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Will California finally fix its community solar programs?

A plan to promote community solar projects paired with batteries has the support of rooftop solar boosters and skeptics alike, plus the state’s building industry.

California regulators are under growing pressure to expand a class of clean energy that’s been notably missing from what’s otherwise a very solar-friendly state: community solar. 

For years, solar developers have complained that California’s mishmash of programs and policies has failed to support community solar projects, which make solar power accessible to people who for one reason or another can’t put panels on their own roofs. 

Some roofs aren’t suited for solar panels because they’re shaded by trees or other buildings. Some building owners lack high enough credit scores to get approved for financing for rooftop solar. And about half of the population lives in rented houses or apartments, where landlords often don’t have any incentive to go solar. 

Community solar projects can be financed and built on cheap and sunny plots of land by utilities or independent developers. Customers can sign up as subscribers to that lower-cost solar power, paying a monthly fee and then earning credits on their electrical bills; in most well-designed programs, subscribers come out ahead financially, although details differ from program to program and state to state. 

Community solar has been taking off in other states, but it has languished in the Golden State — a fact that many advocates blame on poor program design on the part of utilities and the California Public Utilities Commission. 

Now is the time for a change, according to proponents of community solar. The CPUC is currently weighing a major decision on reforming net-metering policy for rooftop solar, and it would make sense to reform rules for community solar projects as part of the same process, they argue. Solar industry, environmental and community groups have flooded the CPUC with multiple proposals to strengthen existing community solar programs — or to create brand-new ones. 

One such proposal that’s getting a lot of traction would promote community solar projects that are paired with batteries. The concept comes from the Coalition for Community Solar Access (CCSA), an alliance of businesses and nonprofits that advocates for community solar projects. 

Unlike most solar policy proposals in play in California, this one has garnered support from both sides of the contentious debate over net-metering reform, including both pro-rooftop-solar groups and state lawmakers, as well as groups that believe the state’s current net-metering policies are driving up electricity costs for customers who can’t afford rooftop solar, such as The Utility Reform Network, the Coalition of California Utility Employees and the Natural Resources Defense Council. 

CCSA’s proposal would pay a lot more than typical utility rates for electricity that’s exported to the grid from community solar farms in late afternoon and evening hours during the state’s hottest months, when solar power fades away and California’s grid faces the greatest stress. Conversely, it would pay a lot less for power exported during other times of the day and year. 

That would give project developers a strong incentive to pair solar with batteries that can store solar power when the grid has more than enough and inject it onto the grid when it’s needed the most. Indeed, critics of the current net-metering regime are asking the CPUC to incorporate similar storage incentives into all of the state’s solar policies.

Homebuilders join the call for better community solar programs

CCSA’s community solar proposal has another key ally: the California Building Industry Association. 

As of 2020, California’s building codes require newly built single-family homes to include solar panels; the requirement will also apply to many new multifamily and commercial buildings starting in 2023. Homebuilders are worried that the CPUC’s current net-metering proposal, which will reduce the value of solar power exported to the grid and add steep monthly charges to the bills of solar-equipped customers, will burden owners of new homes with increased costs. 

The California Energy Commission, which sets state building codes, allows builders to develop community solar projects as an alternative to installing rooftop solar panels on individual homes. But according to the California Building Industry Association, the state’s current community solar programs ​“suffer from serious deficiencies that undermine their use as a compliance pathway for builders.” 

The trade group has asked the CPUC to fast-track its consideration of CCSA’s community solar proposal, in hopes that it could be approved in time to build projects that leverage the rate category as early as next year. 

If the CPUC fails to take quick steps to create a ​“viable community solar program,” that could add undue ​“complexity and uncertainty to the building process,” the group contends in a January filing with the CPUC, which could have the effect of ​“undermining energy efficiency goals and driving up costs for builders.” The group fears that these costs ultimately will be ​“passed on in home prices[,] which exacerbates California’s housing crisis.” 

So far, the CPUC hasn’t fast-tracked community solar as part of its already-controversial net-metering reform process. Its December net-metering proposal characterized such a move as ​“premature,” pointing out that the state’s three big investor-owned utilities are required to file community solar plans in August 2022, which could serve as an opportunity for considering changes to the state’s existing programs. 

But Charlie Coggeshall, CCSA’s director of policy and regulatory affairs, thinks the CPUC should act more quickly to ​“finalize our proposal into a tariff that could be ready in 2023.”

“We have a strong proposal for reaching these unreachable parts of the market,” he said in an interview. Community solar is needed to ​“fill a market gap for buildings that don’t have a rooftop solar option,” which includes roughly half of all U.S. buildings, according to research from the U.S. National Renewable Energy Laboratory.

