StartSun Calculator: A User-Friendly Tool to Unlock Your Solar Energy Potential

As the interest in citizen-driven energy communities continues to grow, the StartSun project has developed a digital tool that empowers individuals and small organizations to explore the feasibility of shared solar energy production. The StartSun calculator is a free, easy-to-use solution designed to help everyday users assess the potential of creating or joining a solar energy community in their area. 

The idea for the calculator was born out of a clear need: while professional tools for solar energy planning exist, they are often too technical, expensive, or inaccessible for the average person. The StartSun calculator fills this gap by offering a simplified, intuitive experience tailored to households and small organizations interested in renewable energy collaboration. 

In addition to estimating solar energy production, the tool includes a unique module that inspires users identify suitable energy community models based on their specific circumstances. Customized versions of the calculator are available in Estonian, Latvian, Finnish, and Swedish, making it accessible to a wide range of users across the Baltic Sea region. 

The calculator guides users through four key steps: 

1. Energy Consumption – Users input their monthly electricity usage and current electricity costs. 

1. Solar Plant Setup – They define the parameters of their planned solar installation, including location, capacity, and orientation. 

1. Financial Inputs – Users can enter investment details such as loans or grants or rely on default cost estimates. 

1. Community Questions – A short questionnaire helps determine the most appropriate energy community model based on the number of members, goals, and other characteristics. 

Once completed, the tool generates a comprehensive summary that includes monthly averages, projected solar production, household consumption, cost savings, and return on investment. It also highlights the three most suitable energy community archetypes based on the user’s inputs, offering both technical and financial clarity. 

Data-Driven, Yet Accessible 

The tool requires only basic data from users—monthly electricity consumption, current costs, and solar plant details. Optional financial inputs allow for more refined analysis. The community module adds further value by helping users understand which energy community models might work best for their situation. 

By processing this data, the calculator delivers meaningful insights into energy production, consumption balance, and financial feasibility—without requiring technical expertise. 

One of the biggest hurdles for individuals exploring energy communities is understanding how to size and plan a shared solar plant effectively. Many existing tools are either too simplistic or too complex. The StartSun calculator strikes a balance by offering a more accurate, case-specific analysis that still remains user-friendly. 

Another challenge in energy communities’ development is the general lack of awareness about energy communities and their diversity and possibilities. The calculator addresses this by educating users on different models and inspiring them with tailored suggestions for community formation. 

Real-World Impact 

Even in its testing phase, the calculator has already proven valuable. It played a key role in planning the Obinitsa energy community, our pilot in Estonia. It has also supported feasibility studies for potential follower energy communities in Viru-Nigula and Lääne-Harju municipalities in collaboration with the LIFE EC4RURAL project. 

These early successes demonstrate the tool’s potential to drive informed decision-making and foster community engagement around renewable energy. 

What’s Next? 

The calculator is currently in its final testing phase. Feedback from users is being collected and used to refine the tool. Once finalized, it will be made publicly available on the websites of StartSun project partners in their respective languages. Users will also be able to submit ongoing suggestions for improvement directly through the tool. 

Looking ahead, the team plans to develop a web-based version to further enhance accessibility. The latest versions of the calculator, including country-specific adaptations, are expected to be released by December 2025. Updates and download links will be shared on the StartSun project website and through partner social media channels.  

By the end of the StartSun project in October 2026, the calculator will be one of the tools in the StartSun Start-Up package – a user friendly and in-depth guidance package for anyone interested in developing and running an energy community.

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