AU2005100876A4 - System and method for supplementing or storing electricity to or from an electrical power grid - Google Patents

Description

Our Ref: 12616001 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION INNOVATION PATENT Applicant(s): Address for Service: Invention Title: Robert Trevor EISLER 26 Thorp Road, Woronora, New South Wales 2232,

AUSTRALIA

DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 "System and method for supplementing or storing electricity to or from an electrical power grid" The following statement is a full description of this invention, including the best method of performing it known to me:- 12616001_innovationdoc- 12/10/05 -1- SYSTEM AND METHOD FOR SUPPLEMENTING OR STORING ELECTRICITY TO OR FROM AN ELECTRICAL POWER GRID c, Technical Field [001] The present invention relates to grid-based electricity supply and storage, and in particular, to a system and/or method for storing electrical power that can be retrieved on 00 demand and introduced into an electrical power supply grid.

Background Art [002] Presently, in many countries, or parts of countries, for example the Eastern States of Australia, the bulk of electricity is generated from coal fired power stations. Generally, these coal fired power stations are located close to coal fields. The electrical output of the power stations is combined and interconnected via high tension (high voltage) power lines, otherwise known as an electrical power grid Contributions to the grid can also be made form non-coal power stations, for example in the Eastern States of Australia, from a hydro-electric power station.

[003] In many, if not most, countries, including Australia, in the average day there are two peak periods of demand for electricity. This is illustrated in the graph shown in Fig. 1 which illustrates electrical power demand (ordinate) versus time during a 24 hour period (abscissa). Peaks in power demand occur for about 3 hours each and commence approximately at about 0700 hours and again at 1730 hours. Historically, the peaks illustrated in the graph used to be season dependent, that is, a winter season generally had the highest demand due to required home heating. However, the popularity of home airconditioning in many countries means that demand during the summer months is equivalent to that of the winter months. The graph presented in Fig. 1 shows a typical daily winter power demand cycle in the Eastern States of Australia.

[004] A benefit of this type of power generation system is the ability to share electrical power between regions or States. This means regions or States can share excess electricity capacity produced by power stations with other regions or States that are experiencing 12616001 innovaIiondo-12/10/05 -2power demands in excess of their available capacity. Excess power can be, and is, traded C and sold as a commodity.

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[005] Power sharing is only of benefit when excess capacity exists at a similar time as other regions or States require additional power. That is, an excess power capacity from one region or State is of no benefit if there is no other party which requires additional r power at that particular time.

0O t[006] There is no currently known system or method to store electrical power for subsequent use in an electrical power grid, with the exception of hydro-electric systems.

SIn a hydro-electric system, stored water passes through turbines to generate electricity.

This electricity is generally used to supplement the supply from coal fired power stations during times of peak demand. When there is less demand in the system the turbines can be reversed and used as pumps to move water back to a top storage area for use when the next peak demand occurs.

[007] Many other problems exist in the present system of generating power to an electrical power grid. Particular problems arise in a heavily loaded system or a lightly loaded system.

[008] In the case of a heavily loaded system, such as during the peak times illustrated in Fig. 1, the voltage supplied by the electrical power grid falls. This is exacerbated when a power station is required to transport/transmit electrical power over long distances. These losses are known as copper or static losses. Also in a heavily loaded system, generators have to work harder to cover these system losses before the electricity reaches a load centre or consumer residence. The peak times, or times of heaviest demand, generally only account for about 6 hours out of a normal 24 hour period. Additional capacity is generally only required for this 6 hour period. For the remainder of a day generators have to reduce electrical power output. However, shutting down generators is not a desirable option due to the extreme stresses on the generating equipment during start-up and shut-down procedures. Starting a generator from cold takes approximately 12 hours before the generator is ready to be put "on-line". Generators also have optimum outputs. Outputs above or below these optimum levels can create other problems for the generating units, such as excess pollution. Generators generally put more pollution into the environment 126 001 innovationdo-12/10/05 -3when they are operating above an estimated 95% output. This is due to inefficiencies with particle collectors above these output levels. Additionally, a heavily loaded system can o become unstable if enough electricity is not available to supply the demand. This is

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generally regulated, in extreme cases, through unplanned blackouts.

