Project Summary
Traction Bulk Supply Points are large capacity grid connections designed to support peak demand on the rail traction system. Because traction power is typically very peaky in nature this capacity is not optimally utilised. Installing battery storage facilities at traction BSPs and unlocking connection agreements to enable two-way dynamic flow could shift rail energy demand away from peak periods, unlocking capacity for other customers; support regional balancing of supply and demand; fulfil unmet demands for flexibility services in areas with network constraints; and increase the commercial scope for new tractionconnected generation capacity, replacing curtailment with load shifting and export capability.
Innovation Justification
As one of the UK's largest electricity consumers, railways should participate in flexibility markets as given their scale, they offer significant benefits. The challenge is overcoming unique barriers preventing T-BSPs from becoming flexible. The Southern Region (DC-railway) is the densest part of the GB electrified rail network, consuming around one third of all traction electricity used by NR.
This project addresses the challenge of transforming non-flexible demand into dispatchable and dynamic demand, releasing capacity across the network and enabling faster demand and generation connections (SIF R4 Challenge 1). This differs from the existing SIF HUBs project, which designs power electronics for charging battery electric trains where grid capacity is limited.
For dynamic power electronics on the DC rail system, we estimate to be -- IRL3; CRL4; TRL3. These levels will be investigated during Discovery but will likely not change until future phases.
Appropriately designed battery storage assets can minimise peaks and troughs from rapidly changing traction demand and provide reactive power compensation to manage the power factor. Railway demand cannot be made flexible without either adding generation or storage to the railway system, although power quality issues on the DC networks means this is not currently possible.
The potential uses cases, financial value and internal business case for lineside storage on GB railways remain unassessed. NR's Southern Region has a live R&D project exploring DC-third-rail-connected flywheel storage for regenerative braking, which this project will build on.
A potential commercial barrier for optimising T-BSPs may be the need to modify legacy connection agreements, which can be over 70 years old and certainly never envisaged these demand assets as bi-directional nodes in a flexible system.
NR has little experience facilitating dynamic grid interactions using their infrastructure to provide non-rail services to the wider energy system. Currently NR is remunerated for electricity export from regenerative braking under their main traction power supply contract (classed as de minimis activity), though this applies to BSPs supplying AC traction systems, not the DC traction system.
Progress on the potential of utilising the DC rail system flexibly has previously been unfocussed and not considered whole system benefits. A new approach is required to quantify these and demonstrate the aggregated benefits for consumers of both rail and electricity.
Impacts and Benefits
The pre-innovation baseline is that the capacity in the rail network continues to be utilised inefficiently with peaks and troughs throughout the day. As the communities around these BSPs decarbonise, they will increase the electricity demand in their region and could be faced with high-cost and time-consuming reinforcement to the network. The potential to shift load on the railway will not be utilised.
Unlocking connection agreements, Conductor will enable two-way dynamic flow across T-BSPs could also support regional balancing of supply and demand within the higher voltage networks. This will increase the amount of flexibility fulfilling unmet demands for flexibility services.
Financial - future reductions in the cost of operating the network
Adding storage assets to NR's T-BSPs will reduce peak demand. Through flexibility services the need for network capacity reinforcement will be reduced. During peak demand periods, NR can supply electricity to the distribution network, releasing capacity and helping balance the load. This benefit will be tracked by measuring avoided and deferred reinforcement costs.
Financial - cost savings per annum on energy bills for consumers
Lower costs of upgrading the infrastructure and operating the network will reduce the network cost element of consumer bills. This will be tracked by annual customer bill savings.
Environmental - carbon reduction -- direct CO2 savings per annum
Optimising installation of lineside renewables could enable faster and cheaper rollout of low carbon train operations, should rail ways adopt ownership of these assets, therefore achieving immediate reduction in direct CO2 emissions. This will be measurable through tonnes CO2 reduction per annum.
Environmental -- carbon reduction -- indirect CO2 savings per annum
Conductor will unlock new flexibility enabling more potential for storage and PV to be connected, and connected faster. . The increase of storage within the distribution network could enable more demand to be met by locally produced renewable electricity therefore indirectly reducing the CO2 of electricity consumption. A greater utilisation of renewables reduces CO2 impact of electricity generation. This will be measurable through tonnes CO2 reduction per annum.
