WO2002099759A2

WO2002099759A2 - Improvements in or relating to a utility prepayment systems

Info

Publication number: WO2002099759A2
Application number: PCT/EP2002/006183
Authority: WO
Inventors: Francesco Ricci
Original assignee: Siemens Metering Limited
Priority date: 2001-06-01
Filing date: 2002-05-31
Publication date: 2002-12-12
Also published as: GB2376125B; GB0113328D0; AU2002319197A1; WO2002099759A3; GB2376125A

Abstract

The present invention relates to a utility prepayment system and a method for purchasing an amount of one or more utility commodities. More specifically the present invention discloses a prepayment system and method for purchasing of one or more commodities in which an amount of commodity allowance is paid for in advance. Certain methods of prepaying for utilities exist in which a consumer purchases a monetary amount of gas or electricity. The monetary amount of credit is stored on a consumer's smart card. The invention provides a utility prepayment system comprising a central processing unit (CPU) in operable association with a plurality of suppliers for one or more commodities. A remote commodity management unit (RCMU) or consumer unit is in operable connection with one or more commodity meters to receive an indication of a commodity flow of a respective commodity. The RCMU includes means to enable a commodity flow of said one or more commodities and storage means to store a value of an amount of commodity allowance units (CAU). The CPU is operable to provide commodity allowance units relating to an amount of commodity in exchange for a monetary value.

Description

IMPROVEMENTS IN OR RELATING TO A UTILITY

PREPAYMENT SYSTEM

Field of the Invention

The present invention relates to a utility prepayment system and a method for purchasing an amount of one or more utility commodities. More specifically the present invention discloses a prepayment system and method for purchasing one or more commodities in which an amount of commodity allowance is paid for in advance.

Background to the Invention

Certain methods of prepaying for utilities exist in which a consumer purchases a monetary amount of gas or electricity. This is usually specified in Pounds (Sterling) or some other suitable currency such as Euros. The monetary amount of credit is stored on a consumer's token/card which may comprise a paper card with a magnetic data strip or a plastics card with a magnetic strip which may be re-usable. The card may be a "smart" card in that there is a two-way transfer of data between a meter and a machine which credits the smart card with a monetary amount. When the card is placed into an appropriate slot associated with a consumer's gas or electricity meter, gas or electricity is allowed to flow up to the monetary value stored on the card. The charge rate for each unit of gas or electricity is set by the supplier and programmed into the gas or electricity meter.

The rate can vary depending on the market conditions. If the rate changes the supplier has to adapt the charge rate for each unit of gas or electricity in the respective gas or electricity meter. This results in much effort being spent by the commodity supplier, especially if the charge rate changes on a day by day basis. Further, if the consumer chooses a prepayment method to purchase a plurality of commodities he has to check on the different commodity meters to realise in a timely fashion, whether the respective commodity allowance units for any of the commodities are running low. Then he has to purchase new commodity allowance units to recharge the respective commodity meter.

Object to the invention

The present invention seeks to provide an improved utility prepayment system. It is an object of the present invention to provide a utility prepayment system which allows the consumer to purchase one or more commodities according to an associated supplier tariff given by a supplier.

Statement of the Invention

According to one aspect of the present invention there is provided a utility prepayment system comprising: a central processing unit (CPU) operatively associated with a plurality of suppliers for one or more commodities, a plurality of commodity meters; a plurality of remote commodity management units (RCMU) operatively connected to one or more commodity meters, and storage means to store a value of an amount of commodity allowance units (CAU), wherein the CPU is operable to provide commodity allowance units purchased in exchange for an amount of monetary value, wherein the amount of said commodity allowance units provided is dependent upon one or more variable commodity ratios (CR), each commodity ratio being related to a specified amount of commodity allowance units per unit of commodity the price per unit of a commodity (PU), and the monetary value (MV), as defined by the following equation:

^_n PU*CAU MV wherein each commodity meter, in communication with an associated remote commodity management unit and storage means, is operable to enable a commodity flow of a respective commodity in an amount relative to said stored value of said amount of commodity allowance units.

The amount of commodity allowance units CAUs can be calculated by taking into account the commodity ratios of the commodities that are being consumed, the price of each commodity and the selected monetary value according to the following:

CAU _Total — CAU _OLD + CAU _NEW ',

where :

CRi is the commodity ratio of the first commodity, and;

PUi is the price per specified unit of the first commodity.

