As the title says: There are countless ways to manufacture solar panels, but there's only one metric that counts: how the cost of solar power compares with that of electricity from fossil fuels. Until energy from the sun can beat energy from coal at the marketplace, solar will remain a niche player, adorning the rooftops of those who care more for their green reputation than for their bottom lines. Enter Nanosolar, a San Jose-based start-up that manufactures thin-film solar panels. Unlike the bulky silicon panels that dominate the solar market, Nanosolar thin-film technology is light and extremely cheap to make. The key is the manufacturing process: while silicon panels need to be baked in batches, Nanosolar's thin-film panels roll off the assembly line, as if from a printing press.

In a revolutionary leap that could transform solar power from a marginal, boutique alternative into a mainstream energy source, MIT researchers have overcome a major barrier to large-scale solar power: storing energy for use when the sun doesn't shine.

Click To Play

Now now... can somebody tell why solar energy did not become ubiquitous in the World? The answer is very simple, it's expensive. Typically a house needs 3KW per hour of energy, and to achieve that with solar panels you would spend about $40,000 $34,000. Even with the 55% incentive that the Italian government gives you it's nearly impossible to consider it affordable for an average family. The rest of the world offers has slightly similar conditions, some a bit better and some other a bit worse.

The bottom line is: Solar power is way too expensive to be used at a large scale. A typical installation will need circa 20 12 years to recover the cost and start saving money. That of course does not take into account the whole picture, in fact the entropy of the system dramatically decreases, having no oil, no coal, no nuclear waste, no CO2 emissions and so on you are actually living sustainably as far as the environment is concerned.