Quantum Commodity Intelligence – Several carbon standards offer methodologies that aim to cut greenhouse gas emissions and generate carbon credits from the use of concrete in the buildings materials sector.
Here Quantum takes a look at some of those methodologies.
Verra
US-based carbon standard Verra first approved a methodology for the use of CO2 in concrete to create carbon credits under the Verified Carbon Standard (VCS) in October 2023.
Since December 23 last year, version one of VM0043 ‘Methodology for CO2 Utilization in Concrete Production’ has been replaced by version 1.1, allowing project proponents to quantify CO2 removals and emissions reductions separately.
As the name suggests, the method is for projects that use CO2 as a feedstock in concrete production. This can either be storing the waste CO2 in the concrete or through lowering the amount of cement used.
It used a positive list to determine additionality – whether or not the project would have gone ahead without the carbon finance aspect. This means a list of technologies or techniques are deemed additional without having to carry out further analysis.
Eight projects are listed in the VCS registry as using VM0043, of which four are registered, two are under development, and one each are under validation or have requested registration. Three of the four registered projects have generated emissions reductions or removals equivalent to about 90,000 tCO2e.
Verra also has a methodology under the VCS – VMR0012 Production of Geopolymer Cement – for projects that produce geopolymer cement to replace the use of Portland cement. Projects using VMR0012 must utilise it with the latest version of Clean Development Mechanism method AM0125 ‘Production of geopolymer cement’, however, the latter cannot be used as a standalone method in the VCS.
Puro.earth
Finland-based registry Puro.earth has an approved methodology for CO2 removal in carbonated materials. The methodology quantifies the net CO2 Removal achieved over 100 years through the production of carbonated materials, as long as the CO2 is of biogenic origin or from direct capture from the ambient atmosphere.
It makes only a small reference to the construction sector, noting that projects must specify what is the end use of the carbonated material, such as the construction sector.
The Puro.earth website lists three suppliers of carbon dioxide removal (CDR) credits, known as CO2 Removal Certificates or Corcs, from carbonated materials projects. All three are operated by OCO Technology and convert CO2 emissions into “solid building materials through accelerated carbonation”. They have so far been issued with almost 107,000 Corcs.
Puro.earth also has a biochar methodology that makes one reference to possible use of the produced biochar in concrete.
Isometric
UK-based CDR standard Isometric certified a biomass carbon removal and storage (BiCRS) module on December 20 last year for ‘CO2 Storage via Carbonation in the Built Environment’.
The module outlines durability and monitoring requirements for storing in the built environment, with concrete defined as the “built material” in which CO2 is to be stored as carbonated minerals or materials.
The module says durability is the “stability of CO2 stored in concrete, and the length of time for which carbon is removed from the Earth’s atmosphere (>1,000 years) and cannot contribute to further climate change”. For the built environment, it adds, “durability is typically used to refer to the structural durability of concrete” referred to as “concrete durability” in the module.
It covers a range of potential projects, including carbonation technologies such as carbon injection during mixing, carbon curing or carbon-sequestering aggregates or carbon-sequestering supplementary cementitious materials (SCMs), among others. The module is also applicable to projects that use a source of CO2 that is a net removal from the atmosphere, such as from direct air or ocean capture or biogenic carbon capture and storage.
Carbon Standards International
In December, Switzerland-based registry Carbon Standards International (CSI) unveiled a new version of its Global Biochar Carbon Sink (C-Sink) standard to allow certification of carbon removal credits based on the use of biochar in concrete. Under the new rules, introducing biochar into the concrete mix can provide for the issuance of C-Sink 1000+ credits, which indicates a carbon sequestering period of 1,000 years, when up to 75% of the carbon is embedded in the mix.
The methodology can also be used for shorter storage periods — C-Sink 100 and C-Sink 60. For C-Sink 100, 17.1% of the carbon is confirmed to be stored in the mix for 100 years, while C-Sink 60 is an option of certifying 100% of the carbon in the first 60 years as a temporary C-sink.
The new options under version 3.1 of the Global Biochar C-Sink standard apply to all biochar certified according to the European Biochar Certificate or the World Biochar Certificate, the registry said.
Gold Standard
The Switzerland-based registry Gold Standard released the Carbon Sequestration Through Accelerated Carbonation of Concrete Aggregate methodology in 2022, making some revisions to it in October last year.
The method is used for projects that aim to sequester CO2 in demolished concrete, known as ‘concrete aggregate’.
It states that “through the applied processes of carbonation, concrete aggregate is exposed to an increased CO2 concentration and the CO2 reacts with the cement phase of the concrete aggregate which contains calcium oxides to form stable carbonate minerals. Through the conversion to calcium carbonate (CaCO3), CO2 is permanently stored”. Two approaches are offered that use either direct or indirect mineral carbonation.
The direct processes “imitate the natural process of weathering of concrete structures but increase the reaction rate through different factors such as an increased CO2 concentration or an increased contact surface between the CO2 and the cement phase”. The indirect approach “extracts the cement phases by means of a solvent and carbonates it”, the methodology states.
The methodology was developed by Switzerland-based Neustark, which has 16 projects currently listed in the Gold Standard registry at various stages of development.
Climate Action Reserve
The US-based Climate Action Reserve (CAR) approved version one of its US Low-Carbon Protocol in October 2023. The protocol provides a method for accounting, reporting and verifying emissions reductions from the production and processing of SCMs or “alternative cementitious materials” that replace Portland cement in ready-mix or concrete products.
Currently only four out of over 1,000 projects in the CAR registry using the protocol. Three are termed ‘listed’ meaning the project’s submittal forms have been accepted by CAR and the project can proceed with reporting and verification. The fourth is ‘registered’, which means it has completed verification of at least one reporting period. No credits have been issued yet.
Japan’s J-Credit scheme
J-Credit methodology EN-S-040 ‘Use of concrete with low Portland cement content’ was first approved in 2016, with the latest version (4.2) released in December 2024. EN-S-040 aims to cut GHG emissions from fossil fuel consumption and the chemical reaction in the cement production by using concrete that contains less Portland cement and more industrial by-products, such as slag from the blast furnace in steel production.
Four projects are listed on the J-Credit scheme website as using the methodology. All four projects are programmatic, meaning they bundle multiple small activities that would not be economically viable alone under a single J-Credit project.
Riverse
France-based Riverse is planning to include biochar storage in concrete as a module under its methodology for biomass carbon removal and storage. It also has a methodology for ‘biobased construction materials’, which was last updated in August last year.
While the methodology does not just cover concrete-related projects – for example, it also includes sustainably sourced wood in buildings – Riverse does list four out of 13 projects using the methodology that utilise hemp concrete blocks. These four projects have so far been issued with over 4,500 Riverse Carbon Credits.
