During early October the Eastern region of Network Rail completed its first zero emissions engineering work.
The engineering work was associated with renewal and upgrade of the overhead line equipment through, and either side of, Royston station, involving the replacement of components supporting the catenary and contact wires. Many of the parts being replaced dated from 1978 and were therefore 45 years old. This work was scheduled to be completed over four successive night time possessions of both the up and down lines through the area. The work was successfully completed with zero carbon emissions by the use of novel welfare facilities and of hybrid, on-track machines which relied on battery power throughout the work.
Hamish Critchell-Ward, environment manager for the Eastern Region of Network Rail, outlined the objectives of piloting zero emissions working which forms part of plans to get to net zero by 2050.
This particular site had been chosen as it fulfilled a number of the requirements for a first trial of zero emissions and low carbon working. These included the scale of the work and the relative accessibility of the site.
The whole site was supported by an 80kWh battery that provided power for the welfare facilities and recharged the on-track machines ready for each of the four overnight possessions. The 80kWh battery had itself been charged off-site, using a large solar array, prior to being transported to Royston for the establishment of the worksite.
On-site lighting around the welfare facilities was provided by battery supported, solar charged, LED tower lights whilst lighting for the work was again provided by battery powered LEDs. In addition, the other tools used were battery operated and all consumable materials were recyclable.
Carbon costs
Hamish identified that currently such working has a slightly higher initial cost, fundamentally due to the battery and its support arrangements, but there are a number of hidden costs associated with diesel generators that ameliorate this. They include not requiring diesel fuel to be brought to site, with associated risks of spillage and containment, and the costs of topping up if required. In addition, the battery is claimed to function over 4,500 recharge cycles which, even at a daily recharge rate, would equate to around 12 years working life. A diesel generator is likely to require several maintenance visits over that period adding significantly to its whole life cost.
In practice the battery on site had commenced operation at around 90% charge and, after providing power to the worksite welfare facilities and charging the hybrid on-track machines for the duration of the work, still had 28% capacity remaining at the end.
A quieter solution
Other benefits of using battery power included the use of some of the first hybrid, on-track machines. As hybrids, these have both a diesel engine and a battery suitable for relatively short distance movement. On this site they were able to be restricted to battery-only operation with very marked reductions in noise. Indeed, the loudest element of the work was the warning sound that beeped whenever the unit was moving.
The fact that the welfare site was also battery powered meant no need for a grid connection or the alternative of a diesel generator, with a further reduction in noise. This has the added benefit of reducing disturbance to railway neighbours, especially during night works, and thus reduces the risk of work being curtailed due to complaints.
Suppliers
Vanguard Services Limited (VSL) provided the welfare facilities in the north car park at Royston station. These were supplied with energy from the 80kWh battery with associated external LED lighting, equipped with their own battery supply recharged using solar panels and small wind turbines. The hybrid on-track machines used for the actual overhead line work were recharged during the day, again from the 80kWh battery in the compound area.
Genista Energy, based in Dundee, supplied two products from its range to VSL to support the work at Royston. Gadget Gen80, one of its mobile battery storage systems, stored the necessary energy to power the welfare facilities, provided the welfare area lighting, and delivered the power to the Electric Vehicle Charging System which recharged the hybrid on-track machines, also supplied by Genista.
Both products are suitable for delivery to site, even relatively remote sites as may be found trackside. The entire operation was therefore able to work off-grid and demonstrated that being off-grid need not be a challenge even when vehicles need to be recharged. Neither of the Genista products have any moving parts and, being relatively new, they are fully equipped with remote monitoring systems that facilitate management and supervision from afar.
The on-track plant was provided by Pro Rail Services based in Welwyn Garden City. They provided four hybrid MWEP/RR14 EVO-2-400 machines that successfully completed all work, from on-tracking through movement to site, working, and return to off tracking, in battery mode. Thus, no diesel fuel was used as part of the work. Pro Rail services prides itself on innovation and sustainability, especially leading to a low carbon worksite, and this was a useful project to demonstrate these capabilities with modern on track plant.
The machines themselves have an articulated and telescopic boom lift with a cage capable of holding up to three people and maximum operating weight of 400kg. The hybrid version has a 400Ah lithium battery driving two 5KW AC electric motors. The battery can support movement over a maximum of 12km, or over shorter distances combined with lifting and working as required. There is an onboard battery management system to control the battery operation and provide an onboard display of the current battery condition. As hybrid units they are also equipped with a diesel engine designed to use HVO fuel and a hydraulic pump able to operate the machine functions and, if necessary, complete off tracking.
A success story Overall, the work at Royston demonstrated that working towards a low emission environment with battery electric systems can deliver significant benefits and is already achievable for the right project scope. Indeed, it is estimated the use of battery energy storage at Royston saved around 750 litres of diesel fuel which delivered a saving of around 2.5 tonnes of carbon dioxide emissions. With ongoing developments in the technology, especially battery capacity, much more can and will be achieved in the near future.
