Review: SolarEdge vs Tigo power optimizers

25 Jul Review: SolarEdge vs Tigo power optimizers

In this article we will explain why the need for power optimization is vital. We will also take a deeper look and compare two module-level optimization systems – SolarEdge and Tigo.

Installing a PV solar system is becoming more and more popular, but the initial cost is still relatively high and harvesting every single kWh is essential to secure a fast return on investment. Considering grid-connected inverters have an efficiency of about 98% and solar panels about 20%, most of the power losses in a PV system occur on the panels. While many factors affect how much electricity solar panels produce, system optimization is one of the best solutions to limit power losses and achieve maximum solar system performance.

Where does power loss in solar panels come from?

A power mismatch occurs – when the electrical parameters of a cell are significantly different compared to the remaining ones, as a result, power is lost in the system. In a solar system, modules are connected in series into strings which are in turn connected in parallel into the inverters. A mismatched module produces far less power than other panels and drags down the power of all other modules in that string. As described in Chouder’s study, up to 10% of the total generated power can be lost by mismatches in the modules.¹

Sources of Mismatch:

  •  Mismatch during the manufacturing process: PV cells have different power output capability even in high-quality modules. For instance, CanadianSolar CS3K-300P has a power tolerance between 0 to 5W (0-1.67%)
  • Mismatch by weather variance: Clouds block sunlight which causes a temporary shading on the module. High temperature is also a factor that decreases the power and can cause power mismatches due to the cooling effect being different for every module on a string.
  • Mismatch by different module orientation and local shading: In many cases, modules suffer from shading on residential roofs because of various obstacles such as chimneys, trees, another module or roof etc. The roof area might also require modules to be installed on multiple orientations and tilted angles.
  • Mismatch by uneven degradation rate: modules degrade for many reasons such as: failed bypass diodes, soiling, mechanical wear and tear, aging…²

Why use power optimizers?

A solar system with power optimizers allows each module to produce the maximum energy. The mismatched module does not affect the performance of the rest of the system. Power optimizers also allow PV modules to be installed at different orientation and angles which means more flexibility in designing the process, improved roof aesthetics, and higher roof area utilization.

SolarEdge’s approach

Complete, robust and cost-effective for a full-scale optimization & module-level monitoring

SolarEdge (SE) system includes SE optimizers and SE inverters as in the images below. Each module is connected to one or two power optimizers. Power optimizers are buck-boost DC/DC converters, that optimize solar energy production of each module by tracking the maximum power point on every PV module. The SolarEdge inverter only converts the DC power into grid-compliant AC power and interacts with the grid. Thanks to an innovative and simplified design, SolarEdge inverters are less costly compared to traditional string inverters. This makes the whole system (optimizers + inverter) more cost-effective.

SolarEdge Residential System
SolarEdge Commercial System​

SolarEdge provides 25 years warranty for power optimizers and 12 years for inverters. When inverters are connected to the internet, they transmit system information to the free monitoring platform which visualizes the performance of each module in the system. 

Furthermore, SolarEdge monitoring system could serve as an energy management platform to utilize produced solar energy for self-consumption, control EV charging and other household appliances.

SolarEdge offers highly comprehensive software tools, which help planners, installers and users:

  • For planner: Designer  tool provides a sophisticated solution from creating site layout, PV modules planning, choosing suitable inverter and power optimizers to yield prediction and creating wiring plan. 
  • For installer: Mapper  tool allows every installer to quickly record optimizer layout into the Monitoring portal right on site. Setapp is a mobile app, which allows the installer to quickly commissioning the inverter even without an internet connection. 
SolarEdge Monitoring Platform

Tigo’s approach

Tigo option is simple, flexible and customized for a specific case.

Tigo technology can be deployed according to your own needs thanks to the Tigo Selective Deployment feature. Tigo’s TS4 optimization technology works independently of the inverters in a solar system, and every panel can be optimized as needed. In other words, if a tree’s shadow falls on one corner of your roof, you won’t have to purchase equipment for every panel on your roof, but only for the panels that fall under the tree’s shade.

Tigo Selective Deployment

This feature is made possible by Tigo’s technology called Impedance Matching and Predictive IV. Impedance Matching creates a bypass tunnel around the shaded module (the red module below) which ensures that the power loss on the mismatched module will not affect other modules. Predictive IV uses module behavior statistics in conjunction with Impedance Matching in order to predict the optimum settings for a module to generate its maximum energy. Tigo optimizers are compatible with all leading inverter manufacturers.³

Impedance Matching
Tigo system with monitoring feature

The Tigo system can work just with TS4-A-O optimizers if monitoring is not necessary. To enable the monitoring feature, one must connect the Modules Optimizers, Tigo Access Point (TAP), and the Cloud Connect Kit. The Cloud Kit is not needed if it is already integrated into the inverter. Tigo provides 25 years warranty for power optimizers and 5 years for Tigo Access Point, and the Cloud Connect Kit.

CONCLUSION

In this article, several sources of power mismatch were reviewed. By using power optimizers, this problem can be significantly minimized. The SolarEdge and Tigo’s approaches and systems were discussed and elaborated to better understand their principles. Both brands provide high quality and safe solutions including Rapid Shutdown. The Tigo option is simple, flexible and customized for a specific case. On the other hand, the SolarEdge option is complete, robust and cost-effective if you want a full-scale optimization and module-level monitoring.

FeaturesSolarEdgeTigo
Module-level MPPT to mitigate mismatch problemYesYes
Multiple module orientations and tilt anglesYesYes
Must have power optimizers on each moduleYesNo
Must have a minimum number of optimizers to workYesNo
Can be used with other inverter brandsNo Yes
Module-level monitoringYesYes 
Subscription for premium monitoring featuresNoYes 
25 years of warranty for the power optimizerYesYes
Complex system with EV charger, Smart House, Energy StorageYesNo 

References

 

1

A. Chouder and S. Silvestre, “Analysis Model of Mismatch Power Losses in PV Systems,” Journal of Solar Energy Engineering, vol. 131, no. 2, p. 024504, 2009

2

Solaredge case study mismatch commercial rooftops Netherlands, SolarEdge

3

T. Doyle, R. Desharnais and T. Erion-Lorico, “2019 PV MODULE RELIABILITY SCORECARD,” PVEL, 2019

4

Optimization with Predictive IV and Impedance Matching, Tigo Resource Center, Tigo

5

MySolarSystem Part II. The Problem with Solar: Mismatch, Tigo Resource Center, Tigo

6

Inverter Compliance, Tigo Resource Center,Tigo