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Multi-Site Approach

SEP 50001 logoThe energy savings achieved with ISO 50001 may be easier for organizations to obtain across their sites by employing a multi-site approach to implementation. The Superior Energy Performance 50001 (SEP 50001) program offers multi-site certification for both the energy management system (EnMS) and energy performance improvement for organizations that implements EnMSs across a network of sites. Additionally, multiple sites within close geographic proximity can be certified as a single site if they are under the same management system.

“The multi-site approach enabled us to learn from the other participating locations of the company and to leverage best practices.”

Robin Higgs
3M Decatur Site Manager

How It Works

To use the multi-site approach, the organization implements an EnMS at both a central office and across a network of other sites.

  • Typically, a central office provides tools, training, and resources to individual sites to support their EnMSs, tailoring responsibilities of team members to take advantage of existing corporate and site-level expertise.
  • The organization designates the central function, which could be the corporate office, a site, or a team. The central office is responsible for ensuring a central management review, evaluation of corrective action, internal audit planning and evaluation of results, consistency in the energy planning process, and meeting other energy performance requirements.

The multi-site approach enables the use of sampling for the third-party audit, which reduces the number of sites that must be audited by a third party for SEP 50001 program certification. In order to qualify for sampling, the sites must be similar in their activities. In sampling for the SEP 50001 (2019) program version, third-party auditors verify ISO 50001 EnMS and energy performance improvement at a selected subset of the sites.

certification across multiple sitesFor initial certification and recertification to SEP 50001 (2019), each site can choose its own achievement period of 12, 24, or 36 months. Each site must also have a valid model(s) that meets program requirements and an energy performance improvement greater than zero.

More details about how to use the enterprise approach are included in the Certification Protocol and in the ANSI/MSE 50028-1:2019 standard.  

Options for organizations pursuing SEP 50001 (2019) across multiple sites:

Multiple sites certified under one central function (central office): This option involves SEP 50001 program certification of multiple sites under one certificate, which means there is a central office, and the EnMS and energy performance improvement sampling occur at the site level.

  • The ISO 50001 certification audit is conducted at the central office and at each of the sites chosen for the sample.
  • The EnMS and energy performance are sampled at the site level for each site in the sample.
    • Sampled sites: The Verification Body submits the Energy Performance Improvement Report to the SEP 50001 Program Administrator
    • All sites under the certificate: The organization’s certified SEP Performance Verifier completes an Energy Performance Improvement Report for each site under the certificate. The Verification Body’s Performance Verifier checks the p-values, F-test, R2, RF and confirms that a certified SEP Performance Verifier completed the report.
    • The organization submits the Energy Performance Improvement Reports for all the non-sampled sites to the SEP 50001 Program Administrator.
  • For sites that are similar and qualify for sampling: the audit sample size is determined based on the methodology defined in ISO 50003 Annex B.3. The calculation is always rounded up to the higher whole number. 

Type of Audit

Sampling Formula

Example calculation for an SEP 50001 multi-site that has 30 sites

Initial certification

square root of sites

square root of 30 = 5.5, which round to 6 sites


0.6 * square root of sites

0.6 * square root of 30 = 3.2, which rounds to 4 sites


0.8 * square root of sites

0.8 * square root of 30 = 4.3, which rounds to 5 sites

Single certification for multiple non-contiguous sites within close geographic proximity: For sites that are not similar, grouping techniques may be used.  The method is described in ISO 50003 Annex B.

Multiple sites using the same EnMS and are non-contiguous, but within close geographic proximity can be aggregated together as part of one site under a common ISO 50001 EnMS and SEP 50001 certificate.

Combine separate certifications onto one certificate: Individual sites within an organization that have existing certifications may combine them into a single SEP 50001 multi-site certificate. Some organizations have sites holding individual certifications to SEP 2012 or SEP 2017 and with different baseline and achievement periods. The organization may align these certified sites onto one multi-site certificate. 

  • The sites under the multi-site are aligned using the date of the earliest certification expiration date. This means that some sites may be recertifying early.
  • For the recertification audit, a site does not need to adjust its baseline if it meets each of the following:
    • Achievement period of 12, 24, or 36 months
    • Valid model that meet program requirements
    • Energy performance improvement greater than 0
  • If a baseline adjustment is needed to produce a valid model, then the organization must seek pre-approval (SEP 50001 Form 5) from the SEP 50001 Program Administrator.

Add new sites to an existing multi-site certification: SEP 50001 follows the multi-site rules from IAF MD 1. The Verification Body will determine the activities required before including the one or more new sites in the certificate. Depending on the type of additional sites, sampling will be reviewed and determined.

Organizations Using Enterprise Approach

For insights, view case studies from organizations that have used an enterprise approach. (These organizations used an earlier program version of SEP 50001 that did not yet offer sampling of energy performance.)




Schneider Electric

6 sites

3 sites

3 sites

19 sites

$3.6 million annual energy cost savings

$4.1 million annual energy cost savings

$9.4 million annual energy cost savings

$1.8 million annual energy cost savings

View the Enterprise-wide Fact Sheet and the paper, “ISO 50001 and SEP Faster and Cheaper – Exploring the Enterprise-wide Approach,” for more details on benefits.

Cost-Benefit Analysis of Enterprise Approach

SEP quoteFour companies expanded SEP 50001 program certification to multiple sites, then tallied results and compared multi-site costs to their initial single-site costs. See the study. Results include:

  • Ongoing energy cost savings that average about $600,000 per year per site, with nearly three-quarters of those savings typically provided from low- or no-cost actions
  • Reduced training costs
  • Reduced internal labor
  • Reduced internal and external consultant costs
  • Reduced third-party certification costs

Who is Enterprise Approach Intended for?

The ISO 50001/ SEP 50001 enterprise-wide approach works best for organizations with one or more of the following characteristics: 

  • An established corporate energy goal;
  • An existing energy management program;
  • Implementation of ISO 50001 at one site;
  • Experience with ISO management systems, such as ISO 9001 or ISO 14001;
  • Multiple sites that can benefit from sharing best practices.

Tools Supporting the Enterprise-Wide Approach

Two of the companies, 3M and Cummins, centrally developed their own suites of tools for use by their sites. Cummins has generously agreed to share an external version of its Energy Review Tool through DOE to assist other companies. The Microsoft Excel®-based tool takes users step-by-step through the ISO 50001-required process for conducting an Energy Review, setting an Energy Baseline, and establishing meaningful Energy Performance Indicators.

In addition, check out the 50001 Ready Navigator and Tools, Expertise & Training.