If you’re a homeowner who is thinking of going solar, or you’re already working with a solar installer and have a technical proposal in front of you, you’ll know that one of the key components in a home solar system is the inverter.
Solar panels generate direct current (DC) electricity, which is the kind of electricity you get from a battery. Grid electricity and your home, however, use alternating current (AC). It’s the job of a solar inverter to convert DC electricity to AC electricty that your home can use.
This is a pretty indepth topic, so I recommend reading our guide to solar inverters if this is all new to you. If you’re further along in the shopping process - maybe you’re looking at a solar installer proposal and scratching your head at the inverter line item - there’s a good chance you’ll come across module-level power electronics (MLPE).
Module-level power electronics vs. string inverters
The conventional type of inverter is a central unit that does the DC-to-AC conversion for a group of solar panels. For a small installation, like a home solar system, you’ll usually need just one central inverter. This type is called a string inverter because the solar panels are wired together in one or more strings, like Christmas lights. This is usually the least expensive inverter option. A string inverter is installed near your electrical panel and the solar system cutoff switch. This might be in your basement, on the side of your house, or in a garage.
For more complicated solar installations, an installer will often recommend module-level electronics. There are two types: microinverters and power optimizers, which are also called DC optimizers.
With both types, each solar panel is paired with one electronics package that is bolted to the rack adjacent each panel. That means if your system has 20 solar panels on the roof, you will have 20 MLPE units on the roof. Depending on the manufacturer, there is usually some type of electronics package that is also installed near your electrical panel.
What is a microinverter?
A microinverter is a fully self-contained solar inverter. It’s about the size of a paperback book, and is bolted onto the rack underneath a solar panel. Each microinverter fully handles the DC-to-AC electricity conversion for one solar panel.
The largest player in the microinverter market, by far, is Enphase Energy. They have a large product lineup that is currently on its 7th generation, which has helped the company iron out buggy electronics that plagued early iterations of their products. Because it has such a significant presence in the residential inverter market, we wrote an indepth overview of the Enphase product lineup.
But Enphase isn’t the only microinverter company out there. For example, APsystems and Chilicon Power are US-based companies that offer microinverters comparable to those from Enphase.
What is a power optimizer?
Inside a string inverter, there are usually one or more units called maximum power point trackers (MPPT). An MPPT helps the inverter to better deal with shading that falls across only part of a solar array, a situation that can impair the electricity production of the whole array. This is especially useful if your system has multiple strings, which is common on many homes. For example, you might have one string of panels on part of your house, and the another string installed on your garage. Multiple MPPTs in an inverter would allow it to optimize the power collection from each string.
Power optimizer or DC optimizer inverter systems take this approach a step further and move the MPPT units outside the inverter and put them alongside each solar panel. They resemble microinverters in this respect, even though they don’t handle the actual DC-to-AC conversion. Like microinverters, a power optimizer is a small electronics package that is bolted alongside each solar panel in the array. Because each solar panel has its own optimizer, partial shading across the system has much less of a negative impact.
What are the benefits of MLPEs vs string inverters?
Both microinverters and power optimizers have the following advantages over cheaper string inverters:
- Better shade tolerance. String inverter-based solar systems can suffer significant power reduction when the array is partially shaded. Both types of MLPEs skirt around this problem.
- Module-level monitoring. With a string inverter, you can monitor the power output of the system as a whole, but it can’t tell you how an individual solar panel in your array is performing. Microinverters and power optimizers change that, and let you see how much electricity each panel in your system is producing in real-time. Even if you aren’t the type of person to obsessively check on your system and geek out on how much electricity you’re making, panel-level monitoring is still useful because it will tell you if one panel in your system is underproducing. This could be because of a panel failure, or something as mundane as a big drop of goose poop.
Microinverters, the most advanced inverter option, have some additional advantages:
- Flexible layout and system expansion. With a power optimizer-based system, the DC-to-AC conversion still happens at a centralized inverter unit mounted near your electrical panel. Because of this, there are still constraints on the string layout. For example, an individual string might be limited to a certain total wattage. With microinverters, there are no such limitations, and the solar panel layout can be as crazy as needed to fit your rooftop. While not all homes may need this, it also gives you more options for future expansion. For example, if you decide you want to power an electric car with solar in the future, microinverters will let you add as many panels as you want.
