Unit modeling
Securing grid connection: Why unit modeling and predictability matter
Market insights
May 20, 2025
5 min read
Meeting TSO requirements to obtain grid connection is not a voluntary option, but an indisputable prerequisite. Accuracy and predictability are the criteria that help ensure it. In this blog post, we examine unit modeling and why it is both essential and potentially a strategic advantage in the quest for grid connection.
Why unit modeling matters
As the pressure on the electrical grid increases, so does the need for predictability. Unit modeling involves creating detailed digital representations or simulations of energy facilities down to each specific unit. This includes (hybrid) power plants, storage systems such as BESS, or large-scale consumption facilities such as boilers or data centers. The models simulate how each unit of a facility or plant behaves under various operational scenarios, including normal operations, grid disturbances, and peak demand periods. They must demonstrate stability, controllability, and predictability – key factors in maintaining the overall balance of the grid. Without a compliant and validated unit model, projects risk delays or rejection from TSOs, no matter how advanced the technology behind them. To make matters worse, these risks often emerge just before launch, the time your project should start to generate revenue.
Do you know the requirements affecting your project?
To help ensure grid stability, countries worldwide are introducing various regulatory requirements. Denmark, for example, is introducing updated technical regulations that impose stricter requirements on energy storage and consumption facilities. The Danish TSO, Energinet, mandates that energy storage facilities, whether connected independently or alongside other electrical installations, must meet specific criteria regarding their interaction with the electricity supply system. These regulations demand thorough simulation models to demonstrate compliance, making unit modeling an indispensable tool for facility operators. No models, no TSO approval.
In the United States, Regional Transmission Operators (RTOs) like the California CAISO or the Texas ERCOT require simulation models as part of interconnection studies. These user-defined models are used not only to ensure technical compliance but also to predict grid congestion, manage curtailment, and schedule grid upgrades. As developers compete for limited grid capacity, the ability to present a ready-to-run, validated model can significantly reduce time-to-approval. Some regions even prioritize projects that provide validated models early, creating a competitive advantage for teams who invest in unit modeling up front.
In Spain, unit modeling has been a standard to achieve grid access for years. The Spanish TSO, Red Eléctrica de España (REE), mandates detailed dynamic simulations for grid integration of new generation and consumption assets. Developers must provide validated PSS/E models that demonstrate how the facility will respond to faults and voltage disturbances.
Also, solar PV plants and hybrid assets in Spain cannot obtain operational permits without fully validated models, a clear signal that digital readiness is just as important as physical infrastructure.
Finally, the United Kingdom has embraced unit modeling as a core part of its Grid Code compliance process. National Grid ESO (National Energy Systems Operator) requires that all large power plants and some demand-side units submit detailed RMS or EMT simulation models as part of the connection and compliance process.
In recent years, the UK has expanded these requirements to include energy storage systems and flexible demand units. Projects that lack accurate modeling often face extended testing periods and delayed integration. On the other hand, those using validated models have a smoother path to both compliance and operation.
Reduce time-to-market – unit modeling as a strategic asset
When it comes to designing unit models, many big OEMs have dedicated in-house teams to manage this task. But for small and mid-sized OEMs, such capabilities are far less common.
And while OEMs understand that IPPs need the models to fulfill TSO requirements, limited budget and long development timelines often prevent them from building this expertise internally. This creates a disconnect as OEMs deliver a physical product without the digital tools needed to obtain grid connection. The result? Stalling of projects and dissatisfied customers.
Unit modeling should not be viewed as ‘just’ a compliance task, but rather as a strategic asset. OEMs that treat it as such can differentiate themselves by offering a fully grid-ready package, enabling faster approvals and smoother integration. Hence, unit modeling becomes a key driver for customer satisfaction and reduced time-to-market.
