A comparison of methodologies to quantify avoided emissions

30 April 2026

New research shows high variability in the methodologies for calculating corporate avoided emissions.

Peaceful landscape with water, boats and mountains in the distance and a big sky.

Following on from their 2025 paper that identified 48 different published methodologies for corporate avoided emissions quantification, Senior Research Fellow Michelle O’Keeffe and Professor Matthew Brander take a deeper look at some of the key methodologies that could form the basis for a standardised approach.

Read the first paper: Mapping the landscape of corporate avoided emissions methodologies.

A question of comparability

One of the key drivers behind the research is the question of comparability. With so many published methodologies available, how can the results be interpreted? This is a concern for both critics of avoided emissions reporting, who see considerable scope for greenwashing, and advocates for avoided emissions reporting, who are interested in developing and improving current practice. It is of particular relevance for investors who may be interested in using avoided emissions estimates as part of their portfolio measurement and construction processes.

An emerging academic field

Whilst the analysis of methodologies and their quantitative outcomes is common across the broader carbon accounting literature, to date, no academic studies have looked to evaluate the methodologies that underpin avoided emissions disclosure. Instead, research has focused on the concept of avoided emissions and their social context, alongside how they may fit within an alternative approach to carbon accounting that incorporates positive measures. In the context of the wider carbon accounting literature, this study also offers a novel approach in its comparative analysis of multiple methodologies as opposed to the more common approach of considering a single methodology.

Content analysis of five methodologies

This study explores the problem of comparability, using content analysis. Five methodology documents are chosen based on their characteristics and level of adoption identified O’Keeffe and Brander’s 2025 paper1. A grounded theory approach is utilised whereby component and categories are identified based on the documents assessed rather than a pre-existing framework. This process led to the characterisation of fourteen methodological components for avoided emissions assessment across the five documents analysed.

Methodological fragmentation and limited definitional clarity

The analysis demonstrated that the methodologies for calculating corporate avoided emissions shown high variability. There is a lack of consistency in the components included, which is exacerbated by poor definition of components of the calculation and variability in the guidance given to practitioners across documents. The only area of relative alignment is on the use of a life cycle approach, however, even here there is divergence on whether to adopt an attributional or consequential life cycle perspective. Overall, the study concludes that the current set of protocols are unlikely to support comparable disclosures.

A call for caution and a way forward

Given the current methodological diversity, users of avoided emissions data, including policymakers, sustainable investment managers, and asset owners, are advised to interpret disclosures with caution. A clear understanding of the underlying calculation methods is essential. Recommendations are made to CDP, as one of the principal repositories of this data, to increase the extent of methodological data captured and incentivise the use of published methodologies. Even with this improved disclosure framework in place, however, the research supports the call for standardisation of this form of accounting, using the WBCSD and NZI methodology as a base, with a focus on increasing the specificity with which components are defined. In categorising the components of avoided emissions assessments, this study also provides an important contribution to academia, providing a framework on which future research into methodological content can be advanced.