Solar energy toxins

Producing electricity from solar cells can reduce air pollutants and greenhouse gases depending on type of solar cells used.
Solar panels are manufactured and it is a dirty and energy.” First, raw materials have to be mined: quartz sand for silicon cells, metal ore for thin film cells. Next, these materials have to be treated, following different steps (in the case of silicon cells these are purification, crystallization and wafering). Finally, these upgraded materials have to be manufactured into solar cells, and assembled into modules. All these processes produce air pollution and heavy metal emissions, and they consume energy – which brings about more air pollution, heavy metal emissions and also greenhouse gases.

The ecological burden of energy use depends on the way electricity was generated. The research from the “CrystalClear” European Commission project, investigated the real energy mix used by 11 European and American silicon and PV module manufacturing factories. Since they use comparatively more gas and hydropower, this is the best case scenario.

The researchers investigated 4 types of solar cells: multi-crystalline silicon (with an efficiency of 13%), mono-crystalline silicon (14%), ribbon silicon (11.5%), and thin-film cadmium telluride (9%). (1)

In the best case scenario, one square meter of solar cells carries a burden of 75 kilograms of CO2. In the worst case scenario, that becomes 314 kilograms of CO2. The total CO2 debt of a solar installation is 600 to 3,140 kilograms of CO2 in sunny places, and 1,200 to 6,280 kilograms of CO2 in less sunny regions. These numbers equate to 2 to 20 flights Brussels-Lissabon (up and down, per passenger) – source CO2 emissions Boeing 747.

In the worst case scenario (US grid, mono-crystalline silicon), emissions rise to 104 gram CO2 per kilowatt-hour of solar generated electricity, which makes solar panels only 4 times cleaner than gas. Now let’s play a bit with the life expectancy.,, Agreed, this is the worst case scenario, and even in that case solar panels are still a better choice than fossil fuels, but solar is not a “clean” source of fuel.

“A better strategy would be to use already available solar panels to produce more solar panels”

The scientists note that the environmental score of solar panels will improve, because they are becoming more efficient each year. (They also become thinner, so less energy is needed to make them). Most likely they will also become cheaper.
This map shows the amount of solar energy in hours, received each day on an optimally tilted surface during the worst month of the year.

Solar thermal power should have priority over solar PV power.

It should be realized that solar panels first raise the amount of greenhouse gasses before they help lowering them. If the world would embark on a giant deployment of solar energy, the first result would be massive amounts of extra greenhouse gasses, due to the production of the cells.

A better strategy would be to use already available solar panels to produce more solar panels. The scientists calculated that the ecological burden of solar panels can be halved if 100 percent of energy in the factories would be delivered by solar energy.

(*) in the text, “CO2” stands for CO2-equivalents (which means other greenhouse gases are included).

Excerpts from Kris De Decker – Low-tech Magazine

http://www.lowtechmagazine.com/2008/03/the-ugly-side-o.html

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