APRIL 2019

The Carbon Infrastructure Transformation Tool (CITT)

Our Carbon Infrastructure Transformation Tool (CITT) automatically aggregates data from multiple data sets (estimating, planning, design) and integrates carbon impacts associated with infrastructure projects. Unlike traditional top down baseline estimates, the CITT allows for a very granular bottom up assessment, which means engineers, designers and procurement specialists can act upon the output of the tool with confidence. The tool pinpoints opportunities to reduce carbon through innovation and supply chain engagement. The project, funded by the Construction Climate Challenge (CCC), has a close collaboration between the University of Edinburgh Business School and Costain Group. The Construction Climate Challenge (CCC) is an initiative hosted by Volvo Construction Equipment to promote sustainability throughout the entire construction industry value chain and provide funding for environmental research. As part of this process our team has developed a methodology which means carbon can be quantified alongside cost and time, without any additional labour input required. Because the processes we are integrating the carbon data into are standardised, we can achieve our aspiration of a standardised approach to carbon management.

Estimate

Plan

Design/BIM

Carbon Factory LibraryWorkbench

CarbonBaseline

Commercial

Procurement

Supply Chain

Carbon Infrastructure Transformation Tool (CITT)

In terms of supply chain engagement, linking carbon to cost allows for a quick assessment of commercial benefits linked to low carbon interventions leading to a quick and easy engagement with suppliers.

The following examples delivered by means of the CITT were developed by non carbon experts that wanted to give a more sustainable approach to the solutions delivered on sites.

Area 4 – Aone+Area 4 is a maintenance and operations contract under Highways England based in Kent and East Sussex. The contract involves several renewal and improvement schemes required to sustain the road network, including structures, drainage, and geotechnical projects.

We chose to investigate the surfacing renewal scheme which was still in its budgeting stage. This allowed us to propose solutions before procurement and construction had started, which could be beneficial in the future to reduce carbon before it has even been produced, and is the main advantage of CITT over other carbon reduction tools.

The initial baseline showed that the surface course required for the scheme would produce 77% of the scheme’s carbon (61.8 tonnes of CO2 equivalent), as well as being the most expensive element. We looked at lower carbon surfacing options that could also be applied to the asphalt concrete used in the binder course of the road.

The primary Aone+ surfacing supplier is Tarmac, who supply schemes with their default Ultipave product. This contains 10% recycled materials. Engaging with Tarmac we looked at the Ultilow asphalt which would be a suitable product for the scheme. It is cost neutral with respect to Ultipave, but is produced at a lower temperature and is supplied at a reduced temperature to the site, creating carbon reductions of up to 25%. This allowed us to rerun the baseline and calculate the carbon reductions.

Changing the asphalt from Ultipave to Ultilow reduced the carbon emissions by 20% with no added cost to the scheme.

Dr Noemi Arena, MEng EngD CEng CEnv MIChemE MIEMASustainable Engineering ManagerMobile: +44 (0) 7741247050

HS2 - Green Parkway Vent ShaftHigh Speed Two (HS2) vision is to provide a high-speed railway system that connects London and other UK’s major cities. It’s a Main Works Civils Contract (MWCC) which consists of a 26km tunnel network beneath the City of London.

We carried out a carbon assessment on the Green Parkway Vent Shaft, which is one of the ventilation and intervention shafts located on the Area South of HS2. By means of the CITT we calculated the total quantity of carbon emissions and the total cost for different types of construction materials. The data was produced by inputting the bill of quantities from our chosen asset.

The shaft is located within the Greenpark Way Industrial area in the borough of Ealing in west London, which is a Borough-designated locally significant industrial site within the A40 corridor.

Based on a first run of the baseline we investigated the areas with biggest impact and revised the design. The revised BoQ was the inputted to the baseline tool to provide the results. The results then suggested that the largest CO2 saving came from secondary lining concrete and primary lining precast concrete rings, respectively. The most significant cost savings were from reducing the primary lining shotcrete.

Overall, the total saving from this option was £123,420 which corresponds to 320,000 tonnes of carbon reduction.

Thames Tideway Tunnel We developed a carbon assessment across the permanent works and temporary works in Tideway.

As the CITT supports engagement with different disciplines, we worked closely with the design and engineering manager to articulate possible design changes which had been taken for a commercial saving which could be quantified as a carbon saving.

By doing this engagement and showing the results of a first carbon baseline analysis delivered with the CITT, with the design team we looked at a solution for the shaft base slab and the shaft secondary lining designs following the CIRIA 766 guidance. This implied reduction in rebar from the original design.

The main benefit of using this tool is the engagement with the variety of disciplines. The designers research into future guidance changes meant they could produce designs which when built would be in-line with current regulations.

By using the CITT we could convert the material reduction into a carbon saving of 1380tCO2e for two site’s shaft base slab and shaft secondary lining.

The design changes had saved over half a million pounds and the change in program had results in further financial savings.

With Costain’s CITT we able to show how the sustainable design engineering is helping us meet the Tideway sustainability objectives.