As far as I know, the industry standard is the Lawrence Berkeley National Laboratory's annual 'Tracking The Sun' report[0]. I recommend it as a great primary so

As far as I know, the industry standard is the Lawrence Berkeley National Laboratory's annual 'Tracking The Sun' report[0]. I recommend it as a great primary source - the measurements are well explained and accompanied by helpful charts and analysis of the year-to-year changes. LBNL also publishes other useful resources on energy production/consumption, so it's worth browsing around to see what they have if you're interested. [0]https://emp.lbl.gov/publications/tracking-sun-10-installed-price/ https://emp.lbl.gov/publications/tracking-sun-10-installed-p...