
How to Assess Savings From a Commercial Solar System
A credible savings estimate starts with 12 months of electricity bills and interval load data, then matches those figures against time-based solar production rather than applying one annual percentage. By the end, you will be able to separate self-consumed power, exports, demand-charge reductions, battery value, project costs, and uncertainty into a decision-ready comparison.
Key takeaways
- Collect 12 consecutive electricity bills and matching interval data.
- Measure savings from self-consumption, exported power, and demand charges.
- Model solar production against the hours your business uses electricity.
- Stress-test payback, cash flow, and forecast risk before approval.
Build the Baseline From 12 Months of Electricity Bills
Do not estimate commercial solar savings from an annual kWh total. Collect 12 consecutive months of commercial electricity bills, then request 15-minute or hourly interval data for the same period. The bills show what you paid; interval data shows when the site used power, which determines self-consumption and demand-charge savings.
Record each billing period and extract these figures:
- Monthly kWh consumption, meter-opening and closing dates, and the number of billed days
- E…









