Solar PV Battery Storage System
Trial Project
Funded by the LGA Solar Councils
Innovation Fund 2013
Prepared by:
City Strategy
August, 2014
Solar PV Battery Storage System Trial Project
1. BACKGROUND...........................................................................................3
2. THE PROJECT............................................................................................3
3. SITE SELECTION ....................................................................................... 3
4. INSTALLATION SITE..................................................................................5
a)
Lighting .............................................................................................................................5
b)
Mechanical load ...............................................................................................................6
c)
Other electrical .................................................................................................................6
d)
Electrical phases..............................................................................................................6
5. SYSTEM INSTALLATION ........................................................................... 6
6. SYSTEM OPERATION ................................................................................8
7. BATTERY CAPACITY............................................................................... 10
8. BATTERY LIFE-CYCLE IMPACTS........................................................... 10
9. PROJECT INITIAL OUTCOMES............................................................... 12
a)
Energy savings ............................................................................................................. 12
b)
Billing data changes ..................................................................................................... 14
c)
CO2-e savings ............................................................................................................... 17
d)
Financial savings .......................................................................................................... 17
e)
Economic analysis........................................................................................................ 18
f)
Community benefit ....................................................................................................... 18
10. LEARNINGS............................................................................................ 19
11. ALTERNATIVE RENEWABLE ENERGY SYSTEMS.............................. 20
a)
Off-grid supply – no grid connectivity ........................................................................ 20
b)
European Bosch VS 5 Hybrid – only released in 2013.............................................. 20
c)
ZEN Freedom Powerbank – grid connectivity, approved by SA Power Networks. 21
d)
Silent Power OnDemand Energy Appliance – only available in USA...................... 21
Badminton Hall historical billing data ................................................................................. 22
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Solar PV Battery Storage System Trial Project
1. Background
The City of West Torrens owns 16 grid connected solar photovoltaic (PV) systems
providing renewable energy to community use buildings.
Amendments to the Electricity Act 1996 in 2012 removed Council’s ability to receive
the network feed in tariff for more than the first installed solar panel system; we are
now considered to be a “multiple generator” because Council is the electricity
account owner at more than one site. In response to this, some accounts have been
transferred to tenants so that they are eligible to collect the network feed-in tariff,
however this is not possible for all sites.
This change impacts the return on investment and reduces the financial viability of
future solar panel (grid connected) renewable energy systems. It also has a
detrimental impact on the tenants who pay the electricity bill (via on-charging) as they
no longer receive the financial benefit of a feed-in tariff.
With the constant increase in electricity prices, the City of West Torrens was
interested in investigating alternative renewable energy systems that maximised the
use of energy rather than off-setting the costs via feed in tariffs, such as battery
storage systems, fuel cell technology or tri-generation.
For a small scale approach with practical application at the local level, we chose to
pursue solar PV battery storage through a ZEN Freedom Powerbank.
2. The project
A 7 kilowatt grid connected solar panel system was installed in conjunction with the
ZEN Freedom Powerbank battery storage unit at WA Satterley Hall in Lockleys.
An inline energy monitoring system was installed to capture patterns of energy use
within the building to ensure the balance between day and night power consumption
could be met by a solar PV battery storage system.
The ZEN Freedom Powerbank is currently the only three way renewable energy
system approved for use on the South Australian electricity network. It utilises solar
power direct from the panels, with excess fed into the battery unit and additional
power exported to the grid. Power from the battery is drawn as programmed,
meaning it can supply solar electricity during peak periods (7am-10pm) or off-peak
periods (10pm-7am) as the building requires.
Grid electricity is only used when the solar panels are not generating electricity and
the batteries have been depleted.
3. Site selection
Initially, Council identified a local sporting club with substantial electricity
consumption as the trial site. The site turned out to be unviable for a number of
reasons.
Below is a table of site criteria that can be used to select an appropriate location for a
solar PV battery storage system based on the ZEN Freedom Powerbank. It is
worthwhile investing time and resources to investigate the viability of a site before
seeking quotes for system installation.
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Solar PV Battery Storage System Trial Project
Table 1: Site selection criteria
Criteria
Considerations
Roof space
A 7kw panel system requires 28, 250W modules each
1650mm x 992mm. Enough physical space with room for
access is essential.
Roof orientation
A north facing roofline with a pitch is preferable however
mounting frames to provide an appropriate angle can be
installed at an additional cost.
Roof structure
Shading and
shadowing
Each solar panel module weighs 25kg. A 28 panel, 7kw
system weighs a total of 700kg. A structural review of the
building where the solar panels are being located is
worthwhile.
Shading from overhanging trees or shadowing from nearby
buildings or objects affect the performance of the panel
system. Even if only one panel is obstructed, it may shut
down a string of panels and reduce performance of the
entire system.
Electrical switchboard
The electrical switchboard should be in good working order.
Older Council buildings may not have a suitable
switchboard, or the switchboard may contain asbestos,
delaying installation until a specialist has removed the
hazard.
Electrical wiring
A review of the electrical wiring is essential to ensure it can
connect safely to the new wiring for the inverter and battery
storage unit.
Internet connection
The battery monitoring system uses internet connectivity and
an online portal for managing the battery discharge and
recording data. A local area network (LAN) connection is
preferred, but a Wi-Fi modem set up can be used.
Energy demand of
building
A 7kW solar panel system generates 11,650 kilowatt hours
of energy per year. The battery unit stores 20 kilowatt hours
of useful energy therefore the building should be selected
based on a consumption pattern of at least this (otherwise
more solar energy is exported- rather than used) with an
operational timespan over the entire week.
Energy balance
A battery storage system operates optimally with a building
that consumes some (but not all) energy during the day and
