EU project 2026 to 2029
Solar on Rooftops
SolarSim is a partner in Solar on Rooftops, a Danish-Swedish collaboration that aims to make it easier for municipalities and other building owners to put more solar PV on the roofs that already exist. The project is led by Gate 21 and supported by the EU programme Interreg Öresund-Kattegat-Skagerrak.
Solar on Rooftops is co-funded by the European Union through the European Regional Development Fund and the Interreg Öresund-Kattegat-Skagerrak programme.
From September 2026 to June 2029, 14 partners from Denmark and Sweden develop and test tools, business cases and processes that take solar projects from potential to panels on the roof. SolarSim contributes PV and energy simulations, further development of our screening and solar tools and training in how to use them.
- Project period
- September 2026 to June 2029
- Lead partner
- Gate 21
- Partnership
- 14 partners from Denmark and Sweden
- Total budget
- Approx. EUR 3.5 million (approx. DKK 26 million)
- EU funding
- 60% from the European Regional Development Fund
- Programme
- Interreg Öresund-Kattegat-Skagerrak, priority Green transition
Why Solar on Rooftops?
According to the European Commission's Joint Research Centre, solar PV on existing buildings could cover around 40% of the EU's electricity demand. Today only about 10% of buildings have solar panels. The potential is large, but for many building owners the road from idea to installation is long and uncertain.
At the same time, the EU Energy Performance of Buildings Directive (EPBD) requires solar on public and private buildings towards 2030, and the electrification of heating and transport increases the need for electricity produced close to where it is used. Municipalities play a key role, both as owners of large building portfolios and as the ones who can help housing associations and businesses get started.
Many municipalities, however, lack an overview of their buildings, documented concepts and tools that make the decision simple. That is the challenge Solar on Rooftops takes on in a collaboration across the Øresund, where Denmark and Sweden meet the same EU requirements with different rules and experience.
What the project works on
The project is organised in work packages that together cover the whole path from knowledge and tools to pilot projects and long-term anchoring.
A shared knowledge base
Mapping of EU requirements and national rules in Denmark and Sweden, best practice from earlier solar projects, and an analysis of barriers and potential across the border.
Tools and decision support
Action plans and screening of municipal buildings, technical system design with batteries and smart control, holistic business cases, procurement templates and process tools from idea to operation.
Skills and learning
Targeted training courses, case-based learning between municipalities, study trips and open webinars together with networks in both countries.
Pilot projects
Each partner municipality carries out 1 to 2 pilot projects on buildings such as schools, care homes, swimming pools and car parks, and tests models for helping businesses and apartment buildings get started.
Anchoring and policy
A reference group of industry and network organisations, policy briefs on barriers in the regulatory framework and a closing cross-border conference, so the results live on after the project.
SolarSim's role in the project
SolarSim is one of the project's two private knowledge partners. We contribute what we do every day: independent, data-driven calculations of solar potential and economics.
PV and energy simulations
High-resolution simulations of the solar potential of different building types, assessment of system configurations and financial business cases. The analyses help select pilot projects in the Danish and Swedish partner municipalities.
Screening Swedish municipalities
We integrate Swedish geodata and Swedish settlement and subsidy rules into our screening tool, so it can also screen the entire building stock of Swedish municipalities.
Further development of the solar tool
Further development of SolarSim's solar tool with, for example, bidirectional charging (V2G) of municipal vehicle fleets and life cycle assessment (LCA) in line with the building regulations.
Capacity building
Webinars, courses and workshops on the practical use of simulation tools in planning and decision-making, so municipalities can help private building owners and businesses move forward.
We also act as sparring partner on the municipalities' action plans and building selection, on procurement material and process tools, and on pilot projects in business areas and apartment buildings.
What the project will deliver
The results are developed together with the municipalities and tested in practice before they are shared with other municipalities and building owners across the programme area.
- Solar action plans towards 2030 in all partner municipalities
- 1 to 2 completed pilot projects in each partner municipality
- 5 to 10 solar concepts for typical building types, such as care homes, swimming pools, apartment buildings and car parks
- A portfolio and screening tool, tested and adapted to Swedish conditions
- Procurement templates, business case models and a process guide from screening to operation
- A best practice catalogue, policy briefs and training courses for municipalities and building owners
All results will be publicly available, among other places in Gate 21's knowledge bank.
The partners behind the project
Gate 21 is lead partner and Energikontor Syd coordinates the Swedish partners. The partnership brings together municipalities, universities and consultancies on both sides of the Øresund.
Denmark
-
Gate 21 Lead partner - Albertslund Kommune
- Faxe Kommune
- Høje-Taastrup Kommune
- Københavns Kommune
- Technical University of Denmark (DTU)
- Nordløv
- SolarSim
Sweden
- Energikontor Syd Coordinating partner
- Burlövs kommun
- Hässleholms kommun
- Simrishamns kommun
- Ystads Samhällsfastigheter AB
- Linköping University
Want to know more?
Erik Olsen is SolarSim's contact person in the project. Questions about the project as a whole can be directed to Gate 21, which leads the project.
Supported by the EU
Solar on Rooftops is carried out with support from Interreg Öresund-Kattegat-Skagerrak, part of the EU's cross-border cooperation. Most of the funding comes from the European Regional Development Fund.