- (Possibly) fewer system failures. In the US market, manufacturers of microinverters and power optimizers have standardized on 25 year warranties. (If you come across a product with less than a 25 year warranty, think twice.) However, with power optimizers, this applies only to the external optimizer unit, not the central inverter. For example, SolarEdge offers a 25 year warranty for the optimizer, but only a 12 year warranty with their central HD-Wave inverter. If the duration of a warranty reflects the manufacturer’s expected lifetime for a product, that means budgeting for an inverter replacement halfway through the lifetime of your solar system. Microinverters, on the other hand, have a 25 year warranty for the entire unit.
Manufacturers that offer microinverters and power optimizers
If you do a little internet searching, you might notice that different solar inverters are popular in Europe, Australia, and North America. While each solar installer company will have different preferences and supplier relationships, here are some of the most popular solar inverter companies.
Enphase Energy
Enphase offers a wide variety of products, including their IQ7 series of microinverters. Enphase offers only microinverters - there are no string inverters in their lineup. The microinverters come in different capacities that are suitable for solar panels from 195 watts up to 460 watts or more. (For the lowest wattage panels, Enphase still offers the earlier IQ6 series.)
With Enphase, system monitoring is provided by a separate unit called the IQ Envoy. It’s a WiFi-enabled unit that sends real time data to Enphase cloud servers, and lets you see monitor your system from a web page or smartphone app.
SolarEdge
SolarEdge offers multiple inverters, but the homeowner will be looking at the SolarEdge single-phase HD-Wave inverter. The HD-Wave inverter looks like a conventional string inverter, but it needs to be paired with the SolarEdge power optimizers.
SMA
SMA is a German company that has been around since 1981, but has only recently started offering their Power+ optimizer product. It’s a DC optimizer comparable to the SolarEdge product. The Power+ optimizers are paired with an SMA Sunny Boy inverter.
Other manufacturers
APsystems is based in Seattle and manufactures microinverters. For the home market, you’ll be looking at their APsystems QS1 and YC600 microinverters. These microinverters take a unique approach: instead of one microinverter per panel, each microinverter will handle two panels (in the case of the YC600) or four panels (QS1). This has the advantage of cost savings from lower hardware and installation costs. As with Enphase, you can get a warranty up to 25 years, although the base warranty is only 10 years.
Chilicon Power is another US-based company (California) that is making microinverters for the residential market. Their CP-250E microinverter is aimed at the residential market and handles panels up to 345W DC. It also comes with a 25 year warranty.
Should you go with one of these lesser-known manufacturers? Both offer solid warranties, although with APsystems their 25 year warranty is an upgrade. One of the hazards of early microinverters, especially the second generation of Enphase products that suffered from a lot of failures.
This was a big knock on Enphase’s reputation, and they’ve been putting a lot of focus on product reliability since then. From what I’ve heard from installers, their reliability since the second generation microinverters is a lot better. It’s probably safe to say that other companies have treated Enphase’s experience as a cautionary tale, especially with the use of poor quality capacitors that were at the root of those Enphase failures.
The upshot is that it’s probably a safe bet to go with one of these manufacturers if your solar installer is recommending it, especially if you have the 25 year warranty.
MLPEs: other things to look out for
I’ll again point to you our article on solar inverters to better understand that pros and cons of different types of inverters, but here’s a couple other things to think about.
Rapid shutdown requirements
There’s a relatively recent addition to the National Electrical Code (NEC) that requires the ability to close down the electricity in the wiring near a solar panel to 30 volts or less in an emergency. This regulation is there to reduce the electrocution hazard for first responders in an emergency. Here’s the actual language of the code:
690.12 Rapid Shutdown of PV Systems on Buildings.
PV system circuits installed on or in buildings shall include a rapid shutdown function to reduce shock hazard for emergency responders in accordance with 690.12(A) through (D).
(A) Controlled Conductors. Requirements for controlled conductors shall apply to PV circuits supplied by the PV system.