also at night. This energy must come from the peak load (not
off peak e.g. hot water). An energy monitoring unit helps to
identify electricity load patterns and determine the correct
energy balance
Battery storage
system
The battery storage unit and inverters need to be located in
a cool, well ventilated position protected from the weather
and preferably close to the switchboard or electricity meter
box and solar panels to reduce energy loss during transfer.
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Solar PV Battery Storage System Trial Project
4. Installation site
W.A Satterley Hall at Lockleys Oval complex was chosen to host the solar PV battery
storage system trial. This building is tenanted by Badminton SA and is the
headquarters for the South Australian Badminton Association. The building is well
utilised both during the day, evenings and weekends throughout the entire year and it
has a substantial electricity bill. Average annual electricity consumption in the two
years prior to the solar PV battery storage system installation was:
Table 2: Annual electricity consumption - billing data
Peak
Off-peak
Total
2011 - total
kWh
consumed
14,548
27,716
42,264
2012 - total
kWh
consumed
13,874
24,099
37,973
Annual
average kWh
consumed
40,119
The sports hall was built in 1957 and comprises a main playing arena (with 7 indoor
courts), a pro-shop, a large kitchen facility, a clubroom, meeting room and toilet /
shower facilities.
a) Lighting
There is no natural lighting for the main playing arena and special vertical lighting
configurations are used for the courts to prevent overhead glare during badminton
matches.
Each of the seven courts has a bank of six 2x36W magnetic ballast fluorescent
luminaires which consume around 98 watts, totalling 1.2kW per court.
Court lighting is controlled by a basic system (switches and timers), with 2 of the
courts on their own specific electrical phase and the remaining 5 courts linked
together with other building lighting (kitchen, bathrooms, clubroom, security) and
electrical appliances (air conditioner, rainwater tank pump) on a separate phase.
Court lighting accounts for 63 per cent of energy used throughout the building.
The amount of lighting consumed at the site is directly related to the operational use
of the building. Badminton is played all year round at W.A Satterley Hall for club
competitions and for private games (via hire arrangements). Due to the limited
natural light of the playing arena, lighting is always used when the courts are being
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Solar PV Battery Storage System Trial Project
occupied. It is even likely that lights are left on, or more than the required court
lighting is turned on, increasing the demand for electricity at both peak and off-peak
times.
b) Mechanical load
The mechanical electrical load provides power to the refrigerators which run 24/7.
The kitchen is equipped with a large 3 door glass fronted fridge with a capacity of 800
watts, a small domestic fridge / freezer, and a drink vending machine in the
clubroom.
The mechanical load accounts for 27 per cent of the building's total energy demand
and has fairly consistent consumption patterns throughout the year.
c) Other electrical
A number of other miscellaneous electrical devices are used in the building, including
a small reverse cycle split system air-conditioner in the meeting room (the playing
arena is not air-conditioned), computers, a rainwater tank pump and 240V power
points. Hot water is supplied by gas instantaneous units.
d) Electrical phases
The electricity demands of the building are split across the three phases with the
mechanical load on one phase, the lighting for 2 playing courts on one phase and all
other lighting and electrical appliances on the third phase. The exact distribution of
electricity throughout the building is difficult to detect without a specific series of
electrical tests (this is planned to occur shortly).
5. System installation
The ZEN Freedom Powerbank was installed in August 2013.
The solar panels were mounted directly to the north facing roofline and the two
inverters and battery storage unit contained in a storage room (that was insulated to
protect the equipment) adjacent the electrical switchboard.
Prior to installation, a power phase monitoring unit was installed to collect real time
data on the energy consumption of each of the three phases and the electrical wiring
of the building and switchboard were checked.
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Solar PV Battery Storage System Trial Project
It was found that the lighting phase wiring was old and needed significant
replacement to cope with any connection to the new solar PV battery storage system
and that the lighting patterns and consumption levels were too high and sporadic for
the solar battery unit to work optimally.
The mechanical phase provided a more constant demand at levels which could be
managed within the capacity of the storage battery unit. It also demanded electricity
during the peak period (when electricity is at its most expensive) and the off-peak
period which provided a better financial reward.
The solar PV battery storage system was therefore connected to the mechanical
phase and programmed to provide electricity at optimal times.
As installation occurred, new solar panel technology became available with microinverters to reduce the panel generation loss from issues such as shading or faulty
panel, which switch off an entire bank of panels, rather than just one or two affected
by the fault. Unfortunately, it was too late to install the micro-inverter panels at this
site (although shading is an unlikely issue).
In the first two months of installation (September - October 2013) the inverters
showed a total solar generation value of 3,592 kWh.
It took nearly 6 months for SA Power Networks to install the required export meter.
During that time no exported electricity was recorded or credited to the electricity
account. This occurred over the spring months when opportunity for sunlight was
good. An export meter was installed in early January 2014.
Billing account information from the electricity retailer did not show any substantial
changes during the first 5 months (with the old meter). Detecting consumption
changes on the bills was also difficult due to the estimation and adjustment process
used to create the billing consumption figures (by Powerdirect). The 3,592kWh
saving indicated by the inverters could not be easily identified in the billing data.
The ZEN Freedom Powerbank has an online portal which provides ongoing data
relating to the activity of the solar battery unit. The data provided is quite technical
and requires some level of expertise in electrical knowledge to decipher its meaning
and patterns. The total kilowatt hours of electricity discharged by the battery is
provided on the main dashboard.
The online portal is web based and therefore requires an internet connection. The
badminton hall did not have internet access and requests to Telstra to create a Local
Area Network (LAN) connection failed due to a "blackspot" issue. In the end a
wireless network was used, with a new account and service plan having to be
created in Council's name (so the club didn't incur the cost).
Data from the electricity meter, solar inverters, online portal and electricity bills were
collated, however evaluating the actual results and patterns of use from the
installation of the solar PV battery storage system was difficult.
Subsequently an e-Gauge monitoring device was installed to gather real time data of
all the electricity use patterns for each of the electrical loads (lighting, some lighting
and appliances, mechanical, solar generation and battery discharge.) This provided
more detailed analysis of the workings of the solar PV battery storage system.
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Solar PV Battery Storage System Trial Project
6. System operation
The solar PV battery storage system was designed to operate specifically for the site
where it is installed. The system comprises:

7kW of solar panels - includes 28, 250w panel modules

2 Kaco inverters (3.5kW rated output each)

One battery unit system with a 20kWh storage capacity - contains 16 lithium
iron phosphate cells

One control unit.
When the solar panels are generating energy (sunny days) renewable electricity is
dispatched to the mechanical load (blue phase) via the battery bank and additional
energy is stored in the battery for future use.
In peak times (when electricity is most expensive) the battery bank and the solar
panels supply the mechanical load until the batteries are depleted to 30% of their
total capacity. At that time, the renewable energy system automatically switches over
to the grid and imports electricity.
In Figure 1 below, data from the E-Gauge pin points the exact times the mechanical
load (blue phase) is being supplied from the renewable energy system and when it
switches back to grid power. The blue line represents grid energy consumption,
therefore when grid energy is low or almost zero, it identifies the renewable energy
system at work.
Figure 1: blue phase grid electricity consumption 24 hour pattern
In the above example, the solar battery system provides renewable energy to the
mechanical load from 10am until 10pm - well past daylight hours. Grid electricity that
would have been consumed during this time is charged at the peak rate, therefore
the battery system is saving $0.31 cents per kWh it operates.
On June 30, 2014 there were only 3 hours of sunlight recorded at the Adelaide
Airport weather observation station. Yet this level still provided enough solar energy
to support the battery and mechanical load supply for almost 12 hours.
Figure 2 below shows the activity of the mechanical load where solar energy is
exported to the grid. This is identified by a negative record on the E-Gauge.
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Solar PV Battery Storage System Trial Project
Figure 2: blue phase grid electricity with solar energy exported.
The energy balance was carefully determined before the solar PV battery storage
system. This ensures that very little energy is fed back into the grid and that it is
either used onsite or stored in the battery bank for use during peak periods. This did
require some adjustment once the system was up and running.
On some days (even in July - mid-winter) the E-Gauge data monitoring system
shows renewable energy providing electricity right through until 2am or later, offsetting the cost of off-peak power as well as peak power. Savings of off-peak power
also occur over the weekend when up to 30 hours of electricity is supplied by the
solar PV battery storage system.
Figure 3 below shows the pattern of peak and off-peak energy supply from the solar
battery bank over a three day period including a weekend.
Figure 3: solar battery system energy supply at both peak and off-peak times
Solar battery storage system
supplies energy to Satterley
Hall
Off-peak
Peak
Peak
Off-peak
The hybrid operation of the system provides the security of seamless switching to
mains electricity when the renewable energy (solar panels and battery bank) are not
available, in much the same manner as standard grid interactive solar panel systems
operate.
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Solar PV Battery Storage System Trial Project
This is in contrast to remote stand-alone solar systems that require a third back up
power source such as a petrol or diesel generator, together with substantial micromanagement of onsite electricity consumption to ensure the energy balance can
supply the demands of the building.
Table 3: Different types of solar systems
Solar system
Remote solar battery
system
Grid interactive solar
panel system
(most metro domestic
systems)
Hybrid grid/solar
storage system
(Installed system)
Description
Solar energy is used to supply electricity during daylight
hours and charge the battery bank. Once the sun has set,
the battery begins discharging electricity until its capacity is
reached. Additional energy demands are met by a petrol or
diesel generator.
Solar energy is used to supply electricity as demanded
during daylight hours. Additional solar energy that is
generated but not consumed on site is exported to the
main grid to be utilised by other grid users. At night
electricity is provided directly from the grid.
Solar energy is used to supply electricity demands during
daylight hours and to charge the battery bank. The battery
bank continues to discharge electricity until its capacity is
reached and then grid electricity is automatically imported.
Any additional solar energy (once demand is met and
batteries are full) is exported to the main grid.
7. Battery capacity
The system installed uses lithium iron phosphate batteries which are generally
considered a long-life battery and have a very constant discharge voltage. This
improves the battery capacity and hence there is a slower rate of capacity loss
meaning it will last longer than other forms of lithium ion batteries.
The lithium iron phosphate batteries have a life of approximately 2,000 cycles (the
number of times the battery is full discharged).
Based on a rate of 365 cycles per year, as the batteries are discharged daily at the
badminton hall, it is likely the batteries will last at least five and a half years. The
control equipment allows the batteries to discharge down to 30 per cent of their
capacity. This will likely extend the life beyond the five and a half years, but other
factors such as ambient room temperature, the amount of time the battery remains
fully charged and the number of discharges all act to vary the actual life-span of the
battery.
The warranty on the batteries is 5-8 years, which is consistent with the information
above. Depending on the change in technology, it is not known if the batteries can be
simply replaced or an entire system must be re-installed.
8. Battery life-cycle impacts
Lithium iron phosphate batteries operate using iron phosphate as the cathode
material.
Standard lithium-ion batteries are based on a cobalt cathode and are made from:
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Solar PV Battery Storage System Trial Project

