Solar Update: One Year After Installation
On July 9, 2019, after certification of our solar panels (see the January 2020 NAPS article), a new digital “net” meter was installed by NNEC to monitor our power usage and the amount of power we return to the grid. One year later, on July 9, 2020, we had purchased 4713 kWh and returned 3483 kWh to the grid. Except for summer months when the air conditioner is used, our bill was $29, or within $10 of $29, which is the monthly “line fee.” Our highest bill, in August, was $77 compared to previous years when it averaged about $300.
According to data supplied by the manufacturer of the micro-inverters, we generated 5406 kWh, which we either used (1923) or returned to the grid (3483). The maximum output of our 5.25 kW ground-mounted array (15 Hyundai 350 watt panels and Enphase micro-inverters) was 4.2 kW. The least amount of power was produced in December when the sun is lowest.
We heat with propane and wood, not with an electric heat pump. Our electric bill was $1,177/ the year before the solar panels were installed. Last year, after the solar panels were operating, it was $535. Dividing the difference into the cost of the array, after taking the 2019 30% tax credit, yields 17.6 years to pay it back. The warranty is 25 years on the panels and micro-inverters. We do not know the cost of electricity over the next decade or the amount of inflation, so that number is not precise. It is important to remember that the tax credit drops to 26% this year, to 22% in 2021 and zero thereafter, unless changed by a new administration.
The array would have produced more power if it could have been roof-mounted rather than ground-mounted because shading by trees would have been greatly reduced. But even given a less-than-ideal location for the panels, we are satisfied with the performance of the system and have no regrets about installing it.