Photovoltaic (PV) module manufacturers are constantly working to find new, more advanced alternatives to improve the efficiency of solar panels. Efficiency can be improved through innovative cell manufacturing techniques, and now there are a few contenders in the solar photovoltaic market.

The latest module trends expect market growth to focus on HJT and TOPCon solar cells.

The 2022 report from the International Technology Roadmap for Photovoltaics (ITRPV) shows some of the expected trends over the next 10 years:

❖ PERC (passivated emitter rear contact) solar cell technology currently leads the market with a market share of approximately 75%. However, it is expected that the share of p-type monocrystalline PERC cells will drop to about 10% in the next 10 years.

❖ The market share of N-type TOPCon (tunnel oxide passivated contact) technology will increase from about 10% in 2022 to 60% in 2033, becoming the mainstream silicon wafer type. The largest increase is expected to begin in 2024.

❖ N-type HJT (heterojunction solar cells) is expected to increase from approximately 9% (2023) to over 25% in the next decade. The implementation of heterojunction cell technology still faces difficulties due to the high production costs of solar cells and the incompatibility of production lines with existing technologies.

P-type PERC and N-type TopCon

PERC technology is a cost-effective compromise between efficiency and large-scale production. But improving solar panel efficiency using this approach has been slow. The current efficiency of mainstream P-type modules is about 21.4%, and will increase to 22.75% in the next 10 years.

N-type TOPCon solar cells installed in photovoltaic modules look identical to PERC cells. Both P-type and N-type solar cells are made from silicon wafers. The difference between them is the way the wafers are doped with chemicals to increase the amount of electricity generated.

Simply put, P-type cells are doped with boron, while N-type cells are doped with phosphorus. In contrast, phosphorus degrades less than boron when exposed to oxygen. In addition, phosphorus doping can add free electrons to the wafer, thereby increasing efficiency.

Therefore, N-type based modules can achieve higher efficiency. It is estimated that efficiency, currently close to 22.5%, will increase to around 24% over the next 10 years.

The problem with the N-type manufacturing process is that it is still relatively expensive.

What are the advantages of TOPCon technology?

1. Manufacturing process

TOPCon modules can be manufactured using almost the same machines as P-type modules, which means that the use of TOPCon cells does not require a large investment by manufacturers.

2. Higher efficiency

According to the Fraunhofer ISE institute, efficiency can exceed 25%. The maximum theoretical efficiency of PERC cells is approximately 24%.

3. Reduce degradation rate

Compared to PERC panels, TOPCon modules have lower power decay during the first year and 30 years of PV panel life.

4. Lower temperature coefficient

TOPCon batteries have better resistance to extreme weather scenarios.

5. Double-sided rate

The bifacial coefficient of PERC PV modules averages about 70%, while the bifacial coefficient of TOPCon panels is as high as 85%. They capture more energy from the back than PERC bifacial modules, which is beneficial for ground-mounted utility projects. They are also more attractive from an aesthetic perspective than PERC solar panels.

6. Low light performance

TOPcon modules are more efficient in low-light conditions, extending power generation during the day and improving the performance of the installation over time.

In the face of climate change, the world is evolving rapidly, and it comes an urgent need of sustainable energy solutions. One of the innovative solutions to this global problem is Building Integrated Photovoltaics (BIPV). These solar panels not only serve the dual purpose of providing power and generating electricity for house, but also shaping the future urban infrastructure. Let's rearch deeper for why BIPV is not only a viable option for modern construction, but the preferred choice.

Benefits of BIPV Panels

Building-integrated solar panels offer house owners and businesses a unique solution. They are not just additions to the existing structure; they are embedded within the structure itself. Because they act as both a building envelope and an energy generator, no need for a separate solar installation, providing functionality and aesthetics.

