Understanding ESOS
The Energy Savings Opportunity Scheme (ESOS) is a mandatory UK energy assessment and energy-saving scheme designed to help large organisations identify cost-effective opportunities to reduce energy consumption and improve efficiency.
Introduced by the UK Government in 2014, ESOS supports the transition to Net Zero by requiring qualifying organisations to measure their energy use and identify practical actions to reduce energy demand and carbon emissions.
Organisations that qualify for ESOS must carry out a comprehensive energy assessment and produce an ESOS audit once every four years.
Watch our Video: What is ESOS?
Our short video provides a clear introduction to the Energy Savings Opportunity Scheme and its role in helping organisations understand how energy is used across buildings, transport and processes. It explains why structured energy assessments are required, what organisations can expect from an ESOS review, and how the findings can support more informed decisions around efficiency, cost reduction and long‑term compliance planning.
Why ESOS Matters: Compliance, Risk & Business Benefits
ESOS is a legal requirement for qualifying UK organisations and is enforced by the Environment Agency. Failure to comply can result in financial penalties and reputational risk.
Beyond compliance, ESOS provides valuable insight into how energy is used across your business. Many organisations use ESOS to identify cost-saving opportunities, improve operational efficiency, and strengthen sustainability and Net Zero strategies.
Organisations preparing for Phase 4 should be aware of common ESOS delivery issues that typically cause delays or rework.
ESOS Compliance Phases: Current Status & What’s Next
- ESOS operates in four-year compliance phases.
- Phase 4 is the current compliance phase, with audits required to be completed and reported to the Environment Agency by 5 December 2027.
- Phase 3 closed on 5 June 2024 and introduced changes to reporting requirements, including additional obligations for ISO 50001-certified organisations.
For a detailed breakdown of ESOS Phase 4 qualification deadlines and key compliance dates, see our ESOS Phase 4 guidance.
Who Needs to Comply with ESOS?
Companies need to comply if they are:
- Registered or based in the UK, or operating through a UK establishment
- Employ 250 people or more or
- Have an annual turnover greater than £44m, and an annual balance sheet greater than £38m.
SMEs and public-sector bodies are generally exempt from the ESOS scheme.
| Qualification Date | 4 Year Compliance Phase | Compliance Date | |
| Phase 1 | 31 Dec 2014 | 6 Dec 2011 – 5 Dec 2015 | 5 Dec 2015 |
| Phase 2 | 31 Dec 2018 | 6 Dec 2015 – 5 Dec 2019 | 5 Dec 2019 |
| Phase 3 | 31 Dec 2022 | 6 Dec 2019 – 5 June 2024 | 5 June 2024 |
| Phase 4 | 31 Dec 2026 | 6 Dec 2023 – 5 Dec 2027 | 5 Dec 2027 |
ESOS Services
ESOS Support & Resources
Find out if you Qualify for ESOS Phase 4
It sounds like you qualify for ESOS Phase 4.
TEAM Energy can help with your compliance and help you to save energy and money.
Contact TEAM Energy:
Call us on 01908 690 018
Email us at [email protected]
It seems as though you do not qualify for ESOS Phase 4, but you may still qualify as a result of other factors. Contact TEAM Energy to discuss how we can help you on your energy reduction journey.
Contact TEAM Energy:
Call us on 01908 690 018
Email us at [email protected]
Six Business Benefits of Complying with ESOS
ESOS Assessment Explained
An ESOS assessment is a structured review of how energy is used across an organisation, designed to meet scheme requirements and provide a clear, auditable view of energy consumption.
Rather than focusing on implementation, the assessment examines energy use across buildings, transport and industrial activities to identify where energy is consumed and where efficiency improvements may be possible. The assessment must follow recognised ESOS principles and be reviewed by a qualified ESOS Lead Assessor.
A robust ESOS assessment helps organisations:
- Understand their overall energy profile
- Demonstrate compliance with ESOS requirements
- Produce defensible outputs supported by an evidence pack
- Reduce the risk of non-compliance at notification stage.
ESOS Review & Quality Assurance
An ESOS review provides assurance that assessment outputs are complete, accurate and aligned with scheme requirements prior to notification.
Following the assessment, a structured review considers whether energy data, methodologies and conclusions are reasonable, consistent and appropriately evidenced. This helps ensure that documentation meets ESOS expectations and can be clearly demonstrated if requested by the Environment Agency.
Quality assurance activities typically focus on:
- Completeness and accuracy of assessment outputs
- Alignment with ESOS guidance and audit principles
- Evidence pack structure and supporting documentation
- Lead Assessor oversight and appropriate governance.
Our robust review process helps organisations identify and address any gaps early, supporting compliance and reducing the risk of issues at notification or enforcement stage.
ESOS Energy Action Plan Submissions
Organisations will be expected to submit Energy Action Plans to provide annual progress updates to track whether they have achieved the energy saving actions in their plan. Find out more about ESOS Action Plan reporting.
Below, we have included the submission dates for the ESOS Phase 3 and Phase 4 Action Plan:
| Submission Phase | ESOS Phase Compliance and Action Plan Results | New Action Plan | Action Plan Annual Progress Update | Action Plan Annual Progress Update |
|---|---|---|---|---|
|
Phase 3 Action Plan |
N/A |
*5 December 2024 |
5 December 2025 |
5 December 2026 |
|
Phase 4 Action Plan |
5 December 2027 |
5 December 2028 |
5 December 2029 |
5 December 2030 |
*The deadline for the first Energy Action Plan is the 5 December 2024, however the Environment Agency has announced an extension and will accept Action Plans submitted by the 5 March 2025.
