I want to share a real-world case of solar power system longevity –

Production History 2008-2022.jpg Location is 33.75, -118.33. Azimuth = 155 deg, tilt = 26 deg.

24 Panels: Kyocera Solar, Inc.:KC175GT

Inverter: PV Powered LLC:PVP4800

DC Rating 4.2kW STC, 3.72kW PTC

The dashed line is geometric computation. Colors are the various years.

Percentages are of total yearly kWh relative to the geometric computation.

The graph shows a small loss of performance over the first 15 years.

2008 was a standout in October, but a slouch in February.

2022 was variously more, and less, than 2008.

Overall, year 2008 achieved 75% of the geom calculation; while 2022 achieved 71%.

The shape of the geom curve is due to solar elevation path over the year.

Variations at any given date (note, 30-day average) are due to atmospheric conditions.

Production History 2008-2022.jpg Location is 33.75, -118.33. Azimuth = 155 deg, tilt = 26 deg.

24 Panels: Kyocera Solar, Inc.:KC175GT

Inverter: PV Powered LLC:PVP4800

DC Rating 4.2kW STC, 3.72kW PTC

The dashed line is geometric computation. Colors are the various years.

Percentages are of total yearly kWh relative to the geometric computation.

The graph shows a small loss of performance over the first 15 years.

2008 was a standout in October, but a slouch in February.

2022 was variously more, and less, than 2008.

Overall, year 2008 achieved 75% of the geom calculation; while 2022 achieved 71%.

The shape of the geom curve is due to solar elevation path over the year.

Variations at any given date (note, 30-day average) are due to atmospheric conditions.

## Comment