An advantage of the present invention is that the prepayment system can be substantially independent of the value of the monetary and/or energy units in which the commodity consumption is measured. By providing commodity allowance units and commodity ratios the prepayment system can be easily adapted to changes in tariffs, measurement units of the respective commodity and number of commodities to be supplied by the prepayment system. For example, changes in supplier tariffs can be accommodated by adapting the commodity ratio or the amount of commodity allowance units. Supplier tariff changes in a prepayment system where the commodity allowance units are used for more than one commodity can be accommodated by a recalculation of the commodity ratios and the commodity allowance units.

A remote commodity management unit (RCMU) can be located close to the place where the commodity is used and is preferably associated with a specific consumer or household wherein the used commodities are commonly paid for.

The storage means can be operable to store at least one commodity ratio, so that the commodity ratios can be changed during operation of the prepayment system.

The system can be operable to enable the flow of one or more commodities wherein the respective commodity ratio for each is related tό„ the respective commodity. Thus each of the selected commodities can have at least one commodity ratio associated therewith wherein the at least one commodity ratio determines the amount of commodity allowance units relative to each unit of the respective commodity, for example, m³, kWh etc.

The system can also further comprise receiving means which can be operatively connected to said CPU to receive commodity allowance units remaining in said storage means. The receiving means allows the CPU to be connected to, for example, a remote commodity management unit to receive data indicating the remaining commodity allowance units for a calculation of new commodity ratios and new commodity allowance units.

Upon the purchase of further commodity allowance units, the newly purchased commodity allowance units can be added to the commodity allowance units already purchased provided that no item of the supplier tariff data has changed. If one or more items of supplier tariff data have changed, then the commodity allowance units have to be recalculated by taking into account the commodity ratios which have been used for the calculation of the commodity allowance units remaining in the system. The system then calculates new commodity ratios associated with a new total of commodity allowance units including the commodity allowance units remaining and the newly purchased commodity allowance units which were purchased at a different supplier tariff.

Preferably, the RCMU includes means for indicating the amount of commodity allowance units remaining in said storage means, so that the consumer gets an indication of how long or of what amount he is able to be supplied with commodities without purchasing further commodity allowance units. Preferably, requesting means are included which are operable to request a transmission of commodity allowance units to the CPU after the consumer has purchased the commodity allowance units. This allows the consumer to have full control of the purchase of commodity allowance units, for example, this enables the consumer to determine at what time commodity allowance units are being transferred to the RCMUs.

It may be preferred that the requesting means are operable only if said storage means indicate that the amount of commodity allowance units is below a given amount. This could prevent large pre-emptive purchases of commodity allowance units prior to a publicised increase in commodity unit prices. Such a limit may be applied for a limited term after the announcement of the publicised increase until the increase has been made.

In accordance with a further aspect of the invention, there is provided a CPU operable in the utility prepayment system. According to another aspect of the present invention there is provided a method of operating a utility prepayment system, for enabling an amount of commodity units to flow, the method comprising the steps of: receiving an amount of commodity allowance units; storing the value of said amount of commodity allowance units; receiving an indication of a commodity flow of a respective commodity; and, reducing said stored value of said commodity allowance units with an amount corresponding to said indication of a commodity flow; wherein the commodity ratio (CR) is related to the price per unit of a commodity (PU), the commodity allowance unit (CAU) and the monetary value (MV), as defined by the following equation:

_{CR =} PU*CAU MV

The method relates to the use of the commodity allowance units, for example in a respective remote commodity management unit, wherein an amount of commodity is allowed to flow, which amount is determined by the commodity ratio for a specified commodity and the amount of commodity allowance units stored, for example, in the RCMU.