(B) Controlled Limits. The use of the term, array boundary, in this section is defined as 305 mm (1 ft) from the array in all directions. Controlled conductors outside the array boundary shall comply with 690.12(B)(1) and inside the array boundary shall comply with 690.12(B)(2).(1) Outside the Array Boundary. Controlled conductors located outside the boundary or more than 1 m (3 ft) from the point of entry inside a building shall be limited to not more than 30 volts within 30 seconds of rapid shutdown initiation. Voltage shall be measured between any two conductors and between any conductor and ground.
While the risk is extremely low, solar panels do have a small risk of electrical fires when components fail or the system is installed improperly. This risk is higher with string inverters because high voltage DC electricity is carried across your rooftop and converted into lower voltage AC power only at the inverter. You can read our article on solar panel fires and watch the included video to see the difference between DC and AC power when it comes to arcing.
Both microinverters and power optimizers have software that automatically does a rapid shutdown at the panel when a fault is detected. Microinverters have an added safety benefit because the DC-to-AC conversion happens immediately, right at the panel. This means that lower voltage AC power will be flowing across your rooftop with a microinverter system.
The NEC regulation is effective January 1, 2019, but only in some jurisdictions. See the map on this page to find out if it applies to you: https://www.nfpa.org/NEC/NEC-adoption-and-use/NEC-adoption-maps
Inverter clipping
It can be confusing to understand the equipment proposed by your solar installer. When it comes to module-level electronics, there’s one detail that’s worth explaining: inverter clipping.
Let’s say that your installer has specified a really high power solar panel for system - something like a 380 Watt REC Alpha panel. But then you notice that they’re also proposing to use the Enphase IQ 6, a previous generation microinverter with a maximum input power of only 330 Watts. This means that the maximum output per-panel will be 330 Watts, and not the 380 Watts that the panel is rated at. Does that make any sense?
It definitely can. First of all, you should know that the nameplate rating of a panel is only its theoretical power output. Mainly because of operating temperatures, you shouldn’t expect that power level in any real-world setting. There are different testing standards (such as PTC and NOCT) that try to better model real-world output, but as a rough rule of thumb, you can expect the maximum output on a cool sunny day to be 80% of the nameplate rating at most.
Read our article on solar panel specifications to learn more about real-world performance and these different testing standards.
Because your solar panels may only hit maximum performance for part of the year - usually, these will be sunny days that are also cool - it often doesn’t make financial sense to pay extra money to upgrade to a higher capacity inverter to squeeze out a few extra watts from your system, when you can instead save money on the inverter by going with a lower capacity and letting your power output get “clipped” on those maximum output days.
Microinverters and power optimizers: a good choice for you?
There are a lot of advantages to MLPE systems, and the main disadvantage - higher cost - is becoming less of an issue as their market share increases, driving down costs. With 85% of solar homeowners going this route, it’s clear that the MLPEs are here to stay.
TAGS:
#Inverters#Microinverters#Enphase#SolarEdge
FAQs
Are Microinverters better than optimizers? ›
Micro-inverters Are More Reliable
In a DC optimiser system, a single failure will ground the whole solar system. But microinverters have the highest reliability levels of all PV systems because the AC power output has multiple “small sources” of power, so it's not concentrated on a single component.
SMA's current model string inverters all have the ability to provide varying levels of grid support dependent upon the individual requirements of the system and grid operator. Micro inverters are not able to provide the same level of grid support, yet.
What is better SolarEdge or Enphase? ›SolarEdge's scalability is limited in comparison to Enphase micro-inverters. SolarEdge systems are limited to the size of the central inverter, which can intake a certain number of solar panels. Enphase micro-inverters have higher flexibility to scale by simply adding solar panels with compatible micro-inverters.
Is it necessary to use a SolarEdge power optimizer with a SolarEdge inverter? ›Do I have to use power optimizers with a SolarEdge inverter? Yes, for all SolarEdge inverters (Single-Phase, HD Wave, StorEdge, and Three Phase.), power optimizers must be used in order for your solar system to perform and report data to the SolarEdge monitoring platform.
What is the downside of Microinverters? ›The main disadvantage of microinverters is the price. They are typically $1,000 or so more expensive than a string inverter on a standard 5 kW residential solar installation.
