Westminster City Council King Street Low Carbon Trial - Client Report
This report provides an analysis into the King Street Low Carbon Trial by evaluating the carbon reduction measures introduced on the scheme.
Author: Ivan Farrell Reviewed by: Vanessa Hilton & Phil Clark Draft: 01/06/2021
WESTMINSTER CITY COUNCIL KING STREET LOW CARBON TRIAL
© FM Conway This document is the copyright of FM Conway and the information therein may be the subject of a pending or granted patent. It may not be reproduced or used for any other purpose than for which it is supplied without the written permission FM Conway.
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TABLE OF CONTENTS
3 5 6 7 7 7 8 11 11
Executive Summary
Introduction Background
Scope
Limitations
Aims & Objectives Scheme Details
Baseline
Comparison between King Street & Marlborough Hill
14 15 17 19
Plant
Materials
Transportation
Suppliers
20 23 27 29 30
Marketing Campaign
Results
Embodied Carbon Overall Carbon Usage
Other Environmental Benefits
31
Site Feedback Testimonials Financial Impact
32 34
41
Conclusion
44
Recommendations
46 47 48 49 50
Article – Highways magazine
Article – Asphalt Now
Article – Asphalt Industry Alliance
Article – NLA.london
Article – uk.100
TABLES & GRAPHS
9 11
Figure 1 - General Arrangement Drawing for King Street Figure 2 - Shows the differences between the two schemes. Figure 3 - General Arrangement Drawing for Marlborough Hill Figure 4 - The JCB excavator in action on King Street Figure 5 - Demonstrates the sustainable products and plant used
12 14 17 18 19
Figure 6 - Electric Van
Figure 7 - Speedy Hire Electric Taxi Delivery Vehicle
24 Figure 8 - Graph Showing the Comparison of Operational Carbon Produced on King Street & Marlborough Hill 25 Figure 9 - Pie Charts Showing the Carbon Produced by Type Across Both Schemes 26 Figure 10 - Graph Showing the Carbon Breakdown Across All Operations 27 Figure 11 - Bar Chart Showing the Total Carbon Footprint at both sites 28 Figure 12 - Graph showing how the embodied carbon is broken down 29 Figure 13 - Table showing the whole tCO2e carbon footprint for both schemes: 29 Figure 14 - Table showing the King Street carbon savings 36 Figure 15 - The table below shows the approximate costs of the extraordinary items 37 Figure 16 - Stacked Graph showing the additional costs against the scheme estimate
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EXECUTIVE SUMMARY
This report provides an analysis into the King Street Low Carbon Trial by evaluating the carbon reduction measures introduced on the scheme. This was the first time that carbon was measured for a scheme in Westminster and now sets the baseline for monitoring carbon usage and measuring the savings that can be made by changing methods and/or materials. The report has split the carbon savings into:
• Operational Carbon – based on FM Conway’s carbon outputs for installing the scheme
• Embodied Carbon – which considers the greenhouse gases emitted throughout the production of the materials, from extraction of raw material, through manufacturing process and transportation to site. It also takes into account the expected lifecycle of the product The report primarily concentrates on the elements of work within FM Conway control, such as travel, deliveries, and operations, but also reviews the embodied carbon within materials. The working operations, including travel and deliveries were recorded daily with the carbon then calculated using the UK Government Conversion Factors for Greenhouse Gas (GHG) Reporting 2020, published by the Department for Business, Energy and Industrial Strategy and the Department for the Environment, Food and Rural Affairs. The results of the trial have been compared to a standard Planned Preventative Maintenance (PPM) scheme of a similar size and scope, Marlborough Hill, running during the same timeframe to establish the carbon savings made against traditional construction techniques. The embodied carbon contained within the site materials was measured by a tool designed by Metis Consultants Limited on behalf of Westminster City Council. For the trial only, a minor change to the specification was installed to maintain the same look and feel to the street, meaning that there was a limit to the carbon that could be saved. • 79% carbon saving in operational delivery against a standard scheme - 1.74t of carbon was emitted during the operational phase of the scheme, saving over 4t when compared to the comparison site at Marlborough Hill, which equates to just 0.04t per day • 46% carbon saving per m2 in the materials used. The paving slabs were reduced to 50mm from 63mm, with the foundation 58mm shallower and using concrete sub-base grade C10 instead of C20, which reduced the embodied carbon to 17.93t, making a saving of nearly 23t against Marlborough Hill and 53% more carbon efficient overall with a total carbon saving of 27t It was accepted at the outset that there would likely be a trade-off between cost and carbon to make significant carbon savings. The final cost of £94,000 was £53,000 higher than the estimate to carry out the works with traditional techniques. However, it is noted that there were several extraordinary costs against the scheme that would not normally be incurred. The key results of the trial are:
In addition, it is expected that these costs would reduce as electric plant becomes more readily available and is able to service several concurrent schemes on the programme.
