Quick Answer
A typical off-grid solar system's return on investment (ROI) can range from 8-12% over 10-20 years, considering factors like system cost, energy production, and maintenance requirements.
Calculating Off-Grid Solar ROI
Calculating the ROI for an off-grid solar system involves understanding several key components: initial system cost, energy production, maintenance costs, and the value of energy savings. A general rule of thumb is to divide the total system cost by the annual energy production to get the payback period in years, then apply a discount rate to derive the ROI.
System Design and Energy Production
System designers use various tools to size the solar array and battery bank to meet the energy demand of a given load. For example, a 3 kW solar array paired with a 10 kWh battery bank can provide around 12,000 kWh of electricity per year in a moderate climate with 5 peak sun hours per day. By comparing the system cost (e.g., $15,000) to the annual energy production (12,000 kWh x $0.15/kWh = $1,800), we get a payback period of approximately 8.3 years.
Maintenance and Energy Savings
To accurately calculate ROI, maintenance costs and energy savings should also be taken into account. Assuming an annual maintenance cost of 2% of the initial system cost (e.g., $300), and considering that off-grid solar systems can save homeowners around $1,800 per year on energy bills, the net annual savings would be $1,500. By applying a discount rate of 8% to this net savings, we can estimate the ROI to be around 10.5% per annum.
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