SolarEdge - More than optimising

If you only considered SolarEdge for projects requiring panel level optimisation, you'd be overlooking one of the most innovative inverter brands of the past decade. SolarEdge haven't just split the inverter into two funtions, they're leveraging every possible advantage of the DC optimised concept. Power optimisers and other Module Level Power Electronics (MLPEs) are gaining traction fast, but it's SolarEdge's innovation that has them leading the way.

Before SolarEdge

Before power optimisers (optimisers) and SolarEdge, it was really either string or micro inverters. The inverter has two main functions, optimise energy harvest from the panels and convert DC to AC. String inverters do this on the wall and optimise all the panels with one or two MPPTs (trackers) in the inverter. This has proven to be an effective solution, but they are outperformed by micro inverters. Micro inverters are mounted under each panel and track each panel independently. This offers multiple benefits, like higher yields, greater design flexibility and better shade management. However having an inverter, a common point of failure, on the roof is not liked by all - despite some micros being very reliable. Having multiple inverters also increases cost, particularly on big systems.

SolarEdge's "DC Optimised" Approach

SolarEdge's comparison of the three inverter topologies - string inverters, micro inverters and SolarEdge DC optimized inverters.

SolarEdge have split the inverter into two components. A simplified inverter, which is mounted on the wall, and devices called power optimisers (optimisers for short) which are mounted under the panels. By splitting it into two, they've been able to achieve what they describe as a "best of both worlds" approach. You still have the benefit of panel level optimisation, but the DC to AC conversion is done on the wall. This has unlocked a range of benefits.

How is the world warming to this approach? Their numbers suggest very positively. According to GTM Research (link to article), SolarEdge were 5th in the world for inverter revenue, which was comfortably the highest of all the MLPE manufacturers. Let's take a look at their concept in more detail.

Benefits of the SolarEdge Solution

Panel level Optimisation

While this isn't unique to SolarEdge, it's important to understand the benefits created by panel level optimisation. Here's a quick summary:

  • Total design flexibility, as each panel can face any direction or be installed at any angle. 
  • Better shade management, (see blog post) improving output and longevity of the shaded panel while preventing it from negatively impacting others.
  • Differences in performance from degradation and manufacturing are managed better. As are external impacts like birds, patchy cloud cover and variable dirt build up.

Even on an ideal roof for solar, free of the issues mentioned above, you can expect panel level optimisation to provide a 5% yield boost.

Extra Functionality

 SolarEdge Optimiser mounted behind the panel.

SolarEdge Optimiser mounted behind the panel.

The primary benefit of power optimisers is to provide panel level optimisation. SolarEdge's holistic approach however has also enabled the following benefits, some which are unique to their DC Optimised approach:

  • SafeDC™, a safety feature which de-energisers the panels and reduces the voltage of each optimiser to 1V whenever the AC power is shutdown.
  • Panel level monitoring, with the ability to fault find and check output of individual panels remotely. No extra monitoring devices or fees are required.
  • Longer and unbalanced string lengths, making installation easier and reducing balance of system components.
  • Very wide MPPT voltage window. This allows SolarEdge optimisers to perform better in extreme shading than other solutions with panel level optimisation (particularly micros).

Where SolarEdge Have Also Innovated

While SolarEdge have seemingly unlocked all the benefits of optimisers and impressed the world with their "DC Optimised" approach, their innovations in inverter technology extend far beyond optimisers. Here's some recent innovations that show you why they're truly changing what's possible with inverter technology.

Integrated Battery Solution

The StorEdge Interface can be added at any stage and enables easy retrofit of a battery.

When Tesla first announced it's Powerwall, it didn't have an inverter built in. They decided to partner with leading inverter manufacturers to enable customers to connect their battery to their home. The first manufacturer chosen by Tesla was SolarEdge, who designed one of the most innovative and simple solutions on the market - the StorEdge Interface.

The SolarEdge StorEdge Interface enables customers to add a battery to their existing SolarEdge system very easily at any stage. Unlike AC Coupled solutions, the StorEdge Interface is not a second inverter. Rather it enables the existing inverter to be used to convert battery power into AC, in addition to converting the DC power from the panels into AC. This converts the solution into a hybrid solution, which has significant advantages over AC Coupled options (click here for more on this), including:

  • The StorEdge Interface is cheaper than other battery inverters.
  • Store DC power from the panels before it's converted to AC, saving two conversions.
  • Keep your total inverter capacity low, which is a must for some network operators.
  • Oversize the solar array without clipping, as power that would normally be clipped is stored in the battery. This enables you to exceed the 133% CEC oversizing limitation.

