Solar Calculator

Solar Elevation Calculator

• https://keisan.casio.com/exec/system/1224682277

Power Production

This is the key calculator fro NREL. Give it location and fixed tilt, and it calculates total power production per year with surprising results: angle matters very little for fixed tilt. Thus, flat rooftop is almost as good as optimal, non-tracked angle. Tracking does give significant improvement, though.

• https://pvwatts.nrel.gov/pvwatts.php - good. 8.5 MWhr/year with 20 degree tilt or 45 degree tilt. 8.2 MWhr/yr with 12 degree tilt. 8.7 MWhr/yr with 32 degree tilt. 7.8 MWhr/yr with 60 degree tilt. With 2 axis tracking, it is 12 MWhr/yr.
  • Good reality check: Angle optimization in a fixed system gets you only about 6% improvement! 2 axis tracking gets you 50%.

PV Panel Angle Calculator

• Useful to study latitude (not much difference) vs time of day (lots of differentce, as this difference is determined by air mass. Think of space: in space around the earth, insolation would be constant.

https://www.pveducation.org/pvcdrom/properties-of-sunlight/calculation-of-solar-insolation

• Dual axis trackers improve energy gain by 40% [1]. Is that over fixed mount or seasonal change mount?
• Bifacial panels add 14-40% more energy gain, and tracking adds about 40% [2]