What are shingled solar panel systems and why you should get one for your property.
Solar PV modules have been around for many years and attracted by energy savings, generous feed-in-tariffs or just by the good cause of green energy many people all around the world equipped the roofs of their houses, carports or workshops with PV modules and penetrating mounting racks.
Even though global interest in PV is continuously increasing, yet there are many people that are hesitating about the investment into PV systems. They cite either high costs, disbelief in the quality and longevity of the components, roof space and weight load constraints or aesthetic reservations.
The potential alternative to those reluctant people can be solar shingles. Solar shingles, also called photovoltaic shingles, shingled solar panels or simply solar tiles, have been around for over a decade, however they are still unbeknownst to many in the industry, let alone many end users.
Shingled solar panels: materials and technology
Since the early 2000s, more and more companies have invested and set up manufacturing capabilities to produce solar shingles.
Solar shingles belong to the category of building-integrated photovoltaic (BIPV) products, combining conventional, mostly flat-type roof tiles with solar cells.
Similar to normal roof tiles, they can be made of asphalt, concrete, ceramics, clay or other tile material such as glass and thus applied on a large variety of different roof structure types, even including the rather exotic Chinese glazed ceramic roof tiles.
Solar shingles contain small digs in which to fit and laminate the thin solar cells, mostly using either CIGS (copper, indium, gallium, selenium) or mono- or poly-crystalline silicon cells, with some manufacturers offering solutions for the latter type being fit with thin low-iron tempered glass like conventional solar modules.
Solar shingles come in various forms and types, such as shingles with integrated solar cells, shingle-shape PV modules that are the size of several conventional shingles or thin-film shingles with the design and application advantage of added flexibility for architecturally more challenging roof shapes.
Why shingled solar panels and how to install them?
Solar shingles have been created as an aesthetic and integrated alternative to conventional standard photovoltaic system solutions.
Solar shingles can both be used to generate electricity and thus power the in-house loads and/ or feed the grid with the generated electricity, or to convert electricity into heat akin to solar thermal energy (STE) systems.
In theory, and depending on a house's geographic location, roof space and direction of the roof, efficient solar shingles can fully meet the demands of a building's electricity usage.
Similar to standard solar PV modules, the solar shingles work as modular units connected with each other in strings. These strings are then connected to an inverter, converting the direct current (DC) power of the solar shingles into household alternate current (AC) power.
Depending on the solar shingle type and material used, the mounting requirements may differ. Some solar shingles have special compatibility and installation requirements, whereas other types can be mixed and fit with normal, non-solar roof shingles.
Benefits of shingled solar panels
The main advantages of solar shingles are their much lower weight and their arguably more aesthetic roof-integration, being a more low-profile, power-generating add-on than the heavy and clearly visible standard PV modules.
Solar shingles are weather-resistant and meet similar strength and flexibility requirements as conventional roof shingles.
Many manufacturers of solar shingles even offer color-matching solutions for standard black, red, blue or other roof tile colors with similar solar cell colors. Similar color-matching solutions for standard crystalline PV modules are still comparably more expensive and more difficult to come by.
In comparison to standard PV modules, solar shingles serve multiple purposes: apart from simple generation of electricity or heat and offering better aesthetics, they can also be used as¦ well, as roof shingles, serving as waterproof barrier and protecting roofs from ingress of external particles.
Moreover, if for structural issues or regulations your house roof is not allowed to be fitted with traditional solar PV modules, solar shingles are a potential alternative to still go solar with your house.
Lastly, another advantage of solar shingles: in environmental terms, solar shingles offer significant savings on materials such when it comes to frames which are usually used for standard PV modules.
The not-so-great stuff about shingled solar panels
In spite of these many advantages, why do solar shingles have not gained more attention or popularity so far? For long time, the higher price of solar shingles as compared to standard PV modules has been one of the major barriers.
However, the introduction of CIGS-based solar shingles and reduction in production costs in recent years has led to strong price drops. This brought solar shingles closer to being in mainstream-economic terms a serious alternative to standard PV modules.
Also, power output and efficiency are issues to consider. Even though solar shingles could generate a house's total electricity needs, however, depending on the solar cell technology used with the shingles, they may generate up to 50% less power per square meter than conventional solar PV modules. In such cases, logically more space to generate the same amount of power is required.
Another issue with solar shingles is their difficult cooling. Unlike standard PV modules that are installed above the shingles with a gap for airflow, the solar cells are integrated with the roof tile and thus being closely attached to the roof structure.
For this reason, air cannot easily flow circulate underneath the shingles for cooling. Proper ventilation needs to be arranged, which however can be a technical challenge. Otherwise the solar shingles can become very hot, significantly reducing the power output of the solar cells. And: they can heat up the underlying attic as well.
Final thoughts
Solar shingles are expected to hold for at least 20 years, similar to the averages of many standard roof tiles, though less than the expectations for conventional PV modules.
The integration of solar shingles with new solar cell technologies such as PERC (Passivated Emitter Rear Contact) bears however the potential to minimize the heating issue and, with such technology advances, make solar shingles a more and more serious competitor to the old-fashioned PV modules.
