Generation system reliability is an important factor in the long-term planning for future capacity expansion to make sure that the total installed capacity is enough to support demand. This case is very important for smart cities, because it is focusing on the optimal solution. Whenever the number of days very low, the city called a smart city. The planning process utilizes reliability indices as criteria to decide on new investments in new generation capacities. Generation system reliability can be evaluated by using different indexes. In this study, loss of load probability (LOLP) and Loss of Load Expectation (LOLE) are simulated to evaluate the system reliability effects of the system parameters such as forced outage rate is tested on the LOLP index and LOLE index. The traditional use of LOLE is to determine the required installed capacity, based on expected capacity during peak periods. In addition, the LOLP measures a probability of outages to overall resource adequacy. To determine the amount of electric power capacity for a power plant; both indices, the Loss of Load Expectation (LOLE) and Loss of Load Probability (LOLP) are required. These indices help for the analysis of the plant. By calculating the power capacity, we can obtain the desired reliability target. The LOLE and LOLP calculation involves the combination of both the generation outages and load profiles. The probability of generator-forced outages rate (FOR) is required for the calculation. The expected number of days in the year can be obtained when a shortage might occur. The outage assumed coincident with the daily peak load. The index ‘LOLP’ refers to a probability of outages, where the ‘LOLE’ index describing an expected value. The LOLE index analysis forms the basis of calculating how many particular generators, or group of generators contribute towards planning reserve. The output calculation of this capacity contribution called the effective load carrying capability. © 2019 IEEE.