Cost-efficient strategy for high renewable energy penetration in isolated power systems

Remote areas and islands isolated from the main electric power system ensure reliability and stability of power supply using diesel generation. Due to the high purchase and transportation costs of diesel fuel, isolated communities are exploring other options for efficient and reliable power supply. Renewable energy sources can reduce operating costs, although are unable to achieve high penetration without expensive and complex enabling technologies such as energy storage. Furthermore, the stochastic and intermittent nature of renewable sources (i.e., wind and solar) makes the control system complex, decreasing power system reliability and requiring highly qualified personnel in local control centres. The problem becomes particularly acute when diesel engines are forced to operate at partial load, resulting in poor combustion efficiency and potential engine damage. This paper suggests a fuel-efficient control strategy, adopting low load diesel application to reduce fuel consumption and improve renewable energy penetration without overcomplicating the control architecture. A mathematical model is initially developed, then validated against real data, to facilitate comparative assessment of various control approaches. Optimised control methodologies are shown to deliver fuel savings of 16.7%, with a 14% increase in renewable energy penetration, in comparison to conventional management.