How Solar Power Systems Are Sized
Grid-tied solar energy systems are typically sized to provide a specific percentage of total annual electricity consumption.
Solar power systems are designed to produce a set average amount of energy daily or yearly. Solar providers calculate how much energy a home or business will need based on utility bills, then design a system to provide the maximum amount of electricity the available space and budget will allow.
Solar contractors size the solar panel array and battery bank to meet the average daily needs under the worst-case insolation scenario if a solar energy system includes a battery backup. In this case, “insolation” describes the amount of sunlight the solar panels will receive.
Many solar panel installation contractors will oversize a solar panel system by a certain percentage relative to the inverter capacity to account for seasonal variations in temperature and system degradation over time. Depending on local climate conditions, the range is typically 10% to 25%.
Sizing steps for grid-tied solar energy system
Grid-tied solar energy systems are typically sized to provide a specific percentage of total annual electricity consumption. Limiting factors often include available space and budget. Many contractor’s process for sizing a grid-tied solar power system includes these steps:
Determine the number of kilowatts the client requires, given the tilt and azimuth of the site, to generate an annual output close to the target.
Adjust the initial estimate based on available space. To produce one kilowatt requires about 67 square feet of roof space for solar panels.
Make any additional adjustments to account for the electrical characteristics of the system, such as whether the property owners plan to use string inverters, DC optimizers with string inverters, or microinverters.
Sizing steps for off-grid photovoltaic systems
Standalone solar power systems are sized differently than a grid-tied system. Because there is no standby supply from the grid for these systems, it is common to size the system to meet the average monthly load in winter, which typically has the lowest average daily insolation, plus the inefficiencies caused by charging and discharging a battery. The battery storage capacity is sized to handle the electrical loads when insolation is unavailable.
Contractors size off-grid solar systems using these steps:
Determine the size and duration of all electrical loads to calculate the average daily energy use.
Size battery storage capacity based on average daily energy use, depth of discharge limit, and desired days of autonomy.
Size the solar panel array to handle the period with the highest load and lowest solar insolation.
Determine the size of the charge controller and electrical balance of system (BOS) components.
Expert solar panel contractors can accurately size the system to meet a home or commercial property's needs.
SG Electrical is a licensed, bonded, and insured solar and electrical company serving residential, commercial, and industrial customers in Coachella Valley. Highly--trained experts install, repair, clean, and maintain solar panels and provide comprehensive electrical services. Call us at (760)501-2423.
