Sep 09 2010
Solar Panels ..The not so green side of it
By Mike Mufdi
When I was first introduced to solar panels ,I was fascinated about how this simple system can actually produce electricity without emitting green house gases, no CO2 , no by products..it was perfect, so green and will help us reduce our CO2 and GHG(Green House Gases) emission.But at one point I realised that I was missing a fundamental concept; None of the energy sources known to us up to date has absolute zero effect on nature. That made me dig more on how harmful a solar power systems can be and what are the disadvantages of these systems..
The story of solar cells manufacturing starts with mining of Silica, a process that depends in total on burning of fossil fuels at present-with all the GHG associated. Silica is used to produce silicone by heating it up to more than 1,900°C (3,450 °F) with the presence of Carbon. this process requires huge amount of energy , and yes you guessed right, this is not green energy that is used. The result of this backing, is pure silicon, Carbon Monoxide and Carbon dioxide.
for chemistry lovers the equations are as follows:
SiO2 + C → Si + CO2
SiO2 + 2 C → Si + 2 CO
Wait a minute, this is not the end of it, the resultant Silicon is not pure enough to be used in solar cells.To obtaining the high purity required, further processes that involve chemicals and produce chemicals and gases that are known to be harmful, explosive, irritating and cause Green House effect. Some will argue that most of these chemicals and gases are recyclable and controllable, which in theory is true, but knowing the fact that silicon production facilities around the world can not be guaranteed to follow highly strict safety systems, high risk of ending up polluting the environment.
The question that occurred to me after knowing all that was, will solar cells produce energy more than that used to produce them? The answer that I found was YES. but this will be done by around 1-3 years of operating at peak exposure. so the first few years after installing the system will be only to payback the energy used to produce the system. two things to note here, first systems used to supply homes with electricity do not have mechanical positioner to insure peak exposure all the time, they are fixed on roofs usually, and oriented to optimum direction, and second the studies that were made did not put in their consideration the auxiliary systems, like supports, batterers, AC/DC converters, etc.. all that will extend to the energy payback period.
Disposal of these panels is a new challenge we have to face bravely, the expected life of a solar panel is between 25 and 40 years, and that’s almost the time elapsed since solar cells were used commercially, and the first generation of these panels has reached its retirement age now. Again you will hear people talking about recycling of the solar cells to defend it, but they are the same people who most probably know that dumping is still at higher rates than recycling, specially with no regulations to insure recycling is being done.
Yes the solar power is a great source of green energy, but the methods we are using to harness and convert this energy to electricity still have un-green side. The technology is developing and new improved cells are being introduced to over come the disadvantages of current systems. improving the efficiency of the solar cells is a challenge, that will help reducing the sizes of these cells and make them easier and faster to spread.