Preface: The Department of Energy high wind penetration plans require a lot of offshore wind. But is it possible, affordable, or wise to do this? Corrosion leads to a short lifespan of just 15 years. To reduce maintenance, offshore windmills use limited rare earth metals. A 500 MW offshore wind farm could cost $3.04 billion dollars (Table A-1). The materials (i.e. steel & concrete) needed for 730,099 2 MW windmills in America are staggering. Offshore turbines of 6 MW weigh 757 tons, nearly 2.5 times more than onshore turbines (table 4.3), each one weighing as much as 505 cars of 3,000 pounds each. Most components are made in China and Europe, so supply chain disruptions would delay repairs or repowering.
Wind turbines can be battered, rusted, corroded, or destroyed by tides, storms, hurricanes, lightning, icebergs, floes, large waves, and marine growth, shortening their lives and increasing maintenance and operation costs.
Why build risky, expensive, short-lived offshore wind farms if a renewable electric grid may not be possible given the lack of a national grid, lack of commercial-level utility-scale energy storage, and the insurmountable issue of seasonal wind and solar? Peak oil occured in 2018, so sometime within the next 10 years oil shocks will hit and be too precious for building such contraptions, and oil will eventually be rationed mainly to agriculture (if government is not controlled by libertarians, republicans, or demagogues), and after that, the center will not hold. Best to use the energy to build offshore wind turbines on creating organic farms and other postcarbon strategies.
Navigant. 2013. U.S. Offshore Wind Manufacturing and Supply Chain Development. U.S. Department of Energy.
Can we afford offshore wind turbines? A 500 MW farm costs $3 trillion dollars and will last only 15 years