Why California’s existing community solar programs have fallen flat

The trick is designing community solar programs that can do two things at once. First, they must entice developers and financiers with a long-term opportunity to build projects that offer predictable returns on their investment. Second, they must offer customers low-cost, low-risk and low-complexity ways to participate. 

California’s existing community solar programs fall flat on both fronts, according to critics. Many developers have moved on to pursue far more lucrative and compelling opportunities in other states. 

California’s first community solar programs were introduced in 2013. But they have struggled to spur anything close to the total amount of solar they were intended to generate. 

That’s largely because they’re structured in a way that saddles Californians who sign up with higher overall electric bills, Coggeshall said. As community solar developer Solstice points out in its review of the state’s existing programs, most people just aren’t willing to pay more for solar power. 

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solar energy, radiation from the Sun capable of producing heat, causing chemical reactions, or generating electricity. The total amount of solar energy incident on Earth is vastly in excess of the world’s current and anticipated energy requirements. If suitably harnessed, this highly diffused source has the potential to satisfy all future energy needs. In the 21st century solar energy is expected to become increasingly attractive as a renewable energy source because of its inexhaustible supply and its nonpolluting character, in stark contrast to the finite fossil fuels coal, petroleum, and natural gas.

The Sun is an extremely powerful energy source, and sunlight is by far the largest source of energy received by Earth, but its intensity at Earth’s surface is actually quite low. This is essentially because of the enormous radial spreading of radiation from the distant Sun. A relatively minor additional loss is due to Earth’s atmosphere and clouds, which absorb or scatter as much as 54 percent of the incoming sunlight. The sunlight that reaches the ground consists of nearly 50 percent visible light, 45 percent infrared radiation, and smaller amounts of ultraviolet and other forms of electromagnetic radiation.

Reflection and absorption of solar energy. Although some incoming sunlight is reflected by Earth's atmosphere and surface, most is absorbed by the surface, which is warmed.
Reflection and absorption of solar energy. Although some incoming sunlight is reflected by Earth's atmosphere and surface, most is absorbed by the surface, which is warmed.


Reflection and absorption of solar energy. Although some incoming sunlight is reflected by Earth's atmosphere and surface, most is absorbed by the surface, which is warmed.

The potential for solar energy is enormous, since about 200,000 times the world’s total daily electric-generating capacity is received by Earth every day in the form of solar energy. Unfortunately, though solar energy itself is free, the high cost of its collection, conversion, and storage still limits its exploitation in many places. Solar radiation can be converted either into thermal energy (heat) or into electrical energy, though the former is easier to accomplish.

What are the common uses of solar energy?

Solar energy is commonly used for solar water heaters and house heating. The heat from solar ponds enables the production of chemicals, food, textiles, warm greenhouses, swimming pools, and livestock buildings. Cooking and providing a power source for electronic devices can also be achieved by using solar energy.

How is solar energy collected?

The most common devices used to collect solar energy and convert it to thermal energy are flat-plate collectors. Another method of thermal energy conversion is found in solar ponds, which are bodies of salt water designed to collect and store solar energy. Solar radiation may also be converted directly into electricity by solar cells, or photovoltaic cells, or harnessed to cook food in specially designed solar ovens, which typically concentrate sunlight from over a wide area to a central point.

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This guide will help you to select the best solar panels for your property.

Our complete guide to buying solar panels covers:

The top brands

What to look for when selecting a panel

Different types of modules

Clean Energy Council (CEC) approved panels

THE BEST QUALITY PANELS

The best solar panels are more efficient, perform better and will operate for 25 years. SunPower and LG manufacture the best solar panels available in USA, UK, Australia, France, Germany, Canada both provide the best warranties the highest performance ratio and the most efficient modules. However, there are many very good options available.

The table below ranks the best quality solar panels available according to our ranking criteria.

 

THE BEST QUALITY SOLAR PANELS

Brand:

Efficiency:

Performance:

Warranty:

Value:

SunPower

22.6%

92.0%

25 Years

Good

LG

22.0%

90.8%

25 years

Very good

REC

21.7%

92.0%

25 Years

Very good

Q Cells

20.4%

85.0%

25 Years

Good

Solaria

20.5%

86.0%

25 Years

Good

Trina Solar

20.7%

84.8%

12 Years

Good

Jinko

20.4%

86.0%

12 Years

Good

Canadian Solar

20.2%

83.1%

15 Years

Good

 

A Complete Guide To Buying The Best Solar Panels

HOW WE RANK AND COMPARE THE BEST PANELS

We rank the best panels based on:

·        Efficiency

·        Performance

·        Product warranties

·        Value

·        Panel efficiency

Solar panel efficiency is an indicator of the quality of the module and how it might perform throughout 25 years. It’s no coincidence that the most efficient solar panels also have the lowest level of degradation and perform well in adverse conditions. Efficiency isn’t everything, but more efficient panels will take up less of your roof space.

