Insights on solar radiation anomalies, precision data, and the future of high-accuracy PV modelling

Solargis is a global provider of high-precision solar radiation and meteorological data, supporting developers, operators, utilities, and financial institutions across the photovoltaic sector. Co-founder Marcel Suri leads the organisation’s mission to deliver the most accurate digital solutions for solar project performance and risk assessment.

This interview explores the solar radiation anomalies of 2025, how high-resolution data enhances PV project resilience, and the technological trends shaping the industry’s next decade.

Tell us about your current role and history of working in this industry.

Solargis is a solar radiation and meteorological data software provider supporting the industry of photovoltaic power plants, developers, operators, utilities and the financial sector. My co-founder, Tomas Cebecauer, and I started the company in 2010 with an ambition to provide the most accurate and reliable digital solutions across the full lifecycle of solar projects. Our headquarters are in Bratislava, Slovakia.

Solargis data has supported the development of more than 500 GW of PV assets worldwide. Today, we work with over 1,200 active customers across 90 countries. Our aim is to maintain and improve our position as the benchmark in satellite-based solar resource modelling, solar energy simulation, monitoring and forecasting tools, and interactive map products.

As to my personal experience in the industry, prior to founding Solargis I was a renewable resource researcher for the European Commission’s Joint Research Centre. A central theme throughout my career over the last 25 years has been contributing to the change of the global economic strategies towards sustainable energy generation and consumption, supporting mainly the solar energy sector.

Solargis data has supported the development of more than 500 GW of PV assets worldwide.

What were the most notable solar radiation anomalies observed globally in 2025, and why are they significant for the solar industry?

This year has been an interesting one for solar radiation patterns across regions through the seasons. In Western Europe, 2025 brought one of the sunniest springs on record, with solar radiation levels significantly exceeding long-term averages. Solargis data found that parts of Germany, Belgium & the UK recorded Global Horizontal Irradiation (GHI) of up to 50% above Long-Term Average, while most of North-Western Europe and Scotland saw increases of around 35%. However, this increase did not extend to Southern Europe. Countries such as Spain, Portugal, and Italy recorded solar radiation up to 25% below the long-term averages.

The June-July-August season of 2025 remained largely consistent with the long-term averages globally, but several regions witnessed significant anomalies. One of these was Europe, where June was the sunniest month for most parts of the continent, followed by an unusually weak July, suggesting strong month-to-month variability. Positive anomalies persisted along the English Channel and parts of Central and Eastern Europe, where GHI exceeded long-term averages by 14-20%. In contrast, the Baltic States (Estonia, Latvia & Lithuania) experienced one of their cloudiest summers in recent years.

In East Asia, particularly Japan, 2025 was record-breaking: GHI exceeded long-term averages by over 40%, especially in Honshu, Kyushu, and Shikoku. Meanwhile, parts of East China experienced high variability due to extreme weather, with monthly GHI fluctuating between extreme negative to positive variations. A notable exception was the Sichuan Basin, where solar radiation surpassed historical averages for the second consecutive year.

These anomalies underscore the relevance of equipping solar developers with the software and tools needed to monitor weather patterns to improve PV asset performance tasks.

2025 brought one of the sunniest springs on record in Western Europe.

How does Solargis’ technology help solar developers adapt to these fluctuations and improve the accuracy of yield assessments?

At Solargis, precision starts with data granularity. Unlike other data and software providers on the market, we use 15-minute time series data as our standard, with the capability to go as detailed as one-minute resolution when required. This temporal detail allows us to capture short-term fluctuations in solar radiation, the kind that can impact inverter behavior, performance of batteries, and ramp rates at the connection to the grid.

This gives developers and financiers a truly realistic picture of site conditions. The resulting alignment between technical design and financial performance is central to improving the industry’s long-term returns.

During development, these granular datasets are directly linked to the specific PV system design within our energy simulation environment. This integration enables far more accurate PV performance predictions than traditional low-resolution empirical models. Developers can evaluate how their planned configuration responds to real-world variability – not averages, but dynamic data based on the physics of the atmosphere and the solar energy conversion steps.

In January 2025, Solargis launched Evaluate 2.0, a cloud-based platform which integrates satellite-model data with PV design, simulation and setup of the PV plant. Our customers now have real-time data and the software that can interpret them and make the most out of them under one roof. A hybrid approach like this allows for better monitoring of solar assets, enhances the reliability of PV performance predictions, minimizes uncertainty and aligns technical and financial expectations.

Precision starts with data granularity.

Could you share examples where Solargis data has directly supported project resilience or performance in the face of extreme weather variability?

Solargis has been a trusted partner to various leading global solar players – including Iberdrola Group, Apex Clean, candi solar and Shift Energy Japan, etc.

For example, Iberdrola Group, one of the leading electricity providers globally, used Solargis Analyst – a data visualisation and error detection software – in the pre-construction planning of their project. It enabled Iberdrola’s team to store and analyse their project data in Solargis’ central databases, helping them make more informed investment decisions. Solargis Analyst also offered them a user-friendly technical analysis function that could validate data globally across various sources.

Solargis also partnered with leading North American battery energy storage (BESS) solutions provider Convergent Energy for their solar + BESS projects. Hybrid solar projects need to go through rigorous, multi-fold technical and financial analysis before they are developed, to give investors an overview of energy yield estimates. Solargis supported Convergent’s project site in Puerto Rico by generating high-resolution satellite data and creating bankable reports with reliable, site-specific assessments.

Solargis supported Convergent’s Puerto Rico hybrid project with high-resolution, bankable assessments.

How does Solargis collaborate with partners, policymakers, or developers to strengthen the industry’s ability to manage climate-related risks?

As the global solar market scales, project evaluation is becoming more complex and data-driven. Solargis collaborates closely with developers, investors, and policymakers to ensure that every stage of the project lifecycle is supported by reliable, transparent, and scientifically validated data. We are also the first in the industry to use 15-minute time-series data as a standard for PV simulation, offering higher temporal precision for yield analysis and risk assessment.

Another essential element of our collaboration model is site adaptation of the model time series data: the process of calibrating our satellite-based solar models to match client-specific ground measurements. This alignment reduces long-term bias, improves local accuracy, and delivers gapless, long-term time series essential for due diligence and operational benchmarking.

To help stakeholders assess environmental and climate-related risks, we also offer multiple map layers in Solargis Prospect, which visualize regional variability, long-term trends, and exposure to climate extremes. These data insights allow developers to evaluate not just solar potential, but also the broader climatic resilience of their assets.

Site adaptation reduces long-term bias and improves local accuracy.

Looking ahead, what trends in solar resource data and technology do you believe will most shape the industry’s growth over the next decade?

We are witnessing an increasing number of solar operators invest in high-resolution, AI-enabled modelling tools to meet the evolving demands of the industry. But it is crucial to emphasize that scientific integrity must remain at the core of how these technologies are applied. AI is an excellent helper for pattern recognition and automation, yet it must be guided by proven scientific principles, validated models, and transparent physics-based frameworks, otherwise it risks becoming a “black box.”

Looking ahead, the demand for higher precision in both simulation and operational forecasting will only increase. Policymakers are introducing stricter compliance frameworks around grid balancing, forecasting accuracy, and renewable integration. We expect products like Evaluate 2.0 to mark the beginning of a new era of precision and bankability for solar industry professionals.

AI must be guided by proven scientific principles, not black-box models.