Based in America and founded in 2006, Enphase Energy was the first company in the world to commercialise solar microinverters. Since then they have gone from strength to strength and have now shipped over 8 million Enphase microinverter units worldwide (as of early 2015). In early 2014 Microinverters had captured nearly 50 per cent of the rooftop solar market in the US and Enphase microinverters were credited with a 73 per cent share of the global microinverter market. The rapid growth of Enphase microinverters worldwide shows just how big the potential for this new solar technology is.
Enphase S230 Microinverter
Enphase microinverters have a range of benefits over traditional string inverter or DC solar systems.
Below we outline some of their key benefits and why Green Energy Options has chosen to specialise in Enphase microinverter systems. You can also check out our microinverter introduction video for more info.
- Quality & Reliability – 10 year warranty
- Safety – no high DC voltages
- Performance – individual panel performance
- Flexibility – easy expansion and orientation options
Quality & Reliability – 10 year warranty & Monitoring
Enphase microinverters are designed for extremely rugged environmental conditions. Now up to their fourth generation product Enphase are designed for long term reliability. Enphase Energy put their microinverters through what’s believed to be the industry’s most rigorous quality testing procedures during design, through manufacturing and even after their microinverters are installed in the field.
Enphase don’t release a product until it’s been through over 1 million hours of power-on product testing, this includes some of the most extreme temperature and humidity environments you can think of, even operation underwater. In the manufacturing process this high level of quality control is continued, with 100% of their products tested before going to market. If that’s not enough Enphase are in a unique position in the solar inverter industry, where they have over 4 million units connected to the internet, monitoring performance and feeding back information on the grid and environmental conditions to the Enphase team. The Enphase team can then make adjustments to their microinverter in the design process and push out software updates to make improvements to their systems remotely.
As well as feeding back information so that Enphase can improve their products, it allows the installer and end customer to see how the system is performing and will even send email updates and alerts if there are issues with the system. Enphase monitoring helps to minimise system downtime and maximise your return on investment, their monitoring solution is available on both desktop and mobile, so it’s easy to keep track of how your system is performing.
Understanding Enphase Energy’s position as a company and the quality testing procedures they have in place helps to understand why they stand out as a leader in quality and reliability and are able to offer a 10 year product warranty on their microinverters.
Safety – Lower DC Voltage
Microinverter systems are considered a safer system option than traditional string inverter systems and have an advantage in that they don’t operate at high DC voltages. In Australia residential solar systems can operate at up to 600V DC and commercial systems at up to 1000V DC. With this sort of voltage running through your solar panels, isolators and cabling, it puts a lot of stress on the system and increases the risk of a fire should there be an arc fault. Enphase microinverters operate at extra low voltage (ELV) DC with maximum of 48V; this means the risk of an arc fault is virtually eliminated.
As a side note, one of the benefits of running a system at ELV is that it eliminates the risk of Potential Induced Degradation (PID). A solar array in a string inverter will operate at high DC voltages, normally between 200-1000V, this puts a lot of stress on the panels and the other components in the system. Some panels have been shown to degrade over time due to PID, without getting too technical, it occurs when the panel is exposed to a negative voltage to ground.
The other safety benefit from an Enphase microinverter system comes in case of an emergency, when you need to isolate the solar array. In the case of a microinverter system, when you turn off the main switch in the switchboard, the microinverter turns off on the roof leaving ELV (max 48V DC), in the case of a string inverter system the inverter turns off on the wall of the house and the wiring and array are still live at up to 600V DC.
So in summary, Enphase microinverter safety benefits include:
- No high DC voltages
- Virtually eliminates the risk of arc faults
- Isolates the inverters on the roof
Performance – individual panel optimisation
Microinverter systems differ from traditional string inverter systems in the way that they operate. In a string inverter system the panels are connected in series and controlled by a central inverter unit, if one panel is shaded, the entire system’s output can be affected. In a microinverter system the panels are connected in parallel with the microinverters installed under the panels, each panel has their own independent Maximum Power Point Tracker (MPPT) individually optimising their performance and allowing you to harvest the most energy out of each panel. A study by the National Renewable Energy Laboratory (NREL) in the US shows that Enphase microinverters increase energy harvest by up to 12.6% in shaded conditions.
It must be noted that it’s not just in shade conditions where Enphase microinverters have benefits. Small differences in panel outputs within the same solar array can be caused by a number of different factors;
- Uneven dirt and dust build up
- Irregular cloud cover
- Modules operating at different temperatures
- The panels output degrading at different rates
- Panel mismatch due to initial rated output variances
These factors can all impact on an array’s performance. Microinverters allow you to harvest the most out of each solar panel without their neighbours output dragging them down. Particularly over the life of the system when these factors start to impact, the advantages of a microinverter system will start to shine.
Flexibility – easy expansion and orientation options
One of the key benefits of microinverter technology is its flexibility. Because each panel has its own inverter and Maximum Power Point Tracker (MPPT) you have the flexibility to face panels in different directions, this can be really handy if you are dealing with small, tricky roof spaces, or want to split arrays to take advantage of power production at different times of the day. Enphase microinverter systems have also been designed for easy expansion, because of the system’s modularity, it’s simple, you can add one panel or 100. Even if you have an existing string inverter system Enphase microinverters can be a great way to expand your system, taking advantages of different roof spaces and not having to worry about matching panels, like in a string inverter system.