An advantage of this method is that it is able to be adapted for different measuring systems and/or different measuring accuracy, for example, cubic feet, cubic metres etc. The adaptation to the different measuring units and/or different measuring accuracies can be easily done by just changing the respective commodity ratio. The same applies for the use of this system in different countries with different monetary currencies. According to another aspect of the present invention the purchasing of an amount of one or more commodities in exchange for an amount of monetary value is provided. A customer chooses an amount of monetary value for which commodity is to be purchased. He selects a supplier tariff which is associated to a specific commodity provider and/or a specific commodity. An amount of commodity allowance units is calculated taking into account the selected amount of monetary value, the supplier tariff and said commodity ratio, wherein the purchased commodity allowance units and said commodity ratio define the amount of commodity to be consumed according to the price per unit of commodity given in the supplier tariff, as defined by the following equation:

CR= ^PU~CAU

MV

wherein the commodity ratio (CR) is related to the price per unit of a commodity (PU), the commodity allowance unit (CAU) and the monetary value (MV). When a new amount of commodity allowance units are purchased, revised commodity ratios are calculated, taking into account the amount of commodity allowance units remaining and one or more previous commodity ratios.

Depending on the units of measurement for money and for the commodities which are country specific and /or commodity specific, since different commodities are usually measured in different units, for example, kWh, m³ etc., the respective commodity ratio gives a clear indication as to how many of the commodity allowance units the spending of one unit of the respective commodity costs. Whilst a consumer may not wish to be concerned with actual commodity allowance units, the capability of purchasing in a "one-stop- shop", commodity allowance unit's for a given monetary amount useable for all commodities may be attractive. Further the ability to purchase the same commodity from a number of suppliers of such a commodity enables competitive prices to be realised in the market. It may be that a particular multi-commodity supplier may provide preferential tariffs if multi- commodity purchases are made with respect to that multi-commodity supplier by a consumer.

Brief description of the figures

The invention will be described with reference to the Figure as shown on the accompanying drawing sheet, which Figure shows a block diagram of a commodity prepayment in accordance with the present invention.

Detailed description of the invention

There will now be described, by way of example, the best mode contemplated by the inventors for carrying out the invention. In the following description, numerous specific details are set out in order to provide a complete understanding of the present invention. It will be apparent, however, to those skilled in the art, that the present invention may be put into practice with variations of the specific.

The Figure shows a block diagram of commodity prepayment system, which allows a consumer to purchase a commodity allowance from different suppliers and with different tariffs. By means of the prepayment system according to the invention the consumer can purchase commodity allowance units which represent a determined amount of one or more commodities.

The commodity prepayment system comprises a customer management unit (CMU) 1, which is connected to a number of remote commodity management units (RCMU) 2 although only one is shown for clarity. Each RCMU 2 is assigned to a specified consumer and placed close to a location where the specified consumer uses/meters his commodity. The CMU 1 includes a data interface 8 which enables a connection to one or more assigned RCMUs 2 via a data link 3, respectively. The data link 3 may be a dial-up telephone line; it can be wireless or hardwired. It is also possible to provide the data link 3 by means of an internet connection. The data interface 8 can be a modem for allowing a dial-up of the assigned RCMU 2, a network interface and the like, to establish a data connection.

The RCMU 2 is connected to a plurality of metering units 4,5,6, for example an electricity meter 4, a gas meter 5 and a water meter 6, via respective signal connections C4, C5, C6. The metering units 4, 5, 6 are operable to measure a flow of the respective commodity, for example, by transferring an electrical pulse output from the respective metering unit 4,5,6 to the RCMU 2 via the respective signal connection C4, C5, C6. For example, the gas meter 5 may be operable to send out an electrical pulse every time an amount of 1/100 m³ gas has flowed through the gas meter 5, as is known. Similarly, the electricity meter 4 may be adapted to send out an electrical impulse every time an amount of 0.1 kWh electricity which has been supplied to the consumer, the water meter 6 may be adapted to send out an electrical pulse every time an amount of 1 litre of water has flowed through the water meter 6. It may be convenient for a respective pulse to be generated for other amounts of commodities. The CMU 1 further includes storage means 11, which is able to store user account data, including personal data, purchased commodity allowance unit data, supplier data, etc. The storage means may comprise integrated circuit memory means. The CMU 1 includes a central processing unit (CPU) 7 which is able to perform calculations, including calculations relating to the purchase of commodity allowance units for money or moneysworth. Furthermore, the CPU 7 can control several database management processes which are necessary to operate a user account.

