August 15, 2015 by energyskeptic
You ought to watch “MidAmerican Energy Company – From the Ground Up: Building our energy future, one turbine at a time“. The pictures from the video below are also powerful since they capture how low the EROI of wind power must be when you can see the embodied fossil fuels used to build a wind turbine (plus dozens of worker and hundreds of worker and heavy-duty trucks not shown above).
Yet it doesn’t begin to capture all of the energy inputs to wind turbines. Notably, transmission is left out of the picture, and the natural gas plants to balance intermittent energy, the mining of the ores for iron and steel, or crushing of rocks to make cement/concrete, the fossil fuels in the tons of epoxy, and so on to make the 900 short tons of material (it is probably more like 1300 tons given other peer-reviewed publications on materials used in 2 MW turbines, not all of the materials used were included in this short video).
Most wind power will be forever stranded, because it’s too far from cities to run transmission lines to. If you look at the state level wind maps in the Wind Energy Resource Atlas of the United States List of Maps (RREDC) it appears as if cities have been placed as far from commercial wind power as possible. But no diabolical force is to blame. The distance is due to cities arising near good, flat farmland, yet the best wind is on the ridges of highlands. To get around this, wind turbines taller than the St. Louis arch at peak blade tip have been proposed for the Southeast and other areas without commercial wind (February 18, 2015. Mapping the Frontier of New Wind Power Potential. National Renewable Energy Lab.).
You’d need 32,850 wind turbines to replace the Cubic Mile of Oil consumed globally every year, and a grand total of 1,642,000 turbines to replace oil over the next 50 years, which may be conservative given that the wind isn’t blowing all the time so that triple or more would be needed on a national grid with massive energy storage batteries. A wind turbine lifespan is 20 years, so many of them would need to be repowered or replaced before the 50 years are up. Anyhow, clearly wind turbines require too many oil-powered trucks and cement, steel, and so on made with fossil-fired energy to outlast the brief age of oil.
This wind turbine is comprised of at least 875.5 tons of material. The weight of the 40 to 100 geopiers and other components aren’t shown, so let’s assume 900 tons total. An average car weighs 2 tons, so each windmill equals 450 cars — try to top that Burning Man Festival! The crane, excavators, graders, cement, worker, and other trucks required to haul blades, equipment, and workers might weigh 10 times as much as the wind turbine, so some fraction of the energy of all these should count as energy inputs as well, from mining to operational vehicle, and the fuel used (including the 10 foot deep, 100 foot wide, 1650 tons of soil dug out and put back over the concrete base).
- Takes 3 weeks to build from excavation to operation
- 40 to 100 geopiers installed for stability, weight unknown
- Excavate 10 feet deep 100 feet wide
- Set 96,000 pounds of reinforcing steel rebar = 48 tons
- 53 concrete trucks pour foundations. If each truck can haul 8 cubic yards at 2538 lbs/yard * 53 = 1,076,112 pounds = 538 tons
- Move 1,500 cubic yards of soil @ 2,200 lbs per cubic yard = 3.3 million pounds = 1,650 tons
- 3 blades : each 173 feet long and 27,000 pounds for 81,000 pounds = 40.5 tons
- 8 truckloads to deliver turbine components
- Nacelle: weight 181,000 lbs = 90.5 tons with the generator, gearbox, and rotor shaft
- Hub: weight unknown
- Base tower height 53 feet 11 inches, weight 97,459 lbs = 48.7 tons
- Mid tower height 84 feet 6 inches, weight 115,587 lbs = 57.8 tons
- Top tower height 119 feet, weight 104,167 lbs = 52 tons
- Final tower height to blade tip when fully extended 442 feet