If the charts aren't showing for you, click the following link: http://www.businessinsider.com/peopl...nergy-2012-11#
Here are some charts I found re: Green Energy. They include total startup costs, costs of operation and costs passed to the consumer as well as efficiency (Which is actually reflected in the cost/kWh).
Without further ado...
Solar must reach 10 million megawatts of capacity to become cost competitive. The additional solar power panels would cover 2.25 New Jerseys
There are several others here.
Suffice it to say that the cheapest green energy is far more expensive than the cheapest fossil fuels.
The only exception seems to be nuclear power where costs of generation are competitive with fossil fuels (right around NatGas). If you want renewable energy, however... you're kinda fucked. Not only have solar companies been shitting the bed, current efficiencies (Generally 10-12%) don't allow for extremely efficient use of the land they occupy. Wind turbines seem pretty good, but only onshore and not all areas are suitable for wind power.
If you want clean energy, your best bet is nuclear. Right now solar and other "green" sources can go get fucked with the kinds of prices they're running.