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Long-life nickel iron battery functionality / cost comparison for peak demand SWER network voltage support application


Abstract and Figures

SWER line voltage sags, if network upgrade is not possible, eventually require active power injection as one of the intervention technologies. Active power support can be provided by many technologies, and some of these involve battery energy storage. Nickel-iron Edison batteries are an often little known or understood battery. Compared to three other commonly available industrial batteries, and despite their design being over 100 years old, they are a still a long-life contender for large stationary battery energy storage systems. Continuing research into their design may even further improve their performance.
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Australasian Universities Power Engineering Conference, AUPEC 2013, Hobart, TAS, Australia, 29 September 3 October 2013 1
Long-life Nickel Iron Battery Functionality / Cost
Comparison for Peak Demand SWER Network
Voltage Support Application
Andreas Helwig
School of Mechanical and Electrical Engineering
USQ Faculty of Health, Engineering and Sciences
Toowoomba, Queensland, Australia
Tony Ahfock
School of Mechanical and Electrical Engineering
USQ Faculty of Health, Engineering and Sciences
Toowoomba, Queensland, Australia
AbstractSWER line voltage sags, if network upgrade is not
possible, eventually require active power injection as one of the
intervention technologies. Active power support can be provided
by many technologies, and some of these involve battery energy
storage. Nickel-iron Edison batteries are an often little known or
understood battery. Compared to three other commonly
available industrial batteries, and despite their design being over
100 years old, they are a still a long-life contender for large
stationary battery energy storage systems. Continuing research
into their design may even further improve their performance.
Keywords Nickel-iron battery, life costs, SWER line.
Battery technology continues to be challenged by modern
applications such as voltage regulation support by active
power injection during peak load demand periods for single
wire earth return (SWER) rural power. The requirements for
these applications are deep discharge capability and rates with
a long cycle life to minimise costs. Battery types with high
recharge rate and a lack of sensitivity to overcharge or
undercharge are also an advantage. As a background to SWER
network application, in both developed and developing
nations, typically they trend in time from initial light loads for
lighting and small enterprise, gradually growing in demand for
opportunistic rural development for irrigation automation and
on farm post-harvest crop processing (milling, refrigeration,
washing / packing lines etc.). SWER networks normally
radiate out from populous centres to sparse rural settlement
areas to provide cost effective power for development
opportunities in agri-business. Quite often during a SWER
asset’s half-life of 40 60 years of age, the annual load
demand increases (for example, in rural Australia being 2.2%
to 3% per annum) compounds to cause voltage sags to occur
for back end line customers during peak load demand periods.
Overcoming this by network upgrades to a heavier SWER
conductor, or ultimately to a two wire single phase or three
phase network is very capital intensive. Published submissions
[1] and reports from the Victorian Black Friday Royal
Commission [2] into SWER line contribution to bush-fire
spread provides the means to calculate the cheapest upgrade
for a portion of a SWER network backbone line from 3/2.75
SC/GZ to 3/4/2.5 ACSR/GZ as being $18,000 per km or more.
It is difficult to justify high cost capital investment for a very
sparsely distributed SWER network customers in developed
nations, and impossible to do so in developing nations. There
are many options for intervention to support voltage regulation
during peak load periods in SWER networks, each with
advantages and disadvantages in regard to initial investment
and life cycle replacement. These options include series HV
auto-transformer voltage regulators, HV supply side static or
switched capacitive or reactive compensators, LV inverter
compensators to balance the reactive p.f. load component, or
LV customer load side voltage regulators. In spite of the
advantages to SWER customers voltage regulation, these tend
to substantially increase upstream series network resistive
losses. It is inevitable, if the network cannot be economically
upgraded, that active power injection along the network will
be required to support voltage regulation. Correctly placed
active power injection supports voltage during peak demand
periods by reducing electrically far LV network loads and
providing significant upstream series HV network line loss
relief. In doing so, it reduces the SWER network’s high
resistive component losses, particularly on light SWER lines
(such as the galvanised steel wire and lighter aluminium clad
conductor types) that have above unity R/X ratios, or higher R/X
ratios of 5 or above. Active power sources are traditionally
fossil fuel IC engine or gas turbines powered alternators,
sustainable solar, wind and geothermal energy supplies, which
may include battery storage for time-shifting energy to peak
demand periods. An alternative to these is a large battery
array using off-peak base load supply for charging. This latter
option is only possible where there is reserve off-peak SWER
network capacity. This paper compares the current solar deep
discharge nickel-iron Edison battery with three other
industrially manufactured battery types readily available for
application for active power injection to support SWER
voltage regulation during peak periods. As a historical
perspective Junger in Europe first discovered and built the
nickel-iron battery 1899 before choosing the nickel cadmium
battery for patented development. Edison on the other hand
chose to patent the nickel iron battery in the USA during 1901.
