IEEE Electrification Magazine - March 2020 - 10

standardized solution, old systems, outdated policies, and
the evolving requirements and pressures from the EU Commission remain ever-present, resulting in slow cooperation
from member states. In other words, the biggest challenge
is not the technology itself-nor a lack of business understanding-but rather agreeing upon how this technology
should be implemented. In the meantime, sending data to
a country that is not part of the Erex system depends on
when they can and are willing to exchange data.

Erex Settlement
When it comes to energy billing, the infrastructure manager for the country where the train has been running is
typically responsible for collecting the associated costs
from the consumer. In this case, that consumer is the
train operator. Historically, this means that train operators
must talk to the infrastructure managers in each country
and report the weight of their locomotives as well as the
distance traversed during each train journey. From there,
the infrastructure managers calculate the consumption
factor-the average energy consumption of the train per
ton and kilometer-and then bills the train operators
according to that calculation. However, the way this calculation is made differs from country to country due to variations in national rules and in the manual reporting done
by train operators.
A traditional settlement system will only handle the
statistical data of train runs. Figures regarding weight and
distance are reported by the train operators, then translated into an estimate of energy consumption, using general factors. Train operators are invoiced based on these
estimates as well as average energy prices. While the

general rules between EU member states are very similar,
some countries only collect these data from the small
train operators running on their network and subtract the
corresponding energy costs from the overall bill for the
month. The main train operator-their biggest consumer-is then billed for the rest of the energy consumed for
that period. If any of these smaller train operators don't
report the necessary information about how they've been
running their locomotives on the network, then the main
company has to pick up the bill for it. So, invoicing traction energy based on an estimation is not fair for train
operators, nor does it accurately reflect consumption.
With Erex Settlement, infrastructure managers receive
access to a country-specific accounting system that
operates within their national rules. The system calculates the energy cost based on variable data, including
the estimation of any missing data. The price of electricity grids, the cost of energy from suppliers, and comparisons to train-run data are all factored into the equation.
From there, the system assigns the precise amount of
kilowatt hours to the appropriate train operator, along
with the correct allocation and price. With accurate
invoice statistic reports in hand, infrastructure managers
are able to provide fair invoicing to their train operators
and allow for the purchase of energy directly from the
markets going forward (Figure 3).
There are two different approaches to energy settlement within the Erex system. The first is direct: train
operators receive a meter connected to one physical traction unit for similar countries like Norway, Sweden, and
Denmark. In this case, the physical traction unit is the
billing point. Therefore, 1 h of energy is measured for each

Tariffs

Nonmetered Traction Units
Parked Rolling Stock

Costs

Other Consumption

Hedging

Losses

Taxes and VAT
Correct Invoice
Statistics
Reports

DCS
Erex
Exchange

Erex
Settlement
Infrastructure
Manager

Electricity
Grid

Energy
Supplier(s)

Train-Run Data

Figure 3. The Erex Settlement system. VAT: value-added tax. (Source: Eress, used with permission.)

I E E E E l e c t r i f i cati o n M agaz ine / MARCH 2020

Train
Operator

IEEE Electrification Magazine - March 2020

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