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Dokumente > Ineffizienz > Greenies think concrete is green!

Photo: Mojave Desert Blog

Photo: Mojave Desert Blog

Photo: Mojave Desert Blog Vergrößern

Greenies think concrete is green!

A 3 MW 100 meter wind turbine needs 900+ tonnes of concrete. Imagine the millions of tonnes being deposited on our countryside, and the thousands of years it will continue to contaminate and poison the land and water courses. More concrete is required for offshore turbines which will impact on marine life.

Carbon emissions from concrete

The cement industry is one of two primary industrial producers of carbon dioxide (CO2), creating up to 5% of worldwide man-made emissions of this gas, of which 50% is from the chemical process and 40% from burning fuel.

The carbon dioxide CO2 produced for the manufacture of one tonne of structural concrete (using ~14% cement) is estimated at 410 kg/m3 (~180 kg/tonne @ density of 2.3 g/cm3) (reduced to 290 kg/m3 with 30% fly ash replacement of cement).

The CO2 emission from the concrete production is directly proportional to the cement content used in the concrete mix; 900 kg of CO2 are emitted for the fabrication of every ton of cement.

Cement manufacture contributes greenhouse gases both directly through the production of carbon dioxide when calcium carbonate is thermally decomposed, producing lime and carbon dioxide, and also through the use of energy which can only be created from fossil fuels.

Surface run-off

When water runs off impervious surfaces, such as non-porous concrete, it can cause heavy erosion, flooding and poisoning the soil.

Turbine foundations cause five times the amount of run-off as compared to land; this seeps into water courses and causes serious contamination.

Article published courtesy of  Facebook Deborah Pender