Nickel-iron batteries nearly disappeared from technology use
in the 1970’s and are now sometimes little known in many
engineering disciplines. (Note: For this study, Nickel-cadmium
batteries were excluded due to the heavy metal cadmium issue
that currently often limits these to special applications; Nickel
Metal Hydride battery was excluded for large remote battery
arrays as these have temperature performance sensitivity
Australasian Universities Power Engineering Conference, AUPEC 2013, Hobart, TAS, Australia, 29 September 3 October 2013 2
above 25°C necessitating prevention of thermal runaway
damage by significant cooling intervention. Similarly, also the
review of the recent DOE/EPRI 2103 Electricity Storage
Handbook, Chapter 2 [11], (while noting its disclaimer on
accuracy or completeness of information), has prompted
exclusion of high temperature batteries such as the Sodium-
sulphur and Sodium-nickel-chloride batteries on the basis of
increased risk of bushfire ignition for very remote installation
in the event of accident. The Zinc-Air battery is excluded due
to its air electrode’s sensitivity to inlet air temperature and
humidity changes and de-activation by CO2. High
temperature / humidity changes and the prevalence of dust
storms or bush fire with air-borne particles and CO2 emission
are normal remote Australian conditions. These ambient
conditions pose problems for the Zinc-air battery remote
operation and performance. The Vanadium Redox and Iron
chromium Redox batteries are not included in this study, as
the Zinc Bromide battery as it has an Australian
manufacturer, is considered a reasonable representative for
this type of storage.)
Valve Regulated Lead
Acid (VRLA)
Nickel-iron (Edison
pocket plate)
Zinc-Bromide Redox Flow
Fire ignition risk Minimal
Therma l proximit y to anothe r fire
sourc e will caus e internal thermal
run-aw ay
Electrolyte if heated may release toxic and
highly corrosive hydrogen bromide and
bromine fumes that will react directly with
combustible materials causing their self
ignition; with many organic compounds and
hydrogen burn in bromine gas.
Self-ignition risk Minimal
Thermal run-away due to
overcharge, excessive charge
rate in cold conditions, >65°C
temperature while charging.
Thermal runaway can begin at
80°C, self combustion at 135°C.
Nil Minimal
Fire personnel fighting
precaution requirements
Prote ction fro m acid bur ns and
breath ing appara tus to pr event
fumes acid, lead /antimony/ arsenic
dust/f umes fro m inhalatio n.
Full protection against explosion
using full self-extinguishing fire
suits and self powered self-
contained breathing apparatus.
Face s hield, bre athing mas k
and bod y protect ion suit f or
prote ction agai nst alkali ne air
borne mist.
Bromine impervious facemask, neoprene
based gloves and suit, special bromine
proof respirator or self contained breathing
apparatus. Safety shower after, and not to
eat or drink until showered and full change
of clothes.
Fire Extinguishment
CO2, dry chemical or foam
coppe r based, o r powder
Secondary fire of battery
container - use water, foam,
BCF or powder type
Neutra lise with potassium carbonate solution,
Cool s urrounding areas wit h water to prevent
therma l transfe r to elect rolyte. U se sand or
vermi culite in a fire sit uation to s afely abso rb
any liqu id electro lyte.
Fire Extinguishment risks N ever use W ater
Li-ion batteries as these are
combustible in the presence of
lithium, adding to fire severity.
Do not use CO
or any organic based
foam extinguishers if bromide (brown
vapour) or hydrogen bromide are
present from fire.
Environmental hazards
Lead, antimony and arsenic are
toxic heavy metals in animals,
marine life and insects.
Hydrogen Fluoride (HF) and
fluorine based compounds from
combustion of electrolyte are
hazardous and damaging to the
No long term hazard, localised
immediate damage due to
electrolyte alkalinity that c an
be quickly neutralised.
Persistence in environment
Regulated waste due to heavy metal
toxicity persistence.
Not established - under
consideration at present due to
presence of fluorine in
Human general risk
Lithium is a psychoactive agent,
inhalation of combustion gases
or ingestion are to be avoided by
use of self contained breathing
Nil to minor nickel allergy;
Caustic mist from vented gas
can cause lung irritation, eye
damage if direct, or skin
irritation or burns.
Hydrogen bromide and bromine gas
aggressively attack eye, skin, lung and
internal body membranes.
Human toxicity
Fluorine based flame products
from electrolyte combustion are
destructively reactive to mucous
membranes of eye, lungs and
Nickel compounds are skin /
lung irritants to approximately
10% of human population.
Nickel toxicity is minimal,
requiring ingestion of high
doses of nickel based d ust to
act as a minor carcigen agent.
Chronic toxicity affects include significant
mental ability loss, slurred speech, poor
memory, apathy, anorexia, drowsiness and
sensitivity to touch and pain. Bromine is
also a mutinogenic agent to bone marrow.
Overall environmental and
safety risk assessment.
Medium to High
Very High
Lead, antimony and arsenic are
airborne / ingestible cancer
agents, mutagens, and are highly
Lead inhalation or ingestion at
sufficient levels is a neuro-toxin.
