Enphase Energy for the purpose of comparing the energy yield between Enphase Energy’s and...

www.PVEL.com Report #40-16A-1 415.320.PVEL

Enphase Energy

Engineering Report Energy Yield Evaluation at PVUSA Enphase and SolarEdge Side-by-Side September 9, 2013

10 pages

Authors and Contributors


Matt Donovan Staff Engineer

[email protected]

Jason Forrest PV Test Engineer

Nir Jacobson Technical Writer

mailto:[email protected]

Table of Contents


About Us .......................................................................................................................... 1

Summary ......................................................................................................................... 2

System Installation .................................................................................................................................... 2

Measurement Equipment ......................................................................................................................... 3

Systems’ Parameters ................................................................................................... 4

Test Period #1: June 18, 2013 to July 15, 2013 ......................................................................................... 4

Test Period #2: July 16, 2013 to August 27, 2013 ..................................................................................... 4

Energy Yield Results .................................................................................................... 5

Definition of Performance Ratio ............................................................................................................... 5

Performance Data: Test Period #1 ............................................................................................................ 5

Performance Data: Test Period #2 ............................................................................................................ 6

Performance Ratio per Day: Test Period #1 .............................................................................................. 7

Performance Ratio per Day: Test Period #2 .............................................................................................. 8

About Us

- 1 of 10 - www.PVEL.com Report #40-16A-1 415.320.PVEL

For companies developing PV products and projects, PV Evolution Labs (PVEL) is the premier solar panel

performance and reliability testing lab. We provide secure, expert testing and validation services so you

can be confident that you're making intelligent decisions based on the most reliable data.

PVEL is founded on the principle that understanding solar panel aging behavior through testing is a

fundamental aspect of safety, cost reduction, and reliability – all of which are imperative to the growth

and health of the solar industry. PVEL is committed to increasing photovoltaic product quality while

reducing product time to market.

Our dedicated environmental, mechanical, and electrical testing systems are designed specifically for

the flat plate PV module form factor. Utilizing dedicated characterization systems ensures optimal data

quality and repeatability. PVEL’s calibrated equipment base is closely maintained to ensure optimal

availability and reliability. Our specialized services are available for product and process qualification,

raw material and supplier evaluation, ongoing reliability testing (ORT), risk assessment, lot acceptance,

energy yield evaluation, and more.

The PVEL team possesses unparalleled expertise in test and measurement techniques for semiconductor

devices and PV modules. Our highly qualified technical staff is dedicated to serving the needs of the

solar industry with a commitment to excellence in test quality and customer service.

Our mission at PVEL is to facilitate the dramatic growth of the North American solar industry.

Summary


PV Evolution Labs (PVEL) has installed and evaluated side-by-side residential scale photovoltaic (PV)

systems for the purpose of comparing the energy yield between Enphase Energy’s and SolarEdge’s

inverter technologies. The side-by-side systems were installed at PVEL’s premier test facility at PVUSA, a

heavily-monitored research site located in Davis, CA. This Energy Yield Evaluation (EYE) documents the

systems’ performance for the time period of June 18, 2013 and August 27, 2013. During that time

period, the SolarEdge system was placed into two (2) configurations: one (1) with a total of eight (8)

modules on a 3-kW inverter, and one (1) with a total of twenty-four (24) modules on a 6-kW inverter. It

was found that the Enphase systems produced 2.4% more energy than the SolarEdge system in the first

configuration, and 3.1% more energy in the second configuration. This result was determined on a

kWh/kWp basis.

System Installation

Each system consists of eight (8) to twenty-four (24) modules mounted at a 20° slope on an open rack.

A row of dummy modules is installed to the south to ensure that any row-to-row shading is identical for

all systems. Additionally, modules were sorted by the results of their respective flash-tests and

distributed across all systems evenly.

Figure 1 Overview of the field layout. In an effort to equalize testing conditions as much as possible, technology groups are staggered and there is a dummy row in front of the south-most system to ensure uniform row-to-row shading.