[009] On the other hand, in a lightly loaded system, that is when there is an excess of r0 capacity and insufficient load, a new set of problems is created which can significantly 00 Saffect system stability. Due to lightly loaded power lines, the voltage increases such that it can become higher at a load centre or consumer residence than when it left the generators. If not controlled the voltage at a consumer's residence can become dangerously high. To assist in controlling these high voltages the notion of "off-peak" power was devised. However, despite "off-peak" power, other generally ineffective methods are still used to control escalating voltages in a lightly loaded system. Off-peak power has two specific benefits. Firstly, off-peak power offers cheaper electricity to consumers. This can represent a significant cost saving to large companies. Also, domestic hot water heaters are often switched on during low-demand (off-peak) times, generally at night, to take advantage of this cheaper electricity. Secondly, large companies and hot water heaters utilising off-peak electricity during the night do not form part of the daytime peak loads.

[010] Many countries face challenges in supplying electricity in the future to increasing populations. In Australia, there is currently enough electrical power generation capacity based on peak demands. However, Australia is approaching a time when a new power generating facility will need to be considered. As an economy and the population grows, so does the demand for electricity. Building a new power station is a complex decision.

There are many factors to be considered, such as the time required to build a new facility, the location of the facility, the environmental impact and the cost. In Australia, it has been estimated that a new coal-fired power station would take about 5 years to build, have a severe impact on the environment, and cost in the vicinity of A$30 billion.

[011] Alternative or renewable power generation facilities include systems utilising solar or wind power. However, the consistency of the electrical power contribution from these sources of electrical energy needs to be improved. On a particular day these sources of energy may contribute a significant amount of electrical energy to the electrical power 12616001 _movationdom-12/0/05 -4grid, but on other days, may contribute nothing. The power contribution made by these C systems is not time reliant. The demands during a normal day by consumers are relatively O consistent, in contrast, the electricity produced by these alternative or renewable systems is 0only available when, for example, sufficient wind or solar energy is available, but not necessarily when specifically required by consumers. At present, the electricity generated by these systems is unable to be stored to be used at a time when the electricity is most rneeded during peak demand times.

00 [012] This identifies a need for a system and/or method for storing electricity from and/or supplying electricity to an electrical power supply grid which overcomes or at least ameliorates problems inherent in the prior art.

[013] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge.

Disclosure Of Invention [014] According to a first broad form, the present invention provides a system for storing electricity from and supplying electricity to an electrical power grid, the system including: a battery bank consisting of one or more batteries able to store electrical energy; and, an inverter/charger electrically connected between the battery bank and the electrical power grid, the inverter/charger adapted to facilitate charging of the battery bank with electricity from the electrical power grid and supply of electricity from the battery bank to the electrical power grid.

[015] According to a second broad form, the present invention provides a method of storing electricity from and supplying electricity to an electrical power grid, the method including the steps of: providing a battery bank consisting of one or more batteries able to store electrical energy; and, providing an inverter/charger, the inverter/charger connected between the battery bank and the electrical power grid; 12616001 innov0ion.do- 12/10/05 wherein, the inverter/charger is adapted to allow charging of the battery bank with N, electricity from the electrical power grid and to allow the supply of electricity from the battery bank to the electrical power grid.

[016] According to a third broad form, the present invention provides a system for supplying electricity to an electrical power grid on demand, the system including: electrical energy storage means; oO first connection means to transmit electrical energy stored in the electrical Ienergy storage means to the electrical power grid; and, second connection means to transmit electrical energy from the electrical power grid to the electrical energy storage means. In this form, the present invention, according to yet other aspects provided by way of example only, provide that the electrical energy storage means is a series of batteries, the first connection means is an inverter, the second connection means is a charger, and/or the first connection means and the second connection means are the same device.