Zinc-bromide electrolyte is classed a long-
term water based pollutant and is
recognised toxic agent to marine and
aquatic life.
Indicates dangerous hazards requiring detailed risk assessment and hazard management in design, operation and disposal.
Indi cates sig nificant hazard requ iring spe cific ris k managem ent respo nses
Indicates hazard requires risk management
Indicates nil or minimal hazard
Risk Assessment Deep Discharge > 5kWh Storage Battery Bank Type
Recycling legal requirements
Heavy metal - reportable and
traceable legal requirement.
Not established - currently under
review due to presence of
fluorine in electrolyte. Lithium
ion batteries require traceability
in recycling.
Zinc-bromide is a reportable and traceable
marine and biological agent.
Australasian Universities Power Engineering Conference, AUPEC 2013, Hobart, TAS, Australia, 29 September 3 October 2013 3
The four readily available industrial battery types for deep
cycle discharge considered in this review will be valve-
regulated lead acid batteries (VRLA) (with the flat plate low
maintenance gel batteries as an industry benchmark for low
cost deep discharge batteries), the new advanced VRLA AGM
glassmat types, lithium-ion (polymer type), nickel-iron
(Edison type) and zinc-bromide flow battery. These
industrially manufactured batteries are cost effective in
regards for large battery arrays. The risk assessment for these
is found in table 1. With regard to risk, each battery
technology has various levels of environmental and
operational handling risks. Lead acid and zinc-bromide
batteries have specific toxic material risk to environment and
personnel [12] - [15]. VRLA battery recycled materials are
generally 20 - 30% dearer than the new component costs, and
vary within this region of on-costs dependant on base metal
prices, container and separator costs at any given time. Large
lithium-ion batteries have high fire risk associated with its
operation [5], particularly if thermal run-away occurs during
charging or operation or battery safety management / cooling
systems fail [11]. Fire breach of this battery will also release
toxic lithium and fluorine compounds [5]. In comparison, the
nickel-iron Edison battery has minimal toxic material risk
from the active material components (noting only a small part
of the population have minor allergic reactions to dermal
contact with nickel compounds). Its electrolyte, in common
with many batteries, is a corrosive alkaline type that can cause
dermal burns if leakage occurs during handling. But
environmentally, there is no significant disposal or handling
issues. Physical dissection and investigation of the Edison
nickel-iron battery in this project found it could be easily
rebuilt by replacement of the negative iron electrode
provided the cell has not been left in circuit for long periods
when fully discharged. Its electrolyte can also be
reprocessed, re-used or re-vitalised. However, by
comparison there are only a few lithium-ion battery
reprocessing recycling plants world-wide, and they
generally require energy intensive cryogenic conditions
[16]. There are traceability requirements for component
recycling or disposal of the VRLA battery (that is, lead &
alloy elements) and for the lithium-ion battery lithium
compounds and electrolyte fluorine. Similarly
environmental and personnel risk exists with bromide
leakage from the Zn-Br flow battery, and this battery
requires the active material interface in each cell replaced as
a matter of course about every 5 years [13]. The Nickel Iron
Edison battery construction is comparatively
environmentally friendly, easily reprocessed, and utilizes
naturally abundant material elements readily and cheaply
available. It has the lowest environmental impact and risk
factor during operation.
For SWER active power injection application during
peak load periods, the discharge rate will normally fall
within the C(2hr) and C(3hr) discharge rate. Generally in
Australian SWER applications there is the single evening
peak that causes the most significant voltage sags. However
in other cultures and developing nations, there can be two or
more peak demand periods per day depending on the rural
enterprise operation and local cultural practices of time use.
Table 2 gives the comparative characteristics extracted from
manufacturer’s publicly released information for the battery
types under study for this discharge rate. In terms of battery
performance the main draw-backs of the nickel-iron battery, in
comparison to the peak performing lithium-ion battery, are its
1.1V cell voltage and the turn-around efficiency (i.e. 62%
compared to 80%). But on the other hand nickel-iron batteries
have significant advantages of long cycle life in the face of
deep discharge, with the ability to withstand overcharge (and
could actually store significant overcharge for short periods).
Similarly major advantage is to the nickel-iron battery that it is
not damaged by undercharge, and has no cumulative corrosion
fatigue provided its alkaline electrolyte pH remains above 9.5
[3], noting its normal pH is above 11. The nickel-iron’s high
self-discharge rate (measured in weeks) is not a disadvantage
in this daily cycle discharge application.
For large battery array development, coupling of nickel-
iron battery with auto-watering, or recombinant hydrogen and
oxygen technology cell caps, would produce a very long life
low maintenance energy storage array. Unlike other batteries,
occasional full discharges and low state of charge, do not
impact on cycle life. The electro-chemistry of the nickel-iron
battery gives these characteristics and life cycle advantages.
