the scheme has been successful about m of swh installed its main advantage lies in the fact that payment through the utility bill reduces risk of credit default steg can cut off supply in case of default and lowers collection costs the customer now legally carries the debt whereas in the earlier version of prosol the installer was the legal debtor the programme was extended in to the tertiary sector it is also beginning to emerge for residential customers under the tpppa model a third party designs builds owns operates and maintains the solar systems and sells back solargenerated electricity to the enduser