Solar shouldn't be only for people who own a roof.

Rahul Rajan grew up around his father's construction business in Pune, watching buildings rise from bare plots. He went on to study civil engineering at the University of Western Australia, then came home to build.

One thing kept bothering him. An enormous amount of sunshine lands on Indian rooftops every single day, yet the families living in flats under those roofs could not use any of it. Rooftop solar stayed a privilege for people with a bungalow and a roof of their own.

So in 2019 he bet an entire building on a different idea: Scorpio, Fortune Estates. Instead of installing solar that only powers staircases and lobbies, he invented the Smart Power Distribution Unit (SPDU) there, so every one of the building's 24 families gets its own metered share of the rooftop. Each home receives 100 free units of electricity every month.

The flats sold at market price, with zero green premium. The building became India's first net energy positive affordable housing project, earned the IGBC Platinum rating, and won national awards. Today it is taught as a Harvard Business Publishing case study authored by IIM Bangalore.

Protostar Technologies was spun off to bring that same technology to existing buildings everywhere. Today 300 flats run on it, and we are just getting started.