"Renewables can provide more than enough.  Wind in the US could generate twice the electricity we use now.  The earth receives 100,000 terawatts of solar energy continously from the sun, and humans use the equivalent of 4.5 terawatts on average."

One thing that interests me about renewables is that there seems to be a tacit assumption that, because they're renewable, they don't have a significant downside to their use.

All that solar energy being dumped on the Earth isn't going to waste, for example. Much of it heats the atmosphere and the hydrosphere, which makes conditions amenable for life. I wonder what environmental changes would result if humanity were to capture a significant chunk of solar energy, say 10  or 20 percent (20,000 terawatts), and redirect it through technological infrastructure. Sure, waste heat would contribute to keeping things warm (perhaps too warm!), but it would be distributed through the atmsophere in a different way. Could be detrimental.

I wonder what harnessing 4.5 to 9.0 terawatts via wind energy would due to local environments? Wind turbines tap into fluid momentum, and must produce a lot of friction on airflow. On a massive scale, wind "farms" could, perhaps, alter local wind-climates (at the surface), which may also have some interesting effects on local ecosystems.

Just some ideas. I would like to see more deep thought on just what the true ramifications may be for a full-scale "power-up" on renewables.

-best