It has been calculated that £45,000 of these costs were classed as extraordinary costs, thereby making the like for like comparison £49,000 for a carbon efficient scheme, against £41,000 for a diesel-powered scheme. Therefore, a cost uplift of 20% has saved over 50% of carbon on this scheme. This was the first trial of its kind in the UK and there are challenges for a wider rollout, including the lack of electric charging points for vehicles and plant, limited plant options available from suppliers and the cost of making the change.
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In completing the trial, it has identified several recommendations to further reduce carbon across the Westminster network including:
• Prohibiting diesel from work sites
• Increasing the electrical power points available across the City
• Seeking alternative power sources for equipment
• Investigating the use of central compounds to reduce travel
• Running concurrent sites using electric powered operations to increase efficiency
• Working closely with suppliers to increase the availability of plant
• Increasing the ability to monitor energy usage and diesel usage across projects
• Reviewing current specifications to identify carbon savings in embodied carbon
• Trialling of lower carbon materials on the network
• Designing a scheme from early stages to investigate more specification carbon savings
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INTRODUCTION
In response to the climate emergency, FM Conway has undertaken a low carbon trial in King St, SW1 on behalf of the City of Westminster. The works involved relaying a footway on the PPM programme using more carbon efficient methods than the standard practice. The aim of the trial was to take a standard PPM scheme, and identify areas of change that would reduce the carbon output of the scheme. It concentrated on electrifying the working operations and removing some of the cementitious materials in the build-up of the paving. It is the first scheme of its kind in the UK, providing both a blueprint for Westminster and FM Conway for future PPM schemes, as well as a challenge to the industry in tackling carbon reduction over the next decade. A target of 75% carbon saving for operations on the scheme was set. It was hoped that by reducing the thickness of the slab that 25% savings could be made on the embodied carbon within the materials.
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BACKGROUND
Westminster City Council has one of the worst air pollution problems in the country and in September 2019 declared a climate emergency. A target was set to make council activities carbon neutral by 2030 and the Leader of Westminster Council has set this as the top priority. This is an overall council initiative and is being led by the Westminster City Council Corporate Team. To support the corporate goals, the City Highways Team asked the Asset Board, led by Andy Foster, to look at how works on the public highway could be carried out in a more carbon efficient manner. The Asset Board is comprised of members of Westminster City Council and key members of the FM Conway delivery team across all the Highways contracts. A Carbon Working Group was set up to focus solely on carbon reduction, which consisted of Andy Foster, Dan Perks, Westminster Operations Manager and Ivan Farrell, FM Conway Performance Manager. The group was tasked with understanding the existing carbon footprint, determining the requirements to lower it, and finding a way to introduce new measures and innovations. Andrew Cox, FM Conway SHEQ Director was invited into the group to bring industry expertise and advise on other FM Conway initiatives across London and the South East. A workshop was organised with all the Westminster contract leads to look at some of the key areas of improvement across:
• Materials
• Waste
• Design
• Work Methodology & Operations
• Plant & Tools
• Deliveries
• Travel
Several good ideas were raised, particularly around specification, electric vehicles and plant. The group determined that good planning and input around the design stage, looking at the reuse of materials and less reliance on granite from China, were key areas of focus. The next step was to implement these ideas into schemes on the programme and so the PPM programme was chosen where it is normally a ‘like for like’ replacement, so only minor amendments would be needed to the design.
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SCOPE
The scope of the report is limited to the installation of the King Street Low Carbon Trial and the Marlborough Hill PPM Footway Replacement Scheme. The primary focus is the effect of changes to operational methodology to reduce carbon. The report has not looked at any other schemes or initiatives in the public realm, or across the other contracts.
LIMITATIONS
The report is limited by the data produced at the two schemes. They are two typical PPM footway schemes, but they do not reflect works on larger public realm schemes, PPM carriageway schemes or other parts of the contract such as Lighting, Water & Drainage or Structures. Therefore, whilst the recommendations may be viable for PPM, they may be less suitable for other types of works. Note that the jobs were already designed which meant that only minor amendments could be made to the specification. A newly designed scheme would allow for more carbon-friendly measures to be considered. A further limitation is the current availability of electric plant, lack of low carbon paving materials, and scarcity of power points for charging electric equipment.
AIMS & OBJECTIVES
It was agreed that the trial would remain close to the ‘Westminster Way’ and ensure that the finished look of the street was in keeping with the rest of the area. The specification was adjusted to incorporate a thinner slab and a low carbon concrete alternative. The aim and objective was to test what carbon efficient plant is available for live sites now, with the scheme being assessed against a comparison site at Marlborough Hill. The outcomes were to establish:
• Carbon savings that can be made
• Cost of a shift to non-diesel plant
• Operational issues of change
• Barriers to achieving success
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SCHEME DETAILS
King Street is a one-way street from St James’s Square to its junction with St James’s Street and features an existing footway constructed of Artificial sone paving (ASP) with areas of granite setts and block paving. It was selected for the maintenance programme due to its high score on the Annual Condition Survey (ACS). The street featured a life-expired footway with instances of cracked slabs, uneven surfaces and poor utility reinstatements which were too large an area to be treated under reactive maintenance. The works design was to raise the kerb line to deter vehicle overrun and replace the existing paving with new ASP slabs.
