Electrifying Journey

Charging an Electric Bus Fleet With Self-Generated Power


Medium-sized businesses / SMEs, Mobility + Traffic, Tourism
Kochkommt Elektrotechnik

The background

Mario König and his father Lutz run the bus company Salza Tours based in Bad Langensalza, Germany. With its 40 employees and 20 buses, the family-run operation offers services in the local public transport network as well as long-distance coach travel. Almost half of the buses operate in the local public transport network. Although some buses travel all across Europe, the focus of the oper ation is in the Unstrut-Hainich region.

The challenge

Part of the company philosophy of Salza Tours is to take advantage of technical innovations to benefit customers and the environment. As far back as 1993, the company was already using locally produced bio-diesel as fuel for some of its vehicles. When use of the rapeseed-based fuel became too expensive due to a tax increase, the Königs sought an alternative power concept. They weighed up the relative merits of hybrid and electric vehicles and in 2016 acquired their first electric buses with support from the Thuringian government. The company first bought two SILEO S10 city buses with a battery capacity of 200 kWh, and later added a SILEO S12 with 220 kWh for long-distance travel.

Initial procurement costs for electric vehicles, however, are roughly twice that of diesel vehicles. To ensure economical operation, Salza Tours had to negotiate a longterm rate agreement with the local energy supplier. But with rising electricity prices, in-house production of electricity became increasingly attractive, and the company ultimately opted to install a photovoltaic system. With top-up charging impractical in urban transport, Salza Tours generally uses the system to charge the buses overnight. But because the photovoltaic installation only produces electricity during the day, Salza Tours needs a way of storing the electricity.

The requirements for a storage solution:

  • High storability with many guaranteed cycles for sustainable provision
  • High output power with high C-rate to charge electric vehicles quickly

The solution

Through an EU tender process, Salza Tours found a suitable installer for the energy and storage systems. Kochkommt Elektrotechnik subsequently installed three charging stations with TESVOLT battery storage systems of the type TS HV 70. Together, the storage systems have an energy content of 460 kWh and a discharging power per charging station of 75 kW. This enables SalzaTours to deploy the S12 for long-distance travel, as the bus can drive the whole day with a top-up charge in the morning.

The advantages

• Energy price independent, self-sufficient charging of their own electric buses with daily ranges of up to 280 kilometres

• Free battery charging instead of EUR 30–40 from the utility grid

• Given the substantial subsidies, major reduction of investment costs – amortisation in under 8 years

• Powerful and responsive
Thanks to the battery management system, TESVOLT storage systems make the energy they accumulate fully available. TESVOLT storage systems are 1C-capable, meaning they can be fully charged or discharged within an hour with the proper configuration. This makes it possible to operate powerful consumers independently of the utility grid or to charge electric vehicles quickly.

• Safe and long-lasting
The system boasts an above-average lifespan of up to 30 years thanks to extremely robust Samsung battery cells and the one-of-a-kind battery management system. This optimises cells not only within a single module but also between modules within a cabinet.

• Expandable
TESVOLT systems can be expanded or exchanged at any time – not just after the first few months of operation but even many years later.

Key figures and facts

Storage type:
TS HV 70
460 kWh / 75 kW

What we particularly appreciate about the storage systems, which provide such great benefits to us, is that they inconspicuously do their duty here without us having to do anything.

Mario König, Managing Director of Salza Tours König OHG

At first I was doubtful that the storage system could charge the buses fully. But now I’m completely convinced by the TS HV 70 because it does what it says it will.

Thomas Koch, principle installer at Kochkommt Elektrotechnik