Westminster City Council King Street Low Carbon Trial - Client Report

EMBODIED CARBON

Metis Ltd have developed a tool specific to the Westminster contract that calculates the embodied carbon contained within the materials used on the contract. This includes manufacture and delivery but it does not include the carbon involved in installing the materials. The tool works by calculating the carbon per schedule of rate item and multiplying it by the quantities. From the final measures on site the tool calculated that the carbon in the Marlborough Hill materials amounted to 40.69t and the King Street items came to 17.93t. That is a saving of 56% scheme on scheme. When we consider the square meterage, it is 0.13t on Marlborough Hill and 0.07t on King Street, a still impressive 46% saving per m². These savings were made with a small tweak to the design in having a slightly thinner slab, a shallower foundation, and a slightly lower concrete.

The graph below shows the difference in embodied carbon between the two schemes.

Figure 11 - Bar Chart Showing the Total Carbon Footprint at both sites

INDIVIDUAL CARBON ELEMENTS

45

40

35

30

25

20

15

10

5

0

Marlborough Hill

King Street

The tool can show the carbon breakdown per item. The graph below shows the total carbon outputs per series number from the Specification for Highway Works.

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