Residential Electricity Consumption and Loads Pattern Analysis A. Rosin, H. Hõimoja, T. Möller, M. Lehtla Department of Electrical Drives and Power Electronics, Tallinn University of Technology ABSTRACT: This article analyses household electricity consumption in Estonia. Energy consumption of workday and holiday by loads is discussed. The final part describes the evaluation of feasibility of common investments 1. Introduction According to a report by the U.S. Department of Energy in 2008 [1], 74% of the nation’s electricity consumption occurs in buildings. This represents 39% of the total energy consumption among all sectors. There are two general approaches for energy consumption management in buildings: reducing consumption and shifting consumption [2]. The former can be done through raising awareness among subscribers for more careful consumption patterns as well as constructing more energy efficient buildings [3]. It is different DSM (demand-side management) systems for loads priority based scheduling [4, 5, and 6], which feasibility is questionable. For small customers/households exists very simple and fast profitable solutions for energy consumption costs reducing (for example in household device integrated scheduling functionality), just before the investments must be analyzed consumption patterns. Electricity consumption in the households and the service sector in Estonia makes up about 62% of the total consumption. Electrical energy consumption of households is about 27% of the total energy consumption. Use of the multi-tariff system with large tariff differences is a major factor in changing customer habits and behaviour. It is important to take into account all the preferences of a customer, like minimized electricity cost, habits, convenience, high quality and availability. To provide convenience and reduce residential electricity costs in the real-time or multi-tariff system, it is required to investigate the load/consumption patterns, customer behaviour and behavioural predictability to develop optimal control methods, which take into account customer habits and load differences. The inquiry of household owners and energy consumption analysis has shown low awareness about the energy consumption of loads, consumption shifting possibilities and feasibility. About 80% of household owners know that using saving bulbs and consumption shifting to the low tariff period reduces the costs. But less than 20% of people are not aware of consumption distribution between the loads like lighting, water heating etc; high and low tariff consumption distribution by loads; investments feasibility of energy consumption shifting or energy saving devices. In the household without energy generation units, the main cost reducing possibilities are shifting of loads and/or replacing the less efficient loads with more efficient ones. Profitability of load replacing depends on energy costs, consumption amount, investments (replacement costs), exploitation costs and lifetime of the device. The shifting profitability depends on load priorities and storage possibilities. The household consumption is not a homogenous group, the different appliances has different regimes, priorities and roles [9]. Authors have opinion, that consumption priorities can be divided into three main groups: not shiftable (I), almost shiftable (II), and shiftable (III). Shiftable loads can be defined as loads that can be shifted from a high tariff period to a low tariff period without any investments to additional electrical or thermal energy storage systems. Shiftability is closely related to customer’s needs or convenience and depends on the functional possibilities of the loads, technical characteristics and surrounding environment (including building construction). For example, living room windows on the west side of a building will reduce lighting costs. By shiftability, most loads can be divided into three priority groups: I – cooking stoves, kitchen ventilation, coffee machines (without thermos), bathroom lighting and ventilation, TV sets, PCs with modem, home cinema and audio systems, and local lighting. II – lighting, refrigerators, boiling kettles, coffee machines (with thermos), vacuum cleaners, electric irons, and floor heating for drying purposes. III – water heaters, washing machines, dishwashers, and floor heating for heating purposes. 2. Loads Classification The object of analysis was a 3-room (67.4 m2) apartment with four habitants (2 adults, 2 children). The object built in 2005 has a two-tariff energy measurement system. The high tariff period in the winter time is on the workday from 7 to 11 o’clock (on the summer time from