ESOS Energy Savings Opportunity Scheme

The Energy Savings Opportunity Scheme (ESOS) is a compulsory UK energy assessment scheme designed to help large organisations identify practical, cost-effective measures to enhance energy efficiency and reduce carbon emissions.
Overseen by the Environment Agency, ESOS applies to large UK businesses that meet defined eligibility criteria. Every four years, organisations in scope must conduct thorough energy audits across their buildings, transport, and industrial operations. These audits provide insight into energy consumption patterns and highlight actionable steps to boost efficiency, minimise waste, and reduce costs — helping organisations meet regulatory obligations and demonstrate environmental responsibility.

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What is ESOS?

Developed by the UK Government to fulfil the requirements of the EU Energy Efficiency Directive, the Energy Savings Opportunity Scheme (ESOS) enables large organisations to monitor and manage their energy use across all operations.

In Phase 3, qualifying organisations were required to complete their assessments and submit compliance reports to the Environment Agency by 5 December 2023. Looking ahead, Phase 4, anticipated in 2027, will introduce additional measures, including mandatory net zero reporting, enhanced tracking of actions taken, and stricter requirements for implementing recommended energy-saving initiatives.

Kiwa supports organisations in adopting a strategic and forward-thinking approach to energy management and regulatory compliance. Certification to ISO 50001 (Energy Management Systems) offers a recognised and cost-effective pathway to fulfilling ESOS requirements, while also delivering broader business value.

Kiwa’s services include:

  • Accredited ISO 50001 certification for ESOS compliance
  • Comprehensive energy management training (from introductory to lead auditor level)
  • Carbon and greenhouse gas verification (ISO 14064-1)
  • PAS 2060 carbon neutrality guidance
  • Expert consultancy on integrating energy efficiency into wider sustainability initiatives

Aligning with ISO 50001 enables organisations to meet ESOS obligations and foster a culture of ongoing energy performance improvement.

 

Why Choose Kiwa?

As a UKAS-accredited certification body, Kiwa combines technical expertise with practical industry insight to support organisations across all sectors.

The approach is collaborative — working closely with clients to achieve meaningful and lasting outcomes. Compliance is prioritised, ensuring businesses meet all relevant national energy legislation. The certification process is constructive, focusing on identifying opportunities for ongoing improvement and cost savings.

Choosing Kiwa means partnering with a reliable expert dedicated to helping organisations operate responsibly, efficiently, and with a focus on sustainability.

ESOS Phases and Updates

By partnering with Kiwa, organisations can ensure they are fully prepared for these evolving ESOS requirements and positioned as leaders in sustainable energy management.

Phase 3 (2023)

Introduced mandatory reporting of energy intensity metrics, more detailed compliance templates and documentation, and a reduction in the de minimis exemption from 10% to 5%. There is also an increased focus on transparency regarding the actions taken to implement audit recommendations.

Phase 4 (2027)

Expected to require mandatory net zero reporting, stronger obligations for implementing audit recommendations, and an expanded reporting scope to align with the UK’s net zero objectives.

The certification process with Kiwa

    Define Scope and Assessment Plan

    The process begins with a detailed understanding of the organisation’s structure and energy usage. This stage involves setting the boundaries for the energy management system and developing a tailored assessment plan to guide certification.

    Two-Stage Audit

    Certification includes a two-stage audit.
    The first stage reviews management system documentation and evaluates readiness for certification.
    The second stage is an on-site assessment to confirm effective implementation of the energy management system. The system must have been operational for at least three months and have completed a full cycle of internal audits and management review before this stage.

    Certification and Ongoing Improvement

    After successfully completing the audit, Kiwa issues an ISO 50001 certificate valid for three years. Certification is maintained through annual surveillance audits in the first and second years, followed by a recertification audit in the third year. This ongoing process supports continual improvement and ensures compliance with requirements such as ESOS.

Avoid non-compliance

Kiwa’s expert team helps ensure you meet your ESOS obligations efficiently, accurately, and on time.

Failing to comply with ESOS can have serious consequences, including:

• Fines of up to £50,000

• Additional daily penalties of £500 (for up to 80 days)

• Public disclosure of non-compliance by the Environment Agency

Benefits of the Service

Compliance with ESOS legislation

Achieve compliance through an accredited and recognised certification route.

Reduced operating costs

Improve energy efficiency and resource management for long-term savings.

Enhanced sustainability performance

Deliver measurable reductions in carbon emissions.

Legal assurance

Meet statutory and regulatory energy management obligations confidently.

Improved reputation and credibility

Strengthen trust with customers, suppliers, and investors through verified compliance.

Greater business resilience

Drive efficiency, transparency, and continual improvement across operations.

Who Qualifies for ESOS

You will also qualify if your company is part of a corporate group in which another UK undertaking meets either of these conditions.

Organisations that fail to comply may face fines of up to £50,000, daily penalties, and public disclosure by the Environment Agency.
You must comply with ESOS if your organisation:

  • Employs 250 or more people, or

 

  • Has an annual turnover above £44 million and an annual balance sheet total exceeding £38 million.

 

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