It is a characteristic feature for the supply of electricity, gas and water, that consumption metering must be made through reading/registering by means of a meter device at the customer\'s premises. Manual reading of the customer\'s consumption is costly, and connected with error sources.

Two-way communication with electricity customers has been made topical as a consequence of the deregulation of the power market. There exists a need for being able to offer power-based energy products, and there is also a need to be able to make less labor-intensive measurements of the energy consumption.

The present invention has as a starting point a method implying that a) accumulated consumption of electricity, gas or water is recorded by a meter device localized at the customer\'s premises, b) consumption data are recorded per time unit, for example electricity consumption per year, month, week, day, hour or minute, and the consumption data are recorded in a logging unit connected to the consumption meter device, and c) the consumption data are reported from the logging unit via a communi- cation unit providing telecommunication, to a central data base.

In order to establish measurements that depend on the time moment, it is of central importance to establish correct and synchronized time in the system. The system described in patent publication WO 99/65169 provides a summary on how to synchronize time in a system consisting of a central data base and communi- cation units communicating in a wireless communications network.

The object of the invention is to simplify the measurement of electricity consumption (as well as consumption of gas and water) and to make the measure- ment more effective, and further to enable more effective transactions toward end customer.

More specifically, the first object is to give to the customer, or possibly to a central customer service, a possibility to decide which time unit shall be the basis for consumption logging.

The second objective is to provide for a lesser need of data storage space in the logging and communication unit.

The third objective is to reduce the report frequency, i. e. the number of calls between the logging and communication units and the central data base.

The fourth objective is to give the customer an opportunity to make additional measurements and additional reports as desired and needed.

The above mentioned objectives are achieved through a method such as stated in the introduction, which method is characterized by the following features: d) the time unit can be set freely, for example to be one hour, e) only the difference between consumption at the start and end of the time unit is recorded, report intervals and report time points are determined on order from the customer through a terminal connected to the central data base, and g) the exchange of consumption data between the central data base and power companies and bank payment centrals are also determined on order from the customer through a terminal connected to the central data base.

Other preferable features of the method in accordance with the invention, appear from the dependent claims. The invention also comprises a system such as stated in the appended patent claim 10.

In the appended fig. 1 appears a sketch of a system in which the method of the invention can be practiced.

An electricity meter device I is connected to a logging and communication unit 11 through an ordinary low current cable (a) that is connected to the SO interface of the electricity meter.

The logging and communication unit 11 is connected, in a wireless manner, via GSM/SMS, satellite or some other wireless network, to the database III of the central system, which data base has in its turn a telecommunications connection e, f to energy suppliers V and bank payment central VI.

The customer, or possibly the customer service center, has an internet or intranet connection c through terminal IV to the central data base III to be able to receive an updated data basis, and to be able to perform transactions, and additionally an opportunity is provided for wireless telephone connection directly to the logging and communication unit through the mobile telecommunications network.