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Hartwig Westphalen, Managing Director Solar cells and modules are no longer the cost factor, it´s now about the system and the infrastructure.
Solar modules generate electricity, and water flows between them. In drier regions, the system can be used to collect rainwater. OPENSUN can provide the electrical engineering expertise needed to integrate the solar system at each site.
Decades of work in photovoltaics gave Hartwig Westphalen firsthand experience of a recurring challenge: industrial rooftops often require specialized engineering to accommodate solar installations, and limited land can make ground-mounted systems impractical. Existing car parks and other outdoor spaces offer an alternative, but installing solar roofs over them presents engineering challenges of its own.
Westphalen established OPENSUN to address these challenges. Its patented, kit-based “elementary roof” provides shelter and accommodates solar panels. Designed for applications ranging from large commercial car parks to individual carports, its modular structure aims to simplify installation and reduce construction costs.
“Our target was a kit-based solar system, which could be mounted anywhere and used for different applications,” says Westphalen, managing director.
OPENSUN Innovation
OPENSUN’s innovation is a modular steel structure built around four main components, with redesigned support angles and connections. Prefabricated parts are transported to the site and assembled like a kit. This approach aims to reduce the amount of custom engineering and fabrication needed for each installation. Instead of developing a new structure for every project, OPENSUN can adapt a repeatable design to different sites. The intended result is simpler assembly, lower construction costs and a system that manufacturing partners can produce at greater scale.
Simplifying Construction Through Smarter Design
Achieving that simplicity required several design attempts. The first designs used conventional rectangular pillars and numerous connections. The team struggled to achieve sufficient stabilityunder strong winds and potential snow loads. More steel would have added complexity and undermined the goal of a simple, repeatable structure.
Westphalen worked with architects and electrical engineers to rethink the geometry, in particular the angles of the supporting components and their connections to the roof. The resulting structure uses four main, relatively slim steel components. One requires more involved prefabrication than the others. A patent search found no comparable listed design, and OPENSUN secured patent protection and the project has been supported by the German Ministry of Technology.
A Roof for Multiple Applications
The simplified design also makes on-site assembly more straightforward. Its prefabricated components can be transported by truck and assembled on-site. Different configurations suit different site requirements, without the need for a custom design each time. The completed prototype was installed in one day, demonstrating the simplicity of the assembly process. Installation does not require a specialist roofing company or personnel trained in conventional roofing techniques.
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Our target was a kit-based solar system, which could be mounted anywhere and used for different applications.
Solar modules generate electricity, and water flows between them. In drier regions, the system can be used to collect rainwater. OPENSUN can provide the electrical engineering expertise needed to integrate the solar system at each site.
The standardized design aims to reduce the engineering and fabrication costs of customized installations. Westphalen estimates that costs could fall by around 30 percent for installations on the scale of a 100-space car park.
Whereas the main scaling is seen in larger e-charging carparks special projects have potential as showcases.
Examples are early discussions about a possible installation at a major rock festival site in Germany and in the international context a larger commercial car park in Singapore.
For industrial sites, generating electricity on-site can strengthen energy resilience, reduce dependence on costly grid extensions and provide greater electricity-cost stability. Solar car parks make use of existing space and can accommodate EV charging. Westphalen sees further opportunities as parts of Europe introduce requirements for solar installations over large parking areas.
Scaling Through Strategic Partnerships
To bring the elementary roof into wider commercial use, OPENSUN is seeking established partners with the manufacturing capacity, investment resources and sales networks to scale production.
From 2000 to 2017, Hartwig Westphalen, who holds a PhD in astrophysics, founded and led a Hamburg-based photovoltaic company that delivered commercial, industrial, agricultural and technically demanding rooftop projects. He sold the business to one of its customers in 2017. For OPENSUN, he has chosen a different path. He wants to expand the system's reach without building another large company himself.