22% Iron

3% Lithium

18% Cobalt

5% Aluminium

52% other non-metal content.
The lithium is derived from brine (salt lakes) and hard rock and can be recycled an
unlimited number of times, however in general, lithium-ion batteries yield too little in
precious metals to be viable for recycling unless in massive quantities. The cobalt
component of a lithium-ion battery cathode represents the most rare, expensive and
toxic part of the battery. Acute, high-level exposure to cobalt (in production and
processing of the material for products such as batteries) can cause respitory
problems in humans and be dangerous to human health.
The lithium iron phosphate battery does not contain cobalt, it uses iron phosphate in
the cathode material. Iron phosphate is most commonly used in snail bait, so whilst it
is toxic to some creatures, it is less toxic to humans than lithium-ion batteries with a
cobalt cathode.
The US EPA released a study in April 2013, assessing the life-cycle impacts of
lithium-ion batteries for electric vehicles. It compared a number of lithium based
batteries including lithium iron phosphate (LiFePO4), lithium manganese oxide
(LiMnO2) and a tri-metal lithium-ion battery that used nickel-cobalt-manganese oxide
(LiNi0.4 CO0.2 Mn0.4 O2).
The life-cycle assessment commenced at ore extraction, included raw materials
processing, product manufacturing, use (in an electric vehicle), plug in grid electricity
consumption and end of life disposal. While the study doesn't directly relate to the
use of batteries for solar energy storage, the information about the batteries
themselves can be applied.
The study found that batteries with cathodes containing nickel and cobalt, as well as
solvent-based electrode processing, have the highest potential for environmental
impacts. The production, processing and use of cobalt and nickel metal compounds
contributed to resource depletion (mining), global warming, ecological toxicity and
human health impacts (respiratory, pulmonary and neurological).
Cathode material substitution (replacing the cobalt) was considered a viable method
to reduce the negative impacts from lithium-ion battery manufacturing and use, in fact
the cathode material and cathode manufacturing process was considered to be a
significant contributor to negative impacts across all the categories included in the
US EPA study.
The end of life stage of a lithium-ion battery was also assessed as part of the lifecycle. The study was focussed on electric vehicle manufacturing, which already has
an established recovery and recycling attitude due to the scheme created by General
Motors to recover lead acid batteries after the demise of the crank vehicle in the
1940's, so it's comparison to Australian battery recycling opportunities outside of the
vehicle industry is difficult to ascertain.
The study was also based on information from current battery recyclers and recycling
processes (in the USA) and did not take into account future opportunities.
There are four key recycling processes that may be used to recover materials from a
lithium-ion battery:
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Solar PV Battery Storage System Trial Project

Hydrometallurgical Recovery - this can recover the cobalt, some plastics and
steel and lithium brine.

Pyrometallurgical Recovery (high-temperature) - relies on a smelting process
to recover the metal oxides and turn them to molten metal alloy which can be
used for new cathode material.

Direct recycling process - includes physical and chemical separation of metals
and materials which can be made suitable for reuse in battery applications.

