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Overcoming Solar Panel Shading Issues
Shading is a common concern when it comes to installing solar panels, especially in urban or heavily vegetated areas. While you might be eager to tap into the power of the sun and save on your energy bills, shading can present a hurdle that affects your solar system’s efficiency. But fret not, as there are various strategies to overcome this issue.
Key Takeaways:
Shading's Impact on Solar Efficiency: Shading can significantly reduce a solar system's efficiency, especially in traditional string inverter setups. Shading on even one panel affects the entire system's output. Understanding this effect is essential to preventing energy loss.
Common Shading Sources: Common culprits for shading include trees, nearby buildings, chimneys, and power lines. Identifying these sources can help in taking corrective actions, such as repositioning panels or removing obstructions.
Technological Solutions to Combat Effects of Shading on Panels: Microinverters and power optimisers are effective solutions for minimising shading impacts. Microinverters allow each panel to work independently, while power optimisers improve the performance of individual panels, enhancing overall system efficiency.
Evaluating ROI for Shading Solutions: When choosing microinverters or power optimisers, it’s essential to calculate your potential return on investment (ROI). Look at how much shading reduction and energy recovery you might gain versus the added cost, to make the best decision for your needs.
How Does Shade Affect Solar Panels?
Solar panels are generally wired in series to form a “string.” The electricity generated by each panel flows through the whole string before reaching the inverter that converts it to a usable AC current. In traditional systems using string inverters, if just one panel in the string is shaded, it can drastically reduce the performance of the entire string. This means even minor shading can significantly lower the system’s overall performance.
To better understand this, consider a string of Christmas lights. Each light bulb on the string is akin to a solar panel in a series connection. When all the bulbs are fully lit, the string shines brightly. However, if even one bulb goes out or dims, the entire string’s brightness is affected. Similarly, when a solar panel is shaded, it impacts the performance of the entire string, reducing your system’s overall energy output.
Common Sources of Solar Panel Shading
Shading is not just an issue in densely populated urban environments but can also occur in suburban or rural settings. Here are some typical culprits:
Trees and Foliage: Large trees, especially evergreens, can cast long shadows at different times of the day.
Nearby Buildings: Multi-story buildings or even single-story structures with unique architectural features can cause shading.
Chimneys and Vents: Smaller objects on your own roof can sometimes be the most easily overlooked sources of shading.
Power Lines and Poles: Overhead lines, especially in rural areas, can also contribute to shading issues.
Solar Panel Shading Solutions
Option 1: Use the Right Roof Sections
If you have a multi-faceted roof, using the sections that are less prone to shading during peak sunlight hours can be beneficial. Your solar provider can conduct a thorough site assessment to identify the ideal areas for panel placement.
Option 2: Remove Obstructions
Another way to combat shading is to address the source directly by trimming or removing obstructions. If your property has large trees that cast shadows, consider pruning them. If a built structure like a shed or a neighbouring building is causing the issue, it might be more challenging to find a solution, but sometimes small adjustments can make a significant difference.
Option 3: Microinverters
Modern technology offers solutions like microinverters and power optimisers, which are designed to mitigate the shading issue.
Microinverters offer a high-tech solution to the shading problem by allowing each solar panel in the array to operate independently of the others.
With microinverters, each panel has its own small inverter attached directly to it. This device converts the panel’s DC electricity to AC right at the source, allowing the panel to function independently. Therefore, if one panel is shaded, the rest of the panels are unaffected and continue to operate at their maximum efficiency.
Microinverters replace the need for a standard or hybrid inverter but do come at a cost. Generally, you can expect to pay around $150 to $250 per microinverter (one per panel), depending on the brand and specifications. For an average-sized solar system of about 6 kW, which would typically include around 18 to 20 panels, the additional cost could range from $2,700 to $5,000.
Option 4: Power Optimisers
Power optimisers offer another technological avenue for mitigating the impact of shading. Unlike microinverters, power optimisers don’t entirely replace the function of a central inverter. Instead, they work in tandem with it. These devices are connected to each individual solar panel and optimise the DC electricity that the panel generates before it’s sent to the central inverter for conversion to AC. In essence, they pre-condition the electricity, adjusting the voltage and current to maximise the energy harvest from each individual panel.
Because each panel’s performance is optimised, a shaded or underperforming panel has less impact on the system’s overall performance. This offers a good middle ground between traditional string inverters and microinverters, combining the benefits of individual panel optimisation with the cost-effectiveness of a central inverter.
The cost for adding power optimisers to your solar system falls between traditional string inverters and microinverters. Generally speaking, a power optimiser could cost you around $50 to $100 per unit. If you have an average-sized 6 kW system with 18 to 20 panels, this means an additional cost ranging from $900 to $2,000.
