The Indonesian government emphasised its intention this week to use ‘green’ cement in the construction of its new capital city Nusantara in Borneo. However, this begs the question: what exactly is ‘green’ cement?
In this case, Mohammad Zainal Fatah, the secretary general of the Ministry of Public Works and Public Housing, told state media that his department was “seeking to encourage the supply of domestic-industry-based material resources and construction equipment, which can support sustainable infrastructure development principles.” The ministry is working with state-owned cement producers such as Semen Indonesia (SIG) to ensure the provision of sustainable cement and related products. SIG was selected as a supplier for the project in late 2022 and, as of February 2024, has reportedly provided 400,000t of cement from its plants at Balikpapan and Samarinda.
This is admirable stuff. However, the timing of the announcement is curious given that both the head and deputy head of the Nusantara Capital City Authority resigned this week forcing the government to reassure investors that the project was still on. Cue some swift discussion about ‘green’ cement! Previously it was hoped that the first phase of the US$34bn project could be inaugurated on the country’s independence day in August 2024 with civil servants scheduled to start relocating to the site in the autumn.
SIG sells a number of ‘green’ blended cement products and some of these have received Green Label Cement certification from the Green Product Council Indonesia. The group says that these products have contributed up to a 38% drop in CO2 emissions compared to Ordinary Portland Cement (OPC). This compares to the group’s clinker factor reduction rate of 69% and its Scope 1 emissions intensity reduction of 17% to 585kg/CO2/t of cement in 2023 compared to 2010 levels.
Along similar lines, the Alliance for Low-Carbon Cement & Concrete (ALCCC) in Belgium also announced this week that it had released a new policy roadmap aimed at achieving net zero emissions by 2040. Amongst its recommendations were a focus on the standards for cement and concrete to promote low-carbon products and encouragement to create lead markets to develop demand for them.
Crucially, the ALCCC uses low-carbon cement in place of ‘green’ cement and this makes its definition clearer. ‘Green’ cement is a marketing term intended to associate cement with environmentalism. Yet there is no accepted definition describing how these products are more sustainable than, say, OPC. For example, a so-called ‘green’ cement could use 100% clinker manufactured with no CO2 emissions-abatement, but it might be sustainable in other ways such as saving water. For the purposes of this article we’ll assume that ‘green’ cement means a low-carbon one. To further add to the confusion, ‘green’ concrete can be made using OPC in various ways but that’s beyond the scope of this piece. Clearly the world could do with some universal definitions.
US-based research and consulting company Global Efficiency Intelligence came to the same conclusion when it published its ‘What are Green Cement and Concrete?’ report in December 2023. It decided that – despite there being plenty of standards, protocols, and initiatives – there is no general agreement on the definition of ‘green’ cement or concrete. Its emissions intensity for cement summary table can be viewed below. It demonstrates the massive range of emissions intensity between the various standards. It is worth noting here that the description the Indonesian government may have been using for ‘green’ cement could already meet SIG’s Scope 1 emissions intensity reduction for its cement in 2023 depending on the standard being used.
| Standard / Initiative / Policy Name | Emissions intensity target (t/CO2 per tonne cement) |
| Climate Bonds Initiative | 0.437 & 0.58 |
| IEA and IDDI | 0.04 – 0.125 |
| First Movers Coalition | 0.184 |
| U.S. General Services Administration IRA Requirement | 0.751 |
| New York (USA) Buy Clean | 0.411 |
Table 1: Emissions intensity definition for cement as stated by standards, protocols, initiatives, and policies with stated numerical quantity targets. Source: Global Efficiency Intelligence.
Part of the problem here is that there is a language gap between the simple definition of a cement that is less CO2 emissions-intensive than OPC and the technical definitions used in the specifications and standards. Simply describing a cement product as ‘green’ can potentially cover anything that is slightly better than OPC down to a bona-fide net-zero product. Added to this is pressure from the manufacturers of new and existing cement products that use less or no OPC for regulators to move to performance-based standards to replace existing prescriptive standards, because it makes it easier for their products to be used. For more on this issue see Global Cement Weekly #606. Cement associations such as Cembureau and the Global Cement and Concrete Association (GCCA) have also called in their respective net zero roadmaps for changes to the standards system to promote low-carbon cement and concrete products.
The answer to what is ‘green’ cement is whatever the promoters want it to be. So, it might be helpful if the use of the word ‘green’ were banned in connection to any marketing activity related to cement products. Everyone could then adopt some kind of universal grading system using simpler language. One approach might be to copy the colour-coding scheme used by hydrogen to describe how it is made. One could use yellow for limestone blends, silver for slag, orange for clay, black for OPC made with carbon capture and so on… but not green! Another route might be to mandate the use of the carbon labels that some cement producers have used for at least a decade. Or something like the alphabet energy rating system used in the UK and EU for electrical appliances could be used. It’s too much to hope for a global system but simpler systems in the main markets would make it much easier to determine what exactly is ‘green’ cement.