[017] In another particular, but non-limiting, form the present invention further provides that the inverter/charger converts electricity between direct current (DC) in the battery bank and alternating current (AC) in the electrical power grid.

[018] In accordance with a specific embodiment, there is additionally provided at least one isolator between the inverter/charger and the electrical power grid, and/or, there is additionally provided at least one circuit breaker between the inverter/charger and the electrical power grid.

[019] The present invention, according to yet another aspect provided by way of example only, provides that the inverter/charger is adapted to automatically supply electricity from the battery bank to the electrical power grid during peak power period demands on the electrical power grid.

[020] Preferably, the supply of electricity from the battery bank to the electrical power grid is on demand.

1156 i 1nov tio.doc. 12/1105 -6- [021] In still a further particular, but non-limiting, embodiment of the present invention, C the battery bank is additionally charged from an alternate source of electrical power other Sthan from the electrical power grid.

[022] In yet further particular, but non-limiting, embodiments of the present invention, a controller unit is provided to control the inverter/charger, and the controller unit can be

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r provided to be remotely operable.

00 Brief Description Of Figures [023] The present invention should become apparent from the following description, which is given by way of example only, of a preferred but non-limiting embodiment thereof, described in connection with the accompanying figures.

[024] Fig. 1 (prior art) illustrates a typical graph of electrical power demand (ordinate) versus time during a 24 hour period (abscissa); [025] Fig. 2 illustrates an example block diagram of components that can be utilised to embody or give effect to an embodiment of the present invention (inverter mode); [026] Fig. 3 illustrates a further example block diagram of components that can be utilised to embody or give effect to an embodiment of the present invention (charger mode); [027] Fig. 4 illustrates an example flow diagram of a method that can be utilised to embody or give effect to a particular aspect of the present invention; [028] Fig. 5 illustrates an example functional block diagram of components that can be utilised to provide a controller unit.

Modes for Carrying Out The Invention [029] The following modes, given by way of example only, are described in order to provide a more precise understanding of the subject matter of the present invention.

12616001 movation.do-12/10/05 -7- Preferred embodiment N, [030] In the figures, incorporated to illustrate features of an embodiment of the present Sinvention, like reference numerals are used to identify like parts throughout the figures.

[031] Referring to Figs. 2 and 3, there is illustrated a system 200 for storing electricity from and supplying electricity to an electrical power grid 270. The system 200 includes a battery bank 210 consisting of one of more batteries 220 able to store electrical energy.

00 SThe system 200 also includes an inverter/charger 230 which is electrically connected between the battery bank 210 and the electrical power grid 270. The inverter/charger 230 can function in one of two modes, either to supply electrical power to the grid 270 or to take electrical power from the grid 270 and charge the battery bank 210. The inverter/charger 230 thus facilitates charging of the battery bank 210 with electricity from the electrical power grid 270 and also facilitates the supply of electricity from the battery bank 210 to the electrical power grid 270.

[032] Fig. 2 illustrates system 200 in a mode whereby the battery bank 210 is supplying electrical power to the grid 270 via the inverter component of the inverter/charger 230.

Fig. 3, illustrates system 200 operating in a mode whereby electrical power is extracted from the grid 270 and is used to charge batteries 220 of battery bank 210 via the charger component of the inverter/charger 230.

[033] The inverter/charger 230 is connected to the grid 270 via isolators 240 and 260 and circuit breaker 250. Normal electrical power is supplied to grid 270 by power station 280 (or equivalently power stations).

