CIRCE takes curtailment analysis global: from grid data to real impact on each asset

A wind farm connected to a node with 7% curtailment does not necessarily lose 7% of its output. In a case recently analysed by CIRCE, 7% nodal curtailment translated into an estimated impact of around 3% on the production of the wind farm studied.

With an investment at stake, that difference matters. Knowing a node’s curtailment is therefore not enough: it has to be translated into the specific behaviour of the asset and the MWh that could actually be affected.

Why doesn’t nodal data tell the whole story?

The impact of curtailment on a plant depends on several factors:

• Which grid elements become congested. Not all constraints affect all plants in the same way.
• When congestion occurs and how long it lasts. The same annual percentage can reflect very different constraint patterns.
• Which technologies are generating during those hours. Solar and wind profiles do not coincide, so neither does their exposure to the same constraint.
• The asset’s production profile. The energy affected is the energy the plant would have produced precisely during the hours when the constraint applies.

The aim is to move from the grid’s curtailment percentage to the specific impact on the asset, a fundamental distinction when assessing an investment.

Today’s grid is not the grid the project will operate in

A renewable plant may operate for decades. A snapshot of today’s power system therefore gives an incomplete view of the risk.

CIRCE works with power system modelling and scenarios for the evolution of generation, demand and the grid itself, assessing how results vary depending on which elements are congested and on potential infrastructure reinforcements.

The analysis makes it possible to assess how curtailment may evolve over the project’s lifetime, where bottlenecks may emerge, and how the risk would change if generation in an area increases or the infrastructure is reinforced. Curtailment thus stops being merely a historical figure and becomes a variable for assessing different future scenarios of the power system.

From Spain to the world

The key new development CIRCE will present at GENERA 2026 is the international reach of this capability. Until now, the methodology was applied to the Spanish power system. CIRCE can now analyse other power systems, incorporate their specific characteristics and estimate the effect of grid constraints on a specific asset under a given scenario.

This opens up the possibility of incorporating curtailment risk into the assessment of projects in different markets, from a perspective that is particularly relevant to developers, owners and investors: not how much curtailment exists in the abstract, but how it may affect a specific asset.

This capability will be the focus of the CIRCE Talk “Global curtailment forecasting”, taking place on Wednesday 25 November at 13:30. The session will explain how to take the analysis from the grid to the asset and feed its results into decision-making.

Beyond curtailment: a complete view of the renewable asset

In addition to curtailment, CIRCE will address other challenges at GENERA that shape the development, integration and performance of renewable assets.

• On grid integration and voltage control, the centre will explain how to anticipate the requirements of Operating Procedure 7.4 (P.O. 7.4), assess plant behaviour and prepare for the qualification process.
• The talk on operations will focus on performance: using real data to determine how much the plant should be producing, locate lost MWh and identify opportunities for improvement.
• Measurement quality will also be addressed as a key element in correctly assessing plant performance. Ensuring the traceability of pyranometer calibrations yields more reliable estimates of key indicators such as the Performance Ratio (PR). An additional bias of just 1% in irradiance measurement caused by poor sensor calibration translates into an uncertainty of around 1% in estimated energy, putting thousands of euros in guarantees and penalties at risk.

Flexibility and hybridisation will complete this picture, with solutions that combine generation, storage and flexible demand to make better use of assets and improve their interaction with the grid.

10 CIRCE Talks sessions to get more value from renewable assets

The programme will bring together eight technical talks across ten sessions of around 15 minutes each, with limited capacity. CIRCE’s specialists will address specific challenges in the development and operation of renewable assets.

Tuesday 24 November

• 10:30 | Is the plant performing as it should?
  From measurement to real-time assessment.
• 11:00 | P.O. 7.4: arriving prepared for voltage control
  How to anticipate technical limitations and avoid surprises during qualification.
• 13:00 | Where are the lost MWh hiding?
  Operational intelligence to turn data into decisions.
• 14:15 | Flexible demand and hybridisation
  Sponsored by the European project REEFLEX.
• 16:00 | Spain’s power system
  Beyond today’s grid: exploring the potential of planned grid developments.

Wednesday 25 November

• 10:30 | P.O. 7.4: arriving prepared for voltage control
  How to anticipate technical limitations and avoid surprises during qualification.
• 11:00 | Is the plant performing as it should?
  From measurement to real-time assessment.
• 12:00 | Connecting a plant with confidence
  End-to-end support for grid code compliance.
• 13:30 | Global curtailment forecasting
  How to take the analysis from the grid to the asset and factor curtailment risk into decision-making.
• 15:30 | Behind every PR there’s a pyranometer
  Because the reliability of the Performance Ratio depends on the quality of irradiance measurement.

👉 View the CIRCE Talks programme and book your place

From the grid to the asset decision

Curtailment, grid integration, voltage control, performance, measurement quality and hybridisation may seem like separate issues. In reality, they all shape the value that can be obtained from a renewable asset.

CIRCE’s approach is to connect them: anticipate what may happen, assess how it will affect the asset and turn that information into better-founded technical and economic decisions. The CIRCE Talks will bring this approach to specific issues, led by the centre’s specialists.

On 24 and 25 November, at stand 9C31, the sessions will show how to move from grid data to the asset decision.

CIRCE at GENERA 2026

📅 24, 25 and 26 November 📍 IFEMA Madrid | Hall 9 | Stand 9C31

🎟️ Register to attend GENERA 2026