ESOS Compliance

With the second Phase 3 annual progress update due by 5 December 2026 and the Phase 4 compliance deadline on 5 December 2027, now is the right time to confirm your position, organise the required evidence and plan the work ahead.

Our ESOS support is flexible. We can fill a specific gap in your internal capability, or provide a fully outsourced service from initial scoping through to assessment, director approval and notification.

ESOS Phase 3 progress update support

If your organisation qualified for Phase 3, it was required to submit an action plan and report progress against its commitments in the following two years. The first annual progress update deadline was 5 December 2025. The second is due on 5 December 2026, and must be signed off by a board-level director or equivalent and submitted through the Manage your ESOS reporting service.

We can review the commitments in your action plan, confirm which measures were implemented, calculate or estimate the resulting savings in kWh, explain changes to planned measures, assemble a clear audit trail, prepare the information for director review and support submission.

ESOS Phase 4 compliance support

Phase 4 covers the compliance period ending on 5 December 2027. Organisations meeting the large undertaking criteria on the qualification date of 31 December 2026 will need to complete the relevant assessment and notification requirements by that deadline.

Starting early gives you more time to gather reliable energy data, coordinate sites and group companies, secure a registered Lead Assessor, and turn audit findings into useful cost and carbon reductions.

The Energy Savings Opportunity Scheme (Amendment) Regulations 2026 introduced additional Phase 4 requirements. These include stronger reporting of energy savings achieved since the previous compliance deadline, a review of measures from the previous action plan, and a further annual progress update. Display Energy Certificates and Green Deal Assessments have also been removed as alternative compliance routes.

The government published its updated Phase 4 guidance on 30 July 2026, so the requirements are now settled. We work to the current legislation and guidance throughout.

Registered Lead Assessor review and sign-off

If your team is completing the assessment internally, our registered ESOS Lead Assessors can provide independent review, guidance and formal sign-off.

We can become involved early to confirm that your proposed scope, energy data and audit approach are suitable. That reduces the risk of discovering gaps shortly before the compliance deadline, which is the point at which they become expensive.

Independent ESOS advice

Some organisations need strategic advice before committing to a compliance route. We can review your current arrangements and recommend a practical way forward based on your estate, operations, internal resources and existing management systems.

That covers whether to manage the assessment internally or outsource it, where specialist energy audits are required, how to coordinate compliance across a corporate group, how to strengthen energy data collection before Phase 4, how to connect ESOS recommendations to operational and carbon reduction plans, and whether ISO 50001 would provide wider long term value.

Following the review you receive a clear scope of work and a fixed price proposal for any further support.

ISO 50001 as an ESOS compliance route

A certified ISO 50001 energy management system can provide a route to deemed compliance with certain ESOS assessment requirements.

Under the regulations now in force for Phase 4, an organisation can be deemed to have complied with the duties to appoint a Lead Assessor, conduct an ESOS audit and produce an ESOS report where its total energy consumption, or the significant energy consumption representing at least 95% of the total, is covered by the certified system.

This is wider than it was. In Phase 3 the exemption applied only where certification covered the whole of total energy consumption. Extending it to significant energy consumption lowers the bar considerably, and it is worth revisiting if you looked at ISO 50001 before and decided the scope was impractical.

Where ISO 50001 covers only part of the organisation's energy consumption, the remainder may still need to be addressed through the ESOS assessment process. We can assess whether ISO 50001 is a proportionate option and, where it is, help you design and implement the system.