Formulating a construction site carbon criterion in the tender
from pre-assessment to award decision
From 22 August 2026, every public procurement contract must include at least one environmental award criterion (Article 35 Climate Act). Construction site carbon measured by Efficarbone is an objective, quantifiable criterion defensible in pre-contractual proceedings.
Why include construction site carbon in the tender
Article 35 of the Climate and Resilience Act requires, from 22 August 2026, that every public procurement contract includes at least one environmental criterion among the award criteria. Construction site carbon (items A4-A9) is a natural candidate for this criterion:
- Objective The construction site carbon assessment is a measurable figure, not a qualitative statement. It can be compared across bids without subjectivity.
- Quantifiable Expressed in kg CO2e/m2 GFA, it enables a linear or threshold-based scoring scale.
- Defensible Based on traceable ADEME factors, it withstands a pre-contractual legal challenge — unlike a vague "environmental approach" criterion.
The public procurement 2026 page details the full legal framework. This page focuses on the operational method: how the project owner uses Efficarbone to formulate, calibrate and evaluate this criterion.
4-step method
Reference pre-assessment
The project owner carries out an Efficarbone pre-assessment based on the programme and detailed design assumptions. This pre-assessment estimates the reference construction site carbon — the expected level "if nothing particular is done".
Data required: GFA, location, number of storeys, foundation type, estimated cut/fill volumes, planned construction duration.
Criterion calibration
Based on the pre-assessment, the project owner defines the scoring mechanism:
| Mechanism | Principle | When to choose |
|---|---|---|
| Elimination threshold | Above the threshold, bid is non-compliant | When the project owner wants a guaranteed minimum |
| Linear scale | Score proportional between a min and a max | When the project owner wants to encourage performance |
| Tiered scale | Scoring bands (e.g. A/B/C/D) | When the project owner wants to simplify comparison |
The Efficarbone pre-assessment provides the reference value used as the basis for calibration: the "zero effort" value to set the floor, and the "optimised site" estimate to set the target.
Drafting the tender criterion
The project owner drafts the criterion in the consultation rules. Elements to specify:
- — Indicator: construction site carbon in kg CO2e/m2 GFA (items A4-A9 EN 15978)
- — Weighting in the overall score (typically 5 to 15%)
- — Selected scoring mechanism (threshold, linear scale, or tiered)
- — Expected response format from candidates: recognised construction site carbon tool or traced free format
- — Documents to provide: detailed site assessment by item, factors used, assumptions
Bid analysis and benchmarking
Tendering contractors submit their construction site carbon assessments in the format specified in the tender. The project owner uses Efficarbone to:
- — Verify the consistency of received assessments against the reference pre-assessment
- — Compare bids on a consistent basis (same scope, same items)
- — Document the scoring and award decision
- — Produce a defensible report in the event of a legal challenge
Weighting: how much does construction site carbon count?
The weighting of the construction site carbon criterion in the overall score is the project owner's choice. Case law and DAJ recommendations suggest staying within a realistic range:
| Weighting | Signal sent | Risk |
|---|---|---|
| 5% | Minimum compliance criterion — the project owner demonstrates environmental integration | Little differentiation between bids |
| 10% | Meaningful criterion — encourages contractors to optimise their site logistics | Recommended balance for a first carbon tender |
| 15% | Strong criterion — construction site carbon is a strategic priority for the project owner | Must be justified by a robust pre-assessment |
The Efficarbone pre-assessment justifies the chosen weighting: if the pre-assessment shows that construction site carbon represents 8% of the project's total carbon assessment, a 10% criterion weighting is proportionate and defensible.
Legal certainty: pre-contractual proceedings
A poorly formulated environmental criterion can be challenged in pre-contractual proceedings. The main grounds for annulment:
Weak criterion
- — "Environmental approach" with no measurable indicator
- — No explicit scoring method
- — Disproportionate weighting without technical justification
- — Unsourced emission factors
Robust criterion (Efficarbone)
- — Quantitative indicator: kg CO2e/m2 GFA
- — Documented pre-assessment justifying the calibration
- — Explicit scoring scale in the consultation rules
- — ADEME Base Empreinte factors with traceability
The combination of pre-assessment + calibrated criterion + traced factors produces a file that the administrative judge can verify point by point. This is the difference between a "decorative" criterion and an enforceable one.
Frequently asked questions
The tender can include a clause requiring the successful contractor to collect Efficarbone data (delivery notes, energy consumption, waste tracking). The technical specifications detail the expected deliverables and reporting frequency. Template clauses are available from IRICE.
Experience shows that data collection integrates into existing processes (delivery notes, waste tracking slips). The contractual clause in the tender removes ambiguity. Companies familiar with environmental requirements (ISO 14001, HQE Execution) adapt quickly.
Yes. The French Public Procurement Code allows the integration of environmental criteria in construction contracts. Construction site carbon measurement via Efficarbone can be included in the award criteria or the contract performance conditions.
Formulate your construction site carbon criterion
Reference pre-assessment, scoring scale calibration, defensible documentation. Efficarbone structures the project owner's tender criterion.