It was considered a good location for the trial because:
• At 268m² it was not too big to trial new equipment whilst being large enough to test results
• It was a slab replacement scheme meaning deep excavation was not required
• Existing electric excavators were considered adequate for the work involved
• The footway was wide enough to install a feeder pillar for power
• There was enough space on the carriageway to house the welfare unit and plant within one compound • The street usage was mainly business use, many of which were closed for lockdown, meaning minimum disruption
• There was easy access to several tube stations for travel to site
• The site was close to City Hall for client visits
• There was a suitable compound at Carlton House Terrace, less than five minutes away for storage of paving materials
• It was not a heavily trafficked road, making access easy for the excavator
As Figure 1 demonstrates, the only amendment to the specification was to reduce the slab depth, meaning there were no significant changes to the design and the use of electric tools and plant were direct replacements for the usual diesel and petrol tools.
The estimated cost for the scheme was £41,000 based upon the traditional methods of installation.
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Figure 1 - General Arrangement Drawing for King Street
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BASELINE
There are no existing facts on carbon usage for highways within Westminster and there is scarce data across the industry to enable us to understand how much carbon is created on a standard footway scheme. To create a baseline carbon footprint of a standard scheme we identified a comparison site of a similar size and value. A PPM footway scheme on Marlborough Hill was selected as it had a value of £35,500 with the works predominantly ASP replacement (Figure 2 and 3). The results were evaluated and transferred to individual spreadsheets per scheme to calculate the carbon scores. A Supervisor Check Sheet was created to record all vehicle movements, deliveries, plant operations and welfare usage. The same site supervisor looked after both schemes and completed the sheets daily whilst each job was on site to ensure consistency To understand the difference in cost we compared the design estimate against the final turnout cost. However, a ‘like for like’ comparison was difficult because the current schedule of rates was built from plant, labour and material costs. As such, the costs were compared to the existing cost estimate for standard delivery.
COMPARISON BETWEEN KING STREET & MARLBOROUGH HILL
Figure 2 - Shows the differences between the two schemes.
Marlborough Hill
King St
Estimated Value
£35,500 306m2
£41,000 268m2
Paving (m2)
Kerb (m)
108m 32m2 61m3
124m 37m2 29m3
Kerb line Asphalt (m2) Excavation (m3) Excavator Model EV Charging Points
KUBOTA KX015-4
JCB 19C-1 Etec Excavator
N/A
2 x 22kv CityEV Chargers & FP Relocate 8no & reused 8 from other scheme WackerNeuson AP1850WE
Cycle Stands
N/A
Wacker Model
Belle PCLX320 STIHL TS410
Saw Model
Hasqvarna K535i
Welfare Unit Type Grab Lorry Fuel Type
Eco – With Diesel Generator
Eco – With Electric Connection
Diesel Diesel
HVO HVO
Delivery Vehicle Fuel Type No of Operatives on Site Operative Travel Type Supervisor Travel Type
3
3
Diesel Van, Public Transport
Electric Van, Public Transport
Diesel van
Electric van
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Figure 3 - General Arrangement Drawing for Marlborough Hill
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PLANT
It was understood at the outset that the removal of diesel from the site would provide the biggest operational savings. However, due to the reliance on diesel vehicles and machinery within the industry and the limited choice and availability of electric plant, it meant that this saving would be limited. Both JCB and Speedy hire were engaged prior to the trial in order to secure the best equipment available. JCB offered a free trial of a JCB 19C-1 Etec Excavator (Figure 9), which was the perfect size for the shallow excavation required on this scheme. It was understood that as the excavator does not match the power of its diesel alternative that it would take longer, but would still be able to meet the programme demands.
Figure 4 - The JCB excavator in action on King Street
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The excavator would also have been easily charged with their own power pack, but they needed to provide a separate adapter to connect to the feeder pillar. As the excavator was offered as a free trial, no other options were considered, however other suppliers such as Kubota and Caterpillar are developing their own electric mini excavators.