Different commodity suppliers are associated with the CMU 1 for the same or different commodities and are referred to as supplier A, supplier B and supplier C. The suppliers A, B, C provide tariff data which include an indication about a price in monetary units per a determined unit of commodity. The tariff data can be dependent on daytime and/or amount of commodity spent or purchased, respectively, or other. For example, the tariff data can provide that the price for the commodity 'electricity' in the morning or evening hours is higher than during the night-time. Alternatively it may be provided that the price for one commodity is reduced as a function of the amount of commodity already spent.

There is further provided a user data interface 9 which allows an authorised user, who can be a consumer of commodities, to log into the

CMU 1 via a user terminal 10 which can be, for example, a personal computer. The authorised user at the user terminal 10 can then interact with the CMU 1.

Using the CMU 1 a purchase of one or more commodity allowance units can be performed by transferring, for example, a credit card number, authorisation codes, if appropriate, and the amount of money for which commodity allowance units are to be purchased. It is also possible to use other known ways of purchasing if the CMU 1 receives information about the amount of money for which commodity allowance units are to be purchased. If the consumer account does not provide information about the selected supplier for each commodity the consumer is requested to select a specific supplier via the assigned user terminal 10.

A purchase request for commodity allowance units by the consumer is processed by the CMU 1. Given appropriate input means, the customer is requested to enter a monetary value for which he is willing to purchase commodity allowance units. If not already stored with reference to his personal data in the storage means 11 the consumer is requested to enter assigned suppliers or selected tariff data, respectively, for each of the commodities he wants to have supplied by the CMU 1. If preferred suppliers have already been selected, identified and stored in the storage means 11 the consumer can be asked if he wants to change one or more of the suppliers or tariff data, respectively, or not.

The purchase of commodity allowance units according to the invention is performed in the CMU 1. A consumer accesses the CMU 1 either directly via an terminal integrated in the CMU 1 or via the user terminal 10 connected via the user data interface 9, respectively. The consumer gains access to use the CMU 1 by identifying himself in respect of the personal data stored in the storage means 11 of the CMU 1.

In the storage means 11 of the CMU 1, customer specific data is stored, for example, as a customer account. The customer account may include personal data, data indicating newly purchased customer allowance, previously selected supplier, etc.

Once logged in the CMU 1, the customer will be requested to enter a monetary value for which commodity is to be purchased. If the personal account assigned to the authorised consumer already includes selected tariff data for the wanted commodities, the consumer may be requested if he wants to select tariff data associated with a different supplier. If no tariff data has previously been selected then the customer will be requested to enter one or more suppliers for each of the commodities he wants to be supplied with. To every selected supplier, there is at least one set of tariff data wherein the price for the respective commodity, i.e. the price per defined unit of commodity, is fixed.

The tariff data may contain different prices for the same commodity depending on, for example, the time of consumption or depending on the amount of the respective commodity which has been used. An indication of the selected monetary value for commodity allowance units to be purchased and the tariff data for every selected supplier is stored in the respective storage means 11 of the CMU 1. It may also be possible to store. data indicating commodity allowance units and respective commodity ratios for each selected commodity. The respective data is stored in the CMU 1 as newly purchased commodity allowance units which is stored to be transferred to the RCMU 2 assigned to the respective consumer.

In the event that, for example, a consumer notices that there is only a small amount of CAUs remaining he can request a transfer of the newly purchased CAUs and/or commodity ratios from the CMU 1. Conveniently this can be done by pressing a push-button 13 included in the RCMU 2. After the request has been sent via the data link 3 to the CMU 1, the CMU 1 requests the RCMU 2 to send the remaining commodity allowance units to the CMU 1. The remaining commodity allowance units will be stored in the storage means 11 of the CMU 1. The CPU 7 then determines a new amount of CAUs which is to be stored into the RCMU 2 replacing the previous amounts of CAUs. The determination takes into account the CAUs in the storage means 12 of the RCMU 2, the amount of money for which new commodity is to be purchased and the selected tariff data for each selected supplier. A result of this calculation is an amount of CAUs and one or more (depending on the tariff structure) commodity allowance ratios for each of the selected commodities which are transferred via the data link 3 to the RCMU 2 where it is stored in the storage means 12. Financial transactions can be performed by electronic transfer, as is known, or an acknowledgement of receipt of the money by the supplier taken into account, or, indeed, other forms of money transfer.