Refurbishment - a possible transition from vehicle battery to other applications
such as computers or electronics by rejuvenating the battery cells.
The lithium-ion cobalt based batteries are assessed as being the least human and
environmentally friendly through the production and manufacturing stage, however at
the end of life stage the value of the cobalt and nickel creates a better incentive for
these types of batteries to be recovered ($30,000 per tonne of value). On the flip
side, cobalt cathode batteries are starting to decline in use as new chemical batteries
(iron phosphate and manganese) are progressed in the industry, so eventually
incentives to recycle will decline.
The demand for lithium worldwide is expected to exponentially increase as electric
vehicles become more common and this is likely to drive recovery and recycling of all
lithium-ion type batteries as virgin Lithium sources are depleted.
The US EPA full study can be found here:
http://www.epa.gov/dfe/pubs/projects/lbnp/final-li-ion-battery-lca-report.pdf
In West Torrens, general domestic batteries collected by CMA EcoCycle are
transported to Melbourne and then sent to MRI E-Cycle Solutions. They would
accept the lithium iron phosphate batteries from the solar PV battery storage system.
MRI E-Cycle Solutions advised that there is no operation in Australia to recycle
lithium based batteries. These are collected and sent to Korea and a
hydrometallurgical recovery process is most likely used for a lithium iron phosphate
battery.
At present, lithium iron phosphate batteries are considered a relatively new
technology and there have not been high volumes of batteries for disposal. The most
common use is in the production of electric bicycles manufactured in Korea but new
hybrid car technology is under development based on the iron phosphate battery.
So whilst there is a current solution to recycle of lithium iron phosphate batteries
through a local collection service, the overseas transport and reprocessing
component has unquantified environmental and human health impacts.
9. Project initial outcomes
a) Energy savings
The system contributes 11,650 kWh annually to the site. This is equivalent to
approximately 29 per cent of the site's total consumption.
The solar PV battery storage system reduces energy consumption on the mechanical
load (blue phase) so that it represents just 13 per cent of total energy demand of the
building whereas without the solar battery unit it accounted for almost 30 per cent.
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Solar PV Battery Storage System Trial Project
The diagrams below show the difference in the proportion of energy demand with
and without the solar battery unit.
Figure 3: Annual energy consumption by phase type - No solar
Figure 4: Annual energy consumption by phase type - with solar battery unit.
Table 4 shows all the energy consumption types for each of the three electrical
phases in the charts above and the volume of kWh consumed with and without the
solar battery unit.
The blue phase (connected to the solar battery unit) indicates a 61 per cent reduction
in mains energy consumption with the installation of the solar battery system.
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Solar PV Battery Storage System Trial Project
Table 4: Electrical phase connections
Total kWh
(no solar)
Total kWh
(with solar &
battery)
% change
Court lighting - 2 playing courts
8,725
8,725
0
White
Court lighting - 5 playing courts
Kitchen lighting
Clubroom & meeting room lighting
Emergency and outdoor security
lighting
Bathroom lighting
Computers & powerpoints
Reverse cycle split system airconditioner.
Rainwater tank pump
25,269
25,269
0
Blue
Kitchen refrigerators
Drinks vending machine
12,646
4,981
- 61%
TOTAL
46,640*
38,975*
- 16 %
Phase
Red
Type of use
* data is has been extrapolated from the e-Gauge unit and is forecast based on May-June 2014 actual
data.
When comparing the above predicted savings and comparisons forecast for 2014/15
using the onsite monitoring system, it is interesting to note that the billing data
(shown in section b) below) doesn’t always reflect the anticipated changes to
electricity consumption.
b) Billing data changes
The energy savings created by the system are attributed to both the peak and offpeak load.
During the winter months (on sunny days), the battery unit can still supply enough
energy to power the mechanical load from 9.30am till 10pm (peak times) and then up
until 2am or later (off-peak) and provides off-peak electricity supply over the weekend
periods. This is shown by the onsite e-Gauge monitoring system (see Figure 3
above)
The billing data isn’t directly reflective of the e-Gauge for numerous reasons
including:

Timescale of comparisons is not the same.

A change in electricity retailer and meter reading operations has occurred, so
historical comparison is more difficult.

Billing data has moved from a monthly to quarterly cycle.

Some billing data has been estimated.

Some historical billing data has been adjusted due to over or under
estimations.