Like the nickel-cadmium batteries they also have a very slow
decline in capacity, and do not fade rapidly at around 80%
state of capacity. Lead acid and lithium-ion batteries normally
begin rapid capacity fading below 80% capacity due to
FLOW BATTERIES. [13] [14] [15] [17] [18] [19] [20] [21] [22][23]
Notes for table 2: (i) These characteristics are for this C(2hr) - C(3hr) as compared to the
normal C(10hr) and C(20hr) discharge rating curves generally given for deep
discharge batteries. (ii) Zn-Br battery Watt-hr/kg does not include ancillary parts.
Gel/Glassmat VR Lead
Lithium-Ion Nickel-iron Zinc-Bromide Redox
Open Circuit Cell
2.13 3.6 - 3.9 # 1.21 - 1.31 * 1.83
Turn around
Efficiency high
discharge rate
68% 75% 65% 68%
Cell Voltage at end
of High Discharge
Rate (C2hr) - (C3hr)
1.65 (gel)
2.45 0.9 1.3
Turn around
Efficiency low
discharge rate (C20hr)
75% 90% 72% 72%
Cell Voltage at end
of Low Discharge
1.75 (gel)
2.75 1 1.3
Watt-hr. / kg
30 50 - 70
250 - 1100 (gel)
3000-4000 (glassmat)
20 - 30 % (gel) 30 - 65 %
20 - 90% 20 - 85%
40 - 70% (glassmat)
DoD Memory
nil nil nil Nil
Withstand long
periods @ low SoC
No No Yes Yes
Suffers from
Thermal Run-away
Yes Yes No
Needs Heat Ex changer
Maintenance Free Yes Yes
No No
Max. Charge Rate 0.07 x Cap acity 0.2 x Capacity 0.2 x Capacity 0.2 - 0.25 x Capacity
Tolerance to
No Tolerance No Tolerance Very Good
Batt ery must
disco nnect wh en fully
charge d.
Optimal Depth of
10 - 30%
25 - 60%
20 - 90%
50 - 80%
Autonomy Period
To 4 months To 6 months
14 day s
6 months - year
Specific Fire Hazard
Thermal run-away;
hydrogen venting
Thermal run-away
and self-ignitio n /
Hydro gen vent ing
necess ary.
Release of bromid e
Personal Hazard
Acid e lectrol yte
Vented lithium
and flourine gas .
Alkali ne
elect rolyt e
Bromide Gas
Environmental hazards Heavy metal of lea d Almost nil Br omide / Electrolyte
# depends on type of Lithium-Ion Battery
* As these batteries accept and can store some overcharge - lower voltage is fully charged, upper voltage is retained overcharge voltage
Indicates non-desi rable characteristic
In dicates m ediocre characte ristic
Indicates desirable characteristic
Recommended DoD
Deep Discharge Sto rage Battery Type @ C(2hr) / C(3hr) Discharge Rates
Cycle Life
1000 - 3000
2000 - 9000
2000 - 3000
Australasian Universities Power Engineering Conference, AUPEC 2013, Hobart, TAS, Australia, 29 September 3 October 2013 4
corrosion fatigue affects, changes to active materials in
electrodes and needle crystal growth that can cause bridging
shorting failure through from negative to positive cell
electrodes [3], [21]. The Edison battery has its negative
electrode made of iron, which has the unique ability to reform
its electrode metal crystal structure during charging electrode
reduction to its original size and location. Nickel-iron batteries
share very similar electro-chemistry as the Ni-CAD battery.
Nickel-iron batteries, (in common with nickel-cadmium) are
highly alkaline batteries using potassium hydroxide (KOH)
and / or lithium hydroxide (LiOH), with a pH >11. While the
pH remains above 9.5 in the electrolyte, the entire battery
plate’s and bus structures are entirely pacified (meaning there
is no corrosion) at any of the battery components [3] [24] [25].
As the electrolyte remains very constant in pH during charge
and discharge (i.e. very different to the VRLA battery), there
is no point at all during normal discharge / recharge of the
battery when corrosion can take place. As pointed out by
LAST 100 YEARS” [26] these batteries only very slowly
linearly degrade with usage. This is shared in common again
with the nickel-cadmium battery standards [27] that state,
“Capacity decreases gradually during the life of the battery,
with no sudden capacity loss being encountered under normal
operating conditions. Since the rate of capacity loss is
dependent upon such factors as operating temperature,
electrolyte-specific gravity, and depth and frequency of
discharge, an aging factor should be chosen based on the
required service life (see IEEE Std 1106-1995).” Review for
the nickel-iron battery used in electric vehicle trials by the
Department of Energy (DOE) USA [28], and the electro-
chemistry research by Demidov, Kokhatskaya and Chervonets
[28] revealed capacity loss is via the slow leakage of iron from
the negative electrode, and if over-discharged can actually
transport iron to the positive nickel oxy-hydride electrode.