Summary


Measurement Equipment

Table 1: Measurement Equipment

Parameter Equipment Uncertainty

AC power Electro Industries Shark 1001 ± 0.35 %

Plane-of-array (POA) and Global Horizontal (GHI)

Eppley PSP Secondary Standard Pyranometer2

± 2 %

Plane-of-array (POA) Silicon PV Reference Cell

ESTI Sensor ± 2 %

Module Temperature Type-T Thermocouple ± 1.0° C

Wind speed Vaisala WXT520 Greater of ± 0.3 m/s or ± 3 %

Wind direction Vaisala WXT520 ± 3°

Ambient temperature Vaisala WXT520 ± 0.3° C

Precipitation (rain, hail) Vaisala WXT520 ± 5 %

Relative humidity Vaisala WXT520 ± 3 %

Barometric pressure Vaisala WXT520 ± 0.5 hPa

1. Shark 100 meter is ANSI Class C12.20 (0.2%) accuracy. AC power measurement uncertainty includes contribution

from current transducers.

2. Uncertainty of POA radiation, including alignment error and averaging over environmental condition, is ±3%.

Systems’ Parameters


Table 2: Systems’ Parameters

System 1 System 2 System 3 System 4

Inverter Type Enphase M215 Enphase M215

SolarEdge SE 3000A with

OP250-LV optimizers

SolarEdge SE 6000 with

OP250-LV optimizers

Number of Panels 12 12 8 24

DC Capacity 2,880 watts 2,880 watts 1,920 watts 5,760 watts

Module Type Upsolar UP-M240P

Array Orientation 180° azimuth, 20° tilt

Location PVUSA in Davis, CA

Operation Dates June 18, 2013 to August 27, 2013

June 18, 2013 to August 27, 2013

June 18, 2013 to July 15, 2013

July 16, 2013 to August 27, 2013

Test Period #1: June 18, 2013 to July 15, 2013

During Test Period #1, the two (2) Enphase systems were run side-by-side against the SolarEdge system

with the SolarEdge system configured as an array of eight (8) modules on the SE3000 inverter.

Test Period #2: July 16, 2013 to August 27, 2013

During Test Period #2, the two (2) Enphase systems were run side-by-side against the SolarEdge system

with the SolarEdge system configured as an array of twenty-four (24) modules on the SE6000 inverter.

Energy Yield Results


Definition of Performance Ratio

(

) (

)

Performance Data: Test Period #1

Table 3: Performance Data – Test Period #1

System 1 System 2 System 3

Inverter Type Enphase M215 Enphase M215 SolarEdge

SE 3000A with OP250-LV optimizers

DC Capacity per System [kWp nameplate]

2.88 2.88 1.92

Insolation [kWh/m2]

202.2 202.2 202.2

AC Energy per System [kWh]

498.7 498.2 324.6

AC Energy [kWh / kWp]

173.2 173.0 169.1

Performance Ratio [%]

85.6 85.6 83.6

In Test Period #1, the Enphase systems produced 173.1 kWh/kWp, while the SolarEdge system produced

169.1 kWh/kWp. This amounts to 2.4% more energy for the Enphase systems relative to the SolarEdge

system on a kWh/kWp basis.

For the purpose of the Energy Yield Evaluation, days where the systems were offline due to power

outage or maintenance for more than 50% of the energy-producing hours of the day were excluded

from the analysis. For excluded periods, neither energy production nor insolation were counted.

Therefore, the month-average performance ratio is not affected by availability.



Performance Data: Test Period #2

Table 3: Performance Data – Test Period #2

System 1 System 2 System 4

Inverter Type Enphase M215 Enphase M215 SolarEdge

SE 3000A with OP250-LV optimizers

DC Capacity per System [kWp nameplate]

2.88 2.88 5.76

Insolation [kWh/m2]

320.8 320.8 320.8

AC Energy per System [kWh]

770.9 771.2 1496.2

AC Energy [kWh / kWp]

267.7 267.8 259.8

Performance Ratio [%]

83.4 83.5 81.0

In Test Period #2, the Enphase systems produced 267.7 kWh/kWp, while the SolarEdge system produced

259.8 kWh/kWp. This amounts to 3.1% more energy for the Enphase systems relative to the SolarEdge

system on a kWh/kWp basis.

For the purpose of the Energy Yield Evaluation, days where the systems were turned off due to power

outage or maintenance for more than 50% of the energy-producing hours of the day were excluded

from the analysis. For excluded periods, neither energy production nor insolation was counted.

Therefore, the month-average performance ratio is not affected by availability.



