IEEE Power & Energy Magazine - September/October 2019 - 68

EFI aims to disseminate the energy flexibility of devices
by providing all necessary information for control algorithms
without needing any device-specific details.

Responsibility of Congestion Management

measured during the entire planning up to settlement process.
This is also known as baselining. During EFR-II, the measurement and verification of these preagreed-upon conditions
triggered an important issue of matching and authorizing
data exchange from different sources. The synchronization
of these data sets from different sources did not match and
needed manual corrections because different timestamps
were used or the data sets used different time intervals. Technological developments are required before the piloted mechanisms can be rolled out in a fully operational setting.

An important insight from the EFR is that when flexible
load is applied for the BRP (wholesale market), peaks in
the local grid may actually worsen if the objectives of the
DSO and BRP conflict, which, in this case, happened in
16% of the congestion events. This is also referred to as
tier bypassing, i.e., when forward wholesale markets ignore
interzonal constraints and clear energy transactions that
were not feasible on the local grid. When these peak loads
reach capacity limits, the USEF-defined interaction between
the aggregator, the BRP, and the DSO should prevent overloading from happening. In EFR-I, however, this overload
prevention protocol was not applied and thus not tested.
The pilot focused on the "normal" system-operational
mode in which network congestion is solved as part of the
every-day functioning of (local) markets. Hence, not all
local congestion could be prevented because the proposed
coordination mechanism (PowerMatcher) relies completely
on the voluntary response of each participant or customer.
The USEF framework offers an escalation framework, which
includes the opportunity to combine voluntarily operations
with hardwired controls when necessary. This needs to be
further investigated in a follow up, when BRP and TSO operations are combined with the pilot objectives.
Finally, the procurement and settlement of USEF and
PowerMatcher operational protocols and flexibility services
require agreements among all involved entities based on
agreed-upon conditions that must be objectively verified and

Currently, there is no plug-and-play stack available for the
entire end-to-end communication and coordination from the
customers' appliances and devices up to the DSO and BRP.
The goal of EFR-II was to deploy open source software and
protocols, which was quite challenging. Aside from a few
parts of the entire stack, which run on proprietary software, the three key components were based on open source
methodologies:
✔ EFI, the standard device communication protocol
✔ dEF-Pi, the software integration platform
✔ PowerMatcher, the market control algorithm.
Having developed an open source, interoperable end-toend stack, the next challenge is scaling and maintaining the
required service level. For this, standardization is needed.
Although EFI is not yet an international standard, it is
currently being standardized in the European Union by

Battery Power

1.5
1

0.5

0.5
0

-0.5
-1

-0.5

-1.5
Power
PowerMatcher Price ((b) x-axis))
-2
July 30 July 31 Aug 1 Aug 2 Aug 3 Aug 4 Aug 5
Time
(a)

Power Consumption (kW)

2
PowerMatcher Price

Power Consumption (kW)

Interoperability and Scalability

Battery Correlation

1.5
1
0.5
0

-0.5
-1

-1.5
-2
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5
PowerMatcher Price
(b)

figure 8. (a) The price signal and (b) the battery power consumption show a clear correlation. The correlation confirms
that the batteries behave as desired.
68

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