"AC Batteries"
Characteristics
Some specialist battery packs have built in electronics such asinverters which generate the AC power from the battery's DC outputvoltage to provide portable mains power remote from the utilitysupply grid or emergency mains back up power.
Batterycharacteristics / requirements
Short term power supply
Many emergency power systems are only required to provide powerlong enough to enable a graceful shut down of an application toprevent loss of data or loss of continued control of a criticalindustrial process or medical procedure. Where a vital process mustbe maintained it may only be necessary for the battery to power thecritical application until an alternative energy supply (standbygenerator) can be brought on line. For such critical applications adedicated Uninterruptible Power Supply (UPS) may be provided. Thisusually contains a battery with sufficient capacity to power onlythe critical application for the expected duration of any outageand a built in inverter to provide the AC power to the load. Therest of the establishment will have to live with the poweroutage.
These applications require deep discharge batteries but they arerarely called into use and are not subject to repetitive dutycycles.
Long term power supply
Deep discharge batteries are also required for load levellingapplications to provide power on demand from intermittent suppliessuch as solar, wind and wave power applications. These applicationsrequire robust, long life batteries able to tolerate constantcharge-discharge cycling.
For very high power applicationssuch as emergency back ups for the national electrical power gridsystem or temporary storage of surplus low cost energy, very largecapacity batteries are required. While enormous lead acid batterieswith capacities up to 40 Megawatt hours or more have beenconstructed, several unusual systems for storing such largeenergies have also been implemented. See Alter"AC Batteries"
Characteristics
Some specialist battery packs have built in electronics such asinverters which generate the AC power from the battery's DC outputvoltage to provide portable mains power remote from the utilitysupply grid or emergency mains back up power.
Battery characteristics / requirements
Short term power supply
Many emergency power systems are only required to provide powerlong enough to enable a graceful shut down of an application toprevent loss of data or loss of continued control of a criticalindustrial process or medical procedure. Where a vital process mustbe maintained it may only be necessary for the battery to power thecritical application until an alternative energy supply (standbygenerator) can be brought on line. For such critical applications adedicated Uninterruptible Power Supply (UPS) may be provided. Thisusually contains a battery with sufficient capacity to power onlythe critical application for the expected duration of any outageand a built in inverter to provide the AC power to the load. Therest of the establishment will have to live with the poweroutage.
These applications require deep discharge batteries but they arerarely called into use and are not subject to repetitive dutycycles.
Long term power supply
Deep discharge batteries are also required for load levellingapplications to provide power on demand from intermittent suppliessuch as solar, wind and wave power applications. These applicationsrequire robust, long life batteries able to tolerate constantcharge-discharge cycling.
For very high power applications such as emergency back ups for thenational electrical power grid system or temporary storage ofsurplus low cost energy, very large capacity batteries arerequired. While enormous lead acid batteries with capacities up to40 Megawatt hours or more have been constructed, several unusualsystems for storing such large energies have also been implemented.See Alternative Energy Storage Methods.
In these high power applications the inverter will be a separateunit or the system may generate AC power directly as is the casewith pumped storage systems.
Inverter characteristics / requirements
No loss of power to the load
High quality clean sinewave output.
Frequency stabilisation
High efficiency / low loss
Possible integration with battery float or trickle charger
Advantages
Fast acting - Much quicker than rotary or other standby ACgenerators.
Shortcomings
Limited capacity compared with motor driven rotarygenerators.
Applications
Uninterruptible power supplies. See UPS
Emergency power
Standby power sources
Load levelling
Costs
Very wide range of costs
native Energy Storage Methods.
In these high power applications the inverter will be a separateunit or the system may generate AC power directly as is the casewith pumped storage systems.
Inverter characteristics / requirements
No loss of power to the load
High quality clean sinewave output.
Frequency stabilisation
High efficiency / low loss ACBatteries
Possible integration with battery float or trickle charger
Advantages ACBatteries
Fast acting - Much quicker than rotary or other standby ACgenerators.
Shortcomings
Limited capacity compared with motor driven rotarygenerators.
Applications
Uninterruptible power supplies. See UPS
Emergency power
Standby power sources
Load levelling
Costs
Very wide range of costs
AC BatteriesAC BatteriesAC BatteriesAC Batteries