Math is so hard!

Math is so hard!  Well, if you're an environmental wacko, at least.  The “green” propaganda I've seen that promotes wind or solar power always compares the cost of installation based on the “nameplate” capacity of wind turbines or solar arrays (the maximum power they can generate under ideal conditions), not their actual contribution.  The same practice is used for conventional power stations, so one can argue (and the environmentalists do) that this is an apples-to-apples comparison –  but it's not.  The reason it's not is that wind and solar power outputs are determined by Mother Nature.  A wind turbine generates power at the whim of the winds, and a solar array is at the mercy of the daily sun cycle, clouds, snow, etc.  Conventional power plants don't have this problem – they generate power whenever we ask it of them.

The graph above right comes from an excellent post over at Watts Up With That, which goes into some detail about the actual contributions of wind and solar as compared with their nameplate capacities.  For the U.S., the average contributions have been running at just over 20% of the nameplate capacity.  That means if you want to generate one megawatt of solar power on average, you need to install five megawatts of solar panels.  The obvious corollary to this is that environmentalists have been badly underestimating the cost of replacing conventional power with “green” power – that's not a new observation, mind you, but here it is backed up with pesky actual data and experience...