Current billing data is only available for the first 6 months of the solar PV
battery storage system installation.
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Solar PV Battery Storage System Trial Project
Peak energy use as provided on the bill is shown in Table 5. It indicates an increase
in peak energy consumption compared to the same time last year (2013). This may
be as a result of changes to the operational use of the building (an increase in
patronage in 2014, a change in lighting configurations etc).
Table 5: Peak energy consumption - billing data
Year
2011
2012
2013
2014
Consumption
period
Jan - March
Jan - March
Jan - March
Jan - March
Peak
total
kWh
2241
3525
3128
3983
% change
since
previous
year
57.30
-11.26
27.33
Consumption
period
April - June
April - June
April - June
April - June
Peak
total
kWh
4364
4079
2891
4202
% change
since
previous
year
-6.53
-29.12
45.35
Off-peak energy use as provided on the electricity bill is shown Table 6. It indicates a
reduction in off peak energy consumption compared to the same time last year
(2013), but an overall trend in less off peak power consumption. It is difficult to
ascertain the exact reasons, again it may be changes to operational use of the
building but the solar battery bank is likely to be contributing to this reduction given its
weekend supply of off-peak power.
Table 6: Off peak energy consumption - billing data
Year
2011
2012
2013
2014
Consumption
period
Jan - March
Jan - March
Jan - March
Jan - March
Off peak
total
kWh
6951
5951
6526
4286
% change
since
previous
year
-14.39
9.66
-34.32
Consumption
period
Off peak
total
kWh
April - June
April - June
April - June
April - June
8420
7965
5515
4521
% change
since
previous
year
-5.40
-30.76
-18.02
Overall, the increase in peak energy is being offset by the decrease in off peak
energy when looking at total consumption for the first and second billing cycles since
the solar battery system and SAPN export meter was installed. This is shown in more
detail below.
First billing cycle
Total electricity consumption data for the third quarter has been collated from the
billing data and is shown at Table 7. The January to March period in 2014 was the
first full billing cycle after the SAPN solar export meter was installed and so
comparisons against the same time period are helpful to ascertain any changes in
total energy consumption.
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Solar PV Battery Storage System Trial Project
Table 7: Total energy consumption January to March - billing data
Year
Consumption
period
2011
2012
2013
2014
Jan - March
Jan - March
Jan - March
Jan - March
Total
kWh
% change from
previous year
9,192.00
9,476.00
9,654.00
8,269.00
3.09
1.88
-14.35
The January - March 2014 electricity bill showed 104 kWh of solar energy was
exported to the grid which credited just $8.01 to the account; this is the retailer feedin tariff.
Second billing cycle
Total electricity consumption data for the fourth quarter has been collated from the
billing data and is shown in Table 8. The April to June period 2014 was the second
full billing cycle since the SAPN solar export meter was installed.
Table 8: Total energy consumption April - June - billing data
Year
Consumption
period
2011
2012
2013
2014
April - June
April - June
April - June
April - June
Total
kWh
11,315.00
12,044.00
8,406.00
8,723.00
% change
from previous
year
6.44
-30.21
3.77
It is more difficult to determine actual electricity savings as a result of the solar PV
battery storage system when comparing total consumption in the April to June period,
given there was a 30 per cent reduction in total consumption in this period between
2012 and 2013 - before the battery unit was installed.
This consumption change also coincides with a change in energy retailer (from
Powerdirect to Origin) and so may be related to a difference in meter reading or
behaviour change of the building's users.
The April - June 2014 electricity bill showed 110 kWh of solar energy was exported to
the grid, crediting $8.36 to the account.
The trend in electricity consumption patterns as shown on the bills is presented in
Figure 5.
16
Solar PV Battery Storage System Trial Project
Figure 5: Electricity bill data comparisons for the two billing cycles over time
14000
12000
10000
8000
off peak
6000
peak
4000
2000
0
2011 2012 2013 2014
2011 2012 2013 2014
April - June 2014
January - March 2014
Overall, using just the billing data to quantify benefits or changes to electricity
consumption as a result of installing the solar battery system is fraught with
complications due to the numerous factors that affect electricity consumption at the
site. The installed e-Gauge monitoring system provides a more reliable method for
analysis.
The e-Gauge was installed on 1 May 2014 and so it will be imperative to re-evaulate
the performance and outcomes of the solar PV battery storage system after a full 12
months of e-Gauge data and billing information is available.
c) CO2-e savings
The estimated greenhouse gas savings from the system is 4.75 tonnes per annum.
d) Financial savings
The system is programmed to start operating during peak times meaning that the
financial savings are returned at the peak power rate. This increases the financial
savings now that network feed-in tariffs for grid connected solar panel systems are
no longer available to Council.
Actual data patterns (based in July 2014 e-Gauge interval data) indicate that
approximately 55 hours of peak power is provided by the battery unit and 50 hours of
off peak power on a weekly basis. The financial savings are shown below.
Table 9: Financial savings
Electricity
type
Hours per
week of
renewable
energy
55
Weekly
savings
($)
Annual
savings ($)
Peak
Cost per
kWh ($) Origin
Energy
0.31599
17.38
903.76
Off-peak
0.1750
50
8.75
455.00
110
$26.13
$1,358.76
TOTAL
17
Solar PV Battery Storage System Trial Project
These figures may alter in the summer months when sunlight hours are longer or the
price of electricity changes.
Using an average cost of $0.24 cents per kWh, the financial savings gained from
using all the energy provided and stored in the solar battery system is still
significantly better than exporting the peak energy and receiving the current feed-in
tariff rate of just $0.076 cents per kWh.
e) Economic analysis
The ZEN Freedom Powerbank cost $40,000 to purchase and install - this excludes
the ancillary costs associated with SA Power Network meter changeover, general
electrician costs, installation of the e-Gauge and internet connection fee.
Below is an economic comparison between the solar PV battery storage system and
a standard grid interactive solar system based on a simple payback method where all
savings from each system are costed at the peak power rate and export tariffs are
excluded.
Table 10: Economic comparison
System
Cost ($)
Financial
savings ($)
ROI %
Simple
payback (y)
Grid interactive
7,500
1,447
19.3
5.2
ZEN Powerbank
40,000
3,681
9.2
10.87
To be competitive, a ZEN Freedom Powerbank would need to cost approximately
$20,000 fully installed if all other factors stayed the same. Of course, continuous
increases in electricity prices would swing the cost / benefit analysis in favour of the
installed system in the future.
From a purely economic perspective, the simple payback period is longer than the
life expectancy of the battery bank. This means Council's investment would not be
returned prior to further capital investment being made to maintain the solar battery
system.
f)
Community benefit
The badminton hall is used by a wide range of people, both local residents and
interstate visitors. The financial benefits from a lower electricity bill will contribute to
the Badminton Association of SA's economic sustainability which in turn supports an
active population (more tournaments, equipment, improved facilities) and local
tourism (visitors, supporters and game officials) within the City of West Torrens.
The badminton community are also being exposed to the concept of renewable
energy and solar energy storage, and by working with Council on this project they are
learning about the risks and benefits of solar energy. There is educative signage at
the hall that helps to generate curiosity and conversations about new forms of solar
technology which can be exponentially shared amongst family and friends of players
or visitors.
The larger West Torrens community also gains benefit through knowledge and a
better understanding of solar technology because Council is sharing this experience
and learnings with them.
18
Solar PV Battery Storage System Trial Project
10. Learnings
The City of West Torrens Solar PV Battery Storage Sytem Trial Project shows that a
correctly calibrated hybrid solar grid connected / battery bank system can effectively
help reduce the consumption of peak and off-peak electricity at community-use
buildings, generate energy cost savings and reduce greenhouse gas emissions.
The system must minimise the volume of exported renewable energy and utilise
almost all electricity generated within the building, either directly from the panels or
through the battery bank - preferably during peak power times (7am - 10pm, Mon-Fri)
The current cost of installing a battery storage system is less attractive when
compared (on simple payback) to a standard grid connected solar panel system,
however the solar battery system has superior energy cost savings where peak
electricity can be substituted for "free" renewable energy, especially at sites where
feed-in tariffs are low.
The lack of market competition for domestic scale a hybrid solar grid connected/
battery bank systems in South Australia is a barrier to driving the price down on this
type of technology, particularly when the ZEN Freedom Powerbank is the only SAPN
approved system of this type.
A summary of learnings is presented below:

A site which uses both peak and off-peak energy across the entire week and
weekends throughout the entire year provides the best opportunity to
maximise savings from a solar battery system. Not all types of Council
buildings are utilised to this extent, so understanding the operational use is
vital to selecting a viable installation site.

Investing in an electricity demand monitoring system (e-Gauge) for at least 3
months prior to determining a suitable installation site (if all other criteria are
met) provides the best analysis for decision making. An installer (or Council)
which does not do this is simply guessing the patterns of consumption, which
may not be in reality as they seem. A monitoring system that can be adapted
to include a solar system after the initial monitoring period would work best,
so that before / after comparisons can be made.

Relying on the billing data from the electricity retailer to evaluate the cost or
energy effectiveness of a solar battery system is not a true indication of the
benefit (or otherwise) from the investment.

Data provided on the electricity bill cannot provide enough detail to determine
if the solar battery system has been installed and calibrated correctly, this
needs to be done by a dedicated demand monitoring system (e-Gauge).

Undertake an electrical review of the proposed installation site. Many Council
buildings are old and the wiring may not be compatible for easy (and cost
effective) connection to new solar technology.

Book the SA Power Networks meter changeover arrangements as soon as
possible. The delay in installing this is to the detriment of the financial savings
associated with the solar system.

Review internet accessibility. Energy monitoring systems and the ZEN
Freedom Powerbank online portal require internet capabilities. These online
19
Solar PV Battery Storage System Trial Project
systems also allow easy access to real time data monitoring and system
functionality (identifies faults and disconnections with the battery bank).

Lithium iron phosphate batteries have less negative environmental and
human health impacts than standard lithium-ion batteries when assessed
across the life-cycle. The use of an iron phosphate cathode in lieu of cobalt
reduces toxic risks, but also reduces incentives to recycle at end of life as
cobalt has significantly higher recovery value than iron ore.

Lithium iron phosphate batteries can be recovered in Adelaide and are sent to
Korea for recycling, so there is a local disposal option which diverts this waste
from landfill.

