20 Mar '14 20:29>2 edits
At the moment, according to this link, this seems more true for wind than solar power although, because the cost of manufacturing solar panels is steadily going down all the time, the prospects for both having extremely rapid cost-effective growth is looking good. It may not be very long before 99% of all our energy will comes from renewables!
http://phys.org/news/2014-03-farms-society-surplus-reliable-energy.html
"...The worldwide demand for solar and wind power continues to skyrocket. Since 2009, global solar photovoltaic installations have increased about 40 percent a year on average, and the installed capacity of wind turbines has doubled.
...
At issue is whether renewable energy supplies, such as wind power and solar photovoltaics, produce enough energy to fuel both their own growth and the growth of the necessary energy storage industry.
"Whenever you build a new technology, you have to invest a large amount of energy up front," said Michael Dale, a research associate at Stanford. "Studies show that wind turbines and solar photovoltaic installations now produce more energy than they consume. The question is, how much additional grid-scale storage can the wind and solar industries afford and still remain net energy providers to the electrical grid?"
...
from an energetic perspective, the wind industry can easily afford lots of storage, enough to provide more than three days of uninterrupted power. However, the study also revealed that the solar industry can afford only about 24 hours of energy storage. That's because it takes more energy to manufacture solar panels than wind turbines.
....
"Within a few months, a wind turbine generates enough electricity to pay back all of the energy it took to build it,"
...
"
http://phys.org/news/2014-03-farms-society-surplus-reliable-energy.html
"...The worldwide demand for solar and wind power continues to skyrocket. Since 2009, global solar photovoltaic installations have increased about 40 percent a year on average, and the installed capacity of wind turbines has doubled.
...
At issue is whether renewable energy supplies, such as wind power and solar photovoltaics, produce enough energy to fuel both their own growth and the growth of the necessary energy storage industry.
"Whenever you build a new technology, you have to invest a large amount of energy up front," said Michael Dale, a research associate at Stanford. "Studies show that wind turbines and solar photovoltaic installations now produce more energy than they consume. The question is, how much additional grid-scale storage can the wind and solar industries afford and still remain net energy providers to the electrical grid?"
...
from an energetic perspective, the wind industry can easily afford lots of storage, enough to provide more than three days of uninterrupted power. However, the study also revealed that the solar industry can afford only about 24 hours of energy storage. That's because it takes more energy to manufacture solar panels than wind turbines.
....
"Within a few months, a wind turbine generates enough electricity to pay back all of the energy it took to build it,"
...
"