Conspicuously absent in TFA (TFPR?) are any mentions of energy cost to construct, energy break-even point, ongoing maintenance requirements, and useful lifespan. These things are made of some delicate looking stuff, mirrors get dirty and can be broken, the Stirling engines have seals that will degrade, and there are squillions of moving parts to wear out. Who's got the answers? Miracle cure or mammoth boondoggle?