Performance

Measuring the performance of the actual module can be difficult as so many factors affect solar panel output. However, manufacturers must provide a guarantee of the performance of the panel after 25 years, based on laboratory tests. Typically, the performance ratio is around 80%, which indicates the level of degradation after 25 years. The best panels all have higher output ratios after 25 years, with top of the range brands achieving above 90%.

Solar panel warranties

Another important point of comparison is the solar panel product warranty; a manufacturer guarantees that your panel will continue working as it should. Do not confuse the performance warranty with the product warranty. Product warranties range from 10 to 25 years. If a company is prepared to provide a longer product warranty, it’s normally an indication that they are producing a higher quality panel.

Value for money

The final point of comparison is also the most subjective; value. Does the panel represent value for money? Value is very much a decision you need to make for yourself. We assess the value of the best panels if the quality outweighs the added solar panel cost; if it doesn’t, we factor that in too. Value is an important consideration, but ensuring you are buying a good quality panel that will not let you down is more important.

 

TYPES OF SOLAR PANELS

Monocrystalline and polycrystalline are the two most popular types of panels in USA, UK, Australia, France, Germany, Canada. Both of these common panel types have their virtues and choosing one of the other is not as important as selecting a better quality panel with excellent performance and product warranties.

Our list of the best solar panels only features monocrystalline panels, as they are the most efficient modules available. Importantly, the manufacturers provide the same product warranty and performance output guarantee for their polycrystalline solar panels. Cost and efficiency are two of the major differences between monocrystalline and polycrystalline panels.

CLEAN ENERGY COUNCILAPPROVED PANELS

You need to ensure that the solar panels and inverter you buy are approved by the Clean Energy Council. If they are not, you will not be able to receive your solar rebate, but also it means you are buying a module that has not passed the safety and quality tests that the CEC applies to each module. It is far more important to buy CEC approved solar panels than tier 1 panels.

All of the modules in our list of the best solar panels are approved by the Clean Energy Council.

Are Tier 1 panels the best?

We’ll summaries the findings as the term often comes up in discussions of the best solar panels. The Tier 1 criteria consider the use of the modules in large scale projects over the recent two-year period; it does not measure performance.

However, there is typically a strong correlation between tier 1 panels and what we consider to be the best solar panels.

IMPORTANT CONSIDERATIONS

Buying solar successfully is not only about selecting the best solar panels; you also need to consider the other system components, the quality of the installation and your property’s specific needs.

Quality products

Simply selecting high-quality panels isn’t enough. It’s also essential to choose a good quality inverter, cabling and mounting brackets. Inverters are commonly the first component to malfunction. If solar panels seem cheap, it’s more likely that a lower grade inverter is used and shorter product and installation warranties have been issued. Quality cables are also an essential component of an efficient solar panel.

Panel maintenance

Dirt and grime on your solar panels can lead to small efficiency losses, so it’s important to inspect your solar panels if they can be easily accessed to ensure they are relatively clean. The more direct sunlight can easily reach the cells within each module, the better. Fortunately, mother nature does a pretty good job of cleaning them for us when it rains, but it may pay to clean and check them every so often, especially if they are installed flat.

Panel degradation

Solar panels will experience a level of deterioration over time. That is, all else being equal, they’ll perform better in earlier years than later years. The degradation is only natural really when you consider that solar panels have a projected lifespan of 25 years. The level of degradation varies between brands and is an indicator as to the quality of the panel.

WHAT IS BEST FOR YOU?

For all our research into the best panels, you may disagree with the ranking criteria, or, you may place far more importance on one of the criteria like performance in shade conditions, or value. You must, of course, select the best panel for your property and financial circumstances.

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What is a solar inverter? How does a solar inverter work?


Solar panels aren’t the only component that you should be thinking about when you evaluate your solar system equipment. Solar power inverters play an equally important role in a solar system: they convert the electricity your solar panels create into a form that can be used by the appliances, lighting, and other electronics that are in your home. Once you understand how solar inverters work, and the different types of inverters available for solar.

 

What does a solar inverter do? How solar inverters work in a PV system

When the sun shines on your solar photovoltaic (PV) system, electrons within the solar cells start to move around, which produces direct current (DC) energy. Circuits within the cells collect that energy for you to use in your home.

This is where your solar inverter comes in. Most homes use alternating current (AC) energy, not DC, so the energy produced by your solar panels isn’t useful on its own. When your solar panels collect sunlight and turn it into energy, it gets sent to the inverter, which takes the DC energy and turns it into AC energy. At that point, your solar electricity can power your appliances and electronics or, if you’re producing more electricity than you need, it can feed back into the grid.