Performance Ratio per Day: Test Period #1

Table 5: Performance Ratio per Day – Test Period #1

Date

Daily Insolation Performance Ratio

All Systems [kWh/m2]

System 1 Enphase M215 [%]


System 3 SolarEdge [%]

6/18/2013 7.97 85.8 85.8 85.7 6/19/2013 8.14 88.4 88.4 85.9 6/20/2013 8.04 87.4 87.5 84.7 6/21/2013 8.19 87.4 87.6 90.9 6/22/2013 8.03 86.5 86.5 96.3 6/23/2013 3.92 94.6 94.5 91.9 6/24/2013 2.46 101.9 101.4 85.1 6/25/2013 3.74 95.4 95.4 84.6 6/26/2013 7.97 87.5 86.8 82.8 6/27/2013 7.92 86.0 86.5 83.0 6/28/2013 7.81 84.7 84.7 82.1 6/29/2013 7.90 84.6 85.0 81.6 6/30/2013 7.86 83.9 84.0 84.1 7/01/2013 6.54 82.6 83.3 82.4 7/02/2013 5.77 86.7 85.7 82.4 7/03/2013 7.52 84.0 84.4 85.6 7/04/2013 7.21 84.2 84.5 84.1 7/05/2013 8.02 88.2 87.4 83.1 7/06/2013 7.96 86.6 86.1 82.8 7/07/2013 8.02 85.3 84.9 81.3 7/08/2013 8.08 85.0 84.6 80.8 7/09/2013 8.05 82.7 83.2 81.7 7/10/2013 8.20 83.2 82.7 81.8 7/11/2013 8.27 83.9 83.5 80.9 7/12/2013 7.77 83.6 83.5 81.2 7/13/2013 8.22 82.8 82.6 78.2 7/14/2013 8.12 83.0 83.1 83.6 7/15/2013 4.53 80.5 80.0 85.7

Total 202.2 85.6 85.6 85.9



Performance Ratio per Day: Test Period #2

Table 6: Performance Ratio per Day – Test Period #2

Date






7/16/2013 8.28 85.9 85.2 82.8 7/17/2013 8.19 82.7 83.1 80.5 7/18/2013 8.13 81.4 81.8 79.2 7/19/2013 7.89 81.9 82.0 79.5 7/20/2013 7.62 82.1 82.3 79.7 7/21/2013 7.67 82.6 82.3 79.9 7/22/2013 5.94 84.5 84.8 82.2 7/23/2013 5.98 84.1 84.3 81.7 7/24/2013 7.58 81.2 81.4 78.8 7/25/2013 6.58 86.9 85.8 83.7 7/26/2013 7.90 84.6 84.2 81.8 7/27/2013 7.86 85.2 84.7 82.4 7/28/2013 7.93 85.8 85.1 82.8 7/29/2013 7.75 87.0 86.4 84.0 7/30/2013 7.89 84.5 84.4 82.0 7/31/2013 7.92 85.2 84.7 82.4 8/01/2013 8.07 84.1 83.9 81.5 8/02/2013 7.92 83.3 83.5 81.0 8/03/2013 7.98 83.4 83.3 80.8 8/04/2013 7.92 84.3 84.1 81.7 8/05/2013 8.01 83.9 83.8 81.4 8/06/2013 5.71 86.3 86.1 83.6 8/07/2013 7.83 85.4 85.2 82.6 8/08/2013 7.57 84.9 85.1 82.6 8/09/2013 7.69 84.9 84.8 82.4 8/10/2013 7.60 83.9 84.1 81.6 8/11/2013 7.65 82.8 83.2 80.6 8/12/2013 7.76 83.0 83.2 80.8 8/13/2013 7.72 81.7 82.4 79.7 8/14/2013 7.82 81.4 82.0 79.3 8/15/2013 7.76 81.7 81.8 79.3 8/16/2013 7.49 81.2 81.5 78.9



Table 6: Performance Ratio per Day – Test Period #2 (Continued)

Date






8/17/2013 6.39 82.2 82.5 79.9 8/18/2013 6.56 81.7 82.5 79.7 8/19/2013 5.23 81.0 81.8 78.9 8/20/2013 6.79 81.7 82.1 79.6 8/21/2013 7.40 82.1 82.0 79.5 8/22/2013 7.59 82.1 82.2 79.5 8/23/2013 7.50 81.5 82.0 79.4 8/24/2013 7.42 81.8 82.0 79.3 8/25/2013 7.32 82.8 82.8 80.1 8/26/2013 7.51 83.8 83.7 81.3 8/27/2013 7.53 85.0 85.1 82.6

Total 320.83 83.4 83.5 81.0



Figure 2 Performance ratio and insolation per day for Test Period #1.

Figure 3 Performance ratio and insolation per day for Test Period #2.

Enphase Energy for the purpose of comparing the energy yield between Enphase Energy’s and...

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