JustVisiting : those "embodied energy" studies have a major flaw. In the scenarios where it is physically possible to get those panels onto your roof at a lower cost than the power company charges per watt delivered (it is quite possible to do that today. Go to sunelec.com and just look, there's hundreds of kits that would have a payoff within a decade at normal power prices in a state like Texas), how is the manufacturer of the panels able to provide energy at that low a price. If a solar panel manufacturer could create energy to produce a panel at such a low cost as to break even at the prices they are selling them, they could make more money by selling energy on the open market.
It also doesn't pass another test. Modern solar panels have a higher efficiency rating and a higher lifetime than any photosynthetic organism. (I don't think individual cells in any form of tree last for 20 years). Yet, obviously, the energy provided by photosynthesis at the low efficiency ratings nature is capable of (just a few percent) is enough energy to allow the plant to self replicate and generate an energy surplus.
Please link one of these studies. It needs to have a publication date within the last 5 years to have any realistic validity. I earnestly think that the solution to the world's energy problems is to
1. Develop a solar cell design that requires the least amount of rare earths and other expensive materials while providing good efficiency. There's hundreds of university labs that have published varying designs, it is quite likely that such a design has already be developed.
2. Develop an automated manufacturing process for this cell that can produce it in enormous quantities, with the least human labor inputs possible. Build some of these factories.
3. Begin covering the world's unpopulated deserts with these panels, selling the electricity produced and also using it to run the factory and pay for additional factories.
4. Keep going until we've covered enough desert to run the world off of solar. It's possible to store the energy for the night in many ways, from some types of batteries to electrolyzing water to hydrogen (possibly reforming to methane after that) and then reversing the process. There is enough desert, easily. (the U.S. could run off of 100x100 square of arizona, leaving most of the state empty)
The advantages of doing this are myriad, and I think that ultimately the economics will push power production to this. Solar plants won't require a lot of maintainence, or purchasing of fuel, or many environmental impact mitigation actions (since all you have are static panels on the ground somewhere). One has to optimize and automate the manufacturing of a single solar cell type to an extreme degree, and all panels produced world wide will become cheaper. (versus if you tried to say, make nuclear power plant parts cheap to manufacture...there are thousands of unique parts inside a nuclear plant and each one of them would require a separate effort to optimize, while solar panels are all the same)
