Website / Application for counting power consumption

We need to develop a website on php/mysql with a nice and user friendly interface that will do the following. This is the scenario: In a city we have various buildings and infrastructure that we need to observe the consumption in: Power, Gas and Teleheating. So we need an small web based information system that will let our team enter the yearly amounts of power, gas and teleheating consumed so that we can produce statistics on their usage. Our effort is to reduce the consumption over the years, so we need an easy way of entering the data for every unit (either this is a School, a Hospital, City Lights, Vehicles etc). So we will have some specific categories of units. Example: Schools - School 1 Town 1 - School 3 Village 2 - Main School of the City Hospitals - Main Hospital - Medical Care Unit 1 Vehicles - BMW k232 - Mercedes h4333 We need employees with the role of "USER" to be in charge of specific units and be able to add consumptions for power, petroleum and teleheating per year. Then the administrator can produce graphs according to specific fiters. Exampe: - Show me the consumptions of power for Schools - Show me the overall consumption of petroleum over the years - Show me the last 3 years etc... Administrators should be able to: - View Stats - Add/Edit Users - Add/Edit Units - Add/Edit Categories Roles of users: Administrator User Language: The system should be made in english but all the text within the system should be pure text and should be set as variables, made in an easy way that i can translate the system in greek easily. So there should be a file [login to view URL] and a file [login to view URL] (where i can translate in greek).