[034] The inverter/charger 230 thus has a dual function, a primary function is to supplement or support the electrical power grid 270 supply by converting stored DC power in the battery bank 210 into useable AC power that is fed into the grid 270. A secondary role of the inverter/charger 230 is to recharge batteries 220 of the battery bank 210 from the power supply of the grid 270 when excess power exists in grid 270. Additionally or alternatively, batteries 220 of battery bank 210 can be recharged from alternative or renewable power supply systems, such as solar or wind power. This can occur by directly connecting the alternative or renewable power supply system to the battery bank 210, the inverter/charger 230, or a second inverter/charger. Alternatively, power from an alternative 126160 l innovation.doc-12/10/05 -8or renewable power supply system can be connected to some remote point on the grid 270 C and thereby effectively be transmitted to the battery bank 210.

0 [035] The supply of electricity from battery bank 210 to the electrical power grid 270 can be on demand, for example during peak power demand times. The inverter/charger 230 converts electricity between direct current (DC) in the battery bank 210 and alternating current (AC) in the electrical power grid. The inverter/charger 230 may be set up to 00 automatically supply electricity from the battery bank 210 to the electrical power grid 270 during peak power demands on the electrical power grid 270.

S[036] It should also be noted that more than one inverter/charger 230 can be associated with a battery bank 210.

[037] Referring to Fig. 4, the steps of a method 400 of storing electricity from and supplying electricity to the electrical power grid 270 are illustrated. The method 400 includes, at step 410, providing a battery bank 210 consisting of one or more batteries 220 able to store electrical energy. At step 420, there is provided an inverter/charger 230, the inverter/charger 230 connected between the battery bank 210 and the electrical power grid 270. At step 430, the battery bank 210 and the inverter/charger 230 can then be connected to the grid 270. A controller unit 440 can be used to set operation modes 450 in the inverter/charger 230 to perform further steps of method 400. At step 460, electrical power can be provided from the battery bank 210 to the grid 270. At step 470, excess electrical power can be taken from the grid 270 to charge batteries 220 of the battery bank 210. At step 480, the inverter/charger 230 can be placed in a standby mode.

Various embodiments [038] Other embodiments of the present invention are possible. According to another particular embodiment of the present invention, the controller unit 440 can be provided using a processing system, an example of which is shown in Fig. 5. In particular, the processing system 500 generally includes at least one processor 502, or processing unit or plurality of processors, memory 504, at least one input device 506 and at least one output device 508, coupled together via a bus or group of buses 510. An interface 512 can also be provided for coupling the processing system 500 to one or more peripheral devices, for 12616001 i moaiion.do- 12d05 -9o example interface 512 could be a data acquisition card measuring parameters from an N electrical power grid.

[039] At least one storage device 514 which houses at least one database 516 can also be provided, for example to store or retrieve electrical power grid parameters, inverter/charger parameter settings, etc. The memory 504 can be any form of memory r device, for example, volatile or non-volatile memory, solid state storage devices, magnetic 00 Sdevices, etc. The processor 502 could include more than one distinct processing device, for example to handle different functions within the processing system 500. Input device 506 receives input data 518 and can include, for example, a keyboard, a pointer device Ssuch as a pen-like device or a mouse, audio receiving device for voice controlled activation such as a microphone, data receiver or antenna such as a modem or wireless data adaptor, data acquisition card, etc. Input data 518 could come from different sources, for example keyboard instructions in conjunction with data received via a network. Output device 508 produces or generates output data 520 transmitted to the inverter/charger via, for example, a USB port, a peripheral component adaptor, cable, a data transmitter or antenna such as a modem or wireless network adaptor, etc. Output data 520 could be distinct and derived from different output devices, for example a visual display on a monitor in conjunction with data transmitted via a network or telephone line. A user could view data output, or an interpretation of the data output, on, for example, a monitor or using a printer. The storage device 514 can be any form of data or information storage means, for example, volatile or non-volatile memory, solid state storage devices, magnetic devices, etc.

[040] In use, the controller unit processing system) 500 is adapted to allow data or information to be stored in and/or retrieved from, via wired or wireless communication means, the at least one database 516 and/or memory 504. An application program residing on the processing system 500 can process input data 518 and/or data from database 516 to generate output data 508 and thereby control the inverter/charger. The input data 518 may originate from the inverter/charger so that the processing system 500 additionally plays a monitoring role. As an illustrative example, output data 520 may be a signal indicating to the inverter/charger to switch from a charging function to an inverter function and thereby begin to supply stored electrical power from the bank of batteries 210 to the electrical power grid 270.

