I have to agree that the grid in Thailand is one of the dirtiest in the world. However, Thailand is one of best places to install solar - it is close to the equator so gets great solar all year round. Labour rates are very low, so it's cheap to have your panels fitted.
For every ฿100,000 invested in solar you save approximately ฿1,000 per month off your electric bill. That same ฿100,000 sat in the bank at the current interest rate of about 0.5% would give you ฿42 a month of interest to put towards you electric bill. That's why I installed solar to charge my car and power my house