Q1 2026 Solar Model Update: Revised Payback Periods

Updated Cost Inputs

Solar panel prices at the landed cost level for Antigua have fallen from approximately XCD 0.60/Wp in early 2025 to approximately XCD 0.55/Wp in Q1 2026, based on updated quotes from three local installers. This 8% reduction in panel costs, which represent about 35% of total system cost, translates to a total system cost reduction of approximately XCD 1,260 for the 5kW baseline system — bringing the all-in installed cost from XCD 45,000 to approximately XCD 43,740. The new installed cost figure of approximately XCD 2.80/W represents a meaningful improvement and is competitive with commercial-scale pricing in the U.S. residential market, adjusted for purchasing power.

Battery storage costs have seen an even larger percentage decline. The cost of a 10kWh LFP battery storage system — the minimum useful size for meaningful backup and solar self-consumption optimization — has fallen from approximately XCD 25,000 in early 2025 to approximately XCD 22,000 in Q1 2026, a reduction of XCD 3,000. At the battery cell level, LFP prices reached approximately USD$58/kWh in January 2026, continuing a trajectory that has seen costs fall roughly 90% over the past decade. The installed system cost in Antigua reflects battery cell prices plus BMS (battery management system), inverter compatibility, installation labor, and local margins, but the directional trend is unmistakably downward.

Revised Payback Scenarios

For the 5kW solar-only system at the updated XCD 43,740 cost, with APUA's new EC$0.4644/kWh rate and annual generation of 7,008 kWh, the revised simple payback is 7.5 years — down from 8.2 years in the version of the model we published in Issue #2 (which used October 2025 pricing and the old EC$0.45 rate). That's a 0.7-year improvement in payback driven roughly equally by lower system costs and higher electricity rates. Over 25 years, the cumulative savings at the updated inputs total approximately XCD 104,000.

The solar-plus-battery scenario has improved more dramatically on a percentage basis. At updated combined costs (XCD 43,740 solar + XCD 22,000 battery = XCD 65,740 total), with the battery enabling higher self-consumption (modeled at 80% vs 60% without battery) and providing backup value, the payback for the solar-plus-battery system is now 11.2 years — down from approximately 13 years at 2024 pricing. The break-even between solar-only and solar-plus-battery continues to narrow as battery costs fall; we expect it to reach approximately 10 years by Q1 2027 if the cost decline trajectory continues.

The EV Charging Scenario

As electric vehicle adoption begins in Antigua — slowly, given the limited EV import market and charging infrastructure, but noticeably — we've added an EV charging scenario to the model. A household adding a modest EV (consuming approximately 4,000 kWh/year for typical Antiguan driving distances) alongside a 7kW solar system (slightly oversized to accommodate the additional load) has a combined installation cost of approximately XCD 62,000. The combined electricity savings (residential use plus EV charging displacing gasoline) total approximately XCD 8,200/year at current rates, producing a payback of 9.1 years and a 25-year IRR of approximately 13.8%.

The EV scenario is the strongest economic case in our model, because it captures a second stream of savings (gasoline displacement at approximately EC$2.50/liter effective cost per kWh equivalent) in addition to electricity bill savings. Households that are considering EV purchases in the next 2-3 years should strongly consider sizing their solar system for the combined load from the outset — the incremental cost of going from 5kW to 7kW is approximately XCD 11,000, which is recovered in approximately the same payback period as the base system.