A 1.2 MW solar photovoltaic (PV) plant, positioned on the rooftop of a Cape Town office block, would feed excess electricity into the City of Cape Town’s electrical distribution network.

The Black River Park solar project would sell electricity back to the city for 49.72c/kWh – lower than the rate at which the office park buys electricity from the municipality.

“The approval from the City of Cape Town marks a considerable breakthrough in the pursuit of electricity users who invest in independent power production to sell energy back to the distributors during periods where it is not needed on site,” South African PV Industry Association spokesperson and Sola Future Energy MD Chris Haw said in a statement this week.

South Africa-based Sola was responsible for the design, construction and operation of the project, as well as the procurement of all regulatory approvals.

The roof-mounted solar PV system, in Observatory, was able to generate just under two-million kilowatt-hours a year from about 5 500 modules.

The solar plant formed part of a multifaceted approach to reducing the carbon footprint of the 74 000 m2 office park as it moved to become more “self-reliant and efficient”.

The office park, which hosted more than 100 companies, including the Green Building Council of South Africa, had several greening initiatives on site, including a car-pooling network, reverse osmosis plant for landscaping irrigation and on-site sorting for recycling, explained developer and Black River Park co-shareholder Joubert Rabie.

The park boasted “forward-thinking, environmentally conscious” green lease agreements, which saw landlord and tenant sharing responsibility for the effective running of the building and committing the parties to adopting environment-friendly principles.

The second phase of the project, which comprised a further 500 kW of solar power, was approved after the initial 700 kW plant began operating above expectations in August 2013.