CO2 Emission of Wind Farms

An average wind farm creates thousands of tonnes of CO2 emissions: “embedded” in thousands of tonnes of steel and concrete.

What’s the carbon foot print of a wind turbine with 45 tons of rebar & 481m3 of concrete? 241.85 tons of CO2. For a wind farm with 50 turbines, this is more than 12,000 tons of CO2 before any electricity is produced.

Breakdown of the CO2 numbers.

To create a 1,000 Kg of pig iron, you start with 1,800 Kg of iron ore, 900 Kg of coking coal 450 Kg of limestone. The blast furnace consumes 4,500 Kg of air. The temperature at the core of the blast furnace reaches nearly 1,600 degrees C (about 3,000 degrees F).

The pig iron is then transferred to the basic oxygen furnace to make steel.

1,350 Kg of CO2 is emitted per 1,000 Kg pig iron produced. A further 1,460 Kg CO2 is emitted per 1,000 Kg of Steel produced for a total of 2,810 Kg CO2.

45 tons of rebar (steel) are required, 126.45 tons of CO2 are emitted.

To create a 1,000 Kg of Portland cement, calcium carbonate (60%), silicon (20%), aluminium (10%), iron (10%) and very small amounts of other ingredients are heated in a large kiln to over 1,500 degrees C to convert the raw materials into clinker. The clinker is then interground with other ingredients to produce the final cement product. When cement is mixed with water, sand and gravel forms the rock-like mass know as concrete.

An average of 927 Kg of CO2 is emitted per 1,000 Kg of Portland cement. On average, concrete has 10% cement, with the balance being gravel (41%), sand (25%), water (18%) and air (6%). One cubic metre of concrete weighs approx. 2,400 Kg, approx. 240 Kg of CO2 is emitted for every cubic metre.

481m3 of concrete are required, that equals 115.4 tons of CO2.

We have not included the emissions for mining of the raw materials or the transportation of the fabricated materials to the turbine site, the emission calculation above would be on the low end.

We haven’t considered the manufacture of the pylons and kilometres of transmission wire needed to get the power to the grid.

We have not included the extra CO2 that the back up generators produce due to ramping up and down as wind power is not constant. This adds 20 to 80 kg CO2-eq/MWh to the life cycle GHG emissions profile of wind power.

Each wind turbine has a magnet made of a metal called neodymium. The mining and refining of neodymium is so dirty and toxic – involving repeated boiling in acid, with radioactive thorium as a waste product – that only one country does it – China.

Wind turbines will incur far more carbon dioxide emissions in their manufacture and installation than what their operational life will ever save. The environmental damage to land and wild life are very high.

All this for an intermittent, highly unreliable energy source.

References

Metal emission stats from page 25 from the 2006 IPCC Chapter 4 Metal Industry Emissions report.

Cement and concrete stats from page 6 & 7 from the 2012 NRMCA Concrete CO2 Fact Sheet.