Smart charging system and tomorrow’s battery bank
Electrification is essential for phasing out fossil fuel-dependent energy sources and transport. But as more and more electricity is required for businesses, industries and transportation, the challenges of power supply fluctuations and overloaded grids are becoming increasingly apparent. Nobina has therefore developed an advanced optimised charging system to ensure that charging does not overload the grid, and can also support the grid when needed.
Right amount to the right bus at the right time
When many people use a lot of electricity at the same time, the price of electricity rises for everyone. To balance electricity consumption and lower prices, we need to spread energy use more evenly throughout the day. Electricity prices are also influenced by the weather since in the Nordic countries, we have a high share of renewable energy such as wind and solar power in our electricity system.
The Nobina E-Mobility Management System (NEMS) manages the charging of Nobina’s electric buses intelligently. The aim of NEMS is to charge as few buses as possible at the same time, and to avoid charging when electricity prices and the grid load are highest. The system manages the charging automatically so that each bus receives the right amount of energy for its upcoming journeys.
“The optimisation is based on our timetables and the deployment of vehicles that takes place every day. NEMS retrieves data from the operations system to determine which buses are scheduled to go out and the routes they will be taking. The system creates an optimised charging plan in real-time based on when the buses will be used, how they’ll be used, their technical specifications and the capacity of the grid,” says Sammy Johannesson, product owner of NEMS at Nobina.
Energy savings of up to 40 percent
The optimised charging system also uses spot price optimisation to avoid spikes in electricity prices, which can fluctuate considerably. “NEMS considers the total power we have available at a depot and the price fluctuations over the coming 24 hours to avoid price spikes. We mainly charge at night when electricity prices are lower, and we can also distribute the charging over many hours. Both aspects help us to reduce the grid load while also lowering our operating costs,” says Sammy Johannesson. The results speak for themselves. NEMS can reduce Nobina’s electricity costs by up to 40 percent, while also decreasing the need for grid capacity by up to 45 percent when establishing new depots.
Tomorrow’s battery banks
But the system will be able to do much more: Balancing services that can support society by optimising charging based on grid frequency are currently under development. When demand is high, the grid needs additional power to maintain the required frequency of 50 hertz in order to keep the grid stable. Nobina’s charging infrastructure can then step in and support the frequency. This creates a dynamic interaction that helps the grid, and the entire community, to balance electricity consumption and supply.
Nobina is also looking into the possibility of using ‘retired’ bus batteries as a source of energy. Batteries that have reached the end of their service life for powering a bus can still have the capacity to serve as power banks. “We are exploring many different avenues, such as combining multiple batteries and using them locally.
For example, using and saving solar energy at a depot so that we can use it when electricity is most expensive and demand is highest,” explains Ema Ceco, Head of Electrification at Nobina.