What is the disadvantage of power optimizer? ›Disadvantages of micro-inverters & power optimizers
MLPE technologies have higher costs when compared to string inverters, because more pieces of equipment must be used. More equipment may mean a higher likelihood of breakdowns.
Since micro-inverters are not exposed to as high power and heat loads as central inverter, they also tend to last significantly longer. Micro-inverters typically come with a warranty of 20-25 years – 10-15 years longer than central inverters.
Are Microinverters better? ›Microinverters tend to cost a bit more. But they are more efficient in extracting the most energy out of the system. Microinverters will be a better option in situations where the panels will be affected by shading or when they need to be facing different directions on the roof.
How long do enphase microinverters last? ›These units are designed to last the life of a solar panel and generally have a warranty to back that up. Many microinverters, such as those from Enphase, come with a 25-year warranty (10 years outside North America), which is far longer than the standard 10 years for most string inverters.
Which solar panel technology is best? ›Monocrystalline solar panels are often considered the most efficient solar panel option. Therefore, they are typically installed for larger energy systems in commercial and residential properties.
What is the best solar micro inverter for 2023? ›
The Enphase IQ7 Microinverter System wins the top spot. It is a reliable and affordable option for homeowners and businesses. Unlike traditional string inverters, the Enphase IQ7 uses microinverters that attach directly to each solar panel, providing greater efficiency and control over your solar system.
Which brand is best for solar inverter? ›| Inverter | Input Voltage | efficiency |
|---|---|---|
| SolarEdge – SE6000H 6.0kW Inverter | DC 380 v | 99 % |
| LuxPower Hybrid Inverter LPX 5K ACS | DC, 140 v | 97.5% |
| Huawei Sun2000 5k | DC, 200 v | 97.5% |
| SMA Sunny Boy 5.0 | DC, 125 v | 96.5% |
SolarEdge's inverters have historically generally had a good reputation for reliability and efficiency. They are compliant with current remote shut down regulations and approved for use in a number of Virtual Power Plant (VPP) programs across Australia.
Are SolarEdge optimisers reliable? ›Compared to traditional string inverters, SolarEdge inverters are more cost effective, reliable and efficient. SolarEdge inverters have a recording breaking 99% efficiency. In comparison, most string inverters have an efficiency of 93-96%.
Are PV optimizers worth the money? ›Your solar system may work better in bad weather thanks to the MPPT tracking technology than systems without microinverters or solar optimisers. So just in case it was not clear whether are solar panel optimisers worth it, well they are. A single panel's power optimizer may momentarily go offline if it is fully shaded.
What are the disadvantages of Enphase? ›The only significant limitation of Enphase Microinverters is in regard to battery storage. Microinverters aren't compatible with the majority of solar batteries as they are DC coupled, this is because of microinverters output AC power.
Are microinverters better for solar? ›The ability for each panel to work individually using microinverters, however, allows for greater energy production and efficiency - especially when only a few panels are in the shade or under snow. Thus, microinverters are recommended on most home solar projects, since most roofs have some sort of shading.
Can Enphase microinverters be used off grid? ›Enphase Ensemble
Ensemble is a suite of products from Enphase Energy which allow homeowners to have a truly grid agnostic solar system. This means the solar system can be either connected to the grid, operate when the grid is down or be used for off-grid.
Shaded roofs
Some solar PV systems can minimise the impact of shading using 'optimisers'. If you don't have shading, the use of optimisers is not necessary or beneficial, other than the increased monitoring opportunities they offer – they won't generate more energy.
The Microinverters Not Reporting ( ) arises when the Envoy is too far away from the load center or if there is interference on the power lines. If the Envoy was moved from its original location, it may be plugged into an outlet that is too far from the electrical panel (site load center).
When should I use power optimizer? ›
Excessive Shade
So, if you constantly experience even partial shading, you should seriously consider solar optimisers. These optimisers will ensure that unshaded panels operate optimally while also providing the best possible power output from the shaded panel.
Enphase is a micro-inverter system which means a small inverter is attached to each panel, while SolarEdge uses a solar panel optimizer attached to each panel and they connect to a single inverter. To understand the pros and cons for each you have to understand how they both work.
