New Energy Solutions
1KOMMA5° Australia
Unpacking Solar System Efficiency: What Does This Mean for Your Home?
If you’re in the market for solar or really any clean energy solution then you’ve probably heard the word “efficiency” thrown around a lot in reference to the different products and systems designs available in the market. While this sounds appealing, what does solar system efficiency really mean? In this article we’ll explore what makes a solar system efficient, how this is measured and what this means for your home. Understanding solar efficiency is vital to making the most of your solar investment.
Key Takeaways:
Understanding Solar Output: Solar system output is measured in watt-hours (Wh) or kilowatt-hours (kWh), but actual performance depends on factors like weather, location, shading, and panel quality. A well-designed system with high-quality components can often exceed estimated outputs.
Impact of Shading: Shading is a major factor that reduces solar efficiency, especially in standard "string" systems. Solutions like microinverters and power optimizers can help mitigate shading impacts by allowing individual panel performance.
Panel Quality Matters: Higher-efficiency panels like Enphase Microinverters or REC Alpha Series deliver better output. Cheaper, lower-quality panels may come with risks, such as poor warranty support and reduced longevity.
Peak Sun Hours and Location: The effectiveness of a solar system also depends on peak sun hours, which vary by location. Areas with 4-6 hours of peak sunlight per day generally make solar a worthwhile investment.
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Solar System Output
In order to fully grasp the concept of solar efficiency there are a few concepts to go through first. The most important is, of course, solar output. Understanding solar system output is the foundation of the solar efficiency concept.
Measuring Solar System Output
The electricity generated by your solar panels is measured in Watt Hours (Wh) or Kilowatt Hours (kWh). There are three main measurements of solar output
The first is the system size or rated system capacity. This measure isn’t accurate as it is a reflection of panel performance under perfect, standardised test conditions, in reality under real-world conditions this perfect score is unlikely to be achieved. Too many external factors such as weather, peak sunlight hours, location and orientation play a part. These external factors include:
Dirt, debris or buildup on the surface of your panel array.
The operating temperature of your panels, heat does not equal sunlight, although when it comes to energy production the more sunlight the better, heat can actually have a negative effect on production.
Pollution or general haze can be an obstruction to the panels, limiting the light exposure.
The weather areas experiencing increased cloud cover or rainfall are unlikely to reach the same output levels as sunnier areas.
Time of day/year. Obviously the time of day will have an impact on production, with the panels performing their best while the rays are strong and the sun is up high. The same goes seasonally, in winter the weaker rays and lower sun leads to a dip in energy generation, while in summer, production peaks.
Shading and other obstructions, any partial shading from trees or other buildings can limit system performance, this is especially true for string solar systems.
The next measure of solar output you may come across is the estimated output of a system. The Clean Energy Council provides estimates on common system sizes installed by Australian homes. This can be a great indicator of what to expect in some situations, and provides a good generalised prediction of output, that being said, in a lot of cases we find this estimate to be conservative. By installing products that are of a high quality, with a system design that is well thought out and suited to the needs of the home you can often achieve a solar output that is far greater than the CEC’s predictions.
Better quality, innovative products will yield greater generation. For example, Enphase Microinverters operate at an efficiency of 110% compared with standard solar systems.
Essentially the actual output achieved will fall somewhere between the rated output under perfect test conditions and the Clean Energy Council's more conservative projection of output.
Example: The Output of an 8kW Solar System
An 8kW solar system will usually see a peak output of around 6 - 7kW in the middle of the day, although this can vary depending on weather such as cloud cover.
Now let’s take a look at some output figures.
The CEC estimated output: 32kWh per day
Output of a solar system installed using high quality products: reaches a maximum peak output of around 40kWh per day (although this is measured during the summer months)
By installing efficient and powerful solar components you can expect to see a solar output well over the CEC’s estimate.
A Larger Example: The Output of an 8kW Solar System
As a general rule you can expect a 20kW solar system to output around 80kWh of power over the course of the day, although this may vary depending on other factors such as location and orientation. The time of year plays a significant part in the level of solar generation.
In summer you could potentially expect to see peak output up to or over 100kWh
In winter your peak output could be as low as 60kWh.
Overcoming Solar Panel Shading Issues
Shade can be one of the biggest threats to solar output and efficiency. Shade can significantly reduce the overall production of the whole system, even the sections that aren’t in shade. But there’s no need to fret there are ways of mitigating this so you can continue seeing efficient energy generation.
How Does Shade Affect Solar Panels?
Although there are variations, the majority of solar systems are what’s called standard or string systems. Essentially all the panels are connected using one wire or ‘string’. Think of them almost like Crismtas lights. The problem with this model is when one panel is experiencing low production for whatever reason whether it be an obstruction or mechanical failure, all other panels in the string will only generate electricity at the same level as that of the worst performing panel. This makes shading a significant issue for overall system performance as if one panel is shaded they may as well all be.
Common Cause of Solar Panel Shading
Trees and foliage
Nearby buildings
Chimneys and vents
Power lines and poles.
