Intelligent billing system improves electricity utilities' efficiency

New billing system has been introduced by Landis & Gyr, and acceptance, reliability and efficiency are being tested by two Swiss electricity utilities in a two-year pilot project which got off the ground in spring 1997.

The Baden Municipal Works, a medium-sized operation, is testing the system with 50 volunteer customers. The department hopes the pilot project will provide important information as to whether the payment system will allow it to meet present-day competitive challenges. Initial results are promising and, if the system works well , Baden may introduce it for its household segment .

The second trial involves a cantonal works department, which is testing the system for acceptance and functionality in a mixed area of 300 household, commercial and service electricity consumers.

The new system reduces administrative and service costs and improves efficiency and competitiveness in deregulated markets. For the utilities this means an improvement in cash flow. With the gradual deregulation and liberalisation of the traditionally state-controlled energy supply business, more and more power utilities are focusing on commercial processes. And they are finding a growing demand for innovative instruments to simplify operations, cut costs and ensure rapid payment for services rendered.

Landis & Gyr identified these customer needs and, together with British Gas, developed the payment system for the deregulated British market. The system has proved itself in over a million gas meters and several hundred thousand electricity meters. It transfers payment flexibility – and thus greater responsibility – to the end customer. It eliminates expensive customer book-keeping, simplifies the processing of power consumption data and streamlines customer administration.It also allows the customer to set the amount and pace of payments.


The payment system consists of an electricity meter with a card reader, a smart card as the communication medium, a crediting unit and a central crediting computer, as well as a controller that acts as the control unit for the utility.

The system’s core is the smart card, which ensures communication between the electricity meter and the utility. The customer reads a chosen amount of credit into his smart card from the crediting unit. At home the card is inserted into the meter and the amount on the card is credited to the customer as a supply of electricity. The customer’s actual kilowatt consumption is deducted from this supply.

Every time the card is charged, data of relevance to the utility and the meter is exchanged. The utility transmits information to the crediting unit, from where it is transferred via the crediting terminal to the smart card the next time the card is charged.

At the same time, the meter data stored on the smart card is read by the crediting unit. The central crediting computer usually downloads this meter data once a day via modem and transmits it to the controller and thus to the utility.

The meter is a version of Landis & Gyr’s ZMB 120 household meter; more than a million of these units have already been sold in Europe. It consists of three integrated measurement units (DFS), a tariff device, a card reader and it has a 100 A switch per phase. The casing dimensions are standard, which allows simple installation.

Billing can be based either on time (basic charge) or on actual consumption. Flexibility is guaranteed by the different payment modes – prepayment, limited credit, weekly payment and credit mode. In the prepayment mode, the meter supplies electricity to the customer only if a credit is available in the internal memory. Once the credit has been used up, the meter is automatically cut off from the network. The customer can push a button to activate an emergency credit until a new credit is loaded, and the process of loading credit also recharges the emergency credit. By pushing a second button, the consumer can display information about the meter reading, the amount of credit still available, the amount of the emergency credit and tariff data.

In the limited credit mode, the customer is allowed to owe the utility a prearranged amount. The meter is cut off from the network when this limit is reached.

The customer who uses the weekly payment mode pays a fixed weekly amount. The meter is not cut off from the network unless payment arrears exceed, say, six weeks.

Finally, the credit mode involves no direct payment. The energy consumed is measured and displayed on the meter, and the meter data can be read off the smart card before the regular electricity bill is sent. In all modes the meter is especially programmed to ensure that the power is never shut off overnight.


As soon as the smart card is inserted into the meter, a two-way data exchange takes place. Information passed from the card to the meter includes the amount of credit purchased, tariff changes and commands and messages. Meter data such as the reading in kilowatts or francs and error and status messages flow from the meter to the card. The smart card can be used to reprogram the meter with several tariffs.

The crediting unit, about the size of a credit card terminal, is a peripheral device which can be located in a kiosk. The crediting unit allows data to be transferred to and from the customer’s smart card.

The utility’s controller sends data (general tariff information and customer-specific commands) via modem to the central crediting computer. This in turn calls all crediting units to download bookings, messages, customer information, selected meter data and any error messages and to report the new data back to the utility’s controller. The central crediting computer generates customer-specific commands, feeds in tariff changes, adjusts emergency credit limits and generates statistics. It also manages all relevant data on behalf of the utility and processes it to meet its needs.