This calculation can be easily performed if the commodity ratio is unchanged since the last purchase of CAUs, i.e. the consumer has, not changed the supplier and the supplier has not changed tariff data. In this case CAUs are calculated by taking into account the commodity ratios of the commodities that are being consumed, the price of each commodity and the selected monetary value according to the following:

CAU _Tolal = CAU _ow + CAU _NEW\

where MV is the monetary value,

CRi is the commodity ratio of the first commodity, and

PU] is the price per specified unit of the first commodity. The newly calculated commodity units CAU_new are simply added to the CAUOLD previously remaining in the RCMU 2 and the sum CAU_TOTAL is transferred back to the RCMU 2.

If the tariff data of one or more commodities has changed between the last purchase of CAUs and a subsequent purchase of CAUs, then not only do new CAUs have to be calculated but it is also preferred to calculate new commodity ratios for each of the commodities. In this case the commodity allowance units CAU₀id remaining are recalculated according to the following equations which show a case where two different commodities are supplied to a consumer:

Amount of commodity 1 to be used according to CAU OLD CAUQLD

CR 10LD

Amount of commodity 2 to be used according to CAUQ_LD : CAU OLD

CR 20LD

CAUTOTAL = CR (MV CAUOLDΛ

1NEW H PUl CRlOLD J

'MV CAUQLD PUι CRWLD ,

^-^--N_EW ^~~ _1NEW ^

CAU OLD

^■ + ^•

PUl CRlOLD where CRι_NEW is the new commodity ratio for commodity 1 ,

CR_2NEW is the new commodity ratio for commodity 2,

CR_{10 D} is the old commodity ratio for commodity 1,

CR_20LD s the old commodity ratio for commodity 2,

PUi is the price per unit of commodity 1 ,

PU₂ is the price per unit of commodity 2, and

CAU_oid are the commodity allowance units remaining.

As can be seen in the first equation, the total amount of commodity allowance units CAU_Totai which is to be transferred to the RCMU 2 and the commodity ratio CR_INEW depend on one another by a factor given by the equation. Accordingly, the CAU_tot_aι or the commodity ratio CR_INEW can be selected. It is preferable to operate the system such that the values of the

CAU_totai_, the CRinew and the CR_2new are in whole numbers so that the RCMU 2 performs only integer operations. This enables the RCMU 2 to be simplified and thus to reduce the costs of producing such a unit. A possible way to determine the commodity ratios for each commodity is to carry out a least common denominator calculation of the commodity ratios. The transfer of the total amount of the commodity allowance units CAU_new to the RCMU 2 overwrites the CAU₀i_d remaining in the RCMU 2.

In the period between the transfer of the commodity allowance units remaining CAU₀i_d from the RCMU 2 to the CMU 1 and the retransfer of the newly calculated commodity allowance units CAU_Totai from the CMU 1 to the RCMU 2 the commodity allowance units CAU₀i_d already stored in the RCMU 2 have to remain unchanged. Therefore it is necessary to perform the calculation substantially instantaneously so that no commodity allowance units are spent in the RCMU 2 while the calculation is carried out in the CMU 1. If one or more of the metering units 4,5,6 indicate that another unit of a commodity has been spent, then the value has therefore to be buffered until the transfer of the newly calculated commodity allowance units CAUxotai has been finished.

Commodity allowance units CAU as well as the commodity ratios CRi, CR₂ are stored in the storage means 12 of the RCMU 2. The storage means 12 are preferably small whereby to reduce the unit and production costs of the RCMU 2. Further, it is preferable that more than one commodity ratio for one of the commodities being supplied is provided. This enables the provision of a more sophisticated concept of a supplier tariff, which allows, in turn, to have a more accurate cost model of the respective commodity depending on the time of the day or the amount of the respective commodity being spent.

