Abstract Load forecasting plays an important role in power system operation and development. Mastering load variation and selecting the appropriate load forecasting model is the key to improve the accuracy of load forecasting. Load forecasting is one of the important tasks of power utilities. It can be divided into short term load forecasting, Ultra-short-term load forecasting and mid-long term load forecasting, according to the forecast period. Mid-long term load forecasting ,which is judged by year ,is the important basis of the work for power scheme, production and operation. Accurate load forecasting will help improve security and stability of power system, reduce the cost of generating electricity effectively , ensure power requirement, reinforce power reliability, and increase the economical and social benefit of power system. This thesis has studied the mid-long term load forecasting theory and its application, and introduced the purpose, significance and domestic and foreign research trend briefly. And then the detailed classification of load forecasting, load forecasting methods and their characteristics, application conditions, and the main factors affecting the load forecast, etc. have been discussed. The electricity consumption projections of dapu in 2011-2013 have been carried out as a practical example based on some appropriate methods. In this thesis, electricity elasticity coefficient method, is used to mid-long term forecast the electricity consumption of dapu city with the historical data in 2006-2010..
