Mirror/land ratios in solar power tower generating stations

Based on Google imagery, the heliostat field of Ivanpah 1 is very nearly a square, 1995 m on a side, with three corner truncations, giving a heliostat field land area of about 3,800,000 square meters. This unit has 53,527 heliostats each with a mirror area of 15 square meters, giving a total mirror area of 803,000 square meters. The mirror/land ratio is 0.21.

Based on Google imagery, the heliostat field of the Crescent Dunes Solar Energy Project is very nearly circular, with a diameter of about 2804 m, giving a heliostat field land area of about 6,200,000 square meters. This unit will have 17,170 heliostats, each carrying 62.4 square meters of mirror, giving a total mirror area of 1,070,000 square meters. The mirror/land ratio is 0.17.

The mean radius of the heliostat field (the radius of a circle having the same area as the field) is 1100 m for Ivanpah 1; 1402 m for Crescent Dunes. The tower heights are 140 m and 160 m respectively, giving mean field radius to tower height ratios of 7.9 and 8.8.