The RCMU 2 is connected to metering units 4, 5, 6 responsible for measuring each of the commodities being supplied to the consumer. The metering units 4,5,6 are operable to indicate every specified unit of commodity which has been metered through each respective meter. According to the commodity ratio associated with each commodity, the amount of commodity allowance units CAU stored in the storage means 12 of the RCMU 2 is reduced by the value determined by the respective commodity ratio each time the metering unit indicates that a specific amount of units of commodity has been spent. The commodities are supplied as long as there are sufficient commodity allowance units remaining in the storage means 12 of the RCMU 2. If there are no commodity allowance units CAU remaining, the supply of one or more of the commodities may be disabled. One option that may be implemented in a system is the provision of a feature that will prevent the supply being cut off if there are no more commodity allowance units remaining. It is also possible to give the consumer an emergency commodity allowance which allows the consumer to use a credit amount of commodity allowance units in the RCMU 2. The emergency commodity allowance can be regarded, on the one hand, as a credit of commodity allowance units CAU or, on the other hand, as an allowance to consume a maximum amount of commodity allowance units per time unit to allow the consumer to be supplied with commodity for emergency purposes, such as supplying the fridge with electrical energy etc. There may also be provided the option for guaranteed supply periods to maintain a minimum supply to the consumer.

In another preferred embodiment of the present invention the consumer could assign an account number (with direct debit capability) for his RCMU 2. So when a request is made for a new commodity allowance, for example, if the commodity allowance is below a certain predefined level, a predefined amount is deducted from the consumer's account and the commodity allowance is automatically updated by transferring newly purchased CAUs to the RCMU 2. For example, a consumer could set the direct debit amount to 10 Pounds(Sterling) which is transferred if his allowance falls below three Pounds(Sterling)-worth of units.

The remote commodity management unit 2 can also include indicators indicating a commodity allowance level for reminding the consumer if there are sufficient commodity allowance units left. There may be also provided indicating means for to indicate if the supply of commodities is switched on or off. For example, these indicators can be LED's or other means for indicating. The RCMU could also be configured to automatically enable a certain amount of CAUs to be purchased if the level of CAUs stored in the RCMU (or CPU if the system is so configured) falls below a predetermined level. Direct debiting or similar methods of pre-authorised payment would be appropriate. The predetermined minimum level may vary as a function of reason.

The invention can also allow the provision of different rates for the same commodity, for example for different time periods of the day/different days of the week etc. This could be implemented by treating the different rates of the same commodity as different commodities, which would extend the calculations described above. This could assist in a consumer changing his usage habits. Alternatively, since timing signals, typically either from a radio transmitter or an internal clock are employed, the commodity value of the CAU could be automatically increased, upon receipt of the signal, for the duration of the different rate.

As will be appreciated by those skilled in the art various modifications may be made to the embodiment herein before described without departing from the scope of the present invention.

Claims

1. A utility prepayment system comprising:

a central processing unit (CPU) operatively associated with a plurality of suppliers for one or more commodities,

a plurality of commodity meters;

a plurality of remote commodity management units (RCMU) operatively connected to one or more commodity meters, and

storage means to store a value of an amount of commodity allowance units (CAU),

wherein the CPU is operable to provide commodity allowance .units purchased in exchange for an amount of monetary value,

wherein the amount of said commodity allowance units provided is dependent upon one or more variable commodity ratios (CR), each commodity ratio being related to a specified amount of commodity allowance units per unit of commodity the price per unit of a commodity (PU), and the monetary value (MV), as defined by the following equation:

_CR= U__ CAU

MV . wherein each commodity meter, in communication with an associated remote commodity management unit and storage means, is operable to enable a commodity flow of a respective commodity in an amount relative to said stored value of said amount of commodity allowance units.

2. A system according to claim 1 wherein the amount of commodity allowance units CAUs are calculated by taking into account the commodity ratios of the commodities that are being consumed, the price of each commodity and the selected monetary value according to the following:

CAU_Tgtal — CAU _OLD + CAU_NEW ;

where MV is monetary value,

CRi is the commodity ratio of the first commodity, and

PUi is the price per specified unit of the first commodity.

3. A system according to claim 1 or 2, wherein said storage means are operable to store at least one commodity ratio.

4. A system according to claim 2, wherein said value of an amount of commodity allowance units stored in said storage means is reduced by an amount dependant upon said respective commodity ratio and commodity usage.

5. A system according to one of the claims 1 to 4, wherein the system is operable to allow the flow of two or more commodities, wherein each of said respective commodity ratios is related to one of said two or more commodities.

6. A system according to one of the claims 1 to 5, wherein the system further comprises receiving means connected to said CPU to receive commodity allowance units stored in said storage means.