Speedy Hire supplied the following equipment:
• WackerNeuson AP1850WE wacker plate
• Hasqvarna K535i disc cutter
To retain the look and feel of the St James’s area it was decided not to deviate too far from the existing artificial stone paving. This meant there was limited scope for reducing the carbon through a specification change. Across other parts of the City, it may be possible to explore other materials, such as recycled slabs or asphalt, which would require a larger input from the design team and a longer lead time. MATERIALS The Welfare Unit was adapted to run off electricity and solar rather than a diesel generator. This worked well as it was silent when switched on and the benefits were that the site team could use the Unit earlier without being a nuisance to the residents. The one drawback was that the hut could not be relocated as it was connected to the feeder pillar. Under normal circumstances they seldom need to be moved, however, due to an unexpected incident outside of our control involving loose masonry on an adjacent building, a scaffold needed to be erected overhead. This meant that the Welfare Unit and compound could not be used until it was safe to do so which resulted in a time delay. These items were used when required and worked almost as well as their fossil fuel powered counterparts. The wacker plate was quite heavy and difficult to manoeuvre but there was not any significant difference in terms of performance or time taken to carry out the activity. The disc cutter worked quite well cutting through the slab, assisted by the fact they were only 50mm thick. However, the battery needed to be changed after every eight cuts, meaning that a fully charged spare battery needs to be ready each time the saw is used. Another concern was its ability to cut through granite kerb if required, as this would take longer, and the battery may not be powerful enough to cope. SPECIFICATION Following discussions with the paving supplier Marshalls it was decided that the slab could be reduced to 50mm thick instead of the usual 63mm. To ensure that there was no reduction in strength Marshalls also designed the foundation. Mortar bedding with primer was specified to provide extra cohesion than sand and cement, which also enables the slab to take the impact of vehicle overrun in the same manner. The deviation from the standard also allowed the team to use a less carbon intensive C10 concrete instead of C20 without any reduction in performance. It was hoped that a low carbon concrete could also be trialled, however, it is not yet readily available as a dry, lean mix used for this type of works. Usually, the kerb line is then reinstated to match the existing carriageway. On King Street this was replaced with GreenPatch, a product manufactured with recycled asphalt and no petroleum-based ‘cut back’ solvents and hand-laid cold. STORAGE To reduce the size of the storage area on site and to replicate the workings of a centralised depot, a separate compound area was set up on Carlton House Terrace. This was less than a mile from site and allowed ‘just-in-time’ deliveries and reduced vehicle movements to King Street.
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TRANSPORTATION
DELIVERIES The largest items were the paving slabs which came from the Marshalls’ depot in Sittingbourne. These were delivered on a low loader to the compound on Carlton House Terrace. The slabs were delivered to site by an FM Conway grab lorry, powered by HVO on a ‘just-in-time’ basis. This meant that the compound on site was kept to a minimum and there was more room to store the excavator securely. Speedy Hire have an electric delivery vehicle which was not available at the time of the trial, but they delivered their equipment in a HVO transit van. All FM Conway delivery vehicles were fuelled with HVO and these made the bulk of visits to site. For smaller items like PPE, we trialled the use of a cargo bike, which is completely sustainable and can carry up to 250kg. During peak hours, deliveries via cargo bike from the Mandela Way depot in Southwark were actually faster than by lorry. To keep the carbon footprint low, no diesel was allowed on site. All deliveries and visitors to site had to use the most sustainable method available to them. Suppliers were asked to deliver either with electric vehicles, or where this was not possible, replace diesel with HVO fuel.
Figure 5 - Demonstrates the sustainable products and plant used
Product/Plant
Supplier
Delivery Method
Excavator
JCB
HVO 7.5t Lorry
Wacker
Speedy Hire Speedy Hire FM Conway FM Conway FM Conway FM Conway Marshalls
HVO Transit Vehicle HVO Transit Vehicle
Disc Cutter Welfare Unit
HVO 7.5t Lorry
Paving Materials
HVO Articulated Lorry
Aggregates
HVO Grab Lorry HVO Grab Lorry HVO Grab Lorry
Concrete
GreenPatch Asphalt
Consumables
FM Conway Stores
Cargo Bike
Waste
FM Conway
HVO Grab Lorry
HVO FUEL Hydrotreated Vegetable Oil (HVO) is a synthetic paraffin fuel that is a direct replacement for diesel as there is no need to modify the existing engines or infrastructure. It is claimed that it reduces greenhouse gases by up to 90% compared to diesel, but for this exercise we have used a more conservative estimate of 50% carbon savings. For now, there are no electric or hydrogen alternatives for larger vehicles, so this is the most carbon efficient way to fuel deliveries. However, this is only an interim solution, as it is hoped that vehicle manufacturers will have electric vehicle options in place well before Westminster’s 2030 deadline for carbon neutrality.
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TRAVEL TO SITE Electric panel vans were provided to the site supervisor and the mason (see Figure 6), whilst other operatives used public transport to get to and from work.
Figure 6 - Electric Van
SITE VISITORS Visitors to site were requested to either travel to site on public transport or via electric vehicles if they had access to one. Some initial site meetings took place via Microsoft Teams to avoid too many people on site during the pandemic. A VIP day was arranged to allow The Westminster Cabinet member for Highways and the Environment, Andrew Smith to see the works in action. He was joined by Westminster Highways Head of Operations Phil Robson, FM Conway CEO Adam Green, and FM Conway Managing Director Andrew Hansen.
