No, it's not possible to stop paying for energy. If you look at those solar energy devices in the link you gave, you can see that they represent major engineering projects. The initial capital costs are large, and there are of course some upkeep costs. For example, big arrays of computer-controlled mirrors are not cheap, and they have to be kept clean, free of mechanical problems, etc. The power transmission grid for those generators also is expensive. The photovoltaic solar panels are still expensive, too. Since power is needed at night and on cloudy days, some sort of energy storage devices would also be needed.
Still, the net long-term costs of building more solar power sources like those may end up far lower than the net long-term costs of simply burning more coal. Most of the short-term pollution associated with fossil fuel use would be avoided. More importantly, the longer-term costs of altering the climate via CO2
emissions would be avoided.
On your other question, solar cells work well now but it should be possible to gradually improve their performance and reduce their large manufacturing costs.
In sum, "There's no such thing as a free lunch".
(published on 06/04/2011)