What is a solar inverter? How does a solar inverter work?


Comparing solar inverter technologies: string inverter vs. string inverters with power optimizers vs. microinverters

All inverters have the same basic task: convert DC solar energy into useful AC energy for your home. However, there are three different solar inverter technologies that you can choose for your solar panel system, and each of them works slightly differently.

String inverters: a standard centralized inverter

Most small-scale solar energy systems use a string inverter, also known as a “central” inverter. In a solar PV system with a string inverter, each panel is wired together into a “string”, and multiple strings (normally up to three) can be connected to your central inverter. When your panels produce energy, it all gets sent to a single inverter, which is usually located on the side of your home, in a garage, or in your basement. The inverter will convert all of the electricity from your solar panels into AC electricity for use on your property.

Pros: String inverters are the lowest-cost inverter option, and are a very durable inverter technology. They are also the easiest to maintain, because they are in an easy-to-access location.

Cons: A drop in the performance of an individual solar panel (i.e., from shading) can impact the output of all of the panels on an individual string. While multiple strings can accommodate multiple roof planes on the same inverter, string inverters may not be right for more complex system designs or roofs with regular shading.

Best for: Properties with “uncomplicated” roofs that get consistent sun throughout the day, and homeowners looking for lower-cost solar PV systems.


Power optimizers: a panel-located option to pair with a string inverter

Power optimizers can be thought of as a compromise between string inverters and microinverters. Like microinverters, power optimizers are located on the roof next to (or integrated with) individual solar panels. However, systems with power optimizers still send energy to a centralized inverter.

Power optimizers don’t convert the DC electricity into AC electricity at the site of the solar panel. Rather, they “condition” the DC electricity by fixing the voltage of the electricity, at which point the electricity is sent down to the string inverter. A system that pairs power optimizers with a string inverter is more efficient than one that uses a string inverter alone in shading scenarios.

Pros: Like microinverters, power optimizers can improve the efficiency of your solar panel system if you have a complicated roof or frequent shading; however, optimizers tend to cost less than microinverters. They optimize the output of each individual panel to mitigate the impact any one shaded panel can have, and also provide the benefit of monitoring the performance of individual panels.

Cons: A system that pairs power optimizers with a string inverter will cost more than a system with a standard string inverter option. As with microinverters, solar PV systems that include power optimizers can be more difficult to maintain.

Best for: Homeowners with a slightly less than ideal roof for solar who are willing to pay more to increase the performance of their solar panel system, but who don’t want to invest in microinverters.


Microinverters: high-performance at a higher cost

If a string inverter can be considered a “central” inverter, microinverters are “distributed” inverters. Solar PV systems with microinverters have a small inverter installed at the site of each individual solar panel. Rather than sending energy from every panel down to a single inverter, microinverter systems convert the DC solar energy to AC energy right on the roof.

Pros: Having microinverters at every solar panel provides performance benefits, especially for systems with a more complicated design or that experience shading. Microinverters optimize the output of every panel at the panel to mitigate the impact of shading, and to allow for panel-level monitoring of your system.

Cons: Microinverters cost significantly more than a string inverter, and can be more difficult to maintain or repair in the event of a problem because they are located on the roof.

Best for: Systems with solar panels that face multiple directions, homeowners who want to maximize solar production in a small space, and properties that have “complicated” roofs with gables, chimneys, or other objects that can cause shade.


Choosing the best inverter option for your home

Now that you understand how solar inverters work, your next step is to decide which type is best for your solar PV system. Not every system-design is right for string inverters, and it’s not always necessary to pay extra for optimizers or microinverters. Ultimately, there’s no universal right or wrong answer, only what’s best for your own situation and needs.

While you can continue to read about the different technologies, the best way to find out which option works for you is to review actual quotes from qualified local installers in your area.

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How do I choose my solar panels? Guide to choosing your solar equipment

Installing a home solar energy system is a smart financial investment for many homeowners. As you evaluate offers from solar companies, there are many different factors to consider – the equipment that you choose for your system, your financing options, and the installer that you select all have an impact on your solar savings. This guide will help you evaluate the different solar panels and inverters available so that you can choose the best equipment for your home. 

There are two main components to a grid-connected solar energy system: the solar panels themselves, which create electricity from sunlight, and the inverter, which converts the electricity into a form you can use in your home. Some also include a monitoring system, which allows you to see how much power you’re creating and using. And while solar batteries haven’t yet hit the mainstream, the announcement of Tesla’s Powerwall battery and other technologies are making it possible for homeowners to consider incorporating a battery into their system.

