That has been my question for some time. The effciency of some of these alternates just squeak by in unity of input to output. If it were not for subsidies, some wouldn't survive.
Within the 90% reduction of using fossil fuels by 2050, there is going to need to be a huge push to force all energy consuming devices to be at minimum 50% more efficient as a start or removed from existance.
The efficiency of energy productions isn't always what it seems either....
Ethanol 40% efficient? Wind over blown
Which begs the question of replacing fossil fuel use will take 40-70% more in alternate energy generating sources to replace the current usage. Limiting growth in economy, populations and GDP's for developed nations and moving it to undeveloped nations which is ultimately what cap and trade will fund. The members of the UN fully intend to institute Global Welfare with schemes like this. Which seems to go against what the UN foundation of peace and security with its neighbors. There is definitely a shift in motivation and incentive to coerce funding for their own needs, than to worry about ethinic cleansing in some third world country that has nothing to offer them in the first place. Mass genocide is fine, but fossil fuel polution in any form must be stopped, unless of course you write us a check for our foregiveness.
DC