7. A system according to one of the claims 1 to 6, wherein said remote commodity management unit includes means for indicating the amount of commodity allowance units stored in said storage means.

8. A system according to one of the claims 1 to 7, further including requesting means which are operable to request transmission of said commodity allowance units provided by said CPU.

9. A system according to one of the claims 1 to 8, wherein said requesting means is activated when said stored amount of commodity allowance units is below a given amount.

10. A remote commodity management unit operable in a utility prepayment system according to one of the claims 1 to 9.

,

11. A CPU operable in a utility prepayment system according to one of the claims 1 to 9.

12. A method of operating a utility prepayment system according to Claim 1, for enabling an amount of commodity units to flow, the method comprising the steps of:

receiving an amount of commodity allowance units;

storing the value of said amount of commodity allowance units; receiving an indication of a commodity flow of a respective commodity; and, reducing said stored value of said commodity allowance units with an amount corresponding to said indication of a commodity flow.

13. A method according to claim 12, further comprising the step of indicating the amount of said stored commodity allowance units.

14. A method according to claim 12 or 13, wherein the amount of commodity allowance units CAUs are calculated by taking into account the commodity ratios of the commodities that are being consumed, the price of each commodity and the selected monetary value according to the following equation:

CAU_Total = CAU _ow + CAU _NEW ;

where MV is monetary value,

CRi is the commodity ratio of the first commodity, and

PUi is the price per specified unit of the first commodity.

15. A method according to claim 11 to 14, wherein the step of storing a value of commodity allowance units includes the step of adding the amount of said commodity allowance units received to an amount of commodity allowance units presently stored.

16. A method according to one of the claims 12 to 15, including the further steps of:

receiving said one or more commodity ratios; and

storing the value of said one or more commodity ratios.

17. A method according to claim 16, wherein said one or more commodity ratios are received with said commodity allowance units received.

18. A method according to one of the claims 12 to 17, wherein said one or more commodity ratios each determine an amount of commodity allowance units by which the value of said stored commodity allowance units are to be ^•reduced by any indication of said commodity flow of said respective commodity.

19. A method according to one of the claims 12 to 18, wherein said one or more commodity ratios are each associated to a specific commodity type.

20. A method according to one of the claims 12 to 19, with the further step of transmitting said amount of commodity allowance units presently stored to a central processing unit.

21. A method of operating a utility prepayment system according to Claim 1, for purchasing an amount of one or more utility commodities in exchange of an amount of monetary value, said method including the steps of:

selecting said amount of monetary value for which commodity is to be purchased, selecting a supplier tariff associated to a specific commodity provider and/or a specific commodity,

providing one or more commodity ratios,

using the selected amount of monetary value, said supplier tariff and said one or more commodity ratios, calculating an amount of commodity allowance units wherein said amount of commodity allowance units and said commodity ratio determine the amount of commodity to be consumed.

22. A method according to claim 20, comprising the further step of:

transferring said amount of commodity allowance units.

23. A method according to claim 21 or 22, wherein the step of providing said one or more commodity ratios includes a least common denominator determination.

24. A method according to one of the claims 21 to 23 with the further step of receiving an amount of commodity allowance units remaining, wherein said step of calculating said amount of commodity allowance units includes said commodity allowance units remaining.

25. A method according to claim 23 wherein a plurality of supplier tariffs are provided each associated to a specific commodity type, wherein said one or more commodity ratios are calculated and each associated to said specific commodity type,

wherein said amount of commodity allowance units and said one or more revised commodity ratios are calculated by using said amount of commodity allowance units remaining and said one or more previous commodity ratios.

26. A method according to claim 20 to 24 wherein said one or more commodity ratios are transferred to a RCMU.

27. A method according to claim 20 to 25 wherein said one or more commodity ratios and said amount of commodity allowance units are transferred to said RCMU following a request signal transmitted by said RCMU.

28. A method according to one of the claims 20 to 26, wherein said supplier tariffs include condition data determined upon a time basis or consumption basis and ratio data, wherein the ratio data indicates an amount of commodity allowance units by which a total of commodity allowance units is to be reduced related to a consumed amount of one of said commodities or the time when said commodities are consumed.