You'll hear myths like "solar panels are made more energy than they produce" or, "solar panels have more carbon footprint than they will offset. None of this is true!

 

All manufacturing uses energy and has a carbon footprint, and solar panels are no exception.

 

Renewable power generation repays its carbon footprint during its operation. Unlike fossil fuels, which require carbon-intensive fuels throughout the life cycle of the system.

 

With the greening of the manufacturing national grid, the manufacturing footprint will get smaller and smaller over time. Solar panel factories also tend to install solar panels on rooftops to provide their own green energy.

 

 

 

 

Solar power that is used by households or exported to the grid actually offsets the high-carbon gas power generation.

 

Since 2015, solar panel manufacturing has become more efficient and the grids at manufacturing locations have become greener. So I think the payback time is much less these days.

 

Monocrystalline solar panels are the most widely used technology. To produce solar panels, it takes a lot of energy to melt the silicon used in the batteries. Other technologies are being developed that use a fraction of the energy, but these are not yet commercialized and are not very efficient.

 

QCells estimates that their panels will take about 1.5 years to recoup the energy needed for production.

 

The operating period is approximately 30 years, equivalent to 28.5 years of renewable energy generation.

 

recycling solar panel recycling

Solar panel components are all regularly recycled materials.

 

People often ask, "What happens to solar panels at the end of their useful life?". The answer is that they are likely to be recycled.

 

Because in Australia there are many systems that are going to be scrapped. The market is ready for solar panel recycling. Look at Gedlec, they are currently recycling 95% of their solar panels and will be able to recycle 100% by the end of 2021.

 

The most sustainable solar systems are those that operate efficiently and last a long time.

 

Replacing a system before the end of its design life will double the carbon footprint of installing a quality system for the first time.

 

By using experienced designers, experienced installation teams and quality products for your solar system, you can ensure that your system will last, perform well and be sustainable.

Shingled solar cells are solar cells which are cut into typically 5 or 6 strips.  These strips can be overlaid, like shingles on a roof, to form the electrical connections.  The strips of solar cells are joined together using an electrically conductive adhesive (ECA) that allows for conductivity and flexibility.

Shingled solar cell

 

 

 

Shingled solar cell – end elevation

 

 

This allows the cells to be connected differently to conventional solar panels, in that, there are no busbars (ribbons) required and the solar cells can be joined together resulting in no gaps between the solar cells.

 

Shingled solar modules can also be wired differently to conventional solar panels.  Typically, solar cells in conventional solar panels are wired in a series of strings whereas the solar cells in shingled panels can be wired in parallel configuration.

 

 

What are the advantages of shingled solar panels?

Essentially the three key advantages of the shingled solar panel design are they produce more power, improve reliability and are aesthetically pleasing.

 

1. Increased energy harvest

Higher power per square metre

The shingled solar cells do not require busbars across the top of the cells so more of the solar cells are exposed to sunlight.  The cells do not need to be spaced apart like in conventional solar panels so the solar panel area can produce more energy.

 

Comparison between conventional solar panel and Solaria shingle solar panel

 

Less energy loss due to shading

Conventional solar panels have the individual cells wired in series so when a part of the solar panel is shaded it can have a significant effect on the level of power output.  By configuring the solar cells in shingles, they can be wired in groups and configured in parallel which significantly reduces the losses caused by shading.

Current flow comparison

 

Below are some examples of shading and losses for a conventional solar panel and a shingled panel.  The Shingled panels have greater performance except for the vertical shading example.

 

Outdoor shade testing over a 70-day period has shown that the  shingled solar panel performs between 37 to 45% better than conventional solar panel designs.

 

2. Better reliability

 

Low busbar failures

Shingle solar panels do away with approximately 30 metres of busbar and soldered joints that is required on conventional solar panels, so busbar failures are reduced.

 

Better mechanical performance

Static and dynamic load tests show that the shingle approach is more resistant to failure due to external forces being applied to the solar panel compared to conventional solar panels.

 

3. More attractive

Shingled solar panels have no visible circuitry which give them clean simple look providing superior street appeal.

 

 

 

At this point, it's safe to assume that everyone knows the products they buy never do their advertised qualities or quantities any justice. Be it the bag of potato chips which has more air than chips or a car that just won’t touch the mileage its manufacturer claims. We're used to stuff performing below expectations and don’t mind it either.

Solar panels on the other hand, are usually excluded from such handicaps. Most consumers go into a solar purchase expecting their panels to produce as many watts as their sticker states, at least in the best of conditions.