Why is Enphase better? ›AC Power Is Much Safer Than DC – Enphase Is Safer Solar
Because microinverters convert the DC power generated by the solar panels to AC immediately underneath each panel, it means the system has an AC cable run down to the meter board instead of high-voltage DC.
Higher cost is required in terms of commencement, maintenance and replacement due to separately installation on each panel. Comparatively, a central or extra monitoring system is required as each solar micro inverter is separately located.
What is the failure rate of microinverters? ›(Remember it's only 0.18% of Enphase microinverters that have failed.)
What is the failure rate of micro inverters? ›They have found that 34.3% of the devices experienced their first failures after 15 years. “I would say this failure rate is acceptable, even good,” researcher Christof Bucher told pv magazine. “One assumes the inverter must be replaced once in the lifetime of a PV system.”
How do I choose a microinverter? ›- Input Voltage.
- Energy Efficiency.
- Size & Weight.
- Available Warranty.
- Peak Output Power.
The NEC, 120% rule states that solar PV systems should be installed in electrical boxes up to 120% of the busbar's label rating. For example, if the home's electrical meter rating is 175 amps, the rule allows an additional 20%, an equivalent of 35 amps from the solar system.
Is Enphase made in China? ›The company is based in California, but manufactures its products in cooperation with global partners Flex and Salcomp in many locations in Mexico, India, and China.
What are the advantages of Enphase microinverter? ›Enphase microinverters simplify safety by including built-in Rapid Shutdown capabilities. Easily track production and quickly pinpoint issues with module-level monitoring. Maximize rooftop space and adapt to design challenges with microinverters.
Which is the highest efficiency solar panel in the world? ›
The most efficient solar panels on the residential market today are sold by SunPower and Canadian Solar. Both have a maximum efficiency rate of 22.8%. But competitors are closing the gap. Solar panels are made differently, and some are more efficient than others.
What solar panels does Tesla use? ›What brand of solar panels does Tesla use? Tesla uses Q Cells as its solar panel brand.
What is the latest technology in solar panels? ›Emerging technologies include pyramidal lenses, developed by researchers at Stanford University, which promise to concentrate the amount of light that hits a solar cell—getting the same amount of light to hit an area a third of the size—a breakthrough that could make solar panels more efficient in indirect light ...
Will solar get cheaper in 2023? ›Solar costs are very likely to decrease in 2023, making rooftop renewables affordable for more homeowners. In November 2022, the National Renewable Energy Laboratory (NREL) published its analysis of the cost of solar and energy storage (battery) system installations for the first quarter of 2022.
Is SolarEdge cheaper than Enphase? ›Warranty: The 25 year Enphase warranty exceeds the basic 12 year SolarEdge warranty. You can get 25 years with SolarEdge, but it's an optional add-on with a cost. Price: In most cases, SolarEdge systems are cheaper than Enphase - but not always.
What is the price of microinverter Enphase? ›| Installation Size (in KW) | Approx. Price (Per Watt) |
|---|---|
| 1 to 5 | INR 14 – 20/- |
| 5 to 10 | INR 20 – 18/- |
| 10 to 25 | INR 18 – 17/- |
| 25 to 50 | INR 17 – 16/- |
Sungrow Power Supply Co., Ltd. (“Sungrow”) is the world's most bankable inverter brand with over 269 GW installed worldwide as of June 2022.
What type of inverter is most efficient? ›High quality sine wave inverters are rated at 90-95% efficiency. Lower quality modified sine wave inverters are less efficient - 75-85%. High frequency inverters are usually more efficient than low-frequency.
What are the disadvantages of solar inverter? ›Disadvantages of Solar Inverter
This kind of inverters is expensive to afford. Sunlight is necessary to generate sufficient electricity. It requires a huge space for installation. It requires a battery to work at night time to provide proper electricity to the home, commercial, etc.
The average solar panel lifespan for solar panels we recommend is around 25 to 30 years. Most clients make a return on their solar investment by the ninth year, making solar a no-brainer when done by a professional team with high quality materials.
Who is SolarEdge biggest competitor? ›
The main competitors of SolarEdge Technologies include First Solar (FSLR), Enphase Energy (ENPH), Pembina Pipeline (PBA), Coterra Energy (CTRA), Targa Resources (TRGP), Ecopetrol (EC), Marathon Oil (MRO), Evergy (EVRG), EQT (EQT), and Magellan Midstream Partners (MMP).
