Electric Power Systems Research, 27 (1993) 233 246 233 Assessment of the economic penetration levels of photovoltaic panels, wind turbine generators and storage batteries M. A. El-Sayes, M. G. Osman and S. S. Kaddah Electrical Power and Machines Department, Faculty of Engineering, Mansoura University, El-Mansoura (Egypt) (Received April 16, 1993) Abstract Assessment of the economic penetration levels of photovoltaic panels (PVPs), wind turbine generators (WTGs) and storage batteries (SBs) into conventional generation systems is the main target of this article. The economic penetration level is that which achieves the maximum permissible reduction in the kWh cost and a certain value of loss-of-load expectation (LOLE) or expected unserved energy (EUE). To carry out this target, the following steps were performed: proposal of an operation strategy for the studied combined (hybrid) system; introduction of the analysis of the LOLE and EUE; and deduction of the mathematical models for estimating the fuel saving, load carrying capability, levelized annual profit and reduction in the kWh cost. The LOLE and EUE of the studied hybrid system were computed for different penetration levels of PVPs, WTGs and SBs. The reductions obtained in the kWh cost were also recorded. The different penetration levels that achieve a specific value of the LOLE or EUE were determined. The economic level was evaluated on the basis of the reduction obtained in the kWh cost. Keywords: hybrid energy system, power system economics, loss-of-load expectation, expected unserved energy, levelized annual profit. 1. Introduction In recent years, emphasis on energy conversion has led to increased interest in the research and development of alternative energy sources. Of all the renewable energy technologies that have been the focus of encouraging governments and private research and development efforts, wind turbine generators (WTGs) and photovoltaic panels (PVPs) appear to be the leading candidates. Their modular nature is an attractive characteristic, both in terms of investment cost and financial risk [5]. At the megawatt generation level, these tech- nologies are relatively new and the methods to predict the reliability of networks including these systems are not mature. As power generation plants using these new technologies are inte- grated into existing power systems it becomes particularly important to evaluate their reliabil- ity and to assess the effects that they will have on the overall system reliability [4]. The basic approaches available for the modelling of fluctu- ating primary energy sources for reliability eval- uation are the multistate unit approach, the load reduction (adjustment) approach, and the Singh- Lago-Gonzalez approach [2]. The fluctuating nature of PVP and WTG out- puts in economic and reliability evaluation has been studied in refs. 3 and 12. Assessment of the economic penetration levels of PVPs, WTGs and storage batteries (SBs) into conventional generation systems is the main target of this paper. The economic penetration level is that which achieves the maximum per- missible reduction in the kWh cost and a specific value of the loss-of-load expectation (LOLE) or the expected unserved energy (EUE). The opera- tion strategy and analyses necessary to compute the LOLE, EUE, fuel saving, load carrying capa- bility, levelized annual profit, and the reduction in the kWh cost of the studied hybrid system are introduced in this paper. 2. Operation strategy of the hybrid system An operation strategy is suggested in this paper for the studied hybrid generation system shown 0378-7796/93/$6.00 (C 1993--Elsevier Sequoia. All rights reserved