African Utility Week to provide site visit to view Robben Island solar microgrid in action
Robben Island is renowned for being the place where South Africa’s first democratically elected president, Nelson Mandela (‘Madiba’), was jailed for 18 years of his 27-year prison sentence. Keeping in line with Madeba’s vision for a better future, the UNESCO World Heritage Site has recently adopted a sustainable blueprint for its diverse eco-system.
The National Department of Tourism (DoT) commissioned a solar microgrid, awarding Cape Town-based SOLA Future Energy an EPC contract to design and construct a solar energy microgrid to reduce the island’s dependency on expensive heavy fuel oil. The project is the first of its kind on an island as part of a grid resolution, among other things, aimed at reducing the carbon footprint. The system consists of a solar photovoltaic (PV) farm, combined with a lithium-ion battery storage facility and smart controllers to ensure a seamless electricity supply, whilst significantly reducing the island’s fossil fuel consumption.
Robben Island has an energy usage profile that comprises residential needs, desalination, harbour and offices; in total, the island uses almost 2M kWh of electricity annually. The solar microgrid, which comprises 1,960 Canadian Solar (CS6U-M-340 W) high efficiency modules, will produce almost 1M kWh of electricity annually, significantly reducing the costs of buying diesel and transporting it to the island.
The solar microgrid will reduce the island’s fossil fuel consumption by 235,000 litres of diesel per annum or 50% of previous usage. This will result in a reduction of the site’s carbon emission by at least 820 tonnes, and will save the island money during its 25 years of operation. The solar microgrid consists of three power production elements; the solar PV farm consists of 1,960 mono-crystalline modules with a total of 666.4kW power supply. The battery bank, consisting of 2,420 lithium-ion battery cells, is able to store 837kWh with a maximum output of 500kVA. The third power production element is the diesel generators, which are used when no solar or battery storage is available. Multiple controllers between these power production elements are said to balance the power supply and create a smart microgrid, ensuring a seamless supply of power. Due to the high salt content in the air, a material called 3CR12 was used as it is similar to stainless steel; however it can withstand rust from the corrosive nature of sea salt in the air.
In addition to being rich in political history, Robben Island is home to several bird species seeking refuge and breeding grounds on its shores. A refuge for the African jackass penguin – an endangered bird found only on the southern coast of Africa – meant the project design had to adhere to strict environmental standards and requirements. Environmental and archaeological permits were required to commence construction in addition to installing penguin-proof fences and bird-proof wires to protect both the animals and the solar panel wires. The EPC staff were required to attend specialist training in case they had an encounter with any wildlife or had to handle any archaeological artefacts that might be discovered underground.