Inventory of Carbon and Energy (ICE) Version 2.0
About this book
The Inventory of Carbon and Energy (ICE) Version 2.0, produced by Geoff Hammond and Craig Jones at the Sustainable Energy Research Team (SERT) of the University of Bath and released in January 2011, stands as one of the most authoritative and widely consulted reference databases in the field of embodied energy and embodied carbon for construction materials. Far from being a conventional book, ICE is a technical database accompanied by methodological documentation, designed to give building professionals, researchers, engineers, and sustainability assessors a rigorous and freely accessible foundation for conducting life cycle assessments (LCA) and carbon footprint calculations across virtually the entire palette of modern construction materials. The central purpose of the database is to quantify two interrelated metrics for each listed material: embodied energy, expressed in megajoules per kilogram (MJ/kg), and embodied carbon, expressed in kilograms of carbon dioxide equivalent per kilogram of material (kgCO2e/kg).
These figures reflect the cumulative environmental burden associated with extracting raw resources, processing them, manufacturing the finished product, and transporting it to the point of use — a boundary commonly described as 'cradle to gate' or, when transport to the construction site is included, 'cradle to site.' Version 2.0 introduced an important methodological update by converting the bulk of its carbon data to CO2 equivalent (CO2e), a more comprehensive unit that captures not only carbon dioxide but also other greenhouse gases such as methane and perfluorocarbons, thereby making the carbon values more meaningful for full-spectrum climate impact assessments. The scope of ICE Version 2.0 is remarkable in its breadth. The database covers close to 200 distinct material categories, which expand into more than 300 individual entries when material subtypes and variants are taken into account.
The material families represented include metals — among them aluminium in its primary and recycled forms, various grades of steel, iron, copper, and lead — as well as mineral-based products such as aggregate, cement, concrete (including ready-mixed and high-performance variants), brick, glass, ceramics, and natural stone. Organic and plant-based materials such as timber in its many processed and engineered forms are included, along with polymer-based insulation and composite materials like carpets, photovoltaic panels, and window assemblies. For each material, the database distinguishes between virgin production pathways and recycled content scenarios, allowing practitioners to model the carbon benefits of using secondary materials.
The methodology underpinning ICE is fundamentally literature-based: Hammond and Jones systematically extracted data from peer-reviewed academic publications and applied a defined set of five selection criteria to ensure quality, consistency, and relevance. Because the published literature often shows wide variation in reported values — attributable to differences in system boundary definitions, geographic energy grids, age of data, and the rigor of the originating studies — the ICE approach involves selecting 'best values' that represent the most defensible central estimates from the available range. Professional feedback from practitioners using early versions of the database was actively incorporated into later iterations, grounding the database in real-world application as well as academic theory.
A notable feature of ICE Version 2.0 is its transparent handling of biogenic carbon. The sequestration of atmospheric carbon dioxide in timber and other bio-based materials is intentionally excluded from the reported values, a conservative choice that avoids methodological controversy and ensures comparability across material types. The database documentation also clearly acknowledges limitations, including the fact that end-of-life impacts and the operational phase of building use fall outside the 'cradle to gate' system boundary, and that users should supplement ICE data with additional sources when conducting full life cycle assessments.
Since its first public release in 2005 and through its subsequent revisions — including Version 1.5 Beta, Version 2.0 in 2011, and the eventual publication of Version 3.0 — the ICE database has been adopted as the standard reference for embodied carbon work in the United Kingdom and has gained substantial international recognition. It is cited by the GHG Protocol, endorsed by the GlobalABC, and has informed the embodied carbon calculations of tens of thousands of building projects worldwide. The database was also published in a companion volume format under the BSRIA Guide series as 'Embodied Carbon: The Inventory of Carbon and Energy (ICE),' broadening its accessibility to practitioners who prefer a formatted print reference.
In a construction industry increasingly under pressure to address whole-life carbon — not just operational energy use — ICE Version 2.0 filled a critical gap at exactly the right historical moment. It gave professionals credible, peer-reviewed numbers to work with in a landscape previously characterized by fragmented, inconsistent, and often incomparable data. Its lasting impact on UK building standards, LCA software, and sustainability rating systems attests to the quality of the methodological framework that Hammond and Jones established.