UET Witness Test Report-Public Version

A WHITE PAPER
Witness Testing of the UniEnergy Technologies
Uni.System™
Utility Scale Energy Storage System
COMMISSIONED BY
UniEnergy Technologies
Mukilteo, Washington
PREPARED BY
Garth P. Corey, Consultant
Energy Storage Systems Engineer
Albuquerque, NM
July 31, 2014
1 Copyright © UniEnergy Technologies, LLC 2014

A WHITE PAPER
Introduction
UniEnergy has commissioned me, a third party energy storage systems engineer, to produce a
white paper reporting the results of witness testing for the Uni.System™ Vanadium Redox Flow
Battery (VFB) onsite at the UET facilities in Mukilteo, Washington during the week of 21‐25 July,
2014. Specifications of the Uni.System VFB as tested are as follows:
SPECIFICATIONS OF UNI.SYSTEM™
Component Specification
Number of modules per battery (20 ft. containers) 4
Stacks per module 3
Voltage window 450~986 VDC
Current ‐1000~1000 ADC
Electrolyte volume 23 m3 per battery module
Operating temperature range ‐10~55 °C
PCS power ‐600~600 kW (see following charge profile)
The following photograph shows the 500 kW, 2 MWh Uni.System as installed at the UniEnergy
Technologies facility in Mukilteo, Washington. The system consists of four each 20 ft. modules
and one each 20 ft. electronics container. The system ran continuously throughout the testing
activities with no down‐time. Human intervention was needed only for the purpose of activating
the various tests reported here.

A WHITE PAPER
Because of power limitations of the current Power Conditioning System (PCS), the maximum
power available for charging is 400 kW; the maximum power available for discharging is 600 kW.
The following graphic shows the limits in voltage at various states of charge. This limitation did
not impact the results of the witness test and is scheduled to be addressed in the production
version of the Uni.System system so that the maximum power available for discharging and
charging will be 600 kW for both functions.
PCS CHARGE PROFILE
Third Party Witness Test Plan
Witness testing was planned for the following five utility scale application areas:
1. Regulation
Signal “Aggressive” was employed for this testing. The signal is consistent with the PNNL testing
protocol. The starting SOC was controlled around 50%. The duration of regulation testing is
scheduled for 2h.

A WHITE PAPER
Regulation Signal
2. Capacity Testing
The capacity testing included two discharge powers: 600kW and 400kW. The charge power was
set to ‐400kW due to the de‐rating of the PCS. Because the regulation test (test #1) was centered
around a 50% state‐of‐charge (SOC) point, the first charge cycle was started at that SOC.
Roundtrip efficiency will be calculated based on the equation below:
ߟோ௢௨௡ௗ௧௥௜௣ ൌ
ܣܥ ݌ݎ݋݀ݑܿ݁݀ ݁݊݁ݎ݃ݕ െ ܣݑݔ ܿ݋݊ݏݑ݉݌ݐ݅݋݊ ݅݊ ݀݅ݏ݄ܿܽݎ݃݁
ܣܥ ܿ݋݊ݏݑ݉݁݀ ݁݊݁ݎ݃ݕ ൅ ܣݑݔ ܿ݋݊ݏݑ݉݌ݐ݅݋݊ ݅݊ ݄ܿܽݎ݃݁ ൅ ܣݑݔ ܿ݋݊ݏݑ݉݌ݐ݅݋݊ ݅݊ ݈݅݀݁
Aux consumption includes everything except PCS, such as pump loss, electronic loss, cooling loss,
et al.
Testing was scheduled as follows: (Capacity testing was scheduled to run for 36~48 continuous
hours)
 Two cycles of 400 kW charging and 600 kW max power discharging
 Two cycles of 400 kW charging and 400 kW discharges, the second includes CV discharge
to get max energy
 Power Quality Test (to be performed during the peak power points and low power points
in the peak shaving test)
 Power quality was tested at 4 points for the duration of ~ 15 minutes:
 Peak power discharge (600 kW)
 End of peak power discharge interval
 Peak power charge (‐400 kW)
 End of peak power charge interval

