Holistic approach improves Photovoltaic (PV) system energy yield by up to 25% while reducing BoS (Balance of System) and installation cost.
Mass production slated for September 2009.
My interaction with SolarEdge started before Intersolar 2009 during the PV Industry Forum 2009. I decided to skip the Arima EcoEnergy Technologies Corp. presentation (which I wanted to hear) at the Concentrating PV Session to cover Session 8: PV Systems & Applications – Inverter System Configurations:
Breakthroughs in distributed DC architecture
Guy Sella, Chairman and CEO
SolarEdge Technologies, Israel
I was not disappointed.
SolarEdge founder, chairman, and CEO Mr. Guy Sella started his presentation with “The missing 25%”; every PV system fails to harvest 20-30% of the potential power due to Panel Mismatch (1-3%), Partial Shading (2-20%), System intolerance, and Dynamic MPPT (Maximum Power Point Tracking) losses. In addition, Mr. Sella cited known PV system drawbacks including lack of module level monitoring, limited roof utilization (65-75%) because of fixed string lengths, the safety hazards of 400 Volt plus DC (Direct Current) voltages, and module theft.
|From PV Industry Forum 2009|
SolarEdge expects their system will accelerate the drive to Grid Parity by lowering BoS cost (fewer fuse boxes, combiner boxes, and less wiring), faster installation through design flexibility, and simplified O&M (Operations and Maintenance) all while producing more energy over the PV system’s life cycle. Through the combination of cost reductions and increased power harvest, SolarEdge claims to lower the Levelized Cost of Energy (LCOE) by 15%.
|From PV Industry Forum 2009|
SolarEdge DC Distributed Architecture
The SolarEdge System consists of three main elements: the PowerBox, a Fixed Voltage Inverter, and a Monitoring Server and Portal.
The PowerBox replaces the standard PV module junction box and integrates DC MPPT using a proprietary SolarEdge ASIC (Application Specific Integrated Circuit) and power electronics. Per module MPPT extracts the available power from each individual module compensating for the missing 25% issues listed above. The module level MPPT tracks solar irradiance changes faster and with greater accuracy than a centralized inverter approach.
In a key aspect of the SolarEdge architecture, PowerBox equipped modules arranged in a string maintain a fixed string voltage. This innovation enables system design flexibility with strings of different lengths, orientations, power ratings, and module manufacturers. For example, the SolarEdge PowerBox Module Embedded Solution supports single phase system strings from 6 to 25 modules in length while removing temperature design constraints and maximizing roof space. Longer strings help installers use less wiring, connection, and combiner boxes saving cost and simplifying the installation.
Each PowerBox can communicate via DC powerline to the SolarEdge Fixed Voltage Inverter which in turn relays unique ID and module power, voltage, current, and temperature data to the monitoring server. PowerBox units are in Safety Mode whenever the SolarEdge inverter is disconnected or turned off. Safety Mode inhibits high DC system voltages protecting installers, maintenance personnel, or firefighters.
With fixed string voltages and MPPT located at each module, the SolarEdge Fixed Voltage Inverter is optimized for DC to AC (Alternating Current) conversion only at about 400 DC Volts, resulting in a smaller, lighter, and more reliable inverter for a given power rating. An integrated receiver collects the PowerBox data transmitted via powerline and routes it to an Ethernet port for flexible connection options to the Internet.
At first, SolarEdge will offer 3.3 kW (kiloWatt) and 5 kW Fixed Voltage Inverters with their system for residential and small commercial applications.
Once the module data is sent over the Internet to the Monitoring Server, a web application provides module, string, and system level monitoring capability, fault detection and diagnosis via artificial intelligence, and directed maintenance solutions. Besides reducing O&M expenses, monitoring can be used during the system’s installation for debug and validation.
Last, the SolarEdge System has an integrated anti-theft feature. Module PowerBox’s are mated or paired to a SolarEdge Inverter during the installation process. Once completed, the module will only function with a specific SolarEdge inverter. On the monitoring side, the system owner can be alerted if modules are not detected or missing perhaps because of theft.
The SolarEdge Architecture Overview delves into the PowerBox and SolarEdge System including the Concept of Operation under nominal conditions and with partial shading. These two white papers are also worth a read:
|From Intersolar 2009: SolarEdge Technologies|
SolarEdge enjoys explaining their technology while a certain competitor jokes about Magic. SolarEdge also opened the black box and displayed the PowerBox circuit board at their Intersolar stand as shown in the photo above. Sorry about the reflection.
Producing more energy, the complete SolarEdge System is priced to compete with leading brand centralized inverters while reducing installation cost and adding numerous features.
Per this SMA Solar Technology AG Speech of the Managing Board (German) slide 7, the leading inverter manufacturers in the 5.7 GW (GigaWatt) 2008 PV market were SMA (38%), followed by Fronius and KACO (8% each), Ingeteam (6%), Siemens (5%), and the balance (35%) was split between 169 competitors.
Efficiency and Reliability
The PowerBox has greater than 98% DC to DC conversion efficiency backed by a 25 year reliability and limited warranty matching typical PV modules.
SolarEdge’s 3.3 kW and 5 kW Fixed Voltage Inverters are over 97% efficient and have Excellent reliability with standard 12 year warranty.
Regarding PowerBox module reliability, Mr. Sella said:
We believe we can assure 20 FIT (Ed Note: Failures in Time) reliability meaning in every 45 kW installation, you will have one defect module every 25 years. In order to solve the problem for this as well, we have a patent pending bypass mechanism in it so when the box dies, the bypass mechanism covers for it so you are losing the panel but you are not losing the string.
Later, Guy Sella said:
Our goal is to achieve as fast as possible a 20 years life expectancy for the inverters as well.
SolarEdge versus SolarMagic
In response to a question about the competition at the PV Industry Forum, CEO Sella said:
The Competition real world is National which came to the market with SolarMagic it’s called. They optimized only the mismatch and the partial shading. And they ask for extra money for that. If we understand correctly, the pricing that they established is $150 per unit.
Just if you take a 5 kW installation, only 150 times 25 panels, is, if I am not mistaken, $3750 which is much more than what we sell the complete solution. And remember you need to buy the inverter from somebody else.
In addition, they don’t have the monitoring yet nor the safety. So I believe that we are much more advanced. Again, National is a very good company; it’s got lots of heritage, and I am sure they will improve the product.
Schedules and Certification progress
SolarEdge plans to start mass production of their PowerBox and Inverter products in September 2009 at one of the largest global Contract Manufacturers.
SolarEdge’s 3.3 kW and 5 kW Fixed Voltage Inverters obtained EU (European Union) certification just before Intersolar 2009 and are also certified in Australia and Israel. Certification of these inverters per UL 1741 for North America is in progress at CSA with completion expected prior to Solar Power International (SPI 2009) where SolarEdge will launch their solution for the US and North American PV markets. SolarEdge already has two test systems operating in the US and sixteen total installations worldwide.
Besides the PV module (BP Solar, SCHOTT Solar) and system integrator (Gehrlicher Solar AG) partnerships announced at Intersolar, “SolarEdge Wins Exceptional Product Award at Cleantech 2009” announced their receipt of the “The Exceptional Product in the Environmental Protection Arena” award at the June 29-30 CleanTech 2009 Summit and Expo in Tel Aviv, Israel.
Let’s be clear on one SolarEdge point in light of Tesla Motors. I count a total of five founders among the SolarEdge Management Team.