Solar energy on the Moon for fixed or tracked photovoltaic systems

Abstract

Moon exploration will require local renewable energy production system, which design needs estimations of the received solar energy as a function of the location and the installation mode. We developed a novel method to compute the solar energy received by a 1 m2 flat surface anywhere on the Moon, for any period and using four different installation modes used for photovoltaic systems (fixed, 1-axis tracked vertical or horizontal and 2-axis tracked). By computing hourly elevations and azimuths of the Sun from the lunar year 2012 to 2031, we determined the incident angle between the solar rays and the surface, enabling the calculation of the solar energy received over a 20-year cycle, encompassing nearly all Sun-Moon relative positions on a human scale. We applied this method to compare the solar energy received on a one-axis tracked surface (vertical or horizontal axis), a two-axis tracked surface and a fixed surface at optimal azimuth and tilt, at ten locations from equator to poles. While the two-axis tracker exhibits the highest solar energy levels, comparable solar energies are observed near the poles with a vertical axis tracker and near the equator with a horizontal axis tracker. A fixed system, on the other hand, experiences a significant loss of solar energy in comparison to a two-axis tracker, ranging from 37% to 64%. Additionally, we showed that the partial Sun visibility results in reduced solar energy levels, particularly prevalent near the poles where the Sun remains close to the horizon. Near the poles, a vertical axis tracker seems the best solution, and could be theoretically applied with a perfect concentrator photovoltaic system with an acceptance angle above +/−3.5°.

Keywords

• solar energy
• photovoltaics systems
• moon
• solar tracker