Space Efficiency

Building-integrated solar offers unique advantages in urban environments where space is at a premium. By integrating solar panels directly into building facades or roofs, no additional land or space is required to accommodate large solar farms. This efficient use of space is especially beneficial in densely populated areas. By choosing vertical or rooftop solar installations in urban environments, we can leave more land undisturbed. This approach protects natural habitats and supports biodiversity, unlike large ground based solar farms that sometimes damage local eco systems.

Resource Efficiency and Environmental Impact

Integrating solar panels into buildings reduces the need for additional materials and space. This means fewer resources are used and less waste is produced. By reducing the amount of raw materials required for construction and installation, we minimize our environmental footprint and pressure on natural resources. Additionally, because solar energy is green and renewable, it significantly reduces buildings' carbon footprint.

Design Flexibility

A building's aesthetics are an integral part of its appeal, value, and ability to blend in or stand out in its environment. Building-integrated solar panels continue to develop not only as functional components, but also as design elements that can enhance the attractiveness of buildings.

Thanks to advances in technology and manufacturing techniques, building-integrated photovoltaic systems can be integrated into a variety of building styles, from traditional to contemporary. This ensures that the integration of solar panels does not compromise the building's original design vision, but rather complements or even enhances it.

With modern technologies, roof-integrated systems can be customized to match a variety of architectural styles. Whether you want to integrate with existing roof tiles or achieve a seamless look, you have the flexibility to accommodate any design preference.

BIPV offers a range of design options. This includes different colors, textures and opacity. Some BIPV solutions even mimic materials like slate or terracotta, allowing architects and house owners to maintain a specific aesthetic while still reaping the benefit of solar energy.

While rooftops are a common site for building PV integration, the technology's adaptability means it can also be used on facades, awnings, or even as part of a building's shading system. This broadens design possibilities and enables architects to think creatively about how and where to incorporate solar power into their designs.

Photovoltaic Building Integrated Applications

1. Awnings and canopies. Outdoor structures such as awnings. Awnings are ideal for building-integrated photovoltaics, capturing sunlight while providing shade.

2. Facades. BIPV facades convert building appearance into energy, blending aesthetics with functionality. Large glass curtain wall can be equipped with translucent integrated solar panels that filter sunlight while generating energy.

3. Balcony and terrace. Integrating building-integrated photovoltaics into a balcony or terrace.

4. Roof installation. Rooftop installations are the most common application of building-integrated photovoltaics, blending seamlessly with the contours of the building. Here, the roof not only acts as a barrier against the elements, but also acts as a solar generator.

Batteries are important partners in solar energy systems. Batteries store excess energy produced by solar systems and also provide backup power during power outages.

Batteries replace the grid by adding them to your solar system.

When solar energy is generated, it will power your home appliances that need electricity.

If the amount of solar energy is less than what your appliance needs, the rest will be taken from the battery. If the battery is empty or can't provide a full load, the rest will still be pulled from the grid as a last resort.

If more solar energy is generated than your appliance needs, the excess will be stored in the battery. If the battery is full, the excess power is fed into the grid as a last resort.

By adding batteries to your solar system, you can make yourself more self-sufficient. More electricity in your home will come from the sun. Batteries give you backup power in the event of a power outage. Our high-end systems will switch you from grid power to battery power in a split second, and you won't even notice the grid has lost power.

Building-integrated photovoltaics enable buildings to maximize solar energy production while reducing long-term material and energy costs.

What is BIPV?

Building-integrated photovoltaics integrate photovoltaic cells directly into the facade of a building, rather than attaching photovoltaic cells to the existing facade. BIPV is often included in the construction process and architects consider BIPV when designing structures. In some cases, contractors may retrofit a building with BIPV, but it won't be cost-effective upfront.

BIPV can take many forms on buildings. It can be integrated into part of the roof or shingles. Larger buildings often choose to use BIPV as part of the building facade, and the cells are often integrated into the windows.

A building's roof may not get enough sunlight, but a multi-story structure can collect a lot of solar energy through its many windows. Other facades, such as awnings and skylights, are excellent locations for BIPV.

