ProRail, the Dutch rail infrastructure manager, has used the CO₂ Performance Ladder as an award criterion in its tenders for years to drive sustainability performance across the supply chain. With the arrival of Version 4.0, ProRail is now announcing its next move.

From 1 January 2027, ProRail will request Version 4.0 in all new tenders published on TenderNed – the Dutch public procurement platform – using the CO₂ Performance Ladder as an award criterion. This updated version of the Ladder helps organisations achieve ambitious climate targets and accelerate the energy transition.

Proposed weighting

For now, ProRail will apply the following weighting in its tenders:

(note: a different weighting may apply to one-off tenders)

No certificate required when tendering

As is currently the case, tenderers do not need to submit a valid certificate at the point of tendering. They must, however, state the ambition level they are aiming for. Proof of the offered ambition level then follows within an agreed period during performance of the contract.

Transitional arrangement remains in force

For tenders that start before 1 January 2027 and apply the CO₂ Performance Ladder as an award criterion, the current transitional arrangement remains in force.

This means Version 3.1 of the CO₂ Performance Ladder is requested, while certificates based on Version 4.0 are also accepted as proof. Step 1 of Version 4.0 is considered equivalent to Levels 1, 2 and 3 of Version 3.1. Steps 2 and 3 of Version 4.0 are considered equivalent to Levels 4 and 5 of Version 3.1.

Existing contracts

Audits for Version 3.1 can still be carried out until 14 January 2027. The resulting certificates remain valid until the next annual audit and/or until the certificate’s validity period expires.

As a result, an organisation may hold only a Version 4.0 certificate during the term of a contract with ProRail. In line with SKAO’s advice, ProRail applies the same equivalence in such cases as under the transitional arrangement.

Webinar

To explain the changes, ProRail hosted an online webinar in June 2026. During the session, ProRail explained the announced changes and Version 4.0 and the developments behind it were presented. This is part of ProRail’s communication and outreach strategy to prepare suppliers for the new version of the Ladder.

More information

For more information (in Dutch), visit ProRail’s website.