Is SolarEdge made in China? ›SolarEdge is an Israeli company that develops and sells solar inverters for photovoltaic arrays, energy generation monitoring software, battery energy storage products, as well as other related products and services to residential, commercial and industrial customers.
Which is better Microinverters or optimizers? ›Micro-inverters Are More Reliable
In a DC optimiser system, a single failure will ground the whole solar system. But microinverters have the highest reliability levels of all PV systems because the AC power output has multiple “small sources” of power, so it's not concentrated on a single component.
CASE DETAILS: The filed complaint alleges that defendants made false statements and/or concealed that: (i) the designs of the power optimizers, inverters, and components thereof used to develop SolarEdge's products potentially originated with and were misappropriated from Ampt LLC ("Ampt"), a competitor in the ...
What is the rank of SolarEdge? ›SolarEdge Technologies holds the No. 1 rank among its peers in the Energy-Solar industry group. NEXTracker (NXT) and SolarEdge Technologies (SEDG) are also among the group's highest-rated stocks.
Is SolarEdge better than Enphase? ›SolarEdge's scalability is limited in comparison to Enphase micro-inverters. SolarEdge systems are limited to the size of the central inverter, which can intake a certain number of solar panels. Enphase micro-inverters have higher flexibility to scale by simply adding solar panels with compatible micro-inverters.
Can you mix and match SolarEdge optimizers? ›They can be used interchangeably and can be connected in the same string. M series Power Optimizers M2640 and M1600 cannot be used interchangeably and cannot be connected to any other Power Optimizer in the same string.
Why are microinverters better? ›Since micro-inverters are not exposed to as high power and heat loads as central inverter, they also tend to last significantly longer. Micro-inverters typically come with a warranty of 20-25 years – 10-15 years longer than central inverters.
Are micro inverters the same as optimisers? ›Micro-inverters and power optimizers, referred to as Module-Level Power Electronics or MLPEs, are a twist on the traditional solar PV system set up. While micro-inverters completely replace the need for a string inverter, power optimisers work in conjunction with the string inverter to increase power output.
Are Microinverters more efficient? ›Efficiency. Because each panel can work on its own, microinverters offer a 5-15% increase in production for vs string inverters. This is often due to their superiority in the aforementioned shading situations, but it also applies if a solar panel (or microinverter) is damaged or dirty.
What is the difference between Tigo Optimizer and Microinverter? ›
Tigo Energy optimizers do not convert DC to AC. Our DC-DC solution enables greater energy harvest because it is 99.6% efficient and the installation benefits from highly efficient central inverters. In contrast, microinverters are only 95% efficient.
How reliable are Enphase Microinverters? ›Microinverter systems have no single point of failure, which is particularly important in a large system with many panels. This means that unlike with string inverter systems if one panel or microinverter has a serious fault, the rest of the system is unaffected, and it doesn't result in a complete loss of generation.
How long do Enphase microinverters last? ›Microinverters have a longer life. EnergySage said they can often last 25 years – nearly as long as their panel counterparts. Usually, these inverters have a 20 to 25-year standard warranty included.
What is the life expectancy of a micro inverter? ›Microinverter – 15 to 25 years
This is a relatively expensive solar inverter that has numerous advantages. Lower operational costs, a longer life span (15-25 years), and an increase in overall productivity (typically 5-25 percent, depending on shading).
Power optimisers are a great choice if you are building or the roof gets shaded during the day or if you want to boost the performance of your solar system. Solar optimizers should be used to set up your solar panels so that they can operate on their own to get the most out of them.
What is the most efficient solar cell technology? ›Monocrystalline Solar Panels
Monocrystalline (mono) panels offer the highest efficiency rates and power output. Although they have the highest price tag, their long-term benefits are worth the investment. Mono panels are more compact, making them ideal for homes with limited roof space.
Compared to traditional string inverters, SolarEdge inverters are more cost effective, reliable and efficient. SolarEdge inverters have a recording breaking 99% efficiency. In comparison, most string inverters have an efficiency of 93-96%.