No load diesel application to maximise renewable energy penetration in offgrid hybrid systems

Globally diesel generators provide the mainstay of off-grid power supply for remote and isolated consumers. Diesel generators are selected for this role given a variety of considerations, including capital cost, technology risk and engineering support. Increasingly, however, consumers are seeking alternative generation solutions, to address the high cost and environmental emissions associated with diesel generation. Renewable energy integration is one common solution, with a hybrid power system (HPS), combining both diesel and renewable generation, able to reduce both operational cost and environmental emissions. In recent times renewable generation costs have fallen, while diesel costs have risen. A natural response is to increase the amount of HPS renewable penetration, a scenario with potential to place generators in conflict. Such conflict arises when the available renewable penetration exceeds the low load limit of the diesel generators. Under high renewable penetration, diesel load set points produce surplus generation, which must be absorbed via regulating devices such as dump loads or energy storages systems. Hence systems configured for high renewable penetration currently involve increased complexity, expense and waste. The paper presents a power system model for low load diesel integration finding that such an approach can reduce the cost and complexity of HPS seeking high renewable penetration.