How to choose your solar panels in 3 steps

Determine solar panel efficiency and compare to industry average of 16-18%

Check solar panel manufacturer warranties against industry average of 10-25 years

Compare cost to relative efficiency – efficiency is important, but the most efficient panels aren’t always the best value

What criteria should I use when selecting a solar panel?

You can evaluate solar panels on a few main parameters: production, durability and manufacturer quality.

The amount of electricity a given solar panel can produce will produce is dependent on several factors, including the power rating, power tolerance, efficiency and temperature coefficient. Taken together, these factors will tell you how much power your panel will be able to produce.

You’ll also want to look at indicators of panel manufacturer quality. Start with the warrantees and assurances that the manufacturer offers on their equipment. Like all things, solar panels degrade and become less efficient over time. Many manufacturers will guarantee that the power production of their panels doesn’t fall below a certain threshold over twenty-five years. In addition, many panel manufacturers have a materials warranty in case the panels simply fail.

Most solar panels are very durable, but if you live in an area that has heavy snow or high wind, you should also be sure that the panels you install are designed to withstand the conditions in your area. Look for panels that meet the IEC 61215, a reliability standard established by the International Electro Technical Commission (IEC). IEC 61215 uses an accelerated outdoor stress test for panels to ensure their durability.

While some homeowners may choose to invest in the highest quality, most efficient “premium” panels, remember that those will come with a higher price tag. Going solar is a lot like buying a car: not everyone needs a Porsche! Conversely, if you want to save by buying cheap solar panels, your system may produce less electricity over its lifetime, reducing your overall savings. Only you know what is best for your home.

Which inverter should I choose? 

It’s the job of the inverter in your solar energy system to convert the solar energy into something you can use. Solar panels take solar energy and make it into direct current (DC) power. The inverter’s job is to convert that DC power into the alternating current (AC) electricity that can be used in your home.

There are two general types of inverters: string inverters and module-level power electronics (MLPEs). Both micro inverters and power optimizers are both MLPEs.

String inverters are the lowest-cost option for a solar energy system. If your system has optimal conditions for production, they are usually a good choice for your home. When your solar panel system has a string inverter, all of your panels feed all of the DC power they produce to a single inverter. The inverter then changes the DC energy to AC power, at which point your solar energy is ready to use.

MLPEs are generally more expensive, but they can also be more efficient. MLPEs are a good choice if your solar energy system may be slightly shaded or can’t be installed at the best angle. When you use microinverters, each panel has its own inverter to transform the power it creates and feed it to your house. Power optimizers, like microinverters, are also installed on every panel, but power optimizers are paired with a string inverter. The power optimizer “conditions” the energy, making it easier to convert from DC to AC, at which point it is sent to the main inverter.

Picking a solar energy provider: how do I choose the right installer?

Your installer is one of the most important factors of your solar installation! When you choose a solar installer, you should review their certifications, licenses, track record and reputation in the market. You should also be aware that a recent report by the U.S. National Renewable Energy Laboratory revealed that large national solar companies charge more than their small counterparts for the same or lesser quality equipment. The recommendation from NREL’s report: shop around and consider local companies.

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3 Phase Solar System : What you need to know about connecting solar to your 3 phase supply
Solar is compatible with 3 phase

There is an awful lot of confusion (and misinformation) out there about the practicalities of installing solar on a house that has a 3 phase supply. So I’ve written this post to clear up the confusion.

Connecting solar power to a 3 three-phase supply is entirely possible. But you need to decide how you are going to connect your solar system to the grid. Your 3 options are:

1) connect your solar system to only one of your supply phases with a single-phase solar inverter.

2) connect your system into all 3 phases of your supply with a single, 3-phase solar inverter

3) connect your system into all 3 phases with 3 separate single-phase inverters.

Here’s what you need to consider in deciding which option to go for:

Three phase billing

Now that Feed in Tariffs are generally between 6 and 10c per kWh, compared to an electricity price of 30c or more, naturally people installing solar want to self-consume as much of their solar energy as possible and minimize the flow of exported solar electricity.

So most of the emails I get these days about 3 phase worry that if they choose option 1 they will lose out. They worry that any electricity they use on the 2 phases that are not connected to solar will all be imported at 30c per kWh no matter how much solar they are generating on the solar phase.

I have personally never seen an installation where this happens. All the 3 phase meters that I have seen take into account the sum of all the electricity being used on all the phases and then subtract that from the amount of solar energy being generated to calculate the import or export amount for billing. i.e. if you are on a stingy FiT, they don’t penalise you financially for having a single-phase inverter on a 3 phase supply.

But to muddy the waters, I have seen evidence and heard from some installers that say they have seen 3 phase meters that have been configured to only calculate exports based on the solar phase. So buyer beware!

