Concentrating Sunlight

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

The promise of solar energy is that, for all practical purposes, solar energy is unlimited and eternal (if the sun goes away, we go away).  Despite this, only four percent of the world’s energy needs are supplied by solar resources today.  Part of this is the relatively high cost of solar cells, their limited efficiency, and sometimes limited lifespans, which makes expensive replacements a regular necessity. The total amount of solar energy striking the earth is a strikingly high figure, something in the way of terajoules, according to one site.  About 1,000 Watts of energy hit every square meter of the earth’s surface, varying by the angle at which the surface is tilted relative to the parallel rays from the sun.  Most solar cells fall into a 12-to-40-percent efficiency range, though, limiting a photovoltaic array’s output to about 120 to 400 watts per square meter (10.76 square feet) at the best angle. That’s part of what makes solar aircraft problematical.  …