If you’ve been shopping around for a solar panel system, you may have heard of microinverters (from companies like Enphase and SolarBridge) and power optimizers (from companies like Tigo and SolarEdge). These devices – collectively referred to here as Module-level Power Electronics (MLPE) – are quickly gaining popularity in the US as an alternative to conventional string inverters.
In this article we take a look at this emerging trend and examine whether these technologies are the best option for all homes.
Do you need microinverters or power optimizers for your solar power system? To answer that question, you’ll need to understand how MLPE devices work, what benefits they offer, and their cost relative to conventional string inverters. EnergySage has published a series of article on these topics in our Learn section:
Microinverters & power optimizers: Already popular, and set to gain momentum
Analysts: MLPE market to continue growing as costs come down
In the first half of 2014, over half of the residential solar systems installed in the US used some kind of MLPE equipment, according to GTM Research. Many analysts expect this figure to grow in the coming years thanks to falling costs and changing regulations. GTM, IHS and Navigant Research have all predicted that these devices will become more commonplace as the companies who develop and manufacture them refine the technologies.
New NEC safety requirements: Another push towards panel-level equipment
Meanwhile, the National Electrical Code (NEC) requirements for solar panel system safety are gradually being tightened in a way that could change the way that people look at MLPE. The 2014 version of the Code requires that a solar panel array must have a ‘rapid shutdown’ functionality, with a switch located near the solar array. This requirement was added for the safety of emergency responders – particularly firemen.
Some speculate that that the Code will eventually go even further – ultimately requiring that individual panels can be shut off remotely from a central switch. The largest MLPE manufacturers (Enphase, SolarEdge and Tigo, not to mention SolarBridge) have leapt on this opportunity, already having incorporated rapid shutdown functionality into their newer product lines.
This means that instead of needing a separate safety system whose sole purpose is to comply with NEC requirements, solar installers could ‘kill two birds with one stone’ – save money and add value – simply by opting to use microinverters or power optimizers in the solar system. While this doesn’t completely win the pricing game for microinverters & optimizers, it does shift their value proposition further in the right direction. It may only be a matter of years before microinverters – now significantly more expensive – will be priced similarly to string inverters.
Applications for energy storage and energy management?
On top of all this is the question of energy storage and energy management. The growing affordability of energy storage devices for solar systems is projected to launch home batteries into the mainstream in the near future. MLPE technologies could play a role in maximizing the benefits of energy storage for grid-connected solar systems. In fact, both SolarEdge and Enphase have already announced energy storage solutions of their own.
Should a pv system with micro inverters be a no brainer?
The two trends mentioned above – in combination with the fact that MLPE equipment made up over half of the residential market in the US in early 2014- might lead you to think that purchasing a solar system with microinverters or power optimizers is a financial ‘no-brainer’. However, this is not yet the case.
Microinverters and power optimizers certainly do offer certain benefits over string inverters: they perform better on roofs with partial shading or which face multiple orientations (such as a gabled roof), and they allow you to monitor the performance of individual solar panels.
String inverters, meanwhile, do not perform as well on shaded or complicated roofs, and do not allow you to monitor the performance of individual solar panels. However, string inverter technology is time-tested, reliable and costs less and microinverters and power optimizers.
While it does look like microinverters and power optimizers are set to become more affordable, they are still ‘premium’ products and come they come with a premium price tag. As such, anyone looking to purchase a solar system should first carefully consider whether a microinverter or power optimizer solution is truly the best option for them.
Generally speaking, there are only two situations where opting for one of these will deliver greater financial returns in the long-run: when your solar panels are unavoidably shaded (by a chimney, nearby building, etc) or when your roof faces multiple directions. Unless one of these is the case for you, now is probably not the best time to have a system installed that uses this type of equipment.
Solar shopping tip: Thinking about getting a solar system for your home? Be sure to consider all options: String inverters, microinverters and power optimizers. Find the system that offers the best value for you.
When you shop using the EnergySage Solar Marketplace, you can easily compare options from a range of solar installation companies in your area. Our goal is to make it easy for you to go solar.