IEEE Power & Energy Magazine - September/October 2020 - 66

The penetration of renewable energy, batteries,
and EVs with vehicle-to-grid technology will make
managing the power grid very difficult.
a direct DSO-customer relationship and a DSO-FSP relationship in which the FSP could manage different customers' assets. However, the European Commission permits only
DSO-FSP operations and does not allow direct DSO-customer operations. At the European Union level, the general
rules to which those services must adhere were recently
established, although there are different models that could be
applied at a national level. The European Commission has
established its preference for a market-based schema to regulate flexibility transactions (European Union Regulation Act
2019/944, complemented by 2019/943).
The relationship models among the transmission system
operator (TSO), the balance-responsible party (a market
participant or a chosen representative that is accountable for
imbalances in the electricity market), DSO, and customers
define different market paradigms. These markets facilitate tasks related to planning, control, validation, dispatch,
invoicing, and so on, but, in the European regulations, some
different actors have specified roles within markets. This
fact provides several legal scenarios according to the European regulations: separate TSO and DSO congestion management markets, a combined TSO and DSO market, and
a combined balancing and congestion management market.
Each of these options poses different challenges. There are
various European initiatives researching and developing different market models at the national level.
Additionally, the market structure determines the degree
of interaction among actors. For example, in Spain and Portugal (the Iberian Peninsula), the nominated electricity market
operator is OMIE, which runs both a day-ahead market and an
intraday market. This is one of the most common approaches.
However, other types of markets are emerging, such as a distributed type with peer-to-peer transactive energy. In this sense,
some research lines and international initiatives are exploring
the application of new technologies, such as blockchain, to
energy markets to improve cybersecurity and reliability.
In summary, FRs are needed for congestion management
to improve the quality of service in DSO grids. In this sense,
different scenarios that are strongly conditioned by regulations are possible. According to the European regulations,
a DSO cannot directly own and control distributed energy
resources (DERs) (i.e., storage, RESs, DR, and so on) unless
authorized by national regulatory authorities. However, other
markets with less restrictive regulations (i.e., the LATAM
market) could be more open to agile innovation, providing
the opportunity for DSOs to directly test different technologies and their advantages in power grids, without necessarily
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requiring the presence of aggregators and other third parties
in the process.

Flexibility Management
The penetration of renewable energy, batteries, and EVs with
vehicle-to-grid (V2G) technology will make managing the
power grid very difficult. DER control and congestion management are especially important for renewable integration
since the availability of RESs is strongly dependent on weather.
Batteries can soften this effect. However, they have a limited
capacity and require complex management to achieve optimal
benefits. Both renewable generation and batteries could be
spread throughout the entire distribution network, including
the primary distribution [at a medium voltage (MV)] and the
secondary distribution [at a low voltage (LV)]. Additionally,
at the secondary distribution level, EVs with V2G technology
will be an additional concern in smart grids since they may
function either as load or as mobile "batteries with wheels."
Specifically, congestion management is one of the main concerns of distribution companies, which must be able to manage
the energy in, and the status of, grids without having direct
control over the power generation. If the aggregators were to
provide FSs, it would be possible to establish a coordinated
and distributed congestion management process. Thus, the
DSO would orchestrate the congestion management, exchanging rules and information with the aggregators. In this case, a
local market based on capacity would support interoperation
between the DSO and aggregators, establishing the value of
interoperation by balancing awards and penalties.
The recent European regulation about energy markets has
placed DSOs in an intermediate position between the TSO
and consumers. However, new technologies based on batteries, EVs, renewable energy, and so on have modified the
way in which energy is managed, and they have provided new
methods to guarantee proper power supplies, even during
emergencies. There are three main emergency cases for the
distribution system:
✔ Communication breakdown: Smart grids combine information and communication technology (ICT) with new
power generation, storage, and DR technologies. Such
systems could experience communication breakdowns
due to cyberattacks, device faults, and programmed interruptions for maintenance and updating processes.
✔ Energy supply breakdown: This is the traditional fault
provoked by a lack of maintenance, deterioration, illegal manipulation, accidents, natural disasters, and
cyberattacks.
september/october 2020

IEEE Power & Energy Magazine - September/October 2020

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