Survey Results

The DSO data collection exercise provides also a reasonable holistic view of the main difference among DSOs in terms of yearly distributed energy, geographical area covered, power lines length and number of connected customers as shown in Figure2.3. Regarding the survey out of the 28 Member States about 16 countries reach a 100% coverage of those DSOs serving more than 100,000 customers. Among the 28 Member State, the outliers with a high number of larger DSOs are Belgium, Austria and Germany which respectively have 13, 15 and 75 DSOs.

This figure is surprisingly high if we taking into account that the median value equals 3. These different characteristics are even more exacerbate while having a looking at the technical features in section 2.4.1 and the smart grid dimension in section2.4.3.

In Figure 2.3 a more profound categorization of DSOs is highlighted. The Figure illustrates the distribution of energy in GWh (blue), the distributed area in km² (green), the power lines length in km (purple) and the number of connected cus-tomers in million (red). The distributed energy chart (blue) reveals that few DSOs (<3%), among the 99 who participate, are very large, and deliver above 180 TWh.

This number combined with the figure showing the number of connected customers, indicate that these operators deliver electricity to more than 15 million customers.

This is the case for E-Distribuzione in Italy and ENEDIS in France which are by far the leading DSOs in their respective country, covering an area above 100,000 km².

These two countries have a lot of similarities in their distribution sector, indeed France has a total number of DSOs of 148 and Italy 151, which, except for ENEDIS and ENEL, are supplying relatively small regions or even municipalities. Among all Member States the case of Germany deserves a special focus due to the fact that it is composed of 4 principal TSOs and up to almost 900 DSOs, of which 75 subject to the unbundling.

The 3 major DSOs are delivering electricity to slightly less than half of the indus-try sector [10]. This extreme spread of operators require a proper management and demand forecast, thus is surprising that the smart metering roll-out for Germany is still limited to 23% [13]. The opposite cases is found for a series of countries, limited

in terms of geographical area, that are composed by few DSOs such as: Cyprus, Estonia, Latvia, Ireland and Luxembourg. In general the mean and median yearly distributed energy are respectively 23 TWh and 7.9 TWh. Concerning the con-nected customers (red) almost 95% are LV concon-nected customers with a mean and median values of customers supplied per DSO is 2 and 0.7 millions respectively.

It is important to highlight that the LV connected customers within each country may have a complete different connection limit in terms of power, thus affecting also the type and length of power lines.

For instance, single phase contracted power levels in Luxembourg starts from 9.2 kVA and grow up to 18.4 kVA, meanwhile in Italy, Denmark and Slovakia can not exceed 6 kVA. The majority of DSOs (40%) supply electricity to less than 750,000 customers [14].

Figure 2.3: DSOs general features overview

The power lines length figure (purple), in line with the distributed one (green) point out a relative high level of cables utilization. This may be attributed partially to the fact that the cities development (i.e. new district, industrial or commercial areas) along the years may have left some constraints (i.e. land use) affecting the distribution grid layout growth.

Furthermore, another reason can be linked to DSOs, which according to the survey, deliver electricity to both urban and rural areas, and consequently increase the average area served as well as power lines.

This latter is also influenced by the use of underground and overhead ratio, as well as the typology of consumers served (LV, MV or HV). By having a general look at the smart grid dimension, the survey reveals that DSOs in compliance with the EU electricity market legislation are effectively unbundled².

Indeed, concerning ownership DSOs are classified in 4 main classes: private, public owned by municipality, public and other. The one replying ”other” explained that they have a hybrid ownership, which is usually split in 50% private and 50% public.

Up to 87% of the DSOs are part of a bigger group operating in the power sector and with respect to the parent company they are all separated from a legal and functional (organization and decision making rights) point of view. Less than 5%

have also separate in the accounting from their parent company.

2.4.1 Technical Data

This section focuses more in detail on the technical features that describe a distri-bution grid network. The technical questions posed to the DSOs allow to collect up to 36 indicators, shown in Table 2.1, 2.2, 2.3 and 2.4. Table 2.1 focuses on the metrics at different voltage levels of the network structures, such as the number of LV, MV and HV customers per supplied area or the length of the power lines utilized.

2As stated in the preamble of Directive 2009/72/EC, the reasoning behind the new rules was that ”without effective separation of networks from activities of generation and supply (effective unbundling), there is an inherent risk of discrimination not only in the operation of the network but also in the incentives for vertically integrated undertakings to invest adequately in their networks”

Table 2.1: Distribution network structure indicators