BIPV and BAPV

BIPV is part of this structure. They serve the dual purpose of energy collectors and building materials. BAPV (Building Applied Photovoltaics) is photovoltaic generation added to an existing system. BAPV only acts as an energy harvester. These buildings require standard building materials.

Benefits of BIPV?

BIPV systems have many benefits. They provide clean, renewable energy that is not only good for the environment but also saves homeowners money. Businesses are more likely to install BIPV than BAPV because they can be seamlessly integrated into the building’s architecture. Design doesn’t have to sacrifice beauty.

BIPV is more cost-effective in the long run, especially when incorporated during the construction phase. Because the system replaces some traditional building materials, there is no need to purchase these materials and solar equipment. All this can be done for one fee. The building will save money on electricity bills and may offset further costs through tax incentives.

One problem with solar energy is that the energy is not always available when needed. For BIPV, the energy collection peak and energy consumption peak are usually consistent.

The structure can use electricity immediately without the need for additional storage. The system does not have to rely as much on the grid, saving energy costs. Over time, the energy cost savings will far outweigh the initial installation and material costs.

Applications of BIPV

BIPV has several practical applications in the construction sector. Any type of facade that receives a lot of sunlight is a viable option. Designers often use roofs and skylights for BIPV. Since larger buildings require more energy and don't have as much surface area on the roof, windows are another excellent location. Windows are particularly effective on the tallest buildings in the area.

BIPV systems can meet the needs of large buildings while reducing the need for fossil fuels, thus contributing to sustainable construction. Progress is critical, and BIPV can make progress while reducing environmental harm.

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 follow a similar process as solar roof shingles. They are made by cutting a full size solar cell into 6 equal strips. These cells strips are then assembled and stacked, like roof tiles, to form longer strings of up to 40 cells, depending on the size of the panels. This results in one-fifth (or one-sixth) the usual string voltage (V) but one-fifth (or one-sixth) the current (I). Therefore, by reducing the current flowing through the battery, the resistance is also reduced, and by reducing the resistance, the operating temperature is also reduced. And by lowering the operating temperature, the chance of hot spots forming can be reduced.

Advantages

1. Non-busbar connection

In this arrangement, the cells are directly connected by physical contact, with no visible bus bars and straps required to hold the cells together. In the shingled configuration, nearly 30 meters of busbars and welded joints required by traditional solar panels are eliminated. This reduces the risk of bus failure.

2. Increased Power Harvesting

Spaces between cells are completely eliminated. This removes inactive areas of the panel, which can increase cell resistance and reduce performance. Thanks to more modules, almost 100% can be covered by solar cells, so more light can be collected per surface area.

3. Parallel Cell connection

In a traditional solar panel, individual cells are connected in series. So when the cell is shaded, its performance degrades, and with it the performance of the entire solar panel. In a shingled configuration, cells can be wired in groups and configured in parallel, allowing cells to perform more independently of other cells.

4. The best solar panel aesthetics yet

The main attraction of the Ribbon Cell is its state-of-the-art aesthetics. Without any visible circuitry, their surfaces appear to be made of stained glass. How the solar panels blend aesthetically into the roof is an important consideration for manufacturers. Shingled solar panels are by far the most aesthetically pleasing, second only to IBC solar panels.

Shingled cell technology is compatible with more traditional silicon cell technologies such as full black, half-cut, PERC, HJT, etc. and can accommodate these configurations. At present, this emerging technology represents the highest limit of the development of traditional undoped crystalline silicon solar cells so far.

Grid-Tied Solar

A grid-tied solar system consists of solar panels and a grid-tied solar inverter. This is the most common form of solar installed throughout the world. The solar system generates electricity, this electricity is used in the home and the excess is sent back out to the grid. If the solar generation is not enough to cover demand power will be used from the grid.

Most grid-tied systems will disconnect during a power outage. There are two reasons for this:

1. If the lines are down, it would be dangerous to send electricity back to the grid. There is a chance a line worker could get electrocuted.

