Challenges in integrating solar energy into historic architectural projects

Integrating solar energy into historic architectural projects is a task that transcends the technical sphere. It is a dialogue between past and future, where cultural heritage meets sustainable solutions to contemporary energy challenges.

Despite the enthusiasm for adopting clean technologies, this process is fraught with unique challenges that demand a sensitive and interdisciplinary approach.

In this article, we explore the main challenges of this integration, considering aspects such as regulation, structural feasibility, aesthetic quality and energy efficiency.

Asset and regulatory restrictions

When historic buildings are protected by preservation regulations, any intervention must be carefully planned to respect their original aesthetics and structure. Many of these properties do not allow visible modifications, making the installation of photovoltaic modules a complex task.

On the other hand, it is important to that maintenance is also an essential part of preservation. Incorporating solar technologies in a planned manner can even help finance the long-term conservation of these buildings, as long as the project respects local regulations and values ​​the historic character.

An example of this restriction occurred with the Mineirão Stadium, in Belo Horizonte. When we carried out the technical feasibility study for UFSC (Federal University of Santa Catarina), in 2008, one of the premises was that the photovoltaic system would not be visible to pedestrians, so that the architectural aesthetics would not be impacted.

The challenge was the inverted beams up to 2 meters high, which caused large shadows on the slabs. In order to find an aesthetic and energy balance, several scenarios were simulated to optimize this system.

Structural feasibility

Historic buildings often use materials and techniques that were not designed to additional loads. Before any implementation, a structural analysis is essential to ensure that the installation of photovoltaic modules does not compromise the integrity of the building. In this scenario, replacing conventional tiles with photovoltaic tiles It is the solution that will have the least impact on the increase in load.

Aesthetic challenges

Visual harmony is one of the major concerns when it comes to solar architecture applied to historic buildings. Conventional large rectangular modules, usually black or blue, often create an undesirable contrast with the original aesthetics of the building. There are two ways to get around this issue:

• Use of modules that are mimicked in the architecture, repeating colors, shapes and patterns, i.e., customized modules to meet the aesthetics of the building in which they will be installed. Examples: solar tiles with colors similar to conventional tiles and colored photovoltaic modules with matte, glossy or even textured finishes.

• Use of semi-transparent or translucent photovoltaic modules, creating annexes between existing buildings or new glazed roofs. When well planned, such compositions harmonize with the historic architecture by contrasting the modern with the old with lightness and elegance. A very interesting example is the photovoltaic roof inaugurated in December 2024 at the entrance to the Vatican Museums. The solution added aesthetic value to the historic architecture of the site and also contributed significantly to the energy efficiency of the complex.

Another aesthetic challenge arises when expanding or renovating historic buildings. Additions to historic buildings are often implemented to expand the building's footprint and program, connect multiple buildings, or replace parts that have been demolished.

These interferences can integrate harmoniously with the original building envelope or create striking contrasts, with innovative volumes and materials, depending on the heritage preservation and energy conservation policies applicable to the region.

Furthermore, there are cases in which these architectural interventions not only meet the needs of the building's program, but also ensure environmental comfort, resulting in lower energy consumption or even a positive energy balance.

An example of a successful addition to a listed building is the European Commission Building in Brussels. Designed in the 80s to serve 12 countries, it found itself insufficient to meet the growing demand for meetings and events when it reached 27 .

Following an architectural competition, the chosen solution included a suspended roof made of semi-transparent photovoltaic modules, uniting the listed building with a contemporary building. The result brought unity and sustainability, without compromising the original façade.

Energy efficiency and limitations of positioning of photovoltaic modules

We know that the ideal position and inclination of photovoltaic modules are determining factors for the efficiency of the system. However, in architecture, and especially in historic buildings, this premise loses its relevance, as other commitments need to be met. Nevertheless, even in positions that are not considered ideal, photovoltaic systems can still generate energy efficiently.

In this scenario, performing shading simulations and sunlight studies is essential to identify the most efficient points for capturing solar energy. In addition, the use of microinverters and power optimizers can contribute to better performance, even in challenging conditions.

Deployment costs

Renovating historic buildings often involves specific materials and traditional techniques, which already entails high costs. Adding modern technologies, such as photovoltaic systems, can increase the budget, due to the need for customized solutions to maintain harmony between past and present.

However, the higher initial investment may be offset by the long-term savings that renewable energy generation can provide. The key is to present feasibility studies and financial models that show landowners and conservation agencies the benefits of embracing sustainability.

Lack of knowledge about photovoltaic technology

In many cases, a lack of knowledge about solar technologies among asset managers is a barrier. Resistance to modern solutions, often seen as an attempt to maintain authenticity, can prevent sustainable advances that, with due care, could benefit buildings.

Education and training initiatives for professionals in the field are essential. Showing successful examples of integration and presenting solutions adapted to local reality can help to deconstruct prejudices and promote greater acceptance of technologies.

Conclusion

Integrating solar energy into historic buildings is a challenge that requires more than technical expertise; it demands a careful look at the architectural identity and cultural significance of these buildings. Overcoming aesthetic, structural and regulatory barriers requires collaboration between architects, engineers, heritage managers and technology developers.

With careful planning and innovative solutions, it is possible to transform these buildings into benchmarks of energy efficiency, without compromising their history and heritage value. Advances in technology and the adoption of more adaptable approaches allow innovation and preservation to go hand in hand, ensuring that the architecture of the past contributes to a more sustainable future.

The opinions and information expressed are the sole responsibility of the author and do not necessarily represent the official position of the author. Canal Solar.