12616001 iovationdo- 1I1/ [041] The interface 512 may allow wired and/or wireless communication between the r processing unit 502 and peripheral components that may serve a specialised purpose.

0 More than one input device 506 and/or output device 508 can be provided. It should be 0appreciated that the processing system 500 may be any form of terminal, server, specialised hardware, or the like.

r0 [042] Thus, the system has two main operational modes, a supply mode and a recharge 00 Smode. In the supply mode the inverter/charger 230 supplements the power supply to the grid 270 by transmitting stored DC power from the battery bank 210. This is used to boost the grid 270 when the grid is operating at or near capacity. The recharge mode is used to take spare or excess electrical power from the grid 270, or from alternative or renewable energy sources, to recharge batteries 220 as required. This places the battery bank 210 in a ready state for next use and allows generators of traditional power stations to operate at better efficiency levels, thereby reducing maintenance needs and avoiding unnecessary pollution emission into the environment.

[043] Multiple systems 200, comprising multiple battery banks 210 and inverter/chargers 230, could be utilised to provide an effective contribution to the traditional grid power system 270.

[044] The batteries 220 are preferably high capacity deep cycle batteries. These batteries can be connected in various configurations, for example in series or parallel, to form a considerable high capacity storage cell. Electricity is supplied to battery bank 210 from the inverter/charger 230 at consumer voltages, however this can be adapted as required.

The inverter/charger 230 can be controlled via a data cable using a telephone line or direct data link. This allows the inverter/charger 230 to be switched on and off remotely as required. It is anticipated that the battery bank 210 may supplement or support electrical power to the grid 270 for durations of up to 4 hours at maximum output.

[045] Multiple systems 200 can supplement the power supply to the grid 270 as needed.

Inverter/charger 230 can be remotely operated and utilised to the bring battery bank 210 on-line as the need demands at any time of the day or load cycle. Using system 200, electrical power can be stored in the battery bank 210, at any time, as excess power in the 1261600 innovation.do-12/10/05 -11o grid 270 is available, whether it comes from power station generators 280 or alternative or N renewable systems, such as solar panels or wind generators.

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[046] By avoiding the necessity of traditional generators to be shut down during times of low demand, which adds to the stress and required maintenance of generator equipment, generators can operate normally and low power demand times used to recharge batteries r 220. Thus, output from traditional generators is effectively "averaged out" over a 24 hour 00 Speriod, thus reducing peak load demands on generators. Generators can be planned to run at optimum efficiency with electrical power from battery bank 210 providing electrical power for any consumer power demand shortfall by the generators. This has the additional Sbenefit of also possibly extending the working life of a traditional generator.

[047] Additionally, during lightly loaded times, the battery bank 210 can act as an additional load when recharging batteries 220, thus avoiding some problems with lightly loaded power lines. The combined use of coal fired power stations and system 200 could have a significant positive impact to consumers by means of providing lower cost electricity by maximising the efficiency of current power capacity combined with possibly heightened consumer awareness of power consumption limitations. Construction of additional power generation facilities could be delayed by use of system 200. The flexibility in location, size and low environmental impact of the system 200 makes the system a possible alternative option to the construction of a new power station facility.

[048] The system 200 can additionally store power generated from alternative or renewable energy sources and return this electrical power to grid 270 as required. This could assist to increase the popularity of alternative or renewable energy systems.

