Greener power supply in the Seychelles

South of the equator, on the western Indian Ocean, the Seychelles are located in a tropical idyll. With its dream beaches, the archipelago is considered a holiday paradise. But climate change does not stop at an island paradise - rising sea levels and increasingly extreme weather events threaten the existence of the small islands. In order to preserve the idyll in the long term, sustainable solutions must be created. To this end, the island nation is relying on green energy: a 50,000 square metre solar park with a total output of 6 megawatts was built on Île De Romainville in front of the capital Victoria on Mahé. In addition, there are five wind turbines with an output of 750 kilowatts each.

Previously, electricity on Mahé was generated almost exclusively from fossil fuels. Now, the huge solar park and wind turbines ensure that seven million kilowatt hours of green electricity are generated every year - enough for around 2,000 households.

mtu EnergyPacks stabilise the grid when the sun is not shining

"The Seychelles, with its many hours of sunshine and exposed location, is the ideal location for photovoltaic systems and wind turbines," says Alexander Wahlig, Senior Systems Engineer at Rolls-Royce. But even in the island paradise, the sun does not always shine and the wind does not always blow. This leads to fluctuations in electricity production which poses stress on the power generators and utility grid. "And that's where our mtu EnergyPacks come in," says Wahlig. With an output of 5,100 kVA and a storage capacity of 3,363 kWh, they ensure that the fluctuations in generation are balanced and the security of supply is increased.    

mtu microgrid controller defines power setpoints for the EnergyPacks

The heart of the mtu system is a microgrid controller. It has access to the measurement of the generated power of the PV system and the wind turbines. As soon as they fluctuate, the EnergyPacks are charged or discharged to compensate for the fluctuations. The goal: The sum of the power of the renewable energy system and the EnergyPacks must be constant or may only change very slowly. This increases reliability for the grid operator and makes it much easier to control the fossil-fuelled generators. But the mtu EnergyPacks have another task: they compensate for unexpected frequency fluctuations and step in within milliseconds if, for example, a generator unexpectedly fails or a part of the grid unexpectedly disconnects due to a fault. Alexander Wahlig remembers well when a generator suddenly failed in the middle of the night during commissioning - five megawatts and thus about 20 per cent of the total generation at that time broke away without warning. "Without our mtu EnergyPacks, this failure would have caused severe fluctuations in the island's grid frequency," he says. But the batteries stepped in and were able to compensate for half the power in less than 100 milliseconds through decentralised frequency control, significantly reducing fluctuations in the power grid.  

mtu EnergyPacks ensure reliability

"With the mtu EnergyPacks, the generated power of the solar power plant gains significantly in reliability for us. They ensure that the power supply on the island remains stable and thus form the backbone of our green energy production," says Dr Laurent Sam of Public Utilities Corporation, the grid operator in Seychelles.