Normal discharge processes have a small negative electrode
underlying loss of iron in the form of magnetite (Fe3O4) from
the outer edge of the Fe(OH)2.xH2O solgel that forms during
negative electrode active material discharge. In a localized
depletion lower pH boundary between the solgel and the
electrolyte at pH’s above 9.5, high rates of discharge or as
depth of discharge increases, precipitation of black Fe3O4 (a
very stable form of iron oxide) results. It is from this outer
solgel layer, and particularly as the layer of solgel thickens
due to depth of discharge or high rate of discharge, slowing
the hydroxyl (OH-) uptake and passage to combine with the
elemental iron in the negative electrode, which promotes this
slow loss of iron via the Fe3O4 from the negative electrode
results. This iron loss is the black magnetite that DeMar [26]
refers to removing from the old cells as directed by Edison’s
manual [30] for these batteries. There are a number of related
pathways for iron loss leakage via Fe3O4 from the negative
plate of the battery [28], and these will be discussed in a later
paper. One of the observed issue for depth of discharge and
over-discharge in the USA DOE electric vehicle tests [28].
Very severe overcharging splits water into hydrogen and
oxygen, providing a remnant oxygen source in the electrolyte.
In the presence of oxygen there is a zero energy
transformation pathway for formation of from HFeO2-, an
intermediate step in the full hydration of the Fe++ ion directly
to magnetite during immediate high rates of discharge
following an overcharge where dissolved oxygen has not
dissipated from the electrolyte. Alternatively this same end
effect becomes more dominant for ferrous hydroxide to
precipitate magnetite at temperatures above 70°C where the
solgel stability changes state, and then results in increasing
iron leakage losses coating the separators and battery box
surfaces with black Fe3O4. At 120°C the nickel iron battery
works as a primary battery instead of a rechargeable secondary
battery due to this pathway at elevated temperature. To
illustrate this capacity loss and how it relates to depth of
discharge, ChangHong NF-S nickel iron battery characteristics
show the relationship between depth of charge and life cycle
to be below rated 80% capacity in their NF-S battery guide
booklet [31] as shown in figure 1. Management of these
issues during battery array design and operation provides a
very long life for the battery that is only a gradual linear
decline in capacity; i.e. it will not suddenly drop off like most
other batteries. In fact, when nickel iron batteries reach the
standard 80% capacity that is the normal indicative end of life
often accepted criteria in international and Australian battery
standards, it is possible, and makes economic sense for the
20% of additional capacity of nickel iron batteries to be added
to fully replenish the batteries to 100% capacity as a set.
Figure 1: ChangHong NF-S Nickel-Iron Battery Cycle life versus Depth of
Discharge (20°C) [31].
Likewise, nickel iron batteries that have reached a residual
50% of the capacity, provided the batteries had not been so
completely discharged that iron contamination occurs in the
positive electrode, it is possible to just replace the negative
iron electrodes to restore battery capacity. Further, the 80%
state of life capacity neither provides the end of life state for
the nickel iron battery, and re-compensating for lost capacity
can be by additional string of new batteries, or overhaul and
replacement of the iron electrodes in the cells. Alternatively,
if the original nickel iron battery were produced (for such
stationary applications like voltage support active power
injection for SWER networks) with excess iron to allow for
slow dissolution of the iron to magnetite precipitant then any
capacity loss would be further significantly delayed.
To complete this review of battery technology, a standard
30 year capital cash flow present value (PV) costing with 5%
per annum inflation allowance was developed for 5kW-hr
battery array block modules. This final study accounted for
capital costs, depth of discharge (DoD) on cycle life
characteristic, and turn around efficiency. For the
Australasian Universities Power Engineering Conference, AUPEC 2013, Hobart, TAS, Australia, 29 September 3 October 2013 5
characteristic costs and performance variables, the best
compromise was sought for battery size, and DoD effect on
cycle life for each type of battery. The discharge rate range of
C(2hr) to C(3hr) {or averaged C(2.5hr)} characteristic was used
for each type of battery from manufacturers published data.
Table 2 characteristics were accounted for each battery type in
this study. For a 30 year capital life period, 1000A-hr battery
block units were chosen, and the variables considered for cost,
cycle life and disposal were per battery type:
VRLA gel batteries were costed at $1,300 per kWh,
70% turn-around efficiency with DoD for 25% = 3.5
year life [18], or alternatively advanced VRLA AGM
(glassmat) batteries $1,400 per kWh 65% turn-around
efficiency with DoD of 70% = 10 year life [20] [21].
Changhong NF-S nickel-iron batteries at $1,300 per
kWh, ##50% turn-around efficiency with DoD of 50% =
10.5 year life [30]; with residual capacity at 80%,
with the addition of a 20% capacity battery string per
10 years to maintain total system capacity rating. This
is permissible due to the unique corrosion pacification
of this alkaline battery. (##Note the nickel-iron
battery was given a lower turn around efficiency than
normal as a worst case to account for any additional
charging energy required over the other battery types.
The nickel-iron would normally be 60% turn-around
Lithium-ion at $1,500 per kWh with 85% turn-around
efficiency with DoD of 50% = 6 year life [3].
Zinc-bromide flow battery at $1,100 per kWh 73% turn
around efficiency with DoD of 78%; including an
additional $2,500 per 10 year intervals for replacing
active cell replacement costs (also adjusted in time for
inflation) [12] [13] [19].