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Early engagement with key suppliers was key to the success of the trial as it allowed them to demonstrate their own sustainability credentials and express their excitement at being linked with the project. SUPPLIERS
KEY SUPPLIERS The key suppliers for this project were:
• JCB – Excavator
• Speedy Hire – Electric tools and plant
• Marshalls – Paving slabs
JCB were keen to get their product trialled on a high-profile scheme and provided their excavator free of charge, which showed a commitment to carbon reduction and the willingness to forge a partnership going forward. Speedy Hire also stock a number of different electric items and provided the HVO fuel for the trial. They provided disc cutters from Stihl, Milwaukee and Hasqvarna to try out prior to the job before the team decided that the Hasqvarna model was most suitable. They have also pledged to reduce carbon and have an electric taxicab for deliveries (see Figure 7), which unfortunately was not available at the time of the trial. Likewise, Marshalls have been doing a lot of work in the background to reduce their carbon footprint by looking at their processes and have developed their own carbon calculating tool. The team assisted FM Conway in making the biggest single carbon saving by providing the thinner slab and advising on the shallower foundation for it. We hope to continue working with Marshalls to trial further paving options for carbon reduction in the future.
Figure 7 - Speedy Hire Electric Taxi Delivery Vehicle
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To support the works on the ground, a full communications programme in conjunction with Westminster City Council’s Communications Team was set up. The team launched an awareness campaign, including information on site, social media releases and media relations. MARKETING CAMPAIGN
SIGNAGE To highlight the benefits of the scheme, branded POS was displayed on site. These included:
• Banners
• Courtesy Boards
• Information Postcards
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PRESS RELEASES A joint press release between FM Conway and Westminster was prepared by the Westminster City Council Communications Team and distributed to several major news outlets. This was then distributed across relevant industry trade titles and clients from both parties.
WESTMINSTER’S GROUND-BREAKING LOW-CARBON ROADWORKS Westminster City Council and FM Conway break ground on first of its kind low-carbon construction scheme, revolutionising the way public realm projects are designed and delivered in the centre of London. A six-week project to repair public highways and upgrade the footway in King St in the heart of Westminster will see the exclusive use of electric vehicles, tools, welfare, and recycled equipment, to remove the traditional need for diesel and petrol engines and cut carbon emissions by almost 75% compared to traditional industry methods. • Electric JCB excavators and ground tools • Electric ZipCar for carbon-free transport to and from site • ‘GreenPatch’, an FM Conway recycled asphalt product • Quieter electric equipment will reduce noise pollution to local residents • EV charging points for electric vehicles and tools which will remain in situ for local residents as a legacy of this project • Ecargo bike for small deliveries As a local authority set at the heart of London, Westminster Council delivers approximately £50m worth of public realm repair and rejuvenation projects each year, however, their latest collaboration with contractors FM Conway aims to deliver a ground- breaking change, not only for Westminster, but for the future of the industry. Spearheading this new form of sustainable construction is a key priority for Westminster and FM Conway, who have both set out ambitious targets to achieve carbon neutrality ahead of the Government’s target of 2050. Further measures will include the use of:
Cllr Andrew Smith, Westminster’s Cabinet Member for Highways & Environment: “If we are to truly tackle the effects of climate change and meet our ambitious target of Westminster being carbon neutral by 2030, then we must revolutionise the way we do things as a local authority, this includes the way we carry out our essential daily works and operations.” This scheme is not only ground-breaking but also a catalyst for change in the way we do things. We hope that the success of this trial will see public realm works across the city transform for the better and help us towards maintaining a greener and cleaner Westminster.” “It is fantastic to see this great partnership taking such an important step forward in our ambition to tackle carbon emissions. “As an industry leader for driving innovation and change, it is vital that our collaborative efforts are seen as the foundation for transforming our working practices for the better. We all have a responsibility to protect our planet and with the support of our supply chain, we hope to deliver a low carbon legacy for Westminster and London.” Data collected throughout the trial will be used to calculate the total carbon savings, with the hope that the results can be used to transform how highways and public realms work are carried out in the city. Reducing emissions, noise pollution, road conjunction, and ultimately providing a blueprint for all future works to be low-carbon, low-emission, and sustainable. Adam Green, CEO of FM Conway:
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SOCIAL MEDIA CAMPAIGN A bank of social media posts were prepared by the FM Conway Marketing Team and approved by Westminster City Council’s Communication Team. These were scheduled up to be posted before, during and after the project in order to promote and raise awareness, focusing on the low carbon nature of the trial.
HIGHWAYS UK FIRESIDE CHAT FM Conway secured a speaker slot at the annual Highways UK exhibition. Due to COVID-19, the event was hosted virtually over 3 days, with the first day focussing on carbon and sponsored by FM Conway. The speaker session was led by Vanessa Hilton, FM Conway Head of Carbon and Environment and featured an in-depth discussion on the low carbon trial with Ivan Farrell, FM Conway Performance Manager and Dan Perks, Westminster City Council’s Operations Manager.
WORKING BETTER TOGETHER: SHAPING ZERO CARBON FM Conway hosted an event for their key supply chain to discuss the challenges around the journey to net zero. Phil Robson, Head of Operations as Westminster City Council, attended the event to discuss the low carbon trial and Westminster’s ambitions for net zero. The event was designed to encourage the supply chain to provide further solutions to the current carbon challenge and the results of the problems identified in this low carbon trial.