Three-phase load balancing

Having said the above, it is important to note that it is not unusual for the demand across phases to be unbalanced; i.e. a lot more load on one or two of the phases. For solar financial payback, this is less of an issue (due to the summed billing) however, from a technical perspective, balancing consumption and generation across the phases is a good thing for power quality.

I have seen cases where voltage is problematic on a particular phase causing inverters to trip out; such as where a large pump or cool room is on that phase and presents high start-up demands. In such a case, you should consider putting the inverter on a more stable phase; they don’t like unstable voltage or frequency at all.

Ultimately, a bit of instantaneous and energy consumption demand analysis should be considered a prerequisite to connecting solar to three-phase systems. Your utility or perhaps a friendly solar installer can help with this. If you have three-phase, it is even more important that you choose a qualified solar installer to talk to initially, instead of a less qualified solar salesperson – who probably hasn’t got the electrical background to understand the nuances of multi-phase electricity supplies! 

If you have a 3 phase supply, should you get a three-phase or single-phase inverter?

3 phase inverters start at about 5kW so if you want an inverter smaller than 5kW you are looking at single-phase.

If you want a system with an inverter larger than 5kW then your local Electricity Network may insist that you use more than one phase. The best way to do this is to use a 3 phase inverter.

If you want a solar system with a total inverter capacity larger than 15kW (5kw per phase) then the relevant Australian Standard (AS4777.1:2016) says you must balance the phases. The easiest way to do that is simply to use a 3 phase inverter.

If you have skinny wires from your meter to the grid, then you may have a problem with high voltage drops. If the voltage drop is too high, you may not be able to install solar. A 3 phase inverter spreads the power across 3 phases, so makes the voltage drop on each wire 3x smaller. So if you have an issue with voltage drop – a 3 phase inverter is a good solution.

Otherwise, if you are installing a system and have the choice of one single-phase meter, or one 3 phase meter, the choice is yours. The advantage of a 3 phase meter is that it is a more robust system (lower voltage drops, phases balanced). The disadvantage is that is about $600 more for a 3 phase meter. I’d pay the extra personally.

Advantages of 3 Phase Solar

3 Phase Solar System : What you need to know about connecting solar to your 3 phase supply


If you are researching about solar power system, you may have heard of different types of solar inverters especially single phase and 3-phase inverters. Depending on your electricity supply (single-phase or 3-phase power) your decision might become simpler. In most Australian homes, the power supply is single phase, which means one live wire comes in from the grid. Single-phase power supply is commonly used in Australian homes while three-phase power supply pulls more power from the grid and is useful to handle bigger loads for large aircons, pools, heaters, electric car chargers, etc.

Do you have a 3 Phase Power supply?

Check your switchboard - If the main switch is one-pole wide, then your home is connected to a single-phase power supply. If the main switch is 3 poles wide, you have 3-phase power.

Alternatively, you can call your electricity provider and ask them about the power supply. Just keep a copy of your electricity bill handy.

Check the service fuse - Homes connected to a single-phase power will have one service fuse while for a 3-phase power supply, there would be 3 service fuses.

Most of the homes are connected to a single-phase power supply. Large homes, residential apartments and commercial buildings can have a 3-phase supply to manage the high electricity demand.

3-phase power is good to handle heavy loads from:

·        Spa

·        Sauna

·        Pool heater

·        Electric car charger

·        Ducted air conditioners

Single Phase vs 3-Phase Solar Inverter

A single-phase solar inverter has one live wire which connects to your home. While a 3-phase solar inverter has 3 live wires connected to your home.

A 3-phase solar inverter sends the electricity evenly across the 3 wires which minimizes the voltage drop problem associated with a single phase power supply. It needs to be noted that a 3-phase solar inverter will probably cost more than a single-phase inverter.

So should you buy a single phase or 3-phase solar inverter?

A single-phase inverter usually comes in a capacity of less than 5kW. But if you are looking for an inverter larger than 5kW, and you have 3-phase power in your home then a 3-phase solar inverter is ideal. If you have a single-phase power supply, you only need a single phase inverter.

For a 3-phase supply the best solution is to go for a 3-phase inverter. However, if your solar power system is less than 5kW, go for a single-phase inverter.

Benefits of 3-Phase Solar Inverter

The 3 phase inverters come in a capacity of more than 5kW, up to 30kW which allows users to install a high capacity solar system.

3-phase solar inverters manage voltage rise and reduce the chance of appliance failures due to high voltages as the voltage rise in a single-phase connection is higher than that of 3-phase power. By using a 3-phase connection, the power supplied to the grid is distributed evenly and leads to grid stability.

 It increases the local grid voltage and your circuits will have less chance of short-circuiting due to high voltage issues.

If a 3-phase inverter is chosen, the consumers can meet their energy demands easily reducing their dependence on the grid for energy and leading to reduced utility bills.