The 30 year life cycle was chosen as an important
milestone for these battery types to be a coupled asset to a
large solar array (as a potential active power energy source in
SWER networks) that generally has a similar long life cycle.
Included was also costing / replacement cycle method are the
needed inverter/chargers and disposal costs of batteries
requiring replacement during the 30 year battery array life.
These costs also include the difference in turn-around
efficiency for each battery type as shown in table 2. Taking all
of these factors into account, and the specific manufacturer’s
recommended operating / maintenance practices the resulting
capital cost cash flow curves are shown in figure 2 with the
VRLA gel-cell option, while figure 3 shows the advanced
VRLA glassmat option. Cost values are given in 2011
Australian dollars. As can be seen by figures 2 and 3, the
lithium-ion battery has an initial cost advantage up to the 10
year cycle over the nickel-iron battery, even with its absolute
worst case turn around efficiency. At 20 years the nickel iron
battery costs have reduced below those of the lithium-ion, and
at 30 years (to match the life of a large solar array) the
nickel-iron battery has a distinct cost advantage over the
lithium-ion and the zinc bromide flow battery. From figure 2,
the VRLA gel-cell battery is quite expensive as a result of a
standard short cycle life even at 25% DoD; resulting in a
nominally twice the capital outlay compared to the other
batteries studied.
1 2 3 4
$ Cost for 5kWhr Storage System Capacity
Large Run Bulk Production Costs of Usable kWh Capacity for Different
Battery Energy Storage Types (Including Inverter/charger & disposal cost as applicable)
VR Lead Acid Gel-Cell Edison Nickel Iron Lithium-Ion Zn-Br Redox Flow
Start /Commission 10 20 30
Figure 2: 30 year comparison of capital outlay costs of large production run
supply battery production costs of usable 5kWhr modular capacity for
VRLA gel-cell, nickel-iron (Edison), lithium-ion and Zn-Br redox flow
batteries. (Costs included are inverter / charger costs and disposal /
upgrade or replacement capacity costs for each battery life cycle.
1 2 3 4
$ Cost for 5kWhr Storage System Capacity
Large Run Bulk Production Costs of Usable kWh Capacity for Different
Battery Energy Storage Types (Including Inverter/charger & disposal cost as applicable)
VR Lead Acid Glassmat-Cell Edison Nickel Iron Lithium-Ion Zn-Br Redox Flow
Start /Commission 10 20 30
Figure 3: 30 year comparison of capital outlay costs of large production run
supply battery production costs of usable 5kWhr modular capacity for
advanced VRLA glassmat, Nickel Iron (Edison), Lithium-ion and Zn-
Br Redox flow batteries. (Costs include inverter / charger costs,
disposal/upgrade/replacement capacity costs for each battery life cycle.)
Comparing the figure 2’s gel-cell VRLA battery costs to
those of the advanced VRLA AGM (glassmat) costs in
figure 3 show the reduced costs that innovation in the batteries
developed in the past few years by Hitachi [20] and Exide
[21]. Particular development in multi-step charging regimes,
along with no float charging for this type of battery, have been
significant contributors to their life extension to now be 3000
4000 discharge / charge cycles at greater than 50% DoD.
The VRLA battery also would have the second lowest
environmental and operational footprint of the battery types in
this study. (For operational safety reasons alone, the newer
advanced VRLA AGM battery is still a contender against the
lithium-ion technology and zinc-bromide flow battery
technologies.) Summarising figure 3 in cost per kWh for each
battery type for a 2.5hr nominal discharge is as shown table 3.
Comparing these results to the averaged DOE study [10]
results for levelled costs of capacity in commercial/ industrial /
domestic / distributed supplies, ranks Zinc-bromide flow
batteries a cost of $1033 / kW-Yr for a 3hr discharge rate,
advanced VRLA glassmat batteries $810 / kW-Yr for a 2.6hr
discharge rate, and Lithium-ion at $826 / kW-Yr for a 2hr
discharge rate, with each battery technology being costed for a
15 year life. So in scales of relative magnitude, there is
agreement of results with the review undertaken.
Battery Type Adv. VRLA Nickel-Iron Lit hium-Ion Zinc-Bromide
10 year life $1,000 $840 $700 $1,060
20 year life $1,200 $720 $630 $800
30 year life $1,366 $840 $1,100 $1,146
Australasian Universities Power Engineering Conference, AUPEC 2013, Hobart, TAS, Australia, 29 September 3 October 2013 6
Regarding bench marking the nickel-iron battery into this
study, physical testing [32] for a typical domestic RAPS load
profile found that an 85Ahr 11 cell nickel iron NF-S battery
can be used, and is lower by 4% using the Net Present Costs
(NPC) method, than the comparative 6 cell 225Ahr deep
discharge VRLA battery used for this application for a 25 year
life cycle. This was also confirmed by HOMER Energy
software modelling [32]. So even at these reported
comparative costs the nickel-iron battery remains a contender.
