Energy Savings Opportunity Scheme (ESOS)
From Phase 3 action plans and progress updates to Phase 4 compliance
*Phase 4 compliance deadline*
Getting started on your ESOS Phase 4 compliance
What is ESOS?
If your organisation qualifies for the Energy Savings Opportunity Scheme (ESOS), you must complete a mandatory assessment of your total energy consumption and identify cost-effective efficiency measures every four years.
ESOS Phase 4 is now underway. Early preparation is strongly recommended to reduce compliance risks and identify energy saving opportunities.
Why start Phase 4 now?
Beginning your compliance journey early helps you:
- Secure assessor and site visits – ESOS-lead assessors and site auditor availability become limited as deadlines approach.
- Improve data completeness – gathering full-year datasets is easier when processes are in place early.
- Gain board-level buy-in – your ESOS submission will require board level sign-off, engaging early will avoid delays and get initiatives for implementation on the board room agenda.
Mandatory net-zero reporting delayed
Planned changes to introduce mandatory net-zero alignment for ESOS have been postponed until Phase 5.
However, organisations wishing to demonstrate leadership can adopt the new PAS 51215 standards, published by the British Standards Institution (BSI), for energy and decarbonisation assessments voluntarily.
ESOS action plan and progress updates
Regulators recognised that many organisations weren’t implementing identified measures. As a result, ESOS action plans and progress updates were introduced during Phase 3, shifting the focus from recommendations to measurable accountability.
One final Phase 3 progress update is still required by 5th December 2026, ahead of the Phase 4 compliance deadline. Under Phase 4, it is intended that participants will need to report on progress against their Phase 3 action plan within their assessment and explain any unmet commitments.
Acting on your ESOS recommendations will deliver cost, carbon and consumption savings; in turn, strengthening your energy and carbon disclosures. Savvy energy managers will use this compliance exercise as a strategic opportunity to drive their net-zero roadmap.
Risk of non-compliance
The Environment Agency (EA), appointed scheme administrator, oversees enforcement actions, including auditing submissions and issuing compliance notifications.
Failure to notify, maintain adequate records or submit false claims can result in severe penalties. Moreover, if selected for an audit, failing to provide remedial documentation could trigger penalties.
Recently introduced annual notification requirements have quadrupled non-compliance risks.
Civil penalties result in the public listing of a company’s identity, compliance violation and penalty value on the gov.uk website for 12+ months.
As of February 2026, the EA issued ~£780k civil penalties for failure to undertake an audit for Phase 3 participants.
Is your organisation captured by the scheme?
The Energy Savings Opportunity Scheme (ESOS) is a mandatory energy compliance scheme for large enterprises in the UK. Almost 12,000 organisations are captured by the scheme.
Eligible organisations need to review their total energy consumption, including buildings, industrial processes and transport – undertaking surveys to identify energy saving opportunitiess.
Guaranteed compliance
100% of our audits have been passed by the Environment Agency. In fact, our ESOS lead assessors have been highly commended by auditors for their diligent submissions.
Access to lead assessors
You’ll be assigned an ESOS lead assessor to project manage your ESOS compliance journey. It is important to remember, the demand for lead assessors will significantly increase as each reporting deadline approaches.
Act on your insights
By acting on your surveys year on year you will turn your investment into real savings. We can provide a wide range of energy and water efficiency services to help you achieve this.
Gain maximum benefit
Our experts can further support you to maximise the full value of your ESOS compliance by aligning your disclosures with your wider energy and carbon reporting requirements.
Routes to compliance
For ESOS Phase 4, Display Energy Certificates (DECs) and Green Deal Assessments (GDAs) will no longer be accepted as valid compliance routes. Instead, organisations can choose:
- ISO50001 certification, and/or
- ESOS compliant energy audits covering 95% of total energy consumption.
Inspired can support either route to ensure full compliance.
Talk to an expert
Emma Hird
ESG Director
“By choosing Inspired to help you fulfil your ESOS compliance requirements, you’ll be in safe hands. We’ve completed nearly 1000 ESOS submissions and over 3,900 site audits on behalf of our clients.
At Inspired, we are unique in that we are technology agnostic with in-house capabilities to help you go beyond compliance and implement your energy initiatives, ensuring you create long-term energy cost and carbon savings.”
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By choosing Inspired to help you fulfil your ESOS compliance requirements, you’re in safe hands. Get started on your Phase 4 compliance.