Westphalen's team would contribute technical knowhow and specialist engineering support during the initial expansion. Greater production volumes could lower costs and make the system accessible to more commercial and industrial businesses. His long-term goal is decentralized solar generation as a major systemic structure, with electricity consumed where it is produced.
OPENSUN has earned recognition as the Top Solar Power Generation Service in Europe 2026 for its patented, kit-based roofing system designed to make decentralized solar generation more accessible.
Evaluating Solar Generation Systems for Commercial Sites
A manufacturing facility may have plenty of parking space but little roof area suitable for solar panels. Older industrial buildings may also need structural reinforcement to carry the additional weight, making a solar installation more expensive. Installing panels on the ground presents another challenge when the available land is needed for production or future expansion. For commercial property owners, the decision involves more than panel efficiency or the amount of electricity a system can generate. Finding a suitable place for the installation, without disrupting existing operations or adding major construction costs, can determine whether the investment makes sense.
Parking areas offer another possibility. Solar panels can be installed above spaces that are already in use, allowing the same area to serve two purposes. However, conventional solar carports can require large amounts of steel and substantial construction work. The cost depends partly on how the supporting structure is designed, manufactured and assembled. Using standard components can reduce fabrication work and make installation easier across different sites. The structure must still be engineered for local conditions, including wind and snow loads. Some parts of the design may be repeated, while others will need to be adapted to meet the requirements of a particular location.
Installation is another part of the cost. A structure with numerous connections or complicated assembly steps can take longer to build, even if the materials themselves are reasonably priced. Prefabricated components can reduce the work required on-site, especially for contractors installing systems at several locations. The design also needs enough flexibility to suit different parking layouts and provide the roof angle needed for solar generation. A modular system can make expansion easier if additional parking spaces are covered later, without requiring major changes to the original structure.
The electricity generated can also be used by the facility itself. For businesses with significant daytime power demand, producing electricity on-site may be more practical than developing a separate solar installation that relies on distant transmission infrastructure. A solar parking canopy can provide electricity while also sheltering parked vehicles. The amount of power generated still needs to be compared with the facility’s actual consumption to understand how much can be used directly.
Battery storage and electric vehicle charging may add further value where they are technically suitable and financially justified. These features need to be considered during electrical planning, even if they are not part of the initial installation. That allows owners to distinguish what they need immediately from what they may want to add later. Grid connection requirements will also depend on local regulations and how the system is intended to operate.
Project size can make a considerable difference to cost. Manufacturing and installing the same components repeatedly may become more economical across a large parking facility. A smaller installation covering only a few spaces may not achieve the same savings. Production capacity therefore matters, along with how the supplier expects costs to change as installation volumes increase. This is particularly important for newer systems that have not yet reached large-scale production. If future savings depend on manufacturing partnerships still being developed, those assumptions need to be understood before a major rollout. Structural verification and responsibility for installation should also be established early.
OPENSUN has developed a modular photovoltaic roof structure for commercial parking facilities, using prefabricated steel components that simplify assembly and allow the system to expand across different parking layouts. The design uses a limited number of principal steel elements to reduce structural complexity. It also includes integrated rainwater drainage.
The system is still in the early stages of commercialization. OPENSUN is pursuing production and distribution partnerships to support larger installations, with engineering expertise available to assist partners in further development.
For industrial property owners and infrastructure companies planning solar canopies, the approach offers a way to use existing parking areas for electricity generation without taking up additional land. Its modular design is intended to make construction and future expansion more manageable. OPENSUN is particularly relevant to organizations considering scalable installations that can also support the initial deployment and manufacturing needed to bring the system into wider use.
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Company
OPENSUN
Management
Hartwig Westphalen, Managing Director
Description
OPENSUN develops patented, kit-based solar roofing systems for commercial and industrial applications. Its modular elementary roof provides an alternative where existing rooftops are unsuitable or ground space is limited. The simplified steel structure eases installation, accommodates multiple applications and enables standardized production, creating opportunities for cost-effective deployment at scale.
