Providing off-grid communities with secure and reliable electricity

June 1st, 2016, Published in Articles: EE Publishers, Articles: Energize

 

Andrew Johnson

Andrew Johnson

Addressing the audience at the South African National Energy Association’s (SANEA’s) inaugural Young Energy Leaders’ Forum (YELF) recently, Andrew Johnson, a member of YELF’s steering committee, said that YELF, as part of SANEA, provides under-35’s in the energy sector an opportunity to interact and develop ideas together.

James van der Walt from Ugesi Gold, speaking from Cape Town via Skype, said that the solar turtle, a product he developed for rural schools, provides secure and reliable electricity to communities which, for one reason or another, do not or cannot receive electricity from the national grid.

The solar turtle is a containerised solar PV system which uses batteries for storage and can be installed at the point of load. The shipping container is used to house the PV panels overnight, and also offers a retail outlet for the recharging of the batteries of cellphones, tablets, etc.

Van der Walt said that the solar turtle could even be used to create a mini-grid in an informal settlement, providing light and battery-charging facilities to the community.

Stanley Lutchman, a co-director of Ugesi Gold, said that a solar photovoltaic (PV) system offers a distributed and independent source of electricity to communities which have no access to the national electricity supply. The benefits of electricity to these communities have been described as “life-changing”. The concept, he said, calls for a local entrepreneur to run the solar turtle as a business, selling electricity in the form of recharging batteries for the local residents.

Gannie Noble, from RexiVista, spoke about a similar PV concept called “Power Turtle”. Again this is built into a shipping container which can store the PV panels to protect them from theft or vandalism. The difference between the solar turtle and the power turtle, Noble said, is that the power turtle’s container is filled with batteries and supplies power continuously. The solar turtle’s batteries are in the hands of the residents and are returned for recharging as required.

Noble said that a typical power turtle unit costs about R600 000. This should be seen as buying 20 years’ electricity in advance as no further costs, apart from simple maintenance, will be payable.

The company’s first project, said Noble, began in August 2015 and was completed in March 2016 at a school in Ekurhuleni. He said that 750 schools, which currently use 6,5 kVA generators, should install power turtles to reduce their monthly expenses while guaranteeing electrical supply. Furthermore, he said, 2700 informal settlements in South Africa all need power turtles to improve the standard of living by removing the need for the use of candles in shacks, enabling internet access via smartphones and creating commercial opportunities within the communities.

Alistair Armstrong, an electrical engineer and owner of AM Solar, gave a presentation of some of the technical aspects of the power turtle. He explained that a 20-foot shipping container can accommodate 16 PV panels, a 8 kW hybrid inverter and a set of 2 V flooded lead-acid (FLA) cells. The battery, he said, forms the backbone of the system. Each unit provides an output of 25 kWh, but is scalable and many units can be connected in parallel to increase the overall output as required.

The FLA cells could be replaced by lithium-ion (Li-ion) cells, Armstrong said, adding that a local company based in Krugersdorp, Freedom Won, manufactures suitable Li-ion cells for this purpose. He said an advantage of Li-ion over FLA cells is their temperature tolerance. The high temperatures present in a shipping container can easily exceed the recommended maximum for FLAs and result in a shortened operational lifespan.

SANEA YELF invites people under the age of 35 who are involved in the energy sector to join the forum.

 

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