Operation cost minimization of photovoltaic-wind-diesel-battery hybrid systems using “continuous” and “on-off” control strategies

In this paper, two control strategies involving “continuous” and “ON/OFF” operation of the diesel generator in the solar photovoltaic-wind-diesel-battery hybrid systems are modeled. The objective of these proposed models is to minimize the system´s daily operation cost while finding the optimal power flow considering the intermittent solar and wind resources, the battery state of charge and the fluctuating load demand. The non-linearity of the load demand, the non-linearity of the diesel generator fuel consumption curve as well as the battery operation limits have been considered in the development of the models. The simulations have been performed using “fmincon” for the continuous operation and “intlinprog” for the ON/OFF operation strategy implemented in Matlab. These models have been applied to two case studies; the results are compared to the scenario where the diesel generator is used alone to supply the same load demand. The results show that using the developed photovoltaic-wind-diesel-battery optimal operation control models, significant fuel saving can be achieved compared to the case where the diesel is used alone to supply the same load requirements.