When researching for a good solar panel installer, don't forget the Internet. Yes you may start out in the phone book, but the Internet will give you a lot more information as well. You may find testimonials from other clients and ideas for contractors that you may not have realized are out there.
Goa To Get 100MW Renewable Solar Energy: Cabinet Approves Solar Policy Plan.
Ask your solar panel vendor about the certifications they have and about the testing of the panels you are interested in. You might qualified for some rebates offered by the government if you go through a certified vendor and choose panels that have received certifications too. Besides, this is a good way to make sure you are getting a quality product.