This paper proposes an algorithm to analyze the long-term benefits of Wind Turbine (WT) allocation at the demand side of a power distribution system. The benefits are evaluated based on the wind electricity generation and the avoidance of CO2 emissions. The objective function includes the investment cost, maintenance cost, and the cost of loss reduction, subjective to operating limits and line flow constraints. Taking load growth into account, Particle Swarm Optimization (PSO) with a power flow algorithm is proposed to solve this problem. To enhance the performance of the optimization approach, a load flow model with Equivalent Current Injection (ECI) is used to analyze the power flow of distribution systems. By considering the power generation of WTs, electricity prices, and carbon trading prices, the long-term benefits of the installation of wind turbines in different scenarios are evaluated. Examples of IEEE 69-bus systems are presented to illustrate the efficiency and feasibility of the proposed algorithm. Simulation results can help decision makers in selecting the proper installation sites for WTs, as well as in determining the tradeoff between optimal investment and environmental policy for future electricity and carbon markets. (C) 2013 Elsevier Ltd. All rights reserved.