3 Phase Solar Inverters: Do you need one?

3 Phase Solar System : What you need to know about connecting solar to your 3 phase supply


What is 3 phase power?

The more common single phase power has two wires (usually contained in one cable) connecting from the local transformer to your home – an active and a neutral. The power supplied through the active cable is 240V which is standard in Australia for all household appliances. 

Three-phase power has 4 wires – 3 actives and a neutral. It can supply power at the standard 240V and at 415V for appliances that require greater power like some air conditioners. A three-phase connection effectively triples the power available as appliances can be split across each of the three phases. 

Almost all commercial premises have a 3-phase connection. 

How do I know if I have 3-phase power?

Often this information will be written on your electricity meter, which might be located near the main electrical switchboard for the house. If you can’t decipher the electrical jargon on the meter, then you could check one of these things:

Under the circuit break named “Main Switch” does your switchboard have one breaker or three breakers?

Is there one or three wires leading from the electrical transformer on the street to your home?

Call your Distributed Network Service Provider (DNSP). On your electricity bill there will be the company that sells you electricity and another company (your DNSP) who you can call in the case of power outages and emergencies. If you quote your Net Meter Identifier (NMI) from your bill they will be able to tell you what type of connection, you have.

Do 3-phase homes need a 3-phase solar inverter?

The short answer is no, but there are some reasons why you might want to include a 3-phase inverter which usually only cost around $500 more.

If you have a single phase solar inverter it can only be connected to one phase of power. Typically, the appliances in a 3 phase home will be split across the 3 phases. That means a single phase solar inverter can only directly tackle a third of household usage. However, the smart bi-directional meter (that will get installed with you solar system) will offset any additional energy that is consumed across the other phases before buying any energy from the grid.

For example, a 3 phase home has 2kW of usage of power across phases A, B and C and a typical single phase 5kW solar system is connected to phase A. If the 5kW solar system is outputting 4kW of power, then 2kW will be used by directly by phase A and the remaining 2kW will be offset by the smart meter against the other phases.

3 Phase Solar System : What you need to know about connecting solar to your 3 phase supply


In another example, consider if there was only 1kW of usage of power across phases A, B and C and the 5kW solar system was outputting 4kW. In this scenario 3 kW would be offset against the 3 phase home’s usage and 1kW would be sold back to the grid.


There is a downside to installing a single-phase inverter on a three-phase home and it relates to the impact on voltage rise. In a single phase system, the solar power is working much harder to be used. Without diving into the detail this means that the voltage will rise on the grey line in the above diagram, in some cases this may mean your solar inverter trips off. You should be notified via the monitoring software and can easily turn the system back on, but this can become an annoying problem.

High voltages are one of the main issues network operators (DNSPs) are facing across following the installation of almost 3 million household solar systems. Installing a 3-phase inverter will minimize your impact on the grid. As a result, networks usually permit larger systems on three phase connections, which may be an added benefit if you are looking to install an inverter larger than 5kW in capacity. 

Sometimes we see 15kW systems where the solar installer has installed one single phase 5kW inverter on each phase. In the energy system’s eyes this is still an inefficient solution as the solar power cannot directly optimize across phases. If phase B draws 10kW then a system with three single phase inverters must draw power from the grid, while a three phase inverter 15kW inverter could tackle the entire 10kW if there was no usage on phases A & C.

 

3 Phase Solar System

Pros and Cons of installing a 3-phase solar system inverter

Pros of a 3 phase solar inverter

Cons of a 3 phase solar inverter

Minimize voltage issues on grid

Minimize inverter tripping off due to voltage issues

Enables a larger solar system size

~$500 more expensive

Can make battery back-up more challenging (read on this below)

 

How do you know if you have 3 phase power?

There are a few ways to know this, by looking at your:

·        Main switchboard

·        Overhead main

·        Meter

·        Isolation link

Main switchboard

In some countries, a switchboard is referred to as the main electrical fuse, as the fuses are organized together with the main power lines.

Electrical fuses help to prevent major damage to your home when there is a huge surge of electricity as well as separate incoming electricity into different circuits in the house.

When you look at your switchboard, you will see a row of panels or switches, sometimes referred to as ‘poles’. The supply lines in newer switchboards are sometimes red in colour.

Count the ‘poles’. If you see three poles joined by a single bar, you have a 3 phase. In a switchboard of a 3-phase supply, you are forced to switch all the live wires off or on simultaneously by pushing the bar that joins the switches.

If you see only one ‘pole’, then you have a single phase. Homes with 2 phase supply have 2 poles linked by a single bar.

It is also possible to have 3 switches but only a 2 phase supply. In this instance, you may need to check the meter or iso-link.