To truly evaluate the changes and benefits (or otherwise) of the solar PV
battery storage system, at least a full 12 months of data from both the
electricity bill (after the export meter is installed) and an demand monitoring
system (e-Gauge) is required. Seasonal fluctuations, operational and
behaviour changes by site users and billing retailer changes can affect the
calculations in both the long and short term.
11. Alternative renewable energy systems
There are numerous alternative renewable energy systems available and the
continuous advancement in renewable technologies worldwide creates new options,
hybrid systems, centralised and decentralised set-ups and improvements at an
ongoing rate.
Accessing this technology in Australia can be more difficult and the cost/benefits
need to be investigated further, but a short description is provided of each below in
the context of use for Councils.
a) Off-grid supply – no grid connectivity
A stand-alone solar renewable energy system still requires a second source of power
for back up. This is usually provided through a petrol or diesel generator. The
balance of power, control of the generator, maintenance and energy demand are
more difficult to manage in a community use building than for a domestic home.
Councils would require a building manager that has specific expertise in operating
and managing the stand- alone solar system on a day to day basis to ensure the
capital investment is maintained.
In the metropolitan area it is not known if SA Power Networks (SAPN) would approve
a disconnection to the grid without cost, to allow for a stand-alone solar system.
In remote areas where grid electricity is not available, the circumstances are
different. It would be easy to imagine that if demand to disconnect from the SAPN
grid increased substantially, they would look to recover lost income by charging for
disconnection (or reconnection) or introduce a network fee for the infrastructure that
passes by a property (like SA Water).
b) European Bosch VS 5 Hybrid – only released in 2013
The Bosch VS 5 Hybrid system works in the same manner as the ZEN Freedom
Powerbank by allowing onsite use, storage and discharge of solar energy and
"intelligent" switching between the grid for consumption and export.
20
Solar PV Battery Storage System Trial Project
Its price point is comparable, but there is currently no South Australian company
offering this product for sale. The Bosch system uses lithium-ion batteries.
c) ZEN Freedom Powerbank – grid connectivity, approved by SA Power
Networks
The operation and key aspects of the ZEN Freedom Powerbank are discussed
throughout this report. The key features to note is that it uses lithium iron phosphate
batteries and is the only grid interactive solar storage system approved by SA Power
Networks to be connected to the South Australian electricity grid.
d) Silent Power OnDemand Energy Appliance – only available in USA
Silent Power Inc, from the USA, offers the OnDemand Energy Appliance. It utilises
lead acid battery technology to store the solar power and claims the system can
operate during outages. This product is not available in Australia and is most
probably compatible with US grid electricity requirements.
21
Badminton Hall historical billing data
Month
Energy
use Offpeak
$per kwh Offpeak
Energy
use Peak
$ per
kwh Peak
Days
Total
energy
use (kWh)
Total cost of
electricity
Jan-11
Feb-11
Mar-11
Apr-11
May-11
Jun-11
Jul-11
Aug-11
Sep-11
Oct-11
Nov-11
Dec-11
2791
1974
2186
3404
2549
2467
2548
2549
2467
95
2325
2361
0.10658
0.1139
0.1139
0.1139
0.1139
0.1139
0.1139
0.1139
0.1247
0.1247
0.1247
0.1247
-146
1133
1254
1653
1378
1333
1378
1378
1333
1144
1345
1365
0.22132
0.2287
0.2287
0.2287
0.2287
0.2287
0.2287
0.2287
0.2655
0.2655
0.2655
0.2655
31
28
31
30
31
30
31
31
30
31
30
31
2645
3107
3440
5057
3927
3800
3926
3927
3800
1239
3670
3726
265
484
536
766
605
586
605
605
662
316
647
657
2011
27716
$0.1169
14548
$0.2404
365
42264
$6,736.36
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
2001757885
2001757885
2001757885
2001757885
2001757885
2001757885
2001757885
2001757885
2001757885
2001757885
2001757885
2001757885
ANNUAL
TOTAL
2001757885
2001757885
2001757885
2001757885
Jan-12
Feb-12
Mar-12
Apr-12
1812
1959
2180
3268
0.1247
0.1247
0.1247
0.1247
1020
1202
1303
1497
0.2655
0.2655
0.2655
0.2655
31
28
31
30
2832
3161
3483
4765
497
563
618
805
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
2001757885
2001757885
2001757885
2001757885
May-12
Jun-12
Jul-12
Aug-12
2407
2290
4710
2615
0.1247
0.1247
0.1247
0.1401
1309
1273
-1929
972
0.2655
0.2655
0.2655
0.2949
31
30
31
31
3716
3563
2781
3587
648
624
75
653
Site
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
NMI
Solar PV Battery Storage System Trial Project
Badminton Hall
Badminton Hall
Badminton Hall
Badminton Hall
2001757885
2001757885
2001757885
2001757885
Badminton Hall
ANNUAL
TOTAL
Badminton Hall
2001757885
Badminton Hall
2001757885
Badminton Hall
2001757885
Badminton Hall
2001757885
ANNUAL
TOTAL
Badminton Hall
Badminton Hall
2001757885
Badminton Hall
Badminton Hall
Badminton Hall
20017578852
2001757885
20017578852
Badminton Hall
ANNUAL
TOTAL
Sep-12
Oct-12
Nov-12
Dec-12
2530
-3731
1992
2067
0.1555
0.1555
0.155
0.1555
941
3940
1149
1197
0.3243
0.3243
0.3243
0.3243
30
31
30
31
3471
209
3141
3264
699
698
681
710
2012
24099
$0.1362
13874
$0.2876
365
37973
$7,271.95
6526
0.16503
3128
0.2568
90
9654
1880
5515
0.17
2891
0.3099
91
8406
1833
6041
0.175
3394
0.31599
93
9435
2130
4399
0.175
2728
0.31599
89
7127
1632
22481
$0.1713
12141
$0.2997
363
34622
$7,488.33
4286
0.175
3983
0.31599
92
8269
2009
4521
0.17476
4202
0.315505
96
8723
2116
8807
$0.0874
8185
$0.1579
188
16992
$2,062.28
10 Jan - 10
Apr 2013
11 Apr - 10
Jul 2013
10 July - 10
Oct 2013
11 Oct - 07
Jan 2014
2013
8 Jan - 9
April 2014
10 April - 14
Jul 2014
TBA
TBA
2014
23