Solutions to Solar Panel Shading
Option 1. Design a Panel Layout with Potential Shading in Mind
You can discuss potential shading risks with your chosen solar retailer and they will help you design a panel layout that maximases high sun areas of roof and minimises the use of those sections prone to shading.
Option 2: Remove the Obstructions
You can try removing any obstructions such as tree branches and other foliage. For other shading culprits this method may not be feasible.
Option 3: Microinverters
Designed to mitigate the shading related performance losses. Each panel features its own mini inverter, simplifying the energy conversion process.
Option 4: Power Optimisers
DC power optimisers are another way of reducing the impact of shading on system performance, while they don’t exactly convert the electricity to AC at an individual panel level like microinverters. They optimise the DC electricity allowing for maximum yield.
Which Panels to Install: The Most Efficient Panels in Australia
Now we’ve discussed solar output and what that means as well as potential issues to consider when designing the system, we can now jump into the different panels on offer in the market.
Choosing the Best Panel for Your Home
Ensuring your installing products that are both smart and reliable is vital for the safety of your solar system. Industry leading brands have developed new information that allows for high performance solar modules that don’t compromise on safety. Here are our recommendations of the best solar panels currently available in Australia.
Top Solar Panels Available in Australia
1KOMMA5° 420W All-Black Panels
REC Alpha Pure Series
Sunpower Maxeon 6 Series
QCells QPeak DUO Series
Top 4 Best Value Solar Panels in Australia
Trina Solar
QCells
REC Solar
JinkoSolar
Manufacturer's Financial Strength & Local Representation
Cheap solar is a major issue here in Australia, many solar hopefuls fall victim to false claims, shoddy installers and companies that no longer exist when they go to make a warranty claim. There are a great deal of panels on the market for an unbelievably low price, they are usually of low quality and may come with small or not widely known branding and sometimes even no branding at all.
They often do not have a claimable warranty and upon reaching out you’ll find that your call will either go unanswered or be connected to an offshore office where they speak little to no English.
If the panels were not brought in by an official distributor then your warranty may be lost if the company goes under or changes their name, it’s best to go with a manufacturer who is financially stable and committed to the Australian market.
Peak Sun Hours & Estimating Output
Learning when your solar system is at maximum generation can be extremely helpful in making the most of your solar investment. Giving you better guidance on how to alter your patterns of energy consumption.
What are Peak Sun Hours
Peak sun hours refers to the time of day where the sun is at its strongest and best for energy generation. The amount of peak sun hours you’ll experience in a day is largely dependent on where you're located, with Queensland receiving the most and Victoria receiving the least amount per day.
How Many Hours of Sunlight Do Solar Panels Need?
Peak sun hours refers to the time of day where the sun is at its strongest and best for energy generation. The amount of peak sun hours you’ll experience in a day is largely dependent on where you're located, with Queensland receiving the most and Victoria receiving the least amount per day.
Calculating Potential Solar Output with Peak Sun Hours
To find the maximum output of the solar system, use:
Potential Solar Output (kWh) = Solar System Size (kW) x Peak Sun Hours
The typical Australian home uses around 20 - 25 kWh/day, a solar system producing 30kWh per day could easily cover this with excess left over to either store or sell back to the grid.
Solar & Other Electrical Terminology
Here’s a few important terms it might be worthwhile to brush up on.
What is a Volt?
A volt is a standard measure of electromotive (electrical movement). In Australia our power supply is standardised at 240V.
What are Amps?
Amps (or amperes) refers to the volume or amount of electricity flowing through the wires or circuits. Amps is a good measure of the weight of an appliance on your base load. For example, an airconditioning unit is a high drawer of power and therefore uses more amps, whereas a TV is low drawing and uses less amps. Both of these appliances are the same voltage but they require different amps to perform their action.
What is a Watt?
A watt is a combination of amps and volts. To calculate the watts of something, you can use this formula:
Amps x volts = watts
What is a Kilowatt?
A kilowatt is 1,000 watts. For most situations watts is too small a measure to accurately or easily understand, this is where we use kilowatts, much like metres and kilometres.
Converting Watts to Amps:
This is referred to as the Power Formula. In order to convert watts back to amps you’ll need to use this formula:
Power (Watts) = volts x amps → Power(watts)/volts = amps
What is the Difference Between Power & Energy:
Power refers to the amount of electricity used at a certain time (measured in watts or kilowatts), whereas energy refers to the amount of power used over a period of time, measured in Wh or kWh
What is the Right Size Solar System for Your Home?
Now we've covered what goes into the estimated and actual output figures, we can now discuss what this means for specific homes.
Sizing Up a Solar System
The average system size we install today is around the 8 - 10kW mark, this has increases dramatically in the last decade. The reason for this being the initial cost of installing solar has decrease significantly due to government rebates and more efficient manufacturing processes.
With property prices also steadily increasing, solar can help to offset this through reduced electricity bills. Solar is also a great selling point when you put your home on the market.
