Last reviewed · 8 May 2026 · Independent UK SRS Reference
Last reviewed · 8 May 2026 · Independent UK SRS Reference
ESOS Phase 4: Deadline 5 December 2027

UK ESOS Compliance Guide

Comprehensive Energy Savings Opportunity Scheme guidance for UK large enterprises. Navigate ESOS requirements alongside UK SRS compliance.

What is ESOS?

The Energy Savings Opportunity Scheme (ESOS) is a mandatory energy assessment scheme for UK organisations that meet the qualification criteria. ESOS applies to large enterprises and requires them to undertake comprehensive assessments of energy used by their buildings, industrial processes and transport.

ESOS Qualification Criteria

Your organisation qualifies for ESOS if it meets any of the following criteria:

  • Large company: Employs 250 or more people
  • High turnover: Annual turnover exceeding €50 million and balance sheet total exceeding €43 million
  • Group structure: Part of a large group that meets the above criteria

Qualification Assessment

Qualification is determined on the 'qualification date' - 31 December in the year before each compliance period begins. For ESOS Phase 4, this was 31 December 2022.

ESOS Phase 4 Timeline

Key Dates

  • Compliance Period: 1 January 2024 - 5 December 2027
  • Qualification Date: 31 December 2022
  • Notification Deadline: 5 June 2024 (completed)
  • Compliance Deadline: 5 December 2027

ESOS Compliance Requirements

1. Energy Audits

  • Cover at least 90% of total energy consumption
  • Conducted by approved energy auditors
  • Include buildings, industrial processes, and transport
  • Identify energy efficiency opportunities

2. Alternative Compliance Routes

  • ISO 50001: Energy management system certification
  • Green Deal Assessments: For buildings only
  • Display Energy Certificates: For public buildings

3. Board-Level Responsibility

  • Senior management oversight required
  • Board-level sign-off on compliance
  • Designated senior person responsible for ESOS

ESOS Implementation Steps

Step 1: Determine Qualification (Completed)

Assess whether your organisation qualified as of 31 December 2022.

Step 2: Notify the Environment Agency (Completed)

Notification deadline was 5 June 2024.

Step 3: Measure Total Energy Consumption

Calculate your organisation's total energy use across all areas including:

  • Buildings (electricity, gas, other fuels)
  • Industrial processes
  • Transport (company vehicles, business travel)

Step 4: Identify Areas for Energy Audits

Select areas that represent at least 90% of total energy consumption for detailed auditing.

Step 5: Conduct Energy Audits

Engage approved energy auditors to conduct assessments and identify energy saving opportunities.

Step 6: Consider Energy Efficiency Recommendations

Review audit findings and consider implementation of energy efficiency measures.

Step 7: Submit Compliance Notification

Submit compliance notification to Environment Agency by 5 December 2027.

Integration with UK SRS

ESOS compliance can support your UK SRS preparations, particularly for:

  • Energy efficiency data: ESOS audits provide baseline energy consumption data
  • Scope 1 & 2 emissions: Energy audits help quantify direct and indirect emissions
  • Improvement opportunities: Energy efficiency measures support climate transition planning
  • Governance structures: Board-level oversight aligns with climate governance requirements

Getting Started

Begin your ESOS Phase 4 compliance preparation by assessing your current energy consumption and identifying approved energy auditors for your sector.

UK SRS Integration GuideAll Compliance Deadlines