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State rules that apply
- What the rule says: “Electric Suppliers and EDCs shall credit Excess kWh Credits to the customer's subsequent monthly billing periods to offset the customer's consumption in those billing periods.”[1]
What it means for sizing and batteries
When exports earn close to the retail price, sizing the system to cover your yearly use is usually the best value, and a battery is mainly for backup rather than savings.
The calculator uses the statewide rule until we add utility rates. See what solar costs in Delaware.
FAQ
Frequently asked questions
Does Delaware have net metering?
State law (26 Del. C. 1014) and PSC rules require utilities and electric suppliers to offer net metering; excess kWh credits roll forward to offset later bills, and at the end of the annual billing period residential customers may request payment at their supply-service rate.
sources
[ 1 ]Every number on this page links to one of these sources. Dates show when we last checked each one.
- 26 DE Admin. Code 3001 - Final Order No. 10430 (27 DE Reg 983, June 2024)archive.regulations.delaware.gov · checked Nov 5, 2026
Tariffs last re-checked November 5, 2026.
Change log
- Monthly output per kW in Wilmington updated to [77.4, 90.9, 125.5, 134.0, 138.1, 136.0, 145.3, 136.3, 119.8, 99.8, 90.1, 70.3] kWh/kW/month (NREL/NLR PVWatts v8 (1 kW-DC, fixed roof mount, 20° tilt, south-facing, 14% losses, TMY weather)).
- Average solar radiation on the panels in Wilmington updated to 4.8 kWh/m2/day (NREL/NLR PVWatts v8 (1 kW-DC, fixed roof mount, 20° tilt, south-facing, 14% losses, TMY weather)).
- Solar output per kW in Delaware (PVWatts, Wilmington) updated to 1363.6 kWh/kW/yr (NREL/NLR PVWatts v8 (1 kW-DC, fixed roof mount, 20° tilt, south-facing, 14% losses, TMY weather)).