Techno-economic analysis of autonomous PV-wind hybrid energy systems using different sizing methods

The sizing and techno-economic optimisation of an autonomous PV-wind hybrid energy system with battery storage is addressed in this article. A novel sizing method is introduced. It is a developed version of similar earlier sizing methods, taking into account a further design parameter. The techno-economic optimisation of autonomous energy systems should include the following design parameters at the same time: the level of autonomy, i.e. the fraction of time for which the specified load can be met, and the cost of the system. Without one of these, the techno-economic optimisation would be incomplete. New concepts, which combine the system autonomy and cost, are also introduced to be used in the techno-economic optimisation process. The sizing of a PV-wind hybrid system on a yearly basis requires a detailed analysis of the solar radiation and wind speed on a monthly basis. It is common to size such renewable systems for the worst month. It is, however, shown that the worst month scenarios lead to too costly and, therefore, non-optimal a system in terms of techno-economics. It is, therefore, suggested that alternative solutions be sought, rather than using the worst month scenario. An alternative method is applied in the present article. It suggests a third energy source (auxiliary source) be incorporated into the system instead of increasing the hardware sizes excessively for the worst month. It is shown that this leads to techno-economically more optimum systems. (C) 2002 Elsevier Science Ltd. All rights reserved.