AWARDS SUBMISSIONS Due to the pioneering nature of the scheme, submissions were sent to the following: • New London Architecture (NLA) showcasing Zero Carbon London case studies under the Public Realm, Infrastructure and Transport projects category
• Chartered Institute Highways & Transportation (CIHT) Awards - Climate Change category
• Construction News Award – Low Carbon Project of the Year
• Highways Magazine Awards - Award for Environmental Sustainability in the Highways Sector
SCHEME PUBLIC LIAISON OFFICER FM Conway’s Robert Burton was engaged as the Public Liaison Officer for the duration of the project. He visited all the premises in the street prior to the works, publicising the works and advising the public on the benefits. He was also available on site every day and received positive feedback from several of the businesses.
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The carbon results have been split down into the operational carbon, which is under FM Conway control and the embodied carbon, which is built into the materials through their manufacture and transportation. RESULTS
OPERATIONAL CARBON RECORDING The site supervisor recorded all carbon producing elements of the operational impact of works daily
This included:
• Travel to site for all staff and visitors
• Vehicle movements including all deliveries to site
• Time spent on power tools and machinery
• Time generator in use on Welfare Unit
The information was taken from the daily sheets and transposed onto a spreadsheet. The total mileage for travel and vehicle movements, and the hours spent on operational tools was calculated. The carbon was then calculated by multiplying these figures against the appropriate carbon values contained within the Government’s conversion factor document and divided by 1000 to give a carbon cost per tonne figure (TCO2e):
Total Miles Travelled/Total Hours Spent x Item Conversion Factor 1000 The results were independently verified by Norman Rourke Pryme Ltd (NRP) and Metis Ltd
CARBON SAVINGS The operations on King Street saved 4.21t of carbon against the Marlborough Hill scheme. This is equal to 71% saving. When this is averaged out per day, the saving that the new method produces is 79% . If these methods were to be implemented across the whole PPM footway programme, over 100t of carbon could be reduced, which would equate to a lorry travelling around the M25 38 times. The prohibition of diesel from site was the primary factor in these savings, which can be seen when the total carbon figures are broken down into:
• Travel
• Deliveries
• Operation
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The carbon for operations was negligible at just 0.02t for the whole scheme, which was because all the plant was electric.
Travel also saw a large reduction of over 70% as all staff and visitors could only come to site by walking or cycling if they were close, public transport or electric vehicles.
Whereas the deliveries accounted for 1.23t which was a 60% saving against Marlborough Hill since most vehicles were fuelled by HVO instead of diesel. However, we have still assumed that HVO has a carbon footprint 50% of diesel.
The total carbon used on both King Street and Marlborough Hill is shown in the table on page 25:
Figure 8 - Graph Showing the Comparison of Operational Carbon Produced on King Street & Marlborough Hill
KING ST V MARLBOROUGH HILL OPERATIONAL CARBON PRODUCED BY TONNAGE
7
6
5
4
3
2
1
0
Total
Travel
Deliveries
Operations
Marlborough Hill
King Street
The above graph shows the total carbon savings made on King Street compared to Marlborough Hill. The breakdown shows 76% saving on travel (0.01t per day), 60% on deliveries (0.03t per day), 97% saving on operations (0.0005t per day).
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Figure 9 - Pie Charts Showing the Carbon Produced by Type Across Both Schemes
MARLBOROUGH HILL OPERATIONAL CARBON
KING STREET OPERATIONAL CARBON
12.90%
35.40%
1.1%
28.1%
51.70%
70.8%
Travel
Deliveries Operations
Travel
Deliveries Operations
The above pie charts show that the operational carbon using electric plant is just over 1% of the total. The deliveries have increased to over 70% of the total and shows where the next concentration of effort needs to go. HVO fuel is only an interim measure and this percentage will come down when larger vehicles are able to convert to electric.
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Figure 10 - Graph Showing the Carbon Breakdown Across All Operations
INDIVIDUAL CARBON ELEMENTS
2.5
2
1.5
1
0.5
0
Vehicle - Grab
Vehicle - Lorry
Plant - Excavator
Travel - Ops
Travel - Sup
Vehicle - External
Plant - Wacker
Plant - Saw
Plant - Welfare
Marlborough Hill
King Street
Carbon Saving
This graph shows a further breakdown of the carbon for travel, delivery and operations. Note that if an electric grab lorry could be utilised it would represent another significant saving.
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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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Figure 12 - Graph showing how the embodied carbon is broken down
BREAKDOWN OF EMBODIED CARBON BY WORKS TYPE
50
45
40
35
30
25
20
15
10
5
0
Site Clearance
Structural Concrete
Fencing
Earthworks
Paving
Marlborough Hill
King Street
This demonstrates that cementitious products are the biggest producers of carbon within highways works and that if carbon is considered at the outset of the scheme, there are opportunities to introduce lower carbon options at the early design stages.
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OVERALL CARBON USAGE
Figure 13 and Figure 14 demonstrate the overall carbon usage for both schemes and the savings made at King Street. They illustrate that the biggest carbon savings are to be made by changing the materials used on the highway. Exploration of recycled and lower carbon products will increase the embodied carbon savings. The operational carbon showed the biggest percentage saving against the comparison site, as the elimination of diesel reduced it to as low a footprint as possible at this stage. Once all vehicles and plant are able to be powered by sustainable fuels the operational carbon will be carbon neutral.
