key pieces of information:

    electricity usage per day
    number of days of autonomy
    depth of discharge limit (DOD)
    ambient temperature at the battery bank

just to mention a few.