Further, using larger nickel-iron batteries than the tested
85Ahr cells in this study would increase this advantage, as the
cost for nickel iron batteries drops as battery cell capacity
increases towards 500Ahr.
With regard to future stationary applications for large
battery storage systems, such as needed by SWER line voltage
peak period support by active power injection, the Edison type
nickel-iron batteries are already worthy of consideration where
space footprint is not a problem. Their long cycle life is well
matched to suit other 20 40 year infrastructure life cycles
(e.g. Solar cell or remnant half-life of SWER networks). Of
the batteries in this study, they have the highest level of safety
for operation, and are the most environmentally friendly over
their long asset cycle lives, especially for remote or very
remote area deployment. A long term USQ research project
continues into modelling nickel-iron battery capacity/fatigue
aging processes, its electro-chemistry and physical redesign to
electrode structures. Concluding, as the Edison type nickel-
iron battery has undergone very little design changes over the
past 100 years; it is now timely for detailed design review for
further research and development. Areas of current research
include reduction in the overall internal impedance of the
electrode structures to improve turn-around efficiency and
improve the battery’s characteristic voltage droop response to
high transient load disturbances. This will include the addition
super-capacitor carbon electrode structures to the benefit of
higher discharge performance as previously reported from
USQ research [33]. Research also continues into the battery
life degradation modelling and potential for the negative
electrode to have excess iron content to extend cycle life to the
nominal 80% capacity mark - while still retaining the inherent
corrosion resistance and the ability of the iron electrode to
reform without distorted metal crystalline structure or micro-
needle formation. The nickel-iron battery’s highly alkaline
iron ferrous hydroxide solgel chemistry is quite unique in
battery technology. This provides clues to possible design
changes to the original Edison battery structure to further
improve its performance.
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... Outra solução, neste caso mais eficiente, consiste na utilização de reguladores monofásicos de tensão [5]. Algumas formas para contornar grandes investimentos de capital para atender à crescente demanda das propriedades rurais têm sido empregadas [3], [8]. Em [3] são apresentados os impactos causados entre sistemas de geração distribuída implementados por meio de sistemas fotovoltaicos e os sistemas de distribuição MRT. ...
... Em [3] são apresentados os impactos causados entre sistemas de geração distribuída implementados por meio de sistemas fotovoltaicos e os sistemas de distribuição MRT. Já em [8], o uso de sistemas de armazenamento de energia por meio de baterias e sua utilização em horários de pico é discutido. Nota-se cada vez mais a necessidade em se utilizar as redes de distribuição trifásicas para atender a demanda por energia elétrica em áreas rurais, em função das mudanças de características das cargas. ...
... Some ways to bypass large capital investments to meet the growing demand of rural properties have been adopted [3], [8]. ...
... In [3], the impacts caused between distributed generation systems implemented through photovoltaic systems and the SWER distribution systems are presented. On the other hand, in [8], the use of energy storage systems by means of batteries and their use at peak demand is discussed. ...
Full-text available
This paper deals with the deployment of a local three-phase four-wire (3P4W) electrical power distribution system (EPDS), using a single- to three-phase unified power quality conditioner (UPQC) topology, called UPQC-1Ph-to-3Ph. The topology is indicated for applications in rural or remote areas in which, for economic reasons, only EPDS with single wire earth return are accessible to the consumer. Since the use of three-phase loads is increasing in these areas, access to a three-phase distribution system becomes preponderant. By adopting a dual compensation strategy, the proposed UPQC-1Ph-to-3Ph is capable of draining from the single-phase electrical grid a sinusoidal current and in phase with the voltage, resulting a high power factor. Furthermore, the system is also able to suppress grid voltage harmonics, as well as to compensate for other disturbances, such as voltage sags. Thus, a 3P4W system with regulated, balanced and sinusoidal voltages with low harmonic contents is provided for single- and three-phase loads. An analysis of the power flow through the series and parallel converters is performed in order to aid the designing of the power converters. Experimental results are presented for validating the proposal, as well as evaluating the static and dynamic performances of the proposed topology.
... • Positive plate collector grid due to over-potential charging. Marco and Jones [3] describe the impact of oxygen formation at the positive plate resulting in an underlay of the grid support of the plate of insulating lead oxide PbO. This results in increase internal resistance of the plate in turn increasing internal battery losses. ...
... Finally, BESS applications also suit development for integration into remote weak grid connected rural power supplies such as is the case for single-wire earth return (SWER) systems as investigated by Helwig and Ahfock (2013). Here correctly placed and sized BESS storage from renewable sources can bolster electrical supply resilience and voltage regulation during peak load periods. ...
