ACER introduces a framework for monitoring smart grid performance in electricity transmission

Today, ACER publishes a position paper introducing output performance indicators to measure the performance of grid-enhancing technologies in electricity transmission.

Europe’s energy transition is driving rapid growth in electricity demand and renewable generation, putting increasing pressure on transmission networks. While grid expansion remains key, making better use of existing infrastructure through innovative operational practices, digitalisation and grid-enhancing technologies is equally important, as smart solutions of transmission system operators (TSOs) can often deliver additional capacity faster and at a lower cost.

Why are transmission output performance indicators needed?

EU legislation already requires national regulators to monitor the development of smart electricity grids. To ensure smart grid solutions deliver benefits, regulators need ways to assess their real-world performance. 

The June 2025 Copenhagen Infrastructure Forum invited ACER, together with the European Network of Transmission System Operators for Electricity (ENTSO-E) and other stakeholders, to develop a common approach for assessing the performance of smart-grid solutions at transmission level.

In parallel, the Council of European Energy Regulators (CEER) publishes today its report on indicators to measure performance at distribution level.

Assessing transmission smart grid performance

Transmission smart grid infrastructure can be assessed using two types of indicators:

• input, which describe what has been implemented; and
• output, which monitor what has been achieved.

ACER found that few EU countries currently systematically measure how grid-enhancing technologies perform in practice, making it difficult to assess their effectiveness. This ACER paper addresses this gap. It builds a foundation for more consistent and comparable assessments of TSO performance across Europe.

What does ACER recommend?

ACER proposes three output indicators for regulators to assess whether grid-enhancing technologies in transmission grids deliver improvements and cost benefits:

• performance of existing transmission assets in real-time system operations,
• performance of operational security; and
• grid expansion performance.

These performance indicators address grid capacity gains, operational-security cost reductions and cost-efficient alternatives to conventional grid expansion. By capturing their actual performance, these output indicators help ensure that innovative approaches truly unlock grid capacity and reduce system costs. 

Beyond the three proposed output indicators, the paper also highlights complementary areas of monitoring that can enhance regulatory insight.

• ACER recommendation for national regulators: Incorporate the proposed indicators as a common framework for monitoring smart-grid performance at transmission level, allowing a two- to three-year transition period for data collection, process setup and methodological refinement.
• ACER recommendation for transmission system operators: Develop complementary input indicators reflecting the availability of tools that influence the proposed output indicators, with ENTSO-E providing guidance and reference mappings to ensure consistency across the EU.

What are the next steps?

Implementation should follow a phased, learning-oriented approach, starting with national testing of the indicators. A two- to three-year transition period will allow regulators to adjust them where needed as they are further developed and implemented.

Over time, the accumulated data and shared experience can support more systematic assessment of grid performance and innovation across Europe.