The company is presently finalizing a deal with a large insurance company who are investing their pension fund in solar energy funded by domestic installations. The profit ( now reduced from around 25%) returned is around 12%.
Solar panels have got much cheaper and more efficient and as someone else pointed out have a long life.
Energy is seen by many as a good investment platform and inroads into solar farms are already being made in parts of Thailand.When and if the Thai government starts to realise the potential and some MP or similar works out that money is to be made encouraging consumers to "go green" we may see the same opportunity that Europe is having such as grant increased feed in tariffs.
Even without this help a system connected to the grid that would pay for itself in 5 years and have a life of around 20 years sound like good news to me.

And another poster quoted that the west has far higher electricity rates? This may be true but consumption with pools and aircon make for higher consumption and and percentage saving must be considered imo.My bill is around 12000 Baht per month - 10% saving through solar ( a conservative estimate ) would pocket me 15000 Baht per year its a start.