[049] Various other embodiments of the present invention are possible with a variety of applications. For example facilities that critically depend on an electrical power supply, such as hospitals, could utilise the present invention. A hospital is normally supplied with electrical power from grid 270. The battery bank 210 and inverter/charger 230 could be provided as a back-up power supply in the event of failure of electrical power to the hospital from grid 270. Fast switching of the inverter/charger 230 to supply electrical power to the hospital could result in seamless transfer of electrical power in the event of failure from grid 270. Multiple dedicated battery banks 210 and inverters/chargers 230 12616001 innovaion.dc- 12/10/05 -12could be associated with the hospital premises to provide dedicated backup electrical C power support. Hospitals often have backup generators, however, power supply from Sgenerators often takes minutes to activate and often only supplies power to a fraction of the

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hospital. Existing generators could be used to actively recharge battery bank 210 and extend the duration of backup power supply from battery bank 210. This application could be applied to many other scenarios and types of premises that critically depend on a r0 backup source of electrical power should grid 270 fail.

0O [050] Such applications can include, for example, military applications requiring silent O 10 generation of electrical power, remote communities where the normal power supply is unreliable, communities whose power is normally supplied by diesel generators by taking over night time demand to provide silent running conditions during normal sleeping hours, providing reliable power to communities such as those affected by severe weather, such as the Florida area in the United States, and/or the system may be airlifted or transported into areas where power is required without accompanying noise, air pollution or infrastructure.

[051] Hence, the system 200 can be applied to electrical power distribution systems other than the grid 270. Recharging of batteries 220 can occur from a variety of sources, such as the grid 270, when available, alternative or renewable energy power sources and/or diesel generators.

Further example [052] The following example provides a more detailed discussion of a particular embodiment of the present invention. The example is intended to be merely illustrative and not limiting to the scope of the present invention.

[053] The batteries can be Sonnenschein 24 OPzV 3500 batteries. These cells are 2 volt 3500 amp hour capacity, 120 cells are used in series connection to provide an input voltage of 240 volts DC into the inverter/charger.

[054] The inverter/charger may be the 150kva 3 phase MODEL SPP-3P-2DX-150K-230- 50-240-0K. The inverter output is at 240 volts AC phase to neutral or 415 volts AC phase to phase. This provides a capacity of 150kva over three phases. The inverter is provided with: an RS232 serial port for data tracking; time and date stamped system data logs and 12616001 innovalon.do- I2I 0/05 -13fault logs; liquid crystal display and keypad for system control and monitoring; a remote control and monitoring option via a dedicated phone line; full automatic operation with no breaks to the supply during transition; and is capable of integration with distributed generation on an AC bus.

[055] In a particular embodiment, the inverter of the inverter/charger has the specifications illustrated in Table 1.

Table 1 Operating Parameters Information Output Voltage Output voltage 230/400 volts. Voltage can be adjusted by (nominal) 5% via set points to suit other nominal values.

Output frequency 50Hz Continuous rating 150kva with all phases equally loaded Surge rating up to 225kva for a maximum of 30 seconds with all phases equally loaded.

Battery voltage 240 volts dc Control type Voltage source, microprocessor assisted output regulation Waveform Microprocessor generated sine wave output Parallel Operation Phase Controlled Pulse width Modulation (PWM) Power Control THD less than Efficiency up to 94% Internal protection Inverter continuous overload system Peak current (short circuit) protection Heatsink over temperature Over under voltage AC voltage protection Over under frequency protection Over under battery voltage protection RFI designed to minimise both conducted and radiated RFI emissions Alarms Via system fault relay 12616001 innovation.do- 12/lI0/05 Front panel interface 40 x 4 LCD panel with membrane keypad displaying; Inverter kw, voltage, power factor, frequency per phase Battery voltage, current and temperature Solar charge current and ambient or panel temperature Wind charge current Solar radiation and wind speed (with optional pyranometer and anemometer) Inverter kwh summation Operating temperature 5-50 degrees Celsius Humidity 0-90% non-condensing Inverter enclosure Rated for IP30 not weatherproof Computer port Isolated RS232 port Modbus protocol Computer access The system includes local access or a telecommunications dial-up package consisting of a serial modem link that can be connected to a telephone line for remote access System features Adjustable logging period from 60 second averages to 24 hour daily logs Storage capacity of up to 9 days at 15 minute logs Time and date stamped log entries Time and date annotated fault log, holding the fault description and operating statistics View and change system setpoint configurations locally and remotely.