While not compatible with the new Powerwall (Tesla have opted exclusively for a Powerwall 2 with their own inverter), StorEdge is compatible with the new High Voltage LG Chem. They are also looking at other high voltage batteries and have a history of being first with the required firmware for new batteries on the market.

The HD Wave Inverter

The award winning SolarEdge HD Wave Inverter.

Good inverters have already hit high marks for efficiency, with the best sitting around the 97% mark. Since transformerless inverters were introduced into the market, we haven't seen any noticeable leaps. So when SolarEdge promised a boost of 1-2% with their new HD Wave Inverters, there was certainly an air of anticipation in the industry. This may not seem like a big jump, but when you're in the high 90% mark already, it's quite an advancement.

SolarEdge HD Wave Inverter Explained

In addition to the higher efficiency, SolarEdge have been able to reduce the magnetics and cooling components. This has resulted in a much smaller, lighter inverter that requires no fan. While it is early days for this new inverter concept, the initial feedback has been excellent. The SolarEdge HD Wave was recognised by Intersolar, winning an award in the prestigious "Photovoltaics" category in 2016 (click here for more info). Innovating the inverter to this level is just another reason why labelling them an optimiser company is unjust.

EV Charger

Over the next decade, we're going to see a big uptake in electric vehicles. SolarEdge have not only anticipated this, but they have recently announced a highly innovative EV Charger for use with their HD Wave inverter. Unlike standard EV Chargers, it integrates with the solar system and is able to charge the electric vehicle from solar, before it's converted to AC. Not only is this is a very efficient way to use solar production, but it enables much faster charging. For increased speed, you can also combine additional grid power. The EV Charger is also capable of standard grid charging, but it's not as quick.

 Click on the image to go to visit the SolarEdge EV Charger page.

Click on the image to go to visit the SolarEdge EV Charger page.

Charging your vehicle directly from your excess solar is a great way to maximise your savings. The SolarEdge system makes this really easy, as they've integrated the EV Charger with their monitoring. This allows smart controls like charging from the grid only at off-peak times and charging from the solar only when there's excess power. As families start seeing their fuel costs transition into their energy bill, this is paving the way for homes to reduce their energy costs and get even more out of their solar panels - without needing to increase inverter capacity.

Smart Home Energy Management

A system that optimises every available kWh from your panels is great, as is using the DC power from the panels in a battery or electric vehicle before converting it to AC. Once it becomes AC, using energy as efficiently as possible also very important, and this is what SolarEdge is allowing home owners to do with their Home Energy Management platform.

 SolarEdge Load Control Devices

SolarEdge Load Control Devices

The Home Energy Management platform from SolarEdge includes a few different products, like metered AC switches and plug in sockets, and an Immersion Heater Controller. The metered switches enable you to control power to a device and see it's consumption. An Immersion Heater Controller not only turns on a water heater when there's excess power, but can also vary how much power it draws to suit the excess available. All these devices communicate via ZigBee. ZigBee is lower bandwidth communication protocol, but is chosen by most popular home automation products due to it's "mesh" like network and lower power consumption. All of these devices integrate with SolarEdge's monitoring portal, which is rapidly becoming a complete energy management portal for your home.

SolarEdge's Home Energy Management solution, combined with their other battery, panel level monitoring and EV chargers, gives you excellent visibility and control of all your devices in the one easy to manage platform.

Warranties

A warranty isn't an innovation, but it's nice when a manufacturer backs their product, and few do it as well as SolarEdge. SolarEdge has some of the longest warranties around, including 12 years on the inverter, 25 years on the optimiser and 5 years on control devices. All include labour (click here for the SolarEdge warranty document). Also, while we're not financial experts, you'd be hard pressed to find someone that believes SolarEdge are stretched financially - in fact, quite the opposite. This is important, as even good products fail and companies who have disappeared can't honour their warranties.

Summary

While we're not big on pushing specific products in our posts, we've made an exception to address a common injustice - only considering SolarEdge when your project requires panel level optimisation. SolarEdge have gone from strength to strength and innovated at every step. Right from the very beginning with their DC Optimised approach, to just the other week when they unveiled their EV Charger.

We can certainly understand someone not going for optimisers because their installation doesn't need it, but SolarEdge is so much more than just optimisers. The cost of SolarEdge has also come down, and now the price jump from good string inverters to SolarEdge is very reasonable. If in the past you've stuck SolarEdge in the "great, but I don't need optimisers" category, it's time you revisit this highly innovative solution for you or your customers.