Solar Panel Lifetime
How much energy does it take to make, install, and eventually dispose of a Solar Panel?
I am curious about how much of the energy that a solar panel of a given size and capacity will produce in it’s lifetime, and what fraction of that energy was required to produce it in the first place?
At present the technology to create silicon Solar Cells is incredibly energy intensive. It is not logical to compare the cost of oil to the cost of a Solar Cell because they are not priced according to energy input. Oil has a strong advantage in that it is concentrated solar and geothermal chemical energy that has accumulated over millions of years. The price of oil does not reflect its energy content, but the cost to retreive it. Electrical energy used to produce a Photovoltaic cell is not priced in any proportion to oil.
By some calculations it will take about 50,000 KWh of energy produced by the PV cell before it can recover the energy used to manufacture it. This is about 20 years for a typical solar panel. There is still controversy about this, but to some extent it is reflected in the high cost of photovoltaics, which for the average house will cost about $20,000 to $30,000 dollars just to install. Here is a collection of studies that have been done on just this topic, which range in energy payback time from 2.4 to 25.5 years!!!
http://www.energybulletin.net/17219.html
Keep in mind that these studies are assuming ideal conditions for the installation. Cloudy weather, snow, and latitudinal variations in length of daylight will reduce the actual results.
This is one reason there is continuing work being done on things like thin PV, which use less silicon and thus much less energy to manufacture.