The City of Cape Town has published a guide for commercial customers to sell their excess power back to the city, with the amount of energy that customers can produce limited by the size of their system, which is limited by the size of their connection to the city grid.

The city has also published guidelines for residential customers wanting to sell excess power to it, but these will be available later this year, in addition to the existing credit offset against monthly account.

"The city is first focusing on commercial customers. By December 1, the city had more than 2 600 approved grid-tied installations," says City of Cape Town Energy MCC Beverley van Reenen.

"The registration and authorisation process is free. However, some installers may charge customers to complete the registration process."

Commercial customers that want to sell excess power need to have a photovoltaic system and inverter, installers must apply to the city to authorise the system for grid connection, and the city does not charge an authorisation fee, she notes.

Authorised customers will be placed on the applicable non-residential small-scale embedded generation tariff, and meter changes are required where applicable.

"An additional advance metering infrastructure administration fee may also be applicable, which will be quoted as part of the authorisation process where applicable," she says.

The credit roll out for the initiative is immediate. The city will measure the amount of energy fed into the grid and the credit will be reflected on the monthly municipal account.

Commercial customers will be credited with 60.91c/kWh for the 2022/23 financial year, plus 25c/kWh incentive for each kilowatt-hour fed into the city grid.

Further, the credit is offset against the monthly electricity account and, if some credit remains after the offset, the city will pay this to the customer. Payments will only be made on amounts over R5 000 and on a monthly basis. Amounts of less than R5 000 will be held back until the total exceeds R5 000.

"In the past, commercial customers who produced excess electricity could not sell it back to the city. Following the city receiving a National Treasury exemption, businesses and residents may be paid directly for excess power produced in addition to a 25c/kWh incentive available," says Van Reenen.

Customers can view the City of Cape Town small-scale embedded generation frequently asked questions guide for more information and tips.

Meanwhile, residential customers that want to sell excess power are also required to have a photovoltaic system and inverter, while installers must apply to the city to authorise the system for grid connection.

"Authorised customers need to install a specialised advance metering infrastructure meter, which costs approximately R12 850. The city is looking at how to bring the cost down for households," she noted.

Further, a monthly advance metering infrastructure administration fee will be applicable, and if a resident is not on the Home User tariff already, the resident will be moved to the Home User tariff.

Later in 2023, Cape Town will measure the amount of energy fed into the city grid, and the credit will be reflected on the monthly municipal account. Residential customers will be credited with 78.98c/kWh for the 2022/23 financial year, plus a 25c/kWh incentive for each kWh fed into the city grid.

The credit is offset against total monthly municipal account and all accounts linked to the same business partner number. If some credit remains after the offset, the city will pay this to the customer, but payments will only be made on amounts over R1 000. Amounts of less than R1 000 will be held back until the total exceeds R1 000, and will then be paid once a year.