In energy efficiency circles, the story of Jan Schilham's 1997 redesign of a pumping system for a Shanghai carpet-making factory is famous. Schilham saved 92 percent of pumping energy and lowered capital costs by using a well-known principle: Pumping water slowly through fat, straight pipes reduces friction and saves energy relative to pumping the same volume quickly through narrow twisty pipes.
Why isn't it always done that way? Because the bigger pipes cost more than the energy saving. Schilham's insight was that energy is not the only payback. Fatter pipes lower the size of the pumps and motors required, so even with the additional plumbing expenses, total capital costs are lower. Energy savings in this context are free, or better than free.
In a narrow sense, this was an improvement in cost accounting, not technology. Nothing unknown or untested was deployed. No breakthrough enabled the lower costs -- they'd always been possible. Schilham simply counted a benefit that had been overlooked, demonstrating that a technique usually considered unprofitable actually saved money.
The key that allowed Schilham to exercise his genius was that Interface carpets had already decided to reduce its ecological footprint drastically. "Whether" had already been decided -- Schilham was worrying about the "how." Essentially he was in the position of someone complying with a standards-based efficiency rule.