Determine Your Consumption
Before you can decide how big a system you need, you'll need to determine your consumption. Start with your baseload, this usually will include essential circuits such as your fridge & freezer, lights and other necessary appliances left on standby. Next to determine your additional usage you'll need to take a look at your electricity bill and identify the daily usage figure on your power bill.
How Many Solar Panels Do I Need?
Now you've determined your average consumption over the course of the day you can now start designing a system that meets these needs. Most good quality solar panes will be 400W and above. Although high efficiency modules will be more expensive, you will need less panels to achieve the same output.
Determining the Best Size System for Your Needs
Solar can save you around $100 per kW per quarterly bill and will output around 4 times its size, although more in summer than winter.
This step is relatively simple with the help of a trusted solar retailer like 1KOMMA5°, we'll take your daily and yearly consumption and match the best system size and design to these figures.
Understanding Solar Efficiency
In the solar industry the term 'efficiency' is often thrown around haphazardly without any proper explanation in order to entice individuals to buy. I mean efficiency has to be a good ting right? While yes it absolutely is, its also important to have a thorough understanding of what tis looks like in the real world, ensuring you're making the most of your solar investment.
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FAQ
Frequently Asked Questions about Installing Solar Power
No, in Australia a solar system without integrated battery storage turns off in a blackout. There are two reasons why your solar system turns off when the grid goes down:
Safety: during a power outage, repair crews will be working to fix the grid to get power restored. To avoid endangering them, it is essential that there is no power flowing from solar systems out into the grid.
Technical: the appliances in your home need a steady flow of electricity to work properly. In many cases, appliances can also be damaged if the flow of power isn’t steady and constant. Because a solar system doesn’t produce a steady flow of power, the system needs to be turned off when the grid goes down.
For these two reasons, your solar system must automatically shut down in the event of a blackout, unless you have battery storage with backup.
Battery Storage With Blackout Protection
Tesla Powerwall is the battery we recommend for households that want blackout protection.
As a part of our installation service, we will work with you to nominate circuits that can be powered from your battery in the event of a blackout. Typically this will include things like a modem, lights, small pumps, garage doors and other appliances that are of high priority. Anything that uses a lot of power is typically not backed up in a blackout such as air conditioning and pool pumps.
The final step is to nominate how much capacity you want to leave in your battery in case of a blackout. If you choose 30%, for example, your Powerwall will never discharge more than 70% of the battery’s capacity, ensuring that in a worst-case scenario, you still have 30% of the Powerwall’s capacity to get you through the night. In the morning, the solar system will start generating power again and the Powerwall will recharge from the solar power being generated. For more information about how this works, please speak with a member of the 1KOMMA5° Team.
Online monitoring is about making sure you can see what’s going on with the solar power system and how much power it’s generating and what it’s doing, what its status is and importantly, you need to have that because the last thing you want to do is find out your system’s not working when your power bill arrives in three months’ time, but that’s the first step.
The second step is in relation to how your system is actually performing in relation to our expectations. Because when we sell you a system, we tell you how much power we expect your system to generate day on day, month on month, year on year. So it’s important we benchmark that data and understand what’s going on.
So, our system will give you detail around and graph that detail for you, so you can see how much power your system’s generating.
Then it comes to the exciting stuff and that’s when us data junkies get excited because we’re going to give you data and the access to data, so you can start to profile what your system’s doing when you generate power and how you can use it, because we all want to get the best out of self-consumption.
So whether it’s just solar power or you’re putting in solar power and storage, self-consumption is really important and data is really powerful.
Once you sign up for a 1KOMMA5° Installation, we immediately submit your grid application to the relevant energy distributor. For systems up to 5kWs, this is a formality. For larger systems it can take a few days or more. Once we receive approval, your installation will be managed by our installation coordinator, who will welcome you to 1KOMMA5° and book an installation date for you. This is generally booked within around two weeks and installation dates are available Monday to Friday, weather permitting.
We endeavour to have your system installed within 2-4 weeks unless you request us to hold for whatever reason. Due to our strict safety policy, we do not install solar systems when it rains. In the event of inclement weather, we will rebook your installation as soon as possible. We always work with your requests as we strongly recommend that someone be home on the day of installation.
Most solar panels are all approximately 1.7 meters high by 1 meter wide. If you have a flat roof please allow a minimum of 2 meters per row to allow for additional shading from the panels after they are tilted.
As today’s solar panels are about 265W or higher, you should allow 4 panels per kW. For example, a 4kW system can be installed in 2 rows of 8 panels, allowing 1.7 meters for each row plus a little buffer, and 8 meters long. The panels in a row sit flush and they are just under a meter wide, so allowing one meter per panel works out to be quite accurate.
Our Solar Experts have the ability to draw proposed panel diagrams on the computer such as the one below. Because we use aerial maps that do not take into account the pitch of your roof, our estimates are not exact to the centimetre, but we can get pretty close! If it looks like a tight fit we will send an installer out before the installation day to confirm everything for you.