Unfortunately, solar panels are no different from any other consumer product in this sense. In fact, don't be surprised at all if you find your panel’s output well below its rated capacity even on the brightest and sunniest of days when they are sparkling clean.

Here's why this happens.

What Can You Realistically Expect from Your Solar Panels

So, that 300 watt solar panel you've been researching probably doesn’t dishout 300 watts of power. But, just what is its realistic upper limit here? The answer depends on a few key factors.

Firstly, a solar panel's rated output is decided through rigorous laboratory testing. These tests are done in perfect conditions devoid of dust, clouds or any other pollutants with light shining directly on the panels at a perfect 90 degree angle. We've covered this in greater detail in our post on solar panel quality.

At first glance, such tests may seem deceptive since ideal conditions are rare, if not impossible. But, the objective of a solar output test is to determine the absolute power a panel can produce, which is an important figure to have.

So, how much of this power can you actually expect to harvest? Solar panels usually achieve only around 80% of their rated peak capacity, but may fall lower. A number of factors contribute to such losses.

What Causes Solar Power System Losses

Losses in usable power start to occur as the light falls on a solar panel. For the purposes of this article, we're going to ignore power loss due to environmental factors such as clouds, shade, dust, etc and focus on losses that are inherent in a solar power system due to its physical limitations. Here's a rundown of how it happens at each level:

Mismatch losses

Also known as the “mismatch effect”, power losses here are caused if solar cells in an array have different properties, resulting in inconsistent voltages. Mismatches can result in serious power losses since the entire system defaults to the output of the lowest performing solar cell.

Besides low power output, excess electricity trapped in the solar module's electric circuit is converted into heat that can further damage the solar modules. Mismatch losses can result in around 2% power loss.

Temperature loss

Solar cells perform best below 25 degrees celsius, which is also what the temperature they are tested against. The catch here is that these figures refer to the temperature of the cells and not that of ambient air surrounding the panels. So, the panels themselves can get much hotter than 25 degrees even if the ambient temperature is a cool and breezy 20 degrees.

A solar panel's power output can drop drastically as it gets hotter than 25 degrees. Power loss due to heat is measured as “Pmax”, which tells us how much a solar panel's electricity production drops per degree rise in temperature. For example, if a solar panel's Pmax is -0.45%, then that's how much electricity we lose per one degree celsius.

Temperature accounts for the majority of a solar panel's output losses and can range from 10% to as much as 25% in very hot conditions. Since mean temperature in most Australian cities can reach well over 30 degrees celsius during summer months when we have the most sunlight, the solar panels will also experience the greatest power loss here.

Light-induced degradation (LID)

LID typically occurs during the first few days after a solar installation and causes power loss due to build up of boron-oxygen compounds in the solar cell's silicon base. Some solar cells are more predisposed towards LID than others. LID accounts for 0.5% to 1.5% of power loss in photovoltaic systems.

P-type monocrystalline solar cells have higher oxygen content and are doped using boron and accept electrons, which makes them more susceptible to LID.

Multicrystalline solar cells are not as efficient as monocrystalline cells, however have less oxygen making them resistant to LID. Similarly, N-type silicon wafers are doped with chemicals that release electrons making them impervious to LID.

Cable and wiring losses

Solar panels are a collection of photovoltaic cells stacked in an array. These arrays feed into a wire that runs from the panel into the inverter. Since no wire is fully efficient, part of the power flowing through it is lost as heat.

For most solar power systems, cable related power degradation accounts for around 2% of the system's total loss, which can be brought down to 1% by using thicker wires or positioning the system such that it requires shorter wires to reach the inverter.

DC to AC Loss

Solar panels produce DC current that's unusable by household appliances. A solar inverter then converts that DC power into usable AC electricity which is fed into your home’s electrical circuit and the grid.

Since solar inverters are around 93% – 96% efficient, a portion of DC power being fed into them will be lost as heat. The exact amount of electricity lost will depend on your inverter make, and whether it’s oversized or not.

Oversized inverters (or, inverters that are rated for a higher output than the solar power system's total output) are more efficient than those that are matched to their panel's output.

Inverter Clipping

Inverter clipping happens when the DC power input from the panels is greater than its rated capacity. In such a case, the inverter “clips” or derates the overall output to match its own capacity, causing a loss in power.

How Can You Maximize Your Solar Power System's Output

The reasons for power loss we've discussed above are mostly unavoidable, because physics. However, we can also bring down such losses by designing efficient solar power systems.

For example, selecting solar panels with low or no LID potential, using sufficiently thick wires and cables, strategically sizing the inverter to mitigate clipping and positioning the solar panels such that they receive as much direct sunlight as possible can all help increase the system's output.