A WHITE PAPER
3. Ramping (sine wave)
The California CPUC has mandated 1.325GW of storage by 2020 to overcome projected problems
with generation and ramping. The duck curve shown below illustrates California’s looming 12GW
ramping, over‐generation and peaking problem. The most serious aspects of these problems is
the projected over capacity during mid‐day followed by an extreme ramp up of load of 13 GW in
3 hours and then followed by a peaking load. A battery could absorb the mid‐day over‐generation
caused by the high penetration of renewables saving the energy for later use as needed. A
battery could also supply the ramping power to assist in the regulation activity and then supply
some of the shortfall during peaking.
4
Net Load Curve
Reduced Ramp
Battery Output
3GW/9GWh
Storage
6GW Flexible Capacity
Equivalent performance
to 12GW of fossil peakers
3GW/3h storage in 2020:
 Halve ramping to
2013 levels
 Absorb over‐generation
 Reduce system peak by
3GW
and also yield system wide
 frequency regulation
 voltage control
 resiliency
 black start
13GW ramp
in 3 hours
2GW peak
in under 3h
Big changes have
already started!
Over-Generation
The sine wave signal was applied to test the system’s ability to follow a ramping application such
as the California duck curve. The source of the load command signal was a signal generator which
generated the signal as shown in the next graphic. The peak of discharge ramping is ‐400kW AC
(due to PCS de‐rating) for charge and the peak for discharge was 600kW AC. Total energy in
charging and discharging is equal to the area under the curve, in both charge and discharge,
which equates to 1.6 MWh and 1.2 MWh respectively in each function. This test was scheduled
to take about 13 hours.

A WHITE PAPER
Power Ramping Signal
4. Combined Ramping and Regulation
The combined ramping and regulation function was tested with no interruption. The charge
hours were 7 hours (‐400kW charge with regulation), followed by a 4 hours idle period (with
regulation). Then continue with a discharge for 4 hours (400kW discharge with regulation) and
another idle interval for 4 hours (with regulation). The total test time is 19 hours. The
commanded signal is as follows:
Combined Ramping and Regulation Signal

A WHITE PAPER
5. Power Quality Test
The power quality test will be carried out during the cycling and tracking. The meter will be set
up to monitor the power quality.
Testing as scheduled for the 5‐days of witness testing:
21‐Jul 22‐Jul 23‐Jul 24‐Jul 25‐Jul
Monday Tuesday Wednesday Thursday Friday
0:00
Capacity
testing‐
400kWCharg
e/600kW
Discharge
for two
cycles
(around 24
hours)
Capacity
testing‐
400kWCharg
e/400kW
Discharge
for two
cycles
Peak shaving
testing‐Sine
wave cycling
for one cycle
Combined
function
1:00
2:00
3:00
4:00
5:00
6:00
7:00
8:00
9:00
10:00
11:00
12:00
13:00
Combined
function
14:00
Regulation
15:00
16:00
Capacity
testing‐
400kWCharg
e/600kW
Discharge
for two
cycles
17:00
Capacity
testing‐
400kWCharg
e/400kW
Discharge
for two
cycles
18:00
19:00
20:00
21:00
22:00
23:00

A WHITE PAPER
Witness Testing Results
All planned testing activities scheduled for witness testing of the Uni.System was completed
without interruption during the week. Results reported in this section are correlated with the
numbered test in the preceding test plan.
1. Regulation
The regulation control signal from the test plan was directed to the system controller of the
Uni.System system. The following trace is the resulting response of the system.
Of particular interest is the accuracy with which the system is tracking the AC command with one
exception: because the 400 kW limit for the charge mode is present as indicated earlier in this
report, the system was unable to track the signal for higher power charge commands that
exceeded the 400 kW limit. This error will be corrected in the upgraded PCS scheduled for
delivery with the production Uni.System system scheduled for delivery in late summer.
Another item of interest is the Open Circuit Voltage (OCV), a voltage measurement on the
electrolyte that very accurately indicates the state‐of‐charge of the battery in real time. In this
“regulation only” application, the system initially begins operations slightly below the 50 % State
of Charge (SOC) point, a point that is specifically selected to optimize the energy delivery for
power dispatch for the energy storage system. The OCV varies slightly around the 45% SOC point
indicating a changing SOC; however, as expected, there is a “net zero” consumption of energy
during this 2‐hour regulation demonstration. Test 5, combined ramping and regulation is
intended to show how the system can be used for regulation while dispatching in multiple modes
simultaneously taking advantage of the energy available while in a regulation mode.

A WHITE PAPER
The following table summarizes the key data points for the regulation test.
Regulation Data
Data Units
Test Duration 2.0 hr
Aux Power Consumption 16.3 kWh
Charged AC Energy 230 kWh
Discharged AC Energy 185 kWh
Net Energy Consumed 246.3 kWh
Net Energy Produced 185 kWh
AC Efficiency 80.4 %
Roundtrip Efficiency incl aux loads 75.1 %
2. Capacity Testing
Capacity testing consisted of four round trip capacity tests for two different power discharges,
two at 400 kW charge, 600 kW discharge and two at 400 kW charge and 400 kW discharge.
Results shown here are for one test of each of the power settings. For each of the two power
output settings, the two sets of data are very comparable. The system is unable to charge at 600
kW at this time because of a limit in the charge circuit of the inverter. This charging anomaly is
scheduled to be corrected prior to deployment to a field demonstration scheduled for early fall,
2014. All testing proceeded as planned with no unusual or unexpected events.
During the first cycling stage of the first capacity testing sequence, the system tripped off at very
near top‐of‐charge. It was noted that the voltage signal had fluctuated noticeably and an
investigation was initiated to determine the cause of the trip. UET engineers reported the
following finding and introduced a correction to mitigate any further tripping for all remaining
tests:
During the cycling testing we experienced an unexpected shut down of the PCS close to the end
of the charge cycle near 100% SOC. This seems to have been due to an instability in the DC voltage
imposed by the constant voltage control mode. The instability was avoided by operating the PCS
in constant power control mode and relying instead on the integrated voltage limiting function of
the PCS to maintain stability during high Voltage charging at 100% SOC.
After this fix was implemented no further trips were experienced.

