Green Train Fleet

Electric trains consume roughly 40 MW in Denmark which could provide up to half of the frequency service needs in the ancillary service market in DK1. The project will investigate the technical potential of flexibility from the Danish electric train fleet and give recommendations for the most suitable and economic use of the train fleet flexibility in today’s flexibility markets.
This will be achieved in 4 steps:
1. The available potential of electric train flexibility will be assessed and quantified in terms of energy and power flexibility within the Danish price areas. Historical data on train location, speed and power consumption is a crucial asset and will enable us to model and quantify the train flexibility at different times of the day and various operation modes.
2. A forecasting and optimization algorithm will be developed that maximizes the amount of flexibility that can be safely provided to the power system without impacting railway operations on a critical level. The algorithm will predict the securely available flexibility of the train fleet one day before operation. This will help DSB to commit their flexibility in day-ahead markets in a smarter way. To this end, Gridlynx will play a crucial role in providing their solution with pending patent in order to enable this innovation for DSB.
3. Furthermore, the algorithm will support short-term flexibility estimation in real-time operation which monitors the train fleet continuously and computes the flexibility margin on a rolling horizon basis. This algorithm will dispatch the trains in real-time, based on power system real-time needs. Here, Energinet can provide historical real-time frequency data such that realistic operating conditions can be simulated.
4. In parallel, the feasibility of stationary storage solutions at train stations will be investigated for power demand peak-shaving with electric trains during accelerating and braking. For instance, a flywheel at train stations can be charged with the energy of a braking train and discharged when the train is accelerating, thus limiting the peak power demand drawn from the grid. This allows to reduce both energy cost, and potentially also reduce the substation power rating.

The electricity consumption used for traction is critical infrastructure and would in practice not be used to provide flexibility. However, the electric heating and ventilation system can temporarily be used to provide ancillary services like FCR-D. Potential FCR-D revenues are around 1-2 million DKK per year for a fleet of 100 S-trains in the Copenhagen metropolitan area.

Climate change and emission targets are driving rail electrification. Electrically driven trains will consumer around 1% of the Danish electricity. And they can help with integrating renewable energy!
How? By being flexible when the power system needs it. Transmission system operators use a portfolio of ancillary services to balance the grid and to help integrate renewable energy. Electric trains can temporarily shift energy consumption and get compensated for delivering this flexibility. A win-win-win for the train operator, transmission system operator, and the environment.
Instead of building batteries, we can use the existing rail infrastructure to provide flexibility services.