Sustainable solar energy conversion to chemical and electrical energy

Abstract

The Earth receives around 1.9×106EJ of energy in visible light each year and only a fraction of this light energy is being converted to biomass (chemical energy) via the process of photosynthesis. Out of all photosynthetic organisms, microalgae, due to their fast growth rates, have been identified as potential source of raw material for chemical energy production. Solar panels have also been used worldwide for electrical energy production. Here we explore and introduce a novel methodology on combining solar panels with microalgae cultivation systems. These two methods of energy production would appear to compete for use of the same energy resource (sunlight) to produce either chemical or electrical energy. However, some groups of microalgae (i.e. Chlorophyta) only require the blue and red portions of the spectrum whereas certain types of solar cells absorb strongly in the green part of the solar spectrum but not as much in the red or blue portion of the spectrum. This suggests that a combination of the two energy production systems would allow for a full utilisation of the solar spectrum allowing both the production of chemical and electrical energy from one facility making efficient use of available land and solar energy. In this review we propose to introduce a solar panel as a filter above the algae culture to modify the spectrum of light received by the algae and utilise the unused parts of the spectrum to generate electricity.