Are microinverters and power optimizers the future of residential solar power?

Micro inverters and power inverters solar energy storage

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:

String inverters vs Microinverters vs Power optimizers

Microinverters & power optimizers: Advantages & disadvantages

Microinverters & power optimizers: What are your options?

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.

Residential Inverter solar market share GTM

Residential market share of various inverter manufacturers, first half of 2014. Note that Enphase and SolarEdge comprise over 50% of the market. Tigo’s optimizers are compatible with a range of string inverter brands and are therefore not listed by name. (Chart via GTM Research.)

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.





Don



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.





Don



10 thoughts on “Are microinverters and power optimizers the future of residential solar power?

  1. Scott Moser

    It seems to me that you are deliberately ignoring the (much) longer lifespans of microinverters. Also, the fact that the first eastern panel starts producing power the second the sun hits and last western panel keeps going till the the sun is gone adds up to almost an hour of extra production time… every single day.
    Microinverters last longer, they get up earlier and go to bed later while producing the power more efficiently than any string systems.

    Reply
    1. EnergySage

      Hi Scott,

      Two excellent points. Thanks for bringing them up. We have highlighted the benefit of the longer warranty here and here. We’ve also mentioned the benefit of the extra production, but advise our customers to weigh the additional costs associated with microinverter/power optimizer systems with the additional power output over the system’s lifetime.

      Reply
    2. Dave Rust

      The shading question depends on if there is something close to your location shading the panels or not. The further away the object, the less difference this will make. The further away the shading object, the less impact it will have due to the angle. Imagine the sun coming up over a hill at a distance. When the sun comes up from behind it, it will hit all the panels very quickly in succession.

      The 25 year argument isn’t taking into account that there are many more points of failure in the micro-inverter so it is not quite so simple. if you have 16 guns with one bullet instead of 1 gun with one bullet, Is one of the 16 more likely to go off when pulling all the triggers ? Granted the inverters have a longer warranty but you typically have to pay the labor charge for the replacement depending unless the installer covers this. It still really comes down to whether shading is a concern or not.

      At this point, optimizers are a cheaper solution than inverters but this could change over time.

      Reply
  2. Will Noble

    when was this post created? Microinverters have come down in price a lot based on quotes I’m seeing out there today. It appears the main reason not to go with microinverters was cost but if thats not factor I wounder if the writer wouldn’t just say microinverters are the best choice even if you don’t have shade or complex roof issues.

    Reply
    1. Mark

      I hate it when information technology web sites omit the date on the original article. Solar is changing so fast anything even just a year out of date can be suspect. What I usually do is look at the date on the first comment, in this case January of 2015. This means this article is at least this old, which means it is probably somewhat out of date now.

      Reply
  3. Dave Kear

    Does anyone know of a web sight that actually list the price of all the different components of a solar system, Panels, Inverters, Batteries. So I can add up the cost and get a ballpark figure (minus labor) on a system.
    And a sight to figure out, How many panels to how many batteries to how big an inverter. I’m just getting started looking at solar systems. I’ve been reading about all the different components. What they do, How they do it, Everything you would ever want to know. And even things I don’t really need to know except HOW MUCH IS IT!

    Reply
    1. Chuck Lindsey

      I DUPLICATE DAVE KEAR’S QUESTION !!!!!!!Does anyone know of a web sight that actually list the price of all the different components of a solar system, Panels, Inverters, Batteries. So I can add up the cost and get a ballpark figure (minus labor) on a system.
      And a sight to figure out, How many panels to how many batteries to how big an inverter. I’m just getting started looking at solar systems. I’ve been reading about all the different components. What they do, How they do it, Everything you would ever want to know. And even things I don’t really need to know except HOW MUCH IS IT!

      Reply
      1. Dale

        Hey Chuck.

        While it has been a year since your post, check out “Blue Pacific Solar”… while certainly not recommending any one vendor, they sell components and DIY Solar kits and you can get an idea of pricing.

        Reply
    2. Dave Rust

      it is impossible to answer that question for you. Every installation and every customer has different requirements. The prices are constantly changing and the prices are likely to vary depending on your location due to the cost is installation. Solar installers typically have options of inverters, panel mfr’s, etc. The best thing to do is get at least 3 reputable co’s bids, compare them, and read the fine print. Warranty’s especially are a big deal because of the volatility of company’s providing the components. Even some of the larger makers of panels and inverters have either gone bankrupt or are on shaky financial ground. Make sure to ask the installer what will happen in this case.

      Reply
  4. Theodore Winston

    My wife had me convinced about reducing our Carbon footprint so we decided to use renewable energy sources to reduce our power consumption. I always thought that our solar power system is not living up to its potentials. I’ll be sure to keep in mind that the average wattage used by a household would determine which inverter would be used. Would I need to hire an electrician to have this measured or can I do this on my own? Any tips? Thanks!

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *