Customer focused domestic metering

Most manufacturers of electricity metering in the UK provide some form of prepayment variant. Incredible as it may seem, however, very little has been done since the introduction of the microprocessor in electricity metrology to provide the end user – in other words, the consumer – with useful information. Meters are still seen by manufacturers as a tool of the utilities, rather than as a customer interface.

Current Billing System All manufacturers followed the same route in producing electronic meters. They designed electronic equivalents of the tried and trusted electromechanical device (one or two rates) and some even included mechanical registers! Later designs reduced hardware and installation costs by incorporating real-time clocks and relays, thus removing the need for external time-switches. In conjunction with electronic displays, this permitted utilities to indulge in more complex time-of-use tariffs as well as controlling consumers’ loads.

However, displayed information (if it could be called that) was limited to the number of units recorded at each rate, the total units measured, time (and possibly date) and some form of display check. None of these was really meaningful to the majority of consumers.

If you ask electricity consumers what is of real interest to them, they will tell you that they want to pay as little as possible for their electricity and they don’t want any surprises when the bill arrives. (We all consume electricity, and isn’t that what we all want?)


Electronic prepayment, or pay-as-you-go metering, goes some way to providing this information. Meters display the state of the customer’s account (credit or debit); costs per unit for the different rates; fixed charges and debts owed; and their collection rate. If this can be done for prepayment customers, why can’t it be done for all customers? That was the question PRI asked when it decided to enter the domestic metering market.

By updating consumers’ terminals (meters) with the various unit costs and any fixed charges, bills can be calculated and continuously displayed – or called up as required. At the end of a billing period (monthly, bi-monthly or quarterly) the billing data can be transferred from the current register to a billing register for retrieval by the consumer or a meter reader, and the current register can be cleared for the next billing cycle. As very little memory is required to store these readings, a whole year’s worth of billing data can be stored for the consumer’s benefit.

The Self Billing System Clearly, if terminals can calculate billing data, there is no reason why they can’t actually generate the bills themselves. The process of calling up the billing data at the end of each billing period could also produce authentication codes which could be used to validate consumers’ payments (they could be written on the back of cheques, for example). Validation of consumers’ payments would cause consumer-specific release codes to be generated which, when entered into terminals, would allow electricity consumption to continue.

Failure to enter a release code after a prescribed period of time after the billing date would result in terminals disconnecting or limiting a consumer’s load. Sufficient space is available in a 20 digit number to validate payments and to store the advances on up to four unit rates, as well as to indicate if fraud or tampering has taken place.

Thus, for relatively small infrastructure costs, utilities would no longer need to read meters, generate bills or chase payments. The resulting savings in operating costs could be passed on to consumers in reduced unit and/or fixed charges, with consumers further benefiting from billing periods that could be tailored to suit their needs.


Alternatively the same terminals could operate as energy bank accounts, with consumers negotiating individual credit or overdraft terms with their suppliers. Consumers maintaining their terminals in credit would benefit from lower unit costs or a small amount of interest paid on the credit available. Consumers running in debt (overdraft) would pay a higher unit cost or pay interest on any debt owed. Terminals would be programmed to disconnect consumers or limit loads once agreed overdraft limits are exceeded.

Current End Of Tenancy Process Consumers would benefit from this system because they would only pay interest or higher unit charges when in debt. (At present, the current practice of recovering interest on incurred debt is to build it into the tariffs.) Utilities would also benefit from the improved cash flow generated by consumers keeping themselves in credit, to avoid paying higher unit charges or interest.

At the start of this article I touched on prepayment meters. These in essence can be considered consumer terminals, by the nature of the limited information they already provide and the fact that consumers have to interact with them on a regular basis to transfer purchased credit. But even these meters can be improved on to give consumers more meaningful and useful information. Relatively simple calculations and a few bytes of memory can inform consumers of their hourly, daily or even weekly costs of consumption. It’s only a small step from there to estimate the number of days before disconnection occurs, based on average daily consumption.


Disconnection itself could be made more customer focused, particularly in the light of the bad press that prepayment self-disconnection has been receiving. A far better solution would be to progressively limit a consumer’s load as his debt increased. Disconnection would then only occur as a final resort, once the accrued debt had reached a certain value. In this way, consumers would stay connected for longer, much to the relief of electricity consumer groups everywhere, but with more and more inconvenience as their load limit reduced.

At present all electronic prepayment meters in the UK provide some form of emergency credit once normal credit has been used. In essence this itself is the prepayment equivalent of an overdraft, which could easily be adapted to operate in a load-limiting mode.

Taking load limiting further, there is clearly no reason why this could not be used in a profile mode of operation, to provide consumers who have certain budgeting constraints, or utilities with limited generation, with a demand-side management type of domestic tariff.

Only 30-40% of modern meters’ microprocessor capability is used for metrology and general housekeeping functions, which means that a lot of unused functionality is still available. This article has only scratched the surface in discussing what could be provided for consumers – but it must be borne in mind that it is easy to provide meters with numerous bells and whistles from which consumers would receive no benefit. (How many of your video or stereo remote control functions do you actually use?) Consumers like additional functionality – but only if it is of use to them or gives them information which is of use to them. Customer focus groups have already proved this.

Reduced Cost End Of Tenancy Process I have written this article primarily from the electricity metering point of view, but many of the concepts I have covered can be applied to other utility metering. Indeed, there is no reason why one terminal cannot operate as an energy bank account for all utilities, with consumers paying what they like when they like. A single terminal would reduce infrastructure costs, which would be of benefit to all parties, and would provide consumers with one point of reference for all their utility accounts.

The concepts promoted here are not just wishful thinking. PRI’s domestic metering, now on trial, has been developed with the capability of providing this functionality for multi-utility metering in both credit and prepayment modes of operation. We will continue to invest in metering functionality which benefits consumers as well as utilities.