A WHITE PAPER
The following table summarizes the capacity testing results for a 400 kW charge, 600 kW
discharge capacity test:
State
Time
h
Aux
consumption
kWh
Charged
AC energy
kWh
Discharged
AC energy
kWh
Net
energy
consumed
kWh
Net
energy
produced
kWh
AC
efficiency
%
Roundtrip
efficiency
%
Idle 0.25 2.1
Charge 5.82 50.4
Idle 0.25 1.8
Discharge 1.95 22.2
1798 1163 1852 1141 64.7 61.6
The following graphic shows a full 400 kW charge and 600 kW discharge cycle. Details of power
levels and efficiencies are shown in the preceding table. There were no remarkable events
throughout the test cycle. The system operated as predicted.
The following table summarizes the capacity testing results for a 400 kW charge, 400 kW
discharge capacity test:
State
Time
h
Aux
consumption
kWh
Charged
AC energy
kWh
Discharged
AC energy
kWh
Net
energy
consumed
kWh
Net
energy
produced
kWh
AC
efficiency
%
Roundtrip
efficiency
%
Idle 0.25 2.1
Charge 8.25 68.0
Idle 0.25 1.8
Discharge 4.73 49.0
2763 1893 2835 1844 68.5 65.0

A WHITE PAPER
The following graphic shows a full 400 kW charge and 400 kW discharge cycle. Details of power
levels and efficiencies are shown in the preceding table. There were no remarkable events
throughout the test cycle. The system operated as predicted.
This test included a CV voltage discharge to get the max energy, which showed 2.1 MWh for max
energy (graph below).
Throughout the four cycles of capacity testing, the system operated continuously interrupted
only by the trips at near top of charge which are explained earlier in this report. Capacity
delivered meets all claims and specifications.

A WHITE PAPER
Ramping (Sine wave)
The following graphic shows the ramping tracking accuracy of the system as it would be applied
for mitigation following the California duck curve discussed earlier.
3. Combined Ramping and Regulation
The following graphic shows the signals generated during combined ramping and regulation
testing. Regulation was performed during charging, idle and discharging stages. The system
performed as claimed and as specified showing that multiple applications can be performed
simultaneously with the Uni.System system. Note the tracking of the SOC throughout the test
indicating the actual SOC at any given point in time.
The following table summarizes the performance for the combined ramping and regulation test.

A WHITE PAPER
Combined Ramping and Regulation Data
Parameter Data Units
Test Duration 19.8 hr
Aux Power Consumption 184 kWh
Charged AC Energy 2824 kWh
Discharged AC Energy 1961 kWh
Net Energy Consumed 3008 kWh
Net Energy Produced 1961 kWh
AC Efficiency 69.4 %
Roundtrip Efficiency incl aux loads 65.2 %
All results meet all system claims and specifications.
4. Power Quality Test
Total harmonic distortion (THD) was measured for short periods of time at near top of charge,
near the start of a discharge, near the end of a discharge and at near the start of charge during
the peak shaving (sine wave) test sequence. The following table shows THD for an entire cycle
showing the gradual increase in un‐normalized THD as the system moves through lower powers
in both charge and discharge. Normalized THD is shown in the last column.
THD / %
AC power Phase 1 Phase 2 Phase 3 Average of 3 phases Normalized
‐417.37 5.69 6.97 6.33 6.33 4.40
‐401.14 6.09 7.42 6.73 6.75 4.51
‐350.93 6.96 8.52 7.55 7.68 4.49
‐301.21 8.25 9.94 8.75 8.98 4.51
‐250.16 9.72 11.93 10.14 10.60 4.42
‐200.84 11.12 13.70 11.51 12.11 4.05
‐151.11 14.13 17.40 14.61 15.38 3.87
‐101.37 20.15 24.69 20.82 21.89 3.70
‐51.63 36.85 45.60 36.97 39.81 3.43
52.19 49.64 52.69 45.39 49.24 4.28
104.52 23.95 25.38 22.30 23.88 4.16
149.38 16.37 17.28 15.27 16.31 4.06
201.71 11.89 12.31 10.87 11.69 3.93
252.34 9.98 10.39 9.18 9.85 4.14
298.32 8.39 8.67 7.65 8.24 4.10
350.88 7.33 7.59 6.65 7.19 4.20
402.21 6.51 6.68 5.81 6.33 4.25
451.93 5.78 5.91 5.11 5.60 4.22
499.15 4.92 5.06 4.36 4.78 3.98
549.64 4.41 4.56 3.94 4.30 3.94
587.99 4.67 4.82 4.41 4.63 4.54