Figure 13 - Table showing the whole tCO2e carbon footprint for both schemes:
Marlborough Hill
King Street
Duration on site (Days)
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40
Distance travelled, inc labour, supervision & deliveries (Miles) Plant usage, inc welfare (Hours) Operational carbon footprint (KgCO2e) Average operational carbon footprint per day Embodied material carbon footprint (KgCO2e)
7540
9394
71.5
114.8
5.95t
1.74t
0.19t
0.04t
40.69t
17.93t
Embodied carbon per m2 Total carbon footprint Carbon footprint per m2
0.13t
0.07t 19.67t 0.07t
46.64t
0.15t
Figure 14 - Table showing the King Street carbon savings
Tonnes Saved
Percentage Saving
Total operational carbon saving against comparison site Operational carbon savings per day Total Embodied carbon saving against comparison site Embodied carbon savings per m2 Total carbon savings against comparison site Total carbon savings per m2
4.21t
71%
0.15t
79%
22.76t
56%
0.06t
46%
26.97t
58%
0.08t
53%
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OTHER ENVIRONMENTAL BENEFITS
NOISE MONITORING Socotec were commissioned to deliver background noise and construction noise monitoring for Marlborough Hill and King Street. Additional testing on each piece of equipment was carried out to give a better understanding of the individual items contributing to the overall noise levels. The results are below:
DISC CUTTER
Petrol (dB)
Electric (dB)
Running Idle at Source Running Idle 3M away
102.6 88.0
84.2 81.7 101.4 87.8
In Use at Source In Use 3M Away
106
92.4
WACKER PLATE
Petrol (dB)
Electric (dB)
Running Idle at Source Running Idle 3M away
106.1
98.2 86.1 100 85.9
91.1
In Use at Source In Use 3M Away
103.4
92.7
MINI DIGGER
Diesel (dB)
Electric (dB)
Running Idle at Source Running Idle 3M away In Use at Source (Concrete breakout) In Use 3M Away (Concrete breakout)
88.7 77.2
68.4 62.7
107.9
107.2
91.5
99.2
The ‘Running Idle at Source’ figures show how much quieter electric plant is compared to diesel. In addition to the above plant, the electric and solar welfare made no additional noise to the ambient noise. King Street ambient noise is marginally higher than at Marlborough Hill and subject to inconsistent very loud noises such as helicopters, vans and motorbikes. The minimum sound recorded was 6dbA higher at King Street than at Marlborough Hill which indicates a consistent higher output background noise.
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OPERATIVE HEALTH & SAFETY The additional benefit of electric plant is the reduced risk to users’ occupational health which covers noise reduction, inhalation of exhaust fumes, plus some electric equipment provided better ergonomics and manual handling. As the Welfare Unit contributes no additional ambient noise, it allows for an earlier start time with minimal risk to nuisance noise for nearby residents.
AIR QUALITY London’s commitment to reducing air pollution goes hand-in-hand with the electrification of plant and tools which are zero emissions for Carbon Monoxide (CO), Sulphur Oxides (SOx), Nitrogen Oxides (NOx) and particulate matter.
SCHEME LEGACY The scheme has provided the first step on the journey to carbon neutrality. The analysis of this model has demonstrated further sustainable benefits which include the introduction of two rapid charging EV points for residents. Also eight cycle stands were originally located within the new EV bays, which have been relocated in the area along with another eight stands that were taken from another scheme and due to be sent for recycling.
On completion of the scheme a ‘Lessons Learnt’ review was undertaken with the site team. An overview of the findings is detailed below. SITE FEEDBACK
SUCCESSES The team were pleased with the Welfare Unit, which was a lot quieter when compared to the units using diesel generators. This meant it was more peaceful for them inside when the power was on and also that they could arrive earlier on site to prepare for the day if required as the noise was not a nuisance to the neighbours. The excavator was also quieter, making communication easier and better for the occupational health of the operatives, whilst being less of a disturbance for neighbours and passers-by. The hand tools worked well in general, although it was noted that the electric disc cutter could only manage eight cuts per battery charge. This problem, however, was mitigated with good planning and the use of spare battery packs. It was also felt that the electric saw may not work so well if it was required to cut granite kerbs and that the wacker was also heavy and difficult to manoeuvre, however they both worked as well as the standard version.
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CONSTRAINTS There were also some site constraints that the team needed to overcome. The concerns were mainly around power and supply of plant.