2. The grid is used as a buffer for the ever-changing loads in your household. Without a grid connection, the solar inverter wouldn’t be able to manage the varying demand. For example, you are boiling the kettle using all the solar power you are generating, the kettle flicks off, now where does the solar power go if there is no grid? Inverters cannot react that fast.

Hybrid Solar

This system is a mix between a grid-tied solar system and an off-grid system. It consists of, Solar panels, Solar inverter and a battery bank.

A grid-tied send excess solar energy back to the grid. A hybrid system is designed to capture this excess energy and store it in the batteries. This energy can then be used at night or to meet peak demands, reducing or eliminating energy used from the grid.

A major difference between a hybrid system and off-grid system is the battery bank size. An off-grid system will generally have the battery sized to get through a few days of inclement weather, whereas a hybrid system will usually be sized to store enough energy to get through the night until the sun comes out the next day.

As hybrid systems have a battery you would expect to have backup power in the case of an outage. It pays to be careful with components you choose here as some systems will not have the backup function, they are purely to save excess solar power to be used at night. so in a power cut, you will find yourself without power.

If you are unsure about installing a battery or not at first, then that’s no problem at all. Just install a grid-tied system, ensure you have consumption monitoring. Then down the track when you have monitored your system, you will know which battery will be right for your system.

Off-Grid Solar

In some areas, there is no grid to connect to. To supply power in areas without a grid, you need a separate system.

Examples of stand-alone systems are:

Homes that are too far from power lines to connect. Generally, if the house is more than 300m from a power line, it may be worth considering going off the grid.

Cottages in remote areas. They are far from the grid and their only option is to install their own independent power system.

weather station. Often in remote areas, weather stations require their own independent systems.

Radio or telephone antenna. Most of the equipment is located on the top of the mountain to reach the maximum number of people. Connecting power cables to these tops can be expensive, and most of the time it makes more sense to have your own off-grid system.

Off-grid systems include:

• Solar Panels - Power Generation

• Battery Storage - Stores energy for night or off-day use

• Inverter - converts direct current to alternating current for use with common appliances

• Monitoring - Monitor battery charge status and solar input

   

The components we use in off-grid are changing in recent years, mainly in terms of battery types. Lead acid battery packs are traditionally used. In recent years, it has often been beneficial to use lithium batteries such as Tesla, BYD or Pylontech.

In order to avoid damage to the lead-acid battery, it can only discharge about 20-30%. That means a very large battery pack is needed to store energy for several days. With lithium, they can be fully discharged without damaging the battery. This means smaller battery packs and a lower risk of system damage.

Lithium-ion batteries charge much faster than lead-acid batteries, which means that if the sun is out for a short period of time, the lithium-ion battery can make the most of this energy. Lead-acid batteries typically take 7-8 hours to complete a charge cycle, so are often not able to fully utilize the available energy.

Off-grid systems usually also have a generator input. This is a backup in the event of prolonged severe weather. Another advantage of lithium batteries is that in the event that a generator needs to be used, the time the generator will run will be significantly reduced to charge the battery.

Modern off-grid systems are capable of online monitoring. This allows monitoring of the system through a cloud platform, so you can keep an eye on your system from anywhere in the world. At Wanaka Solar, we love this feature because it allows us to keep an eye on your system as well and help you with any queries or system maintenance.

Gel battery is a valve-regulated maintenance-free lead-acid battery. Gel batteries are very strong and versatile. This type of battery produces very little fumes and can be used in places without much ventilation.

How do gel batteries work?

A gel battery is a valve-regulated lead-acid battery in which a predetermined amount of electrolyte is mixed with silica fume along with sulfuric acid. This chemical reaction produces a fixed, gel-like substance that gives these batteries their name. Gel batteries are virtually maintenance-free because they use a valve that opens in one direction, allowing the gas inside to recombine into the water, so there's no need to check top up with distilled water or monitor the water level. Gel batteries are very strong and versatile. They can be safely installed in places with restricted ventilation as their gas/smoke production is very low (nearly zero) meaning you can even install batteries in your home.

Special consideration should be given when choosing a charger for gel batteries, as they charge at lower voltages. Overvoltage can cause malfunctions and performance degradation. The term GEL battery is sometimes used to refer to a sealed, maintenance-free battery marked as a setting on the charge controller. This can be confusing and can lead to the wrong charger selection or wrong settings while charging. If other charging methods such as alternators are used, an appropriate voltage regulator must be installed to control the charging voltage. Typical charging voltages for batteries range from 14.0 volts to 14.2 volts, and float voltages range from 13.1 volts to 13.3 volts.

Advantages of Gel Batteries

Gel batteries are gaining popularity in solar systems for the following reasons:

1.Best for deep cycle applications, typically in the range of 500 to 5000 cycles

2.Maintenance free

3.Spill proof

4.Minimal corrosion and therefore compatible with sensitive electronics

5.Rugged and Vibration Resistant

6.Very safe as there is less risk of sulfuric acid burns

7.Minimum cost per month (cost/months of life)

8.Lowest cost per cycle (cost/life cycle)

Disadvantages of Gel Batteries

1.Can't refill in case of overcharging

2.Requires special charger and voltage regulator

Do not confuse AGM batteries with GEL batteries

Today, AGM batteries are often mistaken for gel batteries because of their many similarities.

1.Both are reconstituted - meaning that the oxygen produced on the positive plate is absorbed by the negative plate. Instead of producing hydrogen, the negative plates now produce water, thus maintaining the water content in the battery. That's why AGM and Gel batteries are valve regulated, sealed, spill proof, maintenance free, vibration resistant and can be installed in any location.

2.The notable difference between the two is the difference in electrolytes. The electrolyte used in gel batteries looks like jelly, while the electrolyte in AGM batteries is absorbed in a glass mat that acts like a separator. Due to the properties of the electrolytes used in gel batteries, the batteries lose power quickly at temperatures below 32 degrees Fahrenheit, whereas AGM batteries work efficiently at low temperatures.

3.Gel batteries are best for deep discharge because they are less acid and protect the plates better than AGM batteries. AGM is more compatible where high current is required

Building-integrated photovoltaics (BIPV) are solar power generating products or systems that are seamlessly integrated into the building envelope and part of building components such as facades, roofs or windows. Serving a dual purpose, a BIPV system is an integral component of the building skin that simultaneously converts solar energy into electricity and provides building envelope functions such as:​

• weather protection
• thermal insulation
• noise protection
• daylight illumination
• safety

 

Applications​   1. Facade – PV can be integrated into the sides of buildings, replacing traditional glass windows with semi-transparent thin-film or crystalline solar panels. These surfaces have less access to direct sunlight than rooftop systems, but typically offer a larger available area. In retrofit applications, PV panels can also be used to camouflage unattractive or degraded building exteriors.
		2. Rooftops – In these applications, PV material replaces roofing material or, in some cases, the roof itself. Some companies offer an integrated, single-piece solar rooftop made with laminated glass; others offer solar “shingles” which can be mounted in place of regular roof shingles.
3. Glazing – Ultra-thin solar cells may be used to create semi-transparent surfaces, which allow daylight to penetrate while simultaneously generating electricity. These are often used to create PV skylights or greenhouses.

 

Benefits of BIPV​

 

The benefits of BIPV are manifold: BIPV not only produces on-site clean electricity without requiring additional land area, but can also impact the energy consumption of a building through daylight utilization and reduction of cooling loads. BIPV can therefore contribute to developing net-zero energy buildings. Turning roofs and façades into energy generating assets, BIPV is the only building material that has a return on investment (ROI). Furthermore, the diverse use of BIPV systems opens many opportunities for architects and building designers to enhance the visual appearance of buildings. Finally, yet importantly, building owners benefit from reduced electricity bills and the positive image of being recognized as "green" and "innovative".

 

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.