Solar Roof Shingles Definition, History, Structure, Types and Installation
In this article, solar roof shingles (Singular: Solar Roof Shingle) are extensively discussed, under the following headings;
Structure and Description of Solar Roof Shingles
How do Solar Roof Shingles Work?
Comparison between Solar Roof Shingles and Conventional Solar Panels
Performance and Efficiency of Solar Roof Shingles
Advantages and Benefits of Solar Roof Shingles
Disadvantages of Solar Roof Shingles
Installation of Solar Roof Shingles
How Long Does it take to Install Solar Roof Shingles?
How Many Solar Roof Shingles do you Need?
Best Brands of Solar Roof Shingles
What are Solar Roof Shingles?
Solar roof shingles (also known as Solar Shingles) are simply a type of solar panels which are designed to resemble the asphalt shingles of a building roof [6].
What this implies, is that solar shingles are dual in their function. They serve as a roofing material for the building, while generating power from solar energy.
Solar roof shingles are part of a relatively recent and still-developing aspect of renewable energy technology, called Building-Integrated Photovoltaics (BIPV). As the term implies, this aspect of renewable technology involves the manufacture of devices and accessories that resemble and act as conventional parts of a building, while also serving the function of generating or facilitating renewable energy.
In general, solar roof shingles are very similar to ordinary shingles in terms of their physical properties of flexibility, resilience and durability. The magnitude of power produced by each solar roof shingle may vary depending on the brand and the method of manufacture of the shingle. Some products deliver as low as 13 watts while others may deliver as much as 100 watts of direct current (DC) per shingle.
We may choose to view solar roof shingles as small solar panels which are fully and seamlessly integrated into the roof of a building, rather than being attached as an appendage to the roof. They are relatively easy to install, in general, and come in different designs such as semi-rigid, strip, and thin-film designs.
History and Development
Solar shingles were developed on the basis of earlier discoveries and technological advancements in the field of solar technology, from the early twentieth century.
The commercial manufacturing and distribution of solar shingles began in the year 2005, as a new product released by Dow Chemical Company in the United States [3].
Although there was a generally fair acceptance for solar shingles in the early stage of their development, progress was limited due to shortcomings in the efficiency and performance of the product.
Notable improvements began in 2011, when Dow released a modified and enhanced version of solar shingles. Other significant developments include the 2016 commencement of manufacturing and sale of solar roof shingles by Tesla Company in partnership with SolarCity [4]. RGS Energy Company began producing solar roof shingles in 2017, before going bankrupt in 2020.
GAF Materials Corporation revealed plans to manufacture and sell solar shingles on the 3rd of January, 2022 [1].
Structure and Description of Solar Shingles
Alternatively referred to as ‘solar roof tiles,’ solar shingles are constructed by melting and casting silicon crystals (or any other suitable semi-conductor material) into well-defined shapes which are then covered with reflective, protective material, and placed in a frame.
The above is a simple description of the general method of manufacturing solar panels, and this applies to solar shingles as well.
PV cells are the basic building blocks of solar shingles, which are made from arrays of solar PV cells that are linked to each other. The design of solar shingles is thinner and flatter than that of conventional solar panels, in order to enable them to effectively integrate with the building when installed.
Based on the above, we may describe solar shingles as thin PV sheets which may either replace or overlie the conventional shingles on a roof.
How do Solar Shingles Work?
Because they are a modified form of solar panels, solar shingles also function just like conventional solar panels.
This implies that they work by capturing and converting solar energy to produce electricity.
The PV cells that make up solar shingles, are composed of semiconductor materials like silicon. While manufacturing the solar shingles, these semiconductor materials are infused with metallic elements like Barium, in a process known as ‘doping’. Based on the element used in doping, the silicon may be N-type of P-type, each of which carries a different ionic charge (N-type carries electrons (-), P-type carries holes (+)).
When sunlight falls on the surface of the solar shingles, it causes the electrons to be energized, and due to the difference in charge distribution in the PV cell, the negatively-charged electrons move to occupy the positions of the positively-charged holes, and vice-versa. The end product of this movement is the continuous flow of DC current, which produces electricity.
The direct current (DC) is usually converted to alternating current (AC) before it can be used to power appliances in a building. This conversion is carried out by an inverter [5].
Also, the power generated by solar shingles can be stored for later use, in an inverter.
Based on the above, we can simplify the process by which solar shingles work, as follows;
1). Sunlight (solar energy) falls on the surface of the shingles
2). The solar energy is captured by the PV cells of the shingles
3). Electrons in each of the PV cells are energized, and begin to travel across the cells to occupy the positions of the positively-charged holes
4). This movement of electrons across the PV cells produces electric (DC) current flow in the solar shingles
5). The DC current generated by the solar shingles is converted to AC current by a transformer. This AC current is then transmitted using electric cables, to the point(s) of need
6). An inverter is used to store an excess electric power, for later use
The working pattern of solar shingles is continuous and has a high level of sustainability, which means that the shingles and their accessories can continue to function for extended periods of time without need for any external operation or interference.
