Really ambitious technical things by their very nature have uncertain outcomes and may prove spectacular, or even slow-motion failures. Concorde was only very barely commercially viable (if that) and ultimately exhibited fatal engineering flaws, as well as susceptibility to alternative (though slower) private jets with more flexible scheduling; still, it flew commercially for 27 years. The Channel Tunnel would have bankrupted the corporation building and operating it (Eurotunnel) without government bailouts.[1] The Airbus A380 has similarly proved a commercial failure with production halted at 254 units built in 18 years, compare against Boeing's 747 with 1,574 units over 55 years.[2]

Even accepting your characterisation of Energiewende as a failure, which I do not, it absolutely IS a "really ambitoius technical" project. And hence refutes the specious assertions of ur-whale.

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Notes:

1. "Megaprojects and Risk: An Anatomy of Ambition" <http://www.josephcoates.com/pdf_files/268_Megaprojects_and_R...> (PDF)

2. Wikipedia provides both Airbus's and Boeing's production years and units.