Deciding What To Do About Solar Panel Shading Issues
Before making a choice between microinverters, power optimisers, or sticking with a traditional setup, it’s crucial to consider the return on investment (ROI). ROI is essentially how long it will take for the added benefits to outweigh the additional costs. One way to assess this is to look at the percentage of shading on your panels and calculate how much energy loss you could potentially recover by using microinverters or optimisers.
For instance, if your traditional system loses 10% of its output due to shading, and a microinverter system could recover half of that, you’re looking at a 5% increase in energy production. If this 5% amounts to, say, $100 savings per year, and the additional cost of the microinverters is $3,000, it would take 30 years to break even—perhaps longer than the lifetime of the panels. In such cases, it might be more cost-effective to trim obstructions or reposition the panels.
This is something your 1KOMMA5° solar expert will help you work out and decide prior to installation.
Conclusion
In summary, overcoming shading issues for your solar installation isn’t just a challenge. It’s an opportunity to maximise your system’s efficiency and, by extension, your energy savings. Whether you’re dealing with shadows from trees or neighbouring structures, options like optimal roof section use, obstruction removal, and technological solutions like microinverters and power optimisers offer effective paths forward. Shading is also something to continue monitoring as time goes on, after you get your system.
FAQ
Frequently Asked Questions about Installing Solar Power
There are great government rebates/incentives still in place for eligible households. Basically, the larger the panel array, the more STCs your solar system generates as it is based on the expected output of the system over time.
When you buy a solar system, the purchase price is normally reduced by the value of the STCs created by your system. You simply fill out a form on the day of installation to confirm that the system has been installed, and that’s it. There is no additional paperwork that you need to do.
Small-scale Technology Certificates (STCs)
Small-scale Technology Certificates (STC’s) – previously known as Renewable Energy Certificates or RECS – are created when a Renewable Energy System such as a Solar PV system is installed.
The number of STC’s depends on the predicted amount of energy generated and hence the larger the system the greater the rebate. In essence, one STC is created for every megawatt-hour of production capacity of the system.
This is further multiplied by the number of years the system is likely to generate energy (for home solar systems, this is usually 15 years, although the life of the solar panels themselves is considerably more than that).
This incentive program is being phased out until 2030, so each year the number of certificates your system is eligible for reduces.
STC Price
The system for trading and pricing STCs for small systems is managed by the Small-scale Renewable Energy Scheme (SRES).
STCs are bought by Liable Parties (usually electricity retailers) and must be surrendered at the end of each quarter. As the number of STCs that are required to be surrendered is a fixed amount each year, but the number of STCs created is variable, the price paid for STCs also varies and is determined by supply and demand.
The Federal Government legislated in 2010 a fixed price for STCs by implementing a Clearing House system where STCs can be bought and sold for $40. However, there is no requirement for Liable Parties to purchase from the Clearing House, so they are likely to only do so if there is a shortage of STCs or the market price exceeds $40. There is currently a surplus of STCs in the market which means the market price of STC’s below $40
The Feed In Tariff is only something you need to worry about if you don’t have battery storage.
The price your chosen energy retailer pays for any excess electricity generated from your solar panels is recorded as a credit on your power bill.
In NSW, solar power is fed into your home as it is generated and your household will use it first before you draw power from the grid.
This means that for every kWh of solar power used in the home you are directly saving money you’d spend on your power bill. This reduction in your power bill is the main financial benefit of solar power.
Everything else will be bought up at an agreed rate by your electricity retailer.
At the moment, most feed-in tariffs are between 5 and 10 cents per kWh, with many being about 7 cents. They bounce up and down a lot, for example in previous years they have been up over 20 cents per kWh. Typically, they are always at least 5 cents per kWh.
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.
Green Loans can be an affordable way to pay for your solar power system and is only available for approved products. As a Clean Energy Council Accredited installer, all our systems qualify.
Green Loans can be used to finance 1KOMMA5° systems from $1,000 to $30,000 over a 2-7 year term. Once you have received a referral from 1KOMMA5°, online approval usually occurs within 1-2 business days. Green Loans have a competitive fixed interest rate that is as low as 7.99% p.a.* | Comparison rate 9.21% p.a.^ Establishment fee of $299 added to the loan amount. $2.70 per week account keeping fee included in repayments.
To be eligible to apply you must:
Be over 18 years old and an Australian resident or citizen
Own or be purchasing a home
Be employed, self-employed, a self-funded retiree; or is receiving the Government Age Pension
Have an Australian driver’s license or Passport
Provide two most recent payslips or 90 days of bank statements
There are a number of good, competitive Green Loan providers – ask us about the options available.
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