Bulk log download for importation into a spreadsheet Logging attributes A summary of the data logging abilities supplied with the control system is listed below: Instantaneous feedback of power, voltage, power factor and frequency of the inverter module.

Instantaneous feedback of battery voltage, current, temperature, solar and wind renewable current contribution, solar radiation wind speed and ambient or panel temperature.

Periodic logging of power, voltage, power factor and frequency of the inverter module.

12616001 _novaio.d- 12/I0/05 Periodic feedback of battery voltage, current, temperature, Ssolar and wind renewable current contribution O Download log parameters 0 o Solar charge current o Wind charge current o Battery current ro Battery voltage 00 o Battery temperature o Ambient or panel temperature o Inverter kw, voltage, pf, frequency o Solar radiation in conjunction with external kit o Wind speed in conjunction with external kit System summation viewing o Inverter output kwh o Inverter input kwh (battery charge) [056] A particular embodiment of the present invention includes a bank of 2 volt 3,500 ampere hour interconnected batteries. These batteries are connected together in series to form a large DC supply. The battery bank is connected to a 150kva inverter which has dual functions, the first function is to convert DC into full sine wave useable AC. A second function is to convert AC into DC to recharge the battery bank. The system is designed to provide full capacity output, that is 150kva from the battery bank via the inverter to the grid supply for a duration of about 4 hours. This duration allows for reasonable utilisation of the battery bank without causing undue damage to the battery bank. The rated output of the inverter at an output of 150kva means that the input current from the DC side at 94% efficiency would equate to 665 amps per hour. Some parallel connection of cells may be required to support extended overloads. Following a discharge of the battery bank, the recharge could be based on a 10% capacity recharge. Therefore, if the battery cells were estimated to be 75% spent, there recharge current would be: 3,500 x 0.75 x 10% 262 amps per hour over approximately 10 hours.

The recharge time can be affected by adding additional capacity to the battery bank. Larger capacity inverters can be created as the need arises.

12616001 innov ion.do-12/I0/0 -16- [057] Thus, there has been provided in accordance with the present invention, a system C and/or method for storing electricity from and supplying electricity to an electrical power o grid.

[058] The invention may also be said to broadly consist in the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features, and wherein specific 00 Sintegers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

[059] Although a preferred embodiment has been described in detail, it should be understood that various changes, substitutions, and alterations can be made by one of ordinary skill in the art without departing fiom the scope of the present invention.

Claims (4)

1. A system for storing electricity from and supplying electricity to an electrical power grid, the system including: a battery bank consisting of one or more batteries able to store electrical energy; r and 00 oO O an inverter/charger electrically connected between the battery bank and the electrical power grid, the inverter/charger adapted to facilitate charging of the battery bank S 10 with electricity from the electrical power grid and supply of electricity from the battery bank to the electrical power grid.

2. The system as claimed in claim 1, wherein the inverter/charger is adapted to automatically supply electricity from the battery bank to the electrical power grid during peak power period demands on the electrical power grid.

3. The system as claimed in either claim 1 or 2, wherein the battery bank is additionally charged from an alternate source of electrical power other than from the electrical power grid.

4. The system as claimed in any one of the claims 1 to 3, wherein a remotely operable controller unit is provided to control the inverter/charger. A system for supplying electricity to an electrical power grid on demand, the system including: electrical energy storage means; first connection means to transmit electrical energy stored in the electrical energy storage means to the electrical power grid; and, second connection means to transmit electrical energy from the electrical power grid to the electrical energy storage means. 12616W01 hnnovadon doc-12/10/05 -18- C1 DATED this 1 4 th day of October 2005 O ROBERT TRE VOR EISLER By His Patent Attorneys DAVIES COLLISON CAVE 00