Rail is the single largest electricity user in the UK, consuming 4 TWh electricity pa (1.2% of UK total), with projected 3TWh electricity demand increase along with railway decarbonisation, requiring £18bn to £26bn investment.
This project will investigate for the first time the feasibility of developing resilient and flexible railway multi-energy hubs around 2500 railway stations and connecting these hubs to form a hub network, with the following objectives:
1. "Efficiency and flexibility improvement" – Maximise opportunities for zero-emission transport modes to deliver smarter energy systems at these stations through coordinated energy supply, power to trains, electric vehicles and buses, non-traction power and energy demand, V2T, V2S, and V2G.
2. "Emission reduction" – Integrate local renewable energy production and energy storage.
3. "Power security" - Strengthen traction power supply along 10,000 miles railway routes by networking the hubs to support on-going railway electrification and decarbonisation and to meet the growth of railway services.
4. "Power grid support" – Improve power grid resilience and flexibility by providing services where possible, such as demand side response, frequency and voltage support.
The discovery phase will select a small sample of suitable railway stations to investigate the feasibility of multi-energy hubs design, addressing the following issues:
1. Energy efficiency and system flexibility improvement potentials of energy hubs.
2. Uncertainties and operational risks.
3. Suitable power electronics architecture to meet AC and DC power demand and exchange at different voltage levels.
4. Operation and control challenges to coordinate energy conversations and exchanges.
5. Business models.
This project will deliver:
• Energy efficiency analysis tools to support Network Rail maximise efficiency improvement potentials around 2500 railway stations.
• Stakeholder engagement to convert sample railway stations into energy hubs in alpha and beta phases to support roll-out of the energy hub technology in achieving decarbonisation of 60% unelectrified routes with reliable traction power supply by 2050.
This project is led by SP Transmission plc and SP Distribution plc with three partners of substantial expertise in energy innovation, railway electrification and rail economics - Network Rail (infrastructure provider): railway expertise and data; University of Leeds (academic user): railway power electronics and railway economics; Ricardo (3rd party innovator): electricity supply decarbonisation and novel power electronic devices connecting traction network to distribution network.
This project addresses the security challenges facing both railways and power sectors when the future energy system almost entirely runs on low carbon energy sources.
Problem Bring Solved
• Transportation generates the largest share of GHG emissions in UK (34% in 2019), 60% British rail has not been electrified, diesel trains produce 1.6 MtCO2e pa.
• Rail decarbonisation requires extensive network upgrades which are often complex and extremely costly, e.g. rail electrification costs £1 million - £2.5 million per km.
• Railway traction power supply lines span wide areas, with feed stations connected to different electric grids (strong grids coexisting with weaker ones), power grids faults may cascade down to the traction power supply systems, causing trains to stall on track and cancellation of service routes, resulting in significant economic losses and public dissatisfaction.
• Integration of intermittent renewable generations to power grids at all voltage levels imposes significant challenges to grid operations, further complicating a reliable power supply to the railway.
The opportunities:
• Railway stations in populous, urban areas are interchange points between different mobility modes travelling to/from the station and rail. Energy exchanges at these station locations are huge and can be made more efficient through novel power electronics solutions and whole system coordination.
• Significant V2X potentials (vehicle-to-grid V2G, vehicle-to-train V2T, vehicle-to- station V2S). Of the 388m rail passenger journeys made in 2020-21, if 1% travel by EV to the station, the aggregated battery storage is in the range of ~200GWh. While over 300 category C or above stations are big energy consumers, e.g. a high-speed railway station consumes 117-470kWh/(m2.a) for non-traction purposes e.g. lighting, HVAC.
• Railway traction uses over 4 TWh of electricity p.a., if all routes are electrified, this adds 3TWh. Taking 1% of the energy consumptions (for both traction and non-traction purposes) at all station locations results in an aggregated energy saving and/or shiftable capacity in the GWh per day range, hence offering significant flexibility capacity for power grid operation to accommodate more renewable generations.
By converting train stations into a first of its kind multi-energy hub network, the project provides the following customer benefits:
• Energy/cost savings (by avoiding electrification works)
• Significantly reduced carbon emissions (by removing diesel generation)
• Reduced traction power supply faults, hence reduced passenger delays, and increased satisfaction and use of train travel, therefore increased revenue
• Enhanced power grid operation (via demand side response, V2G, and grid service provisions)
• Improving the stability of critical infrastructure for both railways and power sectors when the future energy system almost entirely runs on low carbon source
