What is a BIPV solar system? In-roof solar tiles explained

Building-integrated photovoltaics (BIPVs) are solar photovoltaic systems that can be integrated into a building to replace conventional parts of the roof, such as roof tiles or slates and roof windows. Solar tiles such as the Marley SolarTile® are designed to be installed as part of the overall roof covering and generate usable electricity from the sun.

A complete BIPV solar system is made up of some or all of the following components:

• Solar PV modules – For example, a solar tile which captures the sun’s energy.
• A solar inverter – This converts the DC output from the solar panels into AC power suitable for use in the property. When the property’s electricity demand is low, for example, during the daytime when occupants are away from the home, any excess power generated by the solar array can be diverted to a storage battery or exported to the electricity grid.
• A solar storage battery – The size and capacity will vary depending on the building’s size and use.
• Fixings and mounting hardware – These connect cables and ensure the solar array is securely attached to the structure. This category also includes safety disconnects and arc protection devices, such as the Marley ArcBox.

What is the best place to locate a BIPV solar system?

A BIPV system needs to be positioned on the building where it will receive the most sunshine. This is usually on the roof or high up away from shade.

Kevin Taylor, Training and Technical Support Manager at Marley, explains that in the UK and other countries in the northern hemisphere, solar panels work can well on roof elevations facing anywhere from East to West as that is the natural arc of the sun, with due South being the most effective.

“As anyone with a south-facing garden in the UK will know, facing this direction means the sun is visible for most of the day compared to facing north, which is away from the sun and in the shade for most of the day,” he says. “If a solar PV panel is not facing towards the south, it will still produce electricity, just not as much,” he adds.

A solar panel facing fully north will produce around 40%[1] less electricity per year compared to the same south-facing panel. A solar panel facing fully west produces around 15%[2] less electricity than a south-facing PV panel. In the UK, the ideal angle for a solar panel is between 30 and 40 degrees from the horizon.

Why use a BIPV solar system?

With rising energy costs, many people are turning to solar energy to help reduce their bills. Solar PV panels are increasingly used on homes and commercial buildings. They are sometimes fitted on top of the existing roof tile or slates to metal rails and brackets which are fixed to the timber sub-structure of the roof– this is known as an on-roof or above-roof solar system.

In contrast, an integrated solar tile system forms part of the roof covering. “BIPV solar panels sit within, and form part of, the main roof covering, providing a more aesthetically pleasing finish, while improving long-term performance and reducing maintenance requirements,” Kevin says.

Where traditional on-roof solar panels are installed above the roof surface, a gap is formed between the rear of the panel and the roof finish. This can be attractive to nesting birds, causing a mess and affecting the performance of the solar panels.

“Due to the Marley SolarTile® being integrated into the roof finish it sits flush with the tiles, there is no perch for birds to land on or a gap that could encourage nesting at the back or under the panels,” Kevin adds.

What are the advantages of BIPV solar panels?

Traditional on-roof solar panels can be unsightly as they are usually added to a property after its construction, and if not fitted with care, damage can occur to the slates and tiles and the roof timbers below. The main advantage of BIPV solar is the aesthetics. An in-roof solar tile forms part of the roof covering and seamlessly integrates into the building structure for a much cleaner and neater look.

Using integrated solar roof tiles can make roof maintenance easier when compared to add-on PV panels. For example, should a tile fail and need replacing, the cost and complexity of doing so is considerably higher if it is located behind an above-roof solar PV system. The system must be decommissioned, and the on-roof PV panel must be removed for the tile to be replaced. Then the on-roof PV system will have to be reassembled and recommissioned. A job that could have been completed using a ladder could now require scaffolding and electrical works.[3]

Does BIPV cost more than conventional solar panels?

Compared to on-roof solar panels, the cost of a BIPV system can be higher. However, since the BIPV tiles are used instead of roof tiles or slates, some of the additional cost is offset by the reduction in roofing materials and labour. BIPV systems also weigh significantly less than the tiles or slates they replace so they can reduce the overall weight on the finished roof, compared to on-roof systems which increase both the dead-loads and the wind loads on the roof.

In some cases, the costs of traditional roofing materials and installation can be substantial, meaning that the use of BIPV can help to keep costs down.

When considering a solar PV system as part of your design for a new building or refurbishment, using BIPV means that your installation will be far more aesthetically pleasing and easier to maintain than a conventional system. A building incorporating BIPV can be beautiful as well as functional.

BIPV solar panels as part of a Marley Roof System

If you are looking for a BIPV solar system, Marley SolarTile® is an ideal choice. Designed to sit within the existing roof covering, it combines a weatherproof roof covering with electricity generation.
To find out more, visit our Marley SolarTile® page to see how Marley BIPV solar can be incorporated into your next project.

 

Disclaimer - The information shared in this blog is correct at the time of publication. Guidance, standards, and best practices may change over time, so if you’d like further clarification or the latest updates, please get in touch with the Marley Technical Advisory Team, who will be happy to help.

 

[1] https://nxtgenenergy.co.uk/blog/north-vs-south-facing-solar-panels-which-is-best/
[2] https://www.eco-home-essentials.co.uk/solar-panel-orientation.html
[3] http://www.solarblogger.net/2018/05/bipv.html