ESOS Delivery
Key ESOS Questions
There has been some new requirements that have been introduced to ESOS Phase 3, to increase the carbon and cost savings made from the scheme.
In Phase 3 of your ESOS submission you will need to:
- Ensure at least 95% of your total energy consumption is covered, which has increased from 90% that was required in Phase 2
- Provide more detail on the calculation of your energy consumption
- Share details of your ESOS report with all members of your organisation
- Include specific information on how you plan to make energy saving opportunities throughout your business, this includes costs, benefits and how you plan to implement them
- Explain how the site visits that were carried out is a representation of your organisation’s energy use
- ESOS Phase 3 now requires all participants to produce an ESOS report, including those using alternative compliance routes such as the ISO 50001 energy management system
- Submit a yearly Energy Action Plan following your ESOS Phase 3 submission
- Submit a yearly Progress Update which will explore how successfully you are implementing your energy saving opportunities
- The Environment Agency will publicly disclose your ESOS data, by publishing the information in your compliance notification, as well as publishing your Action Plan and Progress Reports
The deadline for Phase 4 of the Energy Savings Opportunity Scheme is 5 December 2027, with a compliance period of 6 December 2023 – 5 December 2027. However, it is never too early to get started, site energy audits can start from January 2024. If you need support with any of the ESOS Compliance Phases, our ESOS consultants will help guarantee your compliance.
Our team of CIBSE Accredited Low Carbon Assessors, Low Carbon Consultants and ESOS Lead Assessors can help you make the most of the ESOS energy scheme. They gained valuable insights during ESOS Phase 1 and 2 in supporting clients through the Environment Agency audit, which will benefit businesses in the ESOS Phase 3 compliance process.
Our team of ESOS consultants can support you in the following ways:
- Help you fully understand the ESOS scheme and what it means for your business
- Collate data for your building, transport and process energy use
- Analyse your data and energy consumption
- Review your portfolio to determine the number of energy surveys required within the site sampling requirements
- Carry out the building(s) energy surveys
- Produce the ESOS survey reports including cost-effective energy efficiency recommendations
- Maximise the ESOS scheme benefits
- Conduct the ESOS review, verification and sign-off
- Prepare the ESOS submission document, evidence pack and sign-off
- Review your ESOS audit results
- Respond to any queries or support on audits conducted by the Environment Agency.
If a qualifying organisation doesn’t meet the deadline, they can expect to receive a fine. Fines start at £5,000 up to £50,000, plus a £500 daily penalty for continued non-compliance up to the value of £40,000.
TEAM’s ESOS Consultancy & Services
TEAM Energy provides expert ESOS consultation and supports organisations at every stage of ESOS compliance, from initial qualification through to audit delivery, reporting and ongoing action plan management. Our consultants combine regulatory expertise with practical energy insight to ensure compliance is met efficiently and confidently.
Our ESOS services include:
- ESOS qualification and compliance support
- ESOS consultation and advisory support
- ESOS energy audits and assessments
- ESOS Lead Assessor sign-off and reporting
- ESOS Energy Action Plan development and submissions
- Ongoing support across ESOS Phase 4 and future phases.
Download your Free Guide to ESOS Here or Contact us for More Information
Mandatory Reporting for ISO 50001 Users
One of the biggest changes to ESOS that came in Phase 3 affects organisations that are certified under ISO 50001. Previously, these organisations have been exempt from ESOS reporting.
These organisations will need to submit detailed reporting that includes data on energy savings achieved by the business since the previous compliance period.
Find out more about ISO 50001 Energy Management System.
Automating Reporting Processes
Generate SECR-compliant reports, investor-ready ESG disclosures, and custom dashboards in minutes. Automated reporting saves time, reduces risk, and ensures you meet deadlines with confidence.
Regular Updates of Emissions Factors
Our platform updates emissions factors regularly, ensuring your carbon footprint analysis reflects the latest data. This guarantees compliance and credibility in every report.
Security and Data Protection You Can Trust
TEAM Energy’s Carbon Management Software is built with enterprise-grade security at every layer. All data in transit is protected by end-to-end encryption (TLS 1.2/1.3), robust authentication, and regular penetration testing. Data is stored in secure AWS West Europe data centres, with strict access controls, continuous monitoring, and full audit trails ensuring your carbon reporting is confidential, resilient, and compliant with ISO 27001 and GDPR.
Why Choose TEAM Energy for Carbon Reporting?
- UK compliance expertise (SECR, Net Zero, GHG Protocol)
- Integration with existing systems
- Scalable for SMEs and large enterprises
- Backed by TEAM Energy’s sustainability consultancy services and our customer success professional services team.
Meet our ESOS Consultants
Our in-house, experienced, ESOS consultants will help you fully understand the ESOS scheme and what it means for your business. Each consultant has the breadth of skills, expertise and sector experience to help you make the most of the ESOS energy scheme.
BSc (hons), Approved EnCO Practitioner, ESOS Lead Assessor
What Our Customers Say
Speak to one of our ESOS Consultants
Call 01908 690018 and find out how our consultants can help you make the most of the ESOS energy scheme