claim: A windmill could spin until it falls apart and never generate as much energy as was invested in building it.
evidence: "A two-megawatt windmill contains 260 tonnes of steel requiring 170 tonnes of coking coal and 300 tonnes of iron ore, all mined, transported and produced by hydrocarbons" "a windmill could spin until it falls apart and never generate as much energy as was invested in building it" [...] "[The concept of net energy must also be applied to renewable sources of energy, such as windmills and photovoltaics.] A two-megawatt windmill contains 260 tonnes of steel requiring 170 tonnes of coking coal and 300 tonnes of iron ore, all mined, transported and produced by hydrocarbons. [The question is: how long must a windmill generate energy before it creates more energy than it took to build it? At a good wind site, the energy payback day could be in three years or less; in a poor location, energy payback may be never.