ENVIRONMENTAL SUSTAINABILITY IN NUMBERS
- More than 3 million tonnes of excavated spoil contributed to the creation of Jubilee Marsh as part of the Wallasea Island Wild Coast project
- Up to 72% cement replacement is helping reduce carbon emissions
- Approximately 2.5 million tonnes of CO2 reduction expected over the 120 year life of the railway
- Over 10,000 objects unearthed in one of the most extensive archaeological programmes ever undertaken in the UK
AIR QUALITY
The Crossrail project is of great scale therefore to help reduce the impact on air quality from diesel emissions, Crossrail uses diesel particular filters or cleaner Euro Stage IIIB engines on construction plants and equipment. Additionally, due to the scale of the project, they are able to stimulate the market therefore the benefit of the reduction of diesel emission also helps other projects, mainly small scale projects as they are unable to effect this level of change.
Within the Low Emission Zone of London, 84% of the equipment used are fitted with emissions controls while a further 10% of equipment were exempted as it was not practically viable to fit emission controls. The air quality in London, especially the areas close to the Crossrail sites, will improve as a result of using these cleaner engines. Some plants and specialist pieces have difficulty implementing these filters therefore Crossrail has allowed for them to be used without the filters. To identify the plants and equipments that uses a form of emission control, some contractors attaches a form of sticker.
The Department of Transport has a Clean Air Fund where green walls are being installed around London to help reduce the pollutant coming from traffic emissions by 10% and 20%. These green walls and planted with plants that flourish in urban environments that will improve the air quality my a reduction in carbon dioxide levels, dust and pollen as well as provide a new habitat for wildlife.
WATER
Crossrail is working together with the Environmental Agency to ensure a proper management and protection of water resources during the project. The largest water consumption is for the tunnel boring machine and spraying of the concrete lining. The train with the mobile concrete batching plant that is used to build the new tracks is cleaned daily and to be able to perform this without contamination of the water, a bespoke concrete washout pit is required. The wash water is then treated to be used for the concrete batching therefore reducing the amount of clean water used. Crossrail is also undergoing a restoration of the contaminated groundwater around historic industrial sites enabling the area for future works. The design of the operational railway has also factored into account water saving features such as low volume flush, leak detection systems for stations and rainwater harvesting that is to be used for washing the trains.
BIODIVERSITY
The area around the existing and new railway tracks, station and depots are designed and built to support wildlife. To be able to protect and improve the environments touched during the project, Crossrail uses the DEFRA biodiversity accounting methodology to analysis the habitats created and lost. One of the habitats being created is done by using the soil from the excavation for the new Crossrail’s tunnels and stations to create a wildlife reserve at Wallasea Island in hopes to home thousands of birds of all species.
MATERIALS AND WASTE
The construction of Crossrail has generated large volumes of waste and excavated material therefore Crossrail has implemented the waste hierarchy in aims to largely reduced, at least 90%, the amount of construction and demolition waste going to landfills as well as reuse 95% of the excavated material.
This large volume of excavated material has been reused in many sites across the south-east and London for recreational and agricultural uses, one of which is Wallasea Island as state previously. It was transported away from the construction site by rail or water transport which helped reduced the number of lorries travelling within London.
As Crossrail will be a major consumer of resources throughout its lifetime, the amount and type of materials procured are carefully analysed to ensure the best environmental approach. Of the new construction materials procured, about 15% of it in value comes from reused or recycled sources. At the closing of the financial year 2015-16, it was seen that the project had reused or recycled 97% of its construction and demolition waste and 99% of the clean excavated material, all of which surpassed their initial goal.
ENERGY EFFICIENCY AND CARBON
Carbon footprint
The construction stage of the project is estimated to produce 1.7 million tonnes of CO2. Once operational, it is predict to have an annual savings ranging from 70000 to 250000 tonnes of CO2 arising from the replacement of diesel trains and reduction of car journeys. Therefore after about 7 to 25 years, there will be a net saving of CO2.
Crossrail targets to reduce their carbon emission during construction by 8% each year with FY2014-15 achieving 11%. They are also aiming to reduce embodied carbon in construction material. To achieve this, they are reducing the material quantities used as well as the cement used for concrete. They targeted to replace at least 50% of the cement used and achieved a reduction of 72%. Due to nature of the project being underground stations and the physical constraints of the sites, the project cannot utilise renewable energy. Therefore, the oversite developments should be designed with technology to be able to capture the ground heat. A solar photovoltaic array will be included in the final design of the Whitechapel station which will provide a large proportion for the energy requirements of the station. The lifts and escalators that will be used for the new stations are also more energy efficient as well as each station being installed with lighting controls and electricity sub-meters. All of these will be incorporated into a building management system to allow for the optimisation of the station’s energy performance. It is predicted that the entire Crossrail project from the start of construction through the lifecycle of the project will have a total carbon saving of 2.5 million tonnes.
Energy saving
The project has introduced many initiatives to help reduce the electrical and fuel cost. As a result of the initiatives, the project has benefitted from a cost saving of £2.2 million. Some of the electrical savings initiatives include the use of LED lighting during construction and fuel saved by using electricity rather than fuel generators. All these initiatives has also led to a reduction of CO2 emission.
LED lighting
LED lighting will be used for the underground tunnels and stations which also includes the tunnel maintenance and emergency access lighting. The use of LED lighting allows for environmental, economical and social benefits. It has reduced the operational and maintenance costs by being more energy efficient, longer lasting bulbs and less frequent maintenance. The station also has a brighter environment as a result thus improving the health and safety for the workers and commuters.
New trains
The Class 345 Rolling Stock programme for Crossrail’s new trains will help meet their goals for energy efficiency by reducing the mass of the trains as well as introducing a regenerative braking system where the motors are used in reverse to act as a break which allows from energy to be obtained, a smart control system for lighting, heating and air conditioning and an advisory system for the driver to help use energy efficient driving techniques. The maintenance depot has also incorporated an energy efficient and low carbon design which includes solar thermal photovoltaic panels, energy piles (where the piles incorporates water filled pipework loops to allow for heat extraction from the ground for the depot) and rainwater harvesting for the cleaning of the trains. These incorporated designs for the depot help reduce the operational carbon emissions by 35%.
Tunnel alignment
To better improve the efficiency of energy use for the trains, the tunnels have been designed to help the trains brake and accelerate by adjusting the gradient of the ground level where the train enters a station on an uphill to assist with breaking and exits on a downhill for better acceleration.
Hybrid equipment
The project is also encouraging their contractors to use hybrid equipment where it combines an internal energy storage system with an internal power producer, combustion engine or an electrical motor, on all their sites. Some are also using hybrid excavators and hybrid tower lighting. The use of the hybrid tower lighting has allowed for a 47% reduction of carbon emission.
Hydrogen fuel cell
Hydrogen fuel cells used to power a noise monitor which leads to a carbon saving of 101 tonnes