3 Phase Solar System Main switchboard


Overhead mains

A 3 phase supply can also be indicated in the number of cables connected to the house. They can be seen hooked up near the roof of the building. The ‘point of attachment’ will show a bundle of 4 cables – 3 cables for 3 phases of live wires and 1 neutral cable.

Overhead mains 3 Phase Solar System

If you see only 2 cables, it means there is only a 1 phase supply because one cable is always allocated for the neutral cable.

Meter

There are many types of three phase meters. Some are digital, and some are not. For the non-digital ones, count the ‘poles’ on the meter isolator. If you see only one pole, it is a single phase meter. The sample image below is for a 3 phase supply.


three phase meter

If it is a digital meter, you’ll need to look at the display. A 3 phase meter will show L1, L2 and L3.

digital meter
In some countries, the phases are not so easily identified through the meters.

3 Phase Solar System Meter

Isolation links

Often referred to as ‘iso-links’, they are a relatively new electrical technology having only been around from 2011. This component is meant to disconnect power from the electric meter in case the meter itself needs to be replaced. 

Not every house may have an iso-link. If it does, the number of iso-links will indicate the number of phases.

Isolation links


What are your solar options if you have a three-phase supply?

Your options are:

a single phase solar inverter

microinverters 

a three phase solar inverter

All of them are valid options but there are additional benefits for the last one, which will be explained in the next section.

When deciding whether to opt for a single phase solar inverter or a 3 phase, you’ll need to understand these two things first: three phase billing and three phase loading.

Three phase billing

The reason most people have solar installations for their grid-connected home is to reduce the cost of their electricity bill by harvesting free solar energy. The incentive for doing so is even greater in countries which have Feed in Tariffs (FIT).

Naturally, people would want to use as much solar-generated electricity as they can and reduce paying the higher rates of grid-powered electricity. However, there are some concerns that a 3 phase solar inverter will affect billing.

What really counts when it comes to billing is the meter. A house with a 3 phase supply will have a 3 phase meter. The meter will take into account the sum of all the electricity being used on all the phases. Then, subtract the amount of solar-generated electricity for export.

Three phase load balancing

The issue of load balancing is a real one. Meaning, one phase has a bigger voltage load than the other two phases.

Having a balanced load across 3 phases of supply is good for power quality. There must be a balance between power generation and consumption. An imbalanced load on one phase can cause the inverter to trip.

Say you have a phase that supports a large swimming pool pump which has a high start-up demand. If the demand for electricity is higher than the supply, it creates an imbalance in the phase and could force the inverter to trip. Inverters generally don’t function well when there is unstable voltage.

Since analyzing the energy consumption demand of your household for a 3 phase system can get quite complicated, it is best to engage a trustworthy and qualified solar installer who is familiar with the nuances of multi-phase electricity supply.


Benefits of a 3 phase solar inverter

The main benefit is that a 3 phase solar inverter can feed electricity evenly into all 3 phases of a property. To better explain this point, let us compare it with the workings of a single phase solar inverter for a 3 phase supply.

A 5 kW single phase solar inverter working at maximum capacity would feed 5kW of solar power into one of the three phases in a property. However, a three phase 5kW solar inverter would divide the 5kW equally into 3 phases. Each phase of the property will receive 1.7 kW each.

The difference matters when the solar power system can generate more electricity than can be handled by a single phase. For instance, if a system produces over 6kW and feeds all of that into one phase, this may cause an overload of that phase.

When an overload occurs, it could trip the circuit of that phase, and you will experience an interruption in electrical supply instead.

Is it cheaper to run on 3 phase solar inverters?

Depending on the country or source which you buy a 3 phase solar inverter from and the brand, it can cost you $300 more than an equivalent single phase solar inverter. 

A 3 phase solar inverter also has to be run with a compatible solar battery, which may be an additional cost to you if you don’t already have one.

Can I get 3 phase power in my home?

Yes, but if your home does not already have 3 phase supply, it can get extremely costly. If you are building a new home, installing a 3 phase inverter won’t cost you much more.

The electrician only needs to pull a couple of extra cables to your switchboard while he is doing the wiring. If done correctly, it will minimize the impact of voltage rise, and it will also allow you to install a much bigger solar electrical system.

Conclusion

Three phase solar inverters have the one up over single phase inverters when it is installed in a solar system on a property with 3 phase supply. Its advantage is that it splits the AC converted electricity from the solar panels into three batches each time. 

When the divided load is fed into the property, which is connected to the power grid, there is little to no likelihood of a voltage rise occurring. 

This is because the split AC amount is minimal compared to the total AC flowing in from a single phase solar inverter. A 3 phase solar inverter, thus, guarantees a smoother and uninterrupted power supply since it does not trip the grid with voltage overload.

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