Net Zero Compare
PAS 51215-1:2025

PAS 51215-1:2025: Energy and decarbonization assessment process specification

Onye Dike
Written by Onye Dike
Updated on February 14th, 2026

Summary

PAS 51215-1:2025 is a UK Publicly Available Specification (PAS) that sets out a single, combined process for assessing an organisation’s energy use and related greenhouse gas (GHG) emissions, identifying improvement opportunities, and producing an implementation plan for achieving net zero within the assessment boundary. It was developed with UK government sponsorship to support the evolution of the Energy Savings Opportunity Scheme (ESOS) and can be used voluntarily in ESOS Phase 4.

Details

Jurisdictions
  • The United Kingdom
  • Global
Voluntary for

PAS 51215-1:2025 may be used on a voluntary basis for UK Energy Savings Opportunity Scheme (ESOS) compliance.

Deep dive

3 min read
Updated Feb 14, 2026

📩 Stay ahead of climate regulation and reporting shifts

Regulatory updates, reporting standards, and new climate software — distilled into one concise weekly brief for decision-makers.

Thanks for signing up. Please check your inbox to confirm your subscription.

Practical updates. Once per week.


Background

PAS 51215-1 sits in a two-part series sponsored by the UK Department for Energy Security and Net Zero (DESNZ). It was created to fill a gap: while standards exist for GHG measurement and for energy audits, there was no national standard for a combined assessment that evaluates decarbonization options and their costs/benefits in a structured way. The PAS is designed to be iterative and to work alongside common compliance routes, including organisations using ISO 50001, or audit standards like ISO 50002 / BS EN 16247, by describing additional activities needed for the combined assessment approach.

Reporting Requirements

PAS 51215-1 is explicitly a process + output specification: it requires a documented assessment process that results in a clear set of findings, recommendations, and a net zero implementation plan within an agreed boundary. It defines a minimum “core” boundary aligned to ESOS-type energy coverage, while allowing organisations to expand scope if desired. Reporting expectations include:

  • Define and document the assessment boundary/scope around energy use and related GHG emissions (minimum coverage includes energy-related Scope 1 and 2, plus business travel Scope 3, with optional additional Scope 1–3 by agreement).

  • Produce an assessment report that communicates findings and recommendations (the PAS includes an example report structure and specific steps for reporting and distribution).

  • Quantify and prioritise improvement opportunities (energy performance + GHG reduction) and translate them into an implementation plan aimed at net zero within the assessment boundary.

  • Be clear about what PAS 51215-1 does not claim: it does not cover implementation, organisational environmental disclosures, verification of net zero/carbon neutrality claims, or the use of offsets for residual emissions.

PAS 51215-1 focuses on the assessment process and outputs, not on verifying outcomes or “net zero achieved” claims. Competence is handled via PAS 51215-2:2025 (the companion competency specification), which can be used voluntarily to judge whether an assessor/team is suitable to conduct an assessment to PAS 51215-1.

Current status and outlook

BSI published PAS 51215-1 and PAS 51215-2 in February 2025, and UK ESOS guidance notes they can be used voluntarily in ESOS Phase 4, signalling an expectation that combined energy and decarbonization assessments will become more common (and potentially more formalised) in future ESOS phases.

Resources


Onye Dike
Added by:
Onye Dike
Sustainability Research Analyst
Onye Dike is a Sustainability Research Analyst at Net Zero Compare, where he contributes to research and analysis on environmental regulations, carbon accounting, and emerging sustainability trends.
Our principle

Cut through the green tape

We don't push agendas. At Net Zero Compare, we cut through the hype and fear to deliver the straightforward facts you need for making informed decisions on green products and services. Whether motivated by compliance, customer demands, or a real passion for the environment, you’re welcome here. We provide reliable information. Why you seek it is not our concern.

Added on Jan 16, 2026 by Onye Dike · Updated on Feb 14, 2026