Porto: Dataset Overview

This page documents the dataset used in articles referencing Green Key Certified Hotels in Porto.
It provides the source, scope, boundary definitions, and interpretation context for city-level certification figures cited in published research.

This dataset supports verification and comparability, not hotel ranking or selection.

Data Source

Green Key International — Certification Registry
Administered by the Foundation for Environmental Education (FEE)

The Green Key registry records hotel-level certification status and validity but does not include performance metrics such as emissions, energy consumption, or operational outcomes.

City Definition

For the purposes of this dataset, Porto refers to Porto city proper, as defined by the municipal boundary.

The following are explicitly excluded from this dataset:

  • properties located in other Portuguese localities containing “Porto” in the city name (e.g. Porto Santo, Porto Moniz)

  • hotels in the wider Porto metropolitan area outside the municipality

  • regional or island accommodations listed under non-urban jurisdictions

This distinction is essential to prevent string-based overcounting and is applied consistently across all comparative analysis.

Certification Count (December 2025)

  • Green Key certified hotels: 23

  • Distinct properties: 23

  • Certification validity: All listings valid into 2026 or later

No weighting is applied by hotel size, room count, or brand portfolio.

Population Baseline

  • Porto municipality population: 231,962
    (2021 national census, most recent stable municipal baseline)

Per-capita normalization is used to contextualize scale rather than to rank cities.

Interpretation Notes

Green Key certification is interpreted in this research as a baseline sustainability signal, indicating that a hotel meets the programme’s environmental management criteria at the time of certification.

Certification presence:

  • ✔ indicates participation in a recognized sustainability framework

  • ✖ does not indicate absolute environmental performance

  • ✖ does not measure carbon footprint, transport emissions, or supply-chain impacts

The absence of certification is not assumed to indicate weak sustainability practices, particularly in cities where compact urban form or regulation may reduce environmental impact independently of voluntary labels.

Methodological Context

City-level certification figures for Porto are interpreted using:

  • municipal boundaries

  • per-capita normalization

  • urban compactness and transport accessibility

Full assumptions, boundary definitions, and limitations are documented in:

  • Methodology & Assumptions

  • Research Desk

This ensures Porto’s certification figures are evaluated relative to structural context, not in isolation.

Limitations

This dataset does not include:

  • hotel-level carbon or energy data

  • Scope 3 emissions

  • operational performance indicators

  • real-time certification updates

Figures represent a snapshot of registry data as of December 2025.

Independence & Use

Hotel inclusion does not imply endorsement, ranking, or commercial relationship.

This dataset is intended to:

  • support verification of published analysis

  • enable transparent comparison

  • provide methodological clarity

It is not intended for booking decisions or consumer recommendations.

Related Research

  • Green Key Certified Hotels in Porto: Adoption Without Saturation (2026 Guide)

  • 10 Hotels with Green Key Certification in Lisbon: What to Actually Expect (2026 Guide)

  • Green Key Certified Hotels in Madrid and Barcelona: Why Fewer Certifications Can Mean Deeper Scrutiny (2026 Guide)

← Back to Research Desk

Downloads

    • porto_green_key_city_2025.csv

    • porto_green_key_city_2025.xlsx

(Files reflect registry data only; no performance scoring applied.)

Related analysis

Green Key Certified Hotels in Porto: Adoption Without Saturation (2026 Guide)