Coffee concrete anchors carbon-cutting sculpture
Holcim UK develops low-carbon coffee concrete for Canary Wharf whale installation
Holcim UK has supplied a new low-carbon concrete made with spent coffee grounds and biochar to support a 12-metre-high whale sculpture unveiled this month in Canary Wharf, London.
The four-storey artwork, titled Whale on the Wharf (Skyscraper) by StudioKCA, is made from reclaimed ocean plastic and installed in a wet dock in the Wood Wharf district. To secure the sculpture, the team needed a concrete mix that would align with its circular economy message — and approached Holcim UK for a solution.
Holcim developed a bespoke ready-mix concrete using a blend of carbon-reducing limestone fines, ground granulated blast-furnace slag (GGBS), and biochar created from coppiced hardwood and spent coffee grounds collected from Canary Wharf cafés.
The resulting mix — dubbed “Bio-Expresso” — was mixed at Holcim’s Battersea Readymix plant, with 32 cubic metres delivered in five loads. Specialist contractor DiveCo Marine then pumped the concrete into the underwater foundations.
Jasen Gauld, Holcim UK’s national concrete solutions and product development director, said: “It was essential that the concrete conveyed a message of circularity, sustainability, and a bold approach to tackling carbon. Collaborating with the Holcim Innovation Centre in Lyon, we developed and tested the biochar mix to meet the project’s environmental ambitions.”
Biochar, a carbon-rich material made through pyrolysis (the heating of biomass in the absence of oxygen), helps reduce greenhouse gas emissions by stabilising carbon that would otherwise decompose and release CO₂ or methane. When incorporated into concrete, the carbon is effectively locked in for the lifespan of the structure.
The Canary Wharf mix achieved a 66% reduction in embodied carbon due to the biochar alone, and an overall 79% reduction (A1-A3) compared to a standard CEM I concrete. Its projected global warming potential is as low as 69 kg CO₂e per cubic metre.
Jonathan Ly, director for structures at Canary Wharf Group (CWG), said: “This is a pioneering moment for CWG and our partners. We’re proud to be the first UK developer to use this coffee biochar mix in concrete. It demonstrates how circular economy principles can be embedded in real-world construction.”
The coffee grounds were sourced through CWG’s in-house waste management system, further reducing the environmental footprint of the project. The Whale on the Wharf sculpture was unveiled on 9 April 2025.
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