• Power:
• Need to charge everything off the feeder pillar
• No power pack available making charging more difficult
• Different items have different connectors so changes were made to the feeder pillar
• Charging must be done during day
• Smaller plant could not be charged in Welfare Unit
• Suppliers & Plant:
• Limited choice of plant
• No deliveries with electric vehicles
TESTIMONIALS
“We hope that the success of this trial will see public realm works across the city transform for the better and help us towards maintaining a greener and cleaner Westminster.” Councillor Andrew Smith, Westminster City Council Cabinet Member for Highways & the Environment “In regard to the recent pavement works I would like to extend my thanks to yourself and the team carrying out the works. The communication has been great and assisted greatly in keeping my building occupiers informed. As for the works themselves I was quite surprised at how quiet they were with the use of the electric machinery. Noise disruption is probably the most complained about part of any works that take place within or in the surrounding area of the building so it was great this wasn’t a disruption factor here. As it happens, I did not get one complaint for the entire duration of the works.” Alex Hall, Building Manager, Almack House, BNP Parabas Real Estate
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FINANCIAL IMPACT
For this exercise we have used the original estimate for the scheme as the cost comparison as the scheme had already been designed prior to the switch to low carbon. This gives us the best indication of the additional costs for the introduction of low carbon measures.
As expected the measures had a significant bearing on the cost.
This is due to several factors:
• It was a stand-alone scheme, meaning that all the plant, labour and material costs were only charged against this job even when not in use. Therefore, there was an inefficiency where costs can normally be spread across several jobs. • Works are normally charged against the agreed schedule of rates per item. However, these rates are built up from the standard plant, labour and material costs. This meant that as different materials and plant were being utilised the standard rates could not be used. Instead, the costs were based upon defined cost, and upon the actual charges for the plant, labour and material. • Electric plant is still in its infancy, and due to research and development costs and lack of supply, they tend to cost three times the purchase cost of standard equipment. • As this was a pioneering scheme there is currently little available power in the network to allow equipment to be charged, which resulted in an expensive feeder pillar needing to be installed as part of the works. • Stand down costs were incurred when an emergency scaffold was erected adjacent to the works compound. Under normal circumstances the Welfare Unit could be easily moved to another location, however on King Street it needed to be connected to the feeder pillar. • Further stand down costs were raised when the JCB sustained some hydraulic problems, unrelated to the electric power. Again, due to the scarcity of supply the machine could not be swapped out for another one. • Other impacts on efficiencies such as getting used to the new equipment, priming of paving slabs and demonstrating the tools in action to visitors on site. COST OF SCHEME Before the scheme was identified as a ‘Low Carbon’ site it had previously been designed as a standard PPM scheme. The estimated cost for the extents under the schedule of rates came to £41,000. The final cost of the scheme has come in at circa £94,000. At first glance this would appear to make a full rollout of the carbon model prohibitive. At more than double the cost of a standard PPM scheme it would have a severe effect on the amount of schemes that could be undertaken in any given year. The further knock-on effect would see a deterioration in the network and an increase in the number of reactive jobs raised. This would result in a further detrimental increase in spend on the revenue budget for Westminster. However, upon further analysis it is not a like-for-like comparison. The estimate is purely based upon the existing schedule of rates. Presently, there are no schedule rates for low carbon operations, so the costs were calculated using defined cost. These are naturally higher as they are not based upon the economies of scale of the contract. In addition to this there were a number of costs experienced that would not normally be encountered when implementing PPM schemes. These extraordinary items have distorted the final amount and are outlined below.
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ANALYSIS OF ADDITIONAL COSTS Within the total bill of circa £94,000, nearly half (£45,000) can be attributed to extraordinary cost. These are essentially costs attributed to this scheme that we would not usually expect to see, and it is hoped they would not be so significant in future. They fall under the below categories:
• Provision of power
• Changes to the specification
• Replacement of diesel with HVO
• Marketing costs
• Monitoring costs
• Lost time costs
One of the biggest barriers to an easy rollout of this working model is how the machinery can be powered. There were no existing EV Chargers within the footprint of the works and no generators were allowed on site, which meant that a feeder pillar needed to be installed to charge all the electric equipment on site. At the end of the scheme this was converted into two EV Charging points for residents. Typically paving will fall under the schedule of rates, but to ensure the thinner slabs were able to withstand the usage of the street, primer and grout was applied. Going forward if this specification is to be used more frequently a scheduled rate will be agreed to bring it into line with existing rates. As this low carbon scheme was managed as a stand-alone, the cost of the HVO fuel was also treated separately. At present market rates it is about 40% higher than diesel. However, if this is to become the accepted substitute for diesel it will also become incorporated within the rates. The marketing costs were for the bespoke banners and signage highlighting the benefits of the scheme for passers-by and also the public liaison delivered for the local businesses and residents. In addition to this, noise monitoring was carried out to understand the noise difference in the equipment, this exercise will not need to be done again. Finally, the largest contributor to the extraordinary costs were the stand down charges, which were due to events outside the control of the site team. An emergency scaffold was erected adjacent to the site compound, making it unsafe to use. Under normal circumstances the Welfare Unit could have been moved with minimal disruption but the fact that it was plugged in to the feeder pillar meant this option was not viable. A second event where the mini excavator needed the hydraulics to be repaired also resulted in lost time. Again, under usual circumstances the machine could have been swapped for another one, however, in this case a lack of supply of back-up excavators meant the job had to be halted.
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