A WHITE PAPER
The graphics shown here are derived from the table on the preceding page. Harmonics
generated are well within tolerance as shown. Note that harmonics are more prevalent at power
levels approaching lowest levels as shown in these graphics.
This photo shows the
voltage waveforms for
the 3 phases at near mid‐charge
taken from the
isolation transformer
secondary during a
capacity test cycle.
Although there is some
apparent distortion, it is
insignificant and has little
impact on the output
voltage power quality.
THD during this period
was approximately 4.35
to 4.55.

A WHITE PAPER
Strengths and Weaknesses of Uni.System
In Witness Testing
Weaknesses: The only weakness I have seen in Uni.System is that it has not been field
demonstrated in a utility application. That will be the final test for this emerging technology
Strengths: There are many strong points in the tested Uni.System system. Some of the more
important points are enumerated here:
1. Since commissioning, the Uni.System has delivered nearly 100 MWh total power, without
testing interruption to correct deficiencies noted during initial testing of the full scale
Uni.System system.
2. With the exception of a system trip at near top of charge early in the capacity testing, all
components and subsystems operated flawlessly throughout the witness test program
which ran continuously from noon on Monday through noon on Friday with operator
intervention only to change testing sequences.
3. The system exhibited high performance both in full and partial power settings and proved
to be stable over the complete operational profiles tested.
4. The system was proven to be able to operate in multiple applications, delivering both
energy and power at the same time, with no compromise in performance.
5. The strong UniEnergy design team consists of electrochemists and engineers with the
necessary skills and attitude to bring the Uni.System development project to a successful
completion. In my opinion, their efforts will result in the near term deployment of a fully
qualified commercial product for the utility scale energy storage market.
Conclusions
Throughout the 5‐day witness testing program, the Uni.System operated continuously under the
several witness test protocols scheduled with no interruptions in test operations. However; one
event occurred that was not in the test plan providing an opportunity to confirm the functionality
of the spill monitoring system in each of the eight electrolyte tanks. An unexpected overnight
rainstorm occurred with the top covers of the container open allowing rain to collect in the top
of the electrolyte service area which is continuously monitored for any liquid which might be
present. Every spill monitor sensed the rain that gathered in the service area which resulted in
the shutdown of all system pumps showing that the spill sensor subsystem operated as specified.
Throughout the 5‐day testing program, no operational issues occurred which compromised the
uninterrupted witness testing plan. All tests were successfully completed and all data correlated
to expected results. In my opinion, with the updated PCS which will eliminate the 400 kW
charging limit issues, the Uni.System system should be fully capable of meeting all application
specifications and ready for a complete field demonstration program.

A WHITE PAPER
Author Biography
Garth P. Corey, retired from Sandia National Laboratories in Nov, 2006 as a Principal Member of
the Technical Staff. During his tenure at Sandia, he had project management responsibilities with
the Energy Infrastructure and Distributed Energy Resources Department. Most of his Sandia
career was dedicated to communicating his system engineering and battery system management
knowledge to engineers involved in the integration of various energy storage technologies with
the balance of plant needed for the development of a successful operational energy storage
system.
During his more than 15 years at Sandia, Garth was involved in high technology energy storage
R&D projects and energy storage systems development. He managed projects that spanned the
utility scale energy storage arena including flywheels and ultracapacitor systems; sodium sulfur,
nickel cadmium, lead acid, (including advanced lead‐acid technologies), and lithium ion batteries;
and several flow battery technologies. Much of his time was dedicated to assisting Sandia
Renewable Power engineers in the proper integration of batteries in both off‐grid and grid‐tied
Photovoltaic systems. Since leaving Sandia, Garth has continued to stay current on new energy
storage systems development.
Garth is an internationally recognized subject matter expert in utility scale energy storage
applications and systems and is frequently sought out to provide expert advice on emerging
energy storage systems and energy storage device development and deployment. He is also very
active in conducting technology due diligence investigations to determine the status of emerging
energy storage technologies. He is a member of the IEEE Power and Energy Society and is active
in balloting energy storage related standards.

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