ESOS vs SECR: What’s the Difference?

The 30-second summary

ESOS is a four-yearly mandatory energy audit programme for large UK organisations. It produces a one-time report at the end of each phase, signed off by a qualified Lead Assessor.

SECR is an annual mandatory disclosure framework. It puts energy consumption and emissions data into your Directors’ Report each year.

Both are administered by the UK government. Both apply to large UK organisations. Both involve calculating and reporting energy data. But they are different obligations with different rhythms, different qualifying thresholds, and different consequences for non-compliance.

ESOS in detail

The Energy Savings Opportunity Scheme (ESOS) was introduced in 2014 to implement the EU Energy Efficiency Directive. It survived Brexit and continues to apply in the UK.

ESOS requires qualifying organisations to conduct a comprehensive energy audit covering all their energy consumption – buildings, industrial processes, and transport – every four years. The audit must identify cost-effective energy savings opportunities and be signed off by a qualified Lead Assessor before being submitted to the Environment Agency.

Who must comply with ESOS

ESOS applies to UK organisations meeting at least one of: 250 or more employees, OR annual turnover above £44 million and balance sheet above £38 million. Public sector bodies are exempt – though their suppliers may not be.

The ESOS phases

• Phase 1 – Compliance deadline December 2015
• Phase 2 – Compliance deadline December 2019
• Phase 3 – Compliance deadline June 2024
• Phase 4 – Compliance deadline December 2027

What an ESOS audit involves

A Phase 4 ESOS audit must calculate total energy consumption across buildings, transport, and industrial processes for a 12-month reference period, audit at least 95% of that consumption through detailed site-level assessments, identify cost-effective energy savings opportunities, be signed off by a qualified Lead Assessor registered with an approved professional body, and be approved by the board before submission to the Environment Agency.

Penalties for non-compliance

Non-compliance with ESOS carries financial penalties of up to £50,000, plus daily fines for ongoing breach. Non-compliance is also published – which creates reputational exposure with customers, investors, and procurement teams.

SECR in detail

Streamlined Energy and Carbon Reporting (SECR) was introduced in 2019. It requires qualifying organisations to publish energy use, carbon emissions, and energy efficiency actions in their annual Directors’ Report. SECR is an annual obligation – every year, qualifying organisations must update the figures and republish them.

Who must comply with SECR

SECR applies to all UK quoted companies regardless of size, and large unquoted companies and LLPs meeting two of: 250+ employees, £36m+ turnover, £18m+ balance sheet.

What SECR requires

The minimum disclosure includes total energy consumption for the financial year (kWh), Scope 1 emissions (direct emissions from owned or controlled sources), Scope 2 emissions (indirect emissions from purchased electricity), at least one intensity ratio, energy efficiency actions taken during the reporting period, and the methodology used to calculate the figures. Scope 3 emissions are not strictly required under SECR but are increasingly expected by investors, ESG ratings, and large customers.

Penalties for non-compliance

SECR doesn’t have a separate penalty regime. Non-compliance is treated as a Companies Act breach – which means the directors who signed the report carry personal liability for material misstatements.

Where ESOS and SECR overlap

The overlap is significant – which is the source of most of the confusion. Both require energy consumption data for the organisation’s UK operations. Both apply to similar size thresholds. Both rely on similar data infrastructure. Both require sign-off by senior management or directors. If you’re already capturing the data needed for SECR, you’re well on the way to having the data needed for ESOS – and vice versa.

Where ESOS and SECR differ

The most important practical difference: ESOS produces an audit and savings recommendations. SECR produces a disclosure. ESOS is about identifying opportunities. SECR is about transparency.

The smart way to approach both

For organisations subject to both frameworks, the practical approach is to treat them as connected outputs from the same underlying energy data infrastructure.

Build the data once

Maintain energy and carbon data continuously through the year. The same data feeds both the SECR disclosure and the ESOS audit baseline. Most organisations now use a platform-based approach – aggregating data from suppliers, meters, transport, and operations into a single system that handles the calculations and reporting.

Use ESOS findings to drive action

The audit recommendations from ESOS are genuinely useful – typically identifying 5-15% in cost-effective energy savings. Don’t treat ESOS as a tick-box exercise. Use the recommendations as input to your operational and capital planning.

Plan for the future

The regulatory direction is consolidation, not divergence. The UK is moving toward more aligned reporting requirements. Organisations that build credible energy and carbon data infrastructure now are positioning themselves for whatever comes next – not just complying with what exists today.

The bottom line

One. ESOS and SECR are related but distinct. ESOS is a four-yearly audit with savings recommendations. SECR is an annual emissions disclosure. Both apply to most large UK businesses.

Two. The data infrastructure that supports one supports the other. Organisations with good energy data management find both straightforward. Organisations without it find both a scramble.

Three. ESOS Phase 4 deadline is December 2027. Lead Assessors book up early. If Phase 4 isn’t on your compliance calendar yet, it should be.