The development and incorporation of energy storage into large electricity networks, micro-grids, and partially or fully islanded energy supplies have numerous applications as the sustainable energy generation uptake increases. The vagaries of sustainable energy supplies are driving the energy storage in two distinct directions. Firstly, there will be large scale energy storage such as pumped land or sea-based hydro-energy that can absorb excess renewable energy for the later discharge when there is a deficit in dispatchable energy available. As an alternative to large industrial scale units, there is a potential to develop smaller but numerous distributed smaller energy storage systems that are based on inertial or electro-chemical battery storage. These developments present huge opportunities to change the way sustainable energy uptake continues. Integrated energy storage into electrical supply networks has the ability to alter the way national, regional tied trade blocks and global energy linkage will occur in the future.
... These units further enhance the domestic energy study undertaken, as adding small wind generation provides a wider diversity factor in regards to time of day generation. The domestic solar BESS costs and characteristics utilised as inputs for the HOMER Energy model are as previously reported by Helwig and Ahfock [12]. The HOMER Energy software models use the solar and wind climatic data from NASA for the Toowoomba Region in Australia. ...
Full-text available
This paper assesses the technical, economic, and environmental feasibility of PV/WT/DG/Battery‐based Hybrid Renewable Energy Systems (HRES) using Lead Acid (LA), Lithium‐Ion (LI), and Iron Edison Nickel Iron (IE) battery technologies. The energy cost is optimized, and the obtained results are compared to select the best hybrid system. The LI battery employed in the PV/DG/Battery system (206.43kW PV, 50kW DG, 53.04 kWh LI batteries, and 61.1 kW converter) performed comparatively much better, as Levelized Cost of Energy (LCOE) was reduced by around 28% and 20%, and GHG (Greenhouse Gas) emissions were reduced by 31% and 6% as compared to the LA and IE batteries employed in HRES, respectively. Additionally, sensitivity analysis reveals that the capital cost of PV and the discount rate are more critical to determining the LCOE and renewable penetration. In contrast, the effect of the battery cost and inflation rate is relatively small. Finally, comparing the optimal resource configuration has confirmed that PV/DG/LI has significantly reduced LCOE (58% less than DG/LI) and GHG emissions (87% less than DG/LI).
Conference Paper
Full-text available
Nickel-iron batteries have long life expectancy and are tolerant of abuse or poor charge regimes. However their larger internal impedance often results in premature voltage cut-out with remote area power supplies (RAPS) inverters. A new method for sizing nickel iron batteries is proposed, which incorporates a technique that helps address this problem at the design stage. An economic analysis is presented which reveals that nickel-iron batteries can represent a cost effective solution in some RAPS applications. (4 pages)
Full-text available
The standard Gibbs energies and standard potentials of reactions expected to occur in discharge of the negative electrode of a nickel�iron battery were calculated.
Conference Paper
Full-text available
Remote areas power supplies (RAPS), with their crucial requirement for good inverter input voltage regulation, differ markedly from other applications such as uninterruptible power supplies (UPS), electric vehicles (EVs) and hybrid electric vehicles (HEVs). Also, the overall cost of remote area power supplies is significantly affected by the life expectancy and the cost of associated battery storage. Ultra-capacitors can be used to smooth battery current demand. A smoother current demand results in a steadier inverter input voltage. There are also claims that a smoother current demand profile improves the life expectancy of lead acid batteries. This case study aims to quantify the potential benefit of ultra-capacitor assisted battery storage. It is shown that significant benefits are possible if ultracapacitors are used together with lead-acid or nickel iron batteries.
This note presents an EMF-pH diagram which contains nickel compounds which are consistent with the results of characterization studies.
Much of the calculated emf-pH (Pourbaix) diagram for iron originally derived by Pourbaix is consistent with actual observations of immunity, passivity, and corrosion versus potential and pH. However, one portion of the diagram that disagrees with experimental observation is the prediction that the area of stability of metallic iron lies adjacent to the area of stability of Fe//3O//4 under mildly alkaline conditions. To correct this deficiency, the emf-pH (Pourbaix) diagram for iron has been rederived using newer, thermodynamic values.
Rural Electricity Networks National Workshop Appendix C
  • The
  • Group
The NOUS Group, " Rural Electricity Networks National Workshop Appendix C ", Melbourne 21 April 2010.
Safety Data Sheet According to Regulation (EC) No Valve regulated Lead Acid Battery
  • Yuasa
Yuasa, " Safety Data Sheet According to Regulation (EC) No 1907/2006 (REACH), Valve regulated Lead Acid Battery ", MSCS No. 853023 Revision 08 Dec 2011.
Lithium-Ion Batteries Hazard and use Assessment Final Report The Protection Research Foundation
  • P Mikolajczak
  • M Kahn
  • K White
  • R T Long
P. Mikolajczak, M. Kahn, K. White, R. T. Long, " Lithium-Ion Batteries Hazard and use Assessment Final Report ", The Protection Research Foundation © 2011.
Lithium Ion Batteries for Stationary Applications: A Safety Perspective
  • A Arora
  • J Harris
  • B Pinnangudi
Arora A, Harris J, Pinnangudi B, "Lithium Ion Batteries for Stationary Applications: A Safety Perspective", BATCON Conference, Florida 2012.