Analysis of the Transition to 100% Renewable Energy on St. Helena

St. Helena is a British Overseas Territory in the South Atlantic Ocean with a population of around 5,000. Most electricity is generated through thermal engines, although small wind and solar farms (Figure 1) are used to augment these, currently contributing 30% of the annual electrical energy demand. SHG has set an ambitious target for all of its electrical power to be sourced from renewables by 2022 [1]. To become completely energy independent however, St. Helena’s electrical grid must be substantially overhauled to be able to support new renewable generators and storage elements, together with demand-side management of large industrial loads and intelligent residential usage.

While the total energy picture on St. Helena is very different from the UK, domestic electricity usage is becoming similar to that of the average British household. The scale of the grid also makes it highly accessible – it is small enough to be modelled at very high resolution while large and diverse enough to provide stochastically relevant usage information. As such, St. Helena provides a unique case study from which lessons immediately relevant to larger nations can be drawn. Large power grids will need to address issues similar to those faced by St. Helena in order to move towards higher renewable penetration and increasingly distributed generation. For example, a key challenge facing the renewable energy sector worldwide is maintaining grid stability and security of supply as a small number of large high-inertia generators are replaced with several physically small, mechanical and electrical dynamic, distributed sources.