Comparison between Solar Shingles and Conventional Solar Panels
As we have already stated, solar shingles are simply a modified design of the conventional solar panel. It is however necessary to compare the two technologies in order for us to fully understand the similarities and differences between them.
The following table gives a simple comparison between solar shingles and conventional solar panels, on the basis of various factors;
| Criteria of Comparison | Solar Shingles | Conventional Solar Panels |
| Average Size | 12″ by 86″ (same size as traditional roof shingles) | 65″ by 39″ |
| Efficiency | 10% – 18% on average | 15% – 20% on average |
| Output/Performance | 13-63 watts on average per shingle | 250-400 watts on average |
| Durability | Highly resilient to harsh weather, heat and mechanical impact (by comparison) | Less resilient than solar shingles |
| Materials and Design | May be made of silicon, or CIGS (Copper-Indium-Gallium-Selenide)
Design is relatively thin and flexible |
May be made of silicon, or CIGS (Copper-Indium-Gallium-Selenide)
Design is relatively thick and rigid |
| Installation | Relatively complex and time-consuming | Relatively simple and fast |
| Appearance | Made to resemble conventional shingles | Have tabular, board-like geometry |
| Lifespan | 20-30 years | 24-30 years |
| Cost (per watt) | $1.80 – $9.00 | $0.90 – $1.45 |
Types of Solar Shingles
So far, the classification of solar shingles has been based on material composition. The two main types of shingles are therefore discussed below;
1). Silicon Solar Shingles
As the name implies, these solar shingles are composed mainly of silicon. Silicon shingles are very similar to conventional solar panels in their material constituency, design and structure.
This is because solar shingles are fairly rigid, and enclosed within a frame. However, they are much thinner than the conventional solar panels.
Like conventional silicon solar panels, silicon solar shingles are of two categories; monocrystalline and polycrystalline.
The monocrystalline solar shingles are made from a single silicon crystal, while the polycrystalline shingles are made from a combination of more than one silicon crystal. Also, silicon shingles are the most common and widely available type.
2). Copper – Indium – Gallium – Selenide (CIGS) Solar Shingles
Compared to silicon shingles, CIGS solar shingles are an innovative improvement. They are lighter, thinner, more flexible and resilient than the silicon type.
The CIGS solar shingles are less similar to conventional solar panels as they are not rigid and may not always require an enclosing frame for support. CIGS shingled are also more suitable for roofs as they tend to integrate better with the building.
Performance and Efficiency of Solar Shingles
As shown in the comparison with conventional solar panels, the efficiency of solar shingles has a broad range from about 10-18% on average.
While this is still low compared to solar panels, it indicates that there is much potential for further improvement in the near future.
The performance of solar shingles depends on some factors, including the brand (manufacturer), size of the shingles, power demand, weather and geographic location, orientation of roof, and level of maintenance. In general, however, solar shingles put up a relatively fair performance.
Cost of Solar Shingles
The average cost of solar shingles far exceeds that of conventional solar panels.
Solar shingles cost between $18 and $2,500 per square foot, or $1.8 and $9.0 per watt. These values vary depending on the manufacturer. For an entire roof to be covered, the cost usually falls between $15,000 and $70,000. Installation cost often differs from the purchasing cost of the shingles.
Advantages and Benefits of Solar Shingles
1). Solar shingles are easier to maintain because they are directly integrated into the building
2). Compared to conventional solar panels, solar shingles are very durable and resilient
3). Solar shingles are much better in appearance than conventional solar panels. They are aesthetically pleasing, as most resemble translucent roofing tiles
4). Because solar shingles can replace conventional roofing materials, they are dual-functional and can be considered cost-effective
Disadvantages of Solar Shingles
1). On a per-watt basis, solar shingles are much more expensive than conventional solar panels
2). The orientation of solar shingles solely depends on the orientation of the building’s roof, since they must be installed as part of the roof. This means that they cannot be adjusted like conventional panels, if necessary, to get the maximum amount of sunlight. The amount of electricity generated may therefore be seriously reduced if the building’s orientation is not favorable.
3). Due to the relatively-new development of solar shingles, there is not much variety in terms of the features and performance of these products. The efficiency and performance are also limited compared to conventional solar panels
4). Efforts to improve the efficiency of solar shingles can reduce the aesthetic quality, and vice-versa
5). Solar shingles also tend to have a shorter lifespan than conventional solar panels
Installation of Solar Shingles
The method of installing solar shingles is fairly identical to the installation of asphalt roof shingles.
Solar shingles are usually fastened directly to the roofing sheets of a building using screws, in such a sequence that each subsequent solar shingle conceals the fastening points of the previous one.
The overall process of installing solar shingles is relatively complex, compared to the installation of conventional solar panels. This is due to the need to carefully lay each piece of the structure in alignment with the building roof.
Additionally, solar shingles come along with other accessories that are usually connected to the shingles during installation. These accessories include inverters and solar batteries.
Things to note before installing solar shingles in a building include;
1). The Size of the Roof
This will help to determine the number of shingles that will be required
2). The Amount of Power that is Required
Amount of power which a building will need depends on the appliances in the building and their power ratings. By estimating the power needs of a building, we are also able to determine the number of shingles that are needed.
3). The Orientation of the Building
In order to get the best performance in terms of power generation, solar roof shingles must be installed on a building that is properly oriented.
Proper-orientation simply means that the roof of the building is tilted at a favorable angle that will allow the solar shingles to capture maximum sunlight when installed.
4). Geographic Location
Because the direction and consistency of sunlight vary with geographic location [2], this factor should not be overlooked when planning the installation of solar shingles. In places where the consistency of sunlight is relatively low, high-quality shingles should be used. Also, the orientation of maximum solar radiation in any given location must be ascertained.
How Long Does it take to Install Solar Shingles?
Because of the complexity involved, installation of solar shingles can take several days, or even weeks. The factors that determine the duration of installation may vary from one scenario to the other. Some of these factors are listed below;
1). The size (area) of the roof
2). Size of each individual shingle
3). The number of workers involved in the installation project
4), Condition of the roof on which the solar roof shingles are to be installed
How Many Solar Roof Shingles do you Need?
It is not always necessary for the entire roof area to be covered with solar shingles. This is because the area of coverage of the solar roof shingles is directly determined by the power output of each solar shingle, and the total power need of the building.
Provided the roof of the building is damaged or old at the time of installation, it would be good to consider replacing it entirely with solar shingles. Although the initial (purchasing and installation) cost of shingles is relatively expensive, their power-generating capability means that they have an equally high Return-On-Investment (ROI).
Best Brands of Solar Shingles
1). Tesla
The tesla shingles are among the most dominant solar shingle products in the market. These products are designed to closely resemble conventional roof shingles. They are also designed with a tempered-glass covering to make them very resilient.
The installation, maintenance and removal of the Tesla shingles is overseen entirely by the company. A software application is also available for monitoring the performance of the solar roof shingles on a timely basis. Tesla solar roof shingles also have a power output-warranty of 30 years.
2). LUMA Solar
LUMA Solar produces solar shingles that are highly durable and which can withstand extreme environmental conditions. They are also very efficient.
3). CertainTeed
With a 25-year warranty, CertainTeed solar shingles are monocrystalline and are mainly compatible with asphalt and concrete conventional roof shingles.
4). SunTegra
The most unique feature of SunTegra solar shingles is the ease of their installation. These shingles are designed to be lightweight and simple. They are also compatible with concrete and asphalt roofs.
Conclusion
Solar shingles represent a relatively recent renewable technology, which is designed to integrate seamlessly into the roof of a building. It may also be referred to as a form of Building-Integrated Photovoltaic (BIPV) technology.
The development of solar shingles dates back to 2005, when the first commercial production and release of solar roof shingles was carried out by DOW Chemical Company. Subsequent developments have resulted in improved solar roof shingles with relatively higher efficiency and resilience than the initial versions.
Compared to conventional solar panels, we may choose to consider solar roof shingles to be a more adaptable option. They are more aesthetically pleasing because they integrate with the building. They are also dual in function, serving as power producer and roofing material.
Solar roof shingles have a higher cost per watt than conventional solar panels, although they also have a higher Return-On-Investment (ROI) than solar panels.
The two main types of solar shingles are Monocrystalline and CIGS (Cadmium-Indium-Gallium-Selenium) types. Performance is determined by the brand of solar roof shingles, geographic factors, among others. Efficiency ranges between 10%-18%, and the lifespan falls between 20-30 years.
Installation of solar roof shingles is usually a long and fairly-complicated process, however, the duration and complexity of installation varies with the characteristics of the solar roof shingles as well as those of the roof. Other solar system accessories which are installed alongside solar roof shingles include solar inverters and batteries.
References
1). Brigham, K. (2022). “Roofing giant takes on Tesla to make solar roof shingles more affordable.” Available at: https://www.cnbc.com/2022/01/03/gaf-energy-taking-on-tesla-to-make-solar-shingles-cheaper.html. (Accessed 17 January 2022).
2). Bykerk-Kauffman, A. (2022). “Seasons and Why the Equator is Warmer than the Poles.” Available at: https://serc.carleton.edu/sp/library/guided_discovery/examples/seasons.html. (Accessed 17 January 2022).
3). Church, K. (2020). “Solar Shingle Experience: Evaluating Their Value in Today’s Market.” Available at: https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi. (Accessed 17 January 2022).
4). Eckhouse, B. (2019). “Tesla has a new rival in its quest to make solar rooftops happen.” Available at: https://www.latimes.com/business/la-fi-tesla-solar-roof-20190319-story.html. (Accessed 17 January 2022).
5). Woodford, C. (2021). “Inverters.” Available at: https://www.explainthatstuff.com/how-inverters-work.html. (Accessed 17 January 2022).
6). Zito, B. B. (2021). “The Only Solar Shingles Buying Guide You Need.” Available at: https://www.forbes.com/advisor/home-improvement/solar-shingles-buying-guide/. (Accessed 16 January 2022).
