What is Open Access Power Purchase mode?

India Electricity Act 2003 allows any HT consumer to purchase power from anywhere in Open source.  Any HT (High Tension line) consumer can purchase power from private power producer. This mode of power purchase called Open Access Power purchase or Third-party power Purchase. Customer can avail power from any sources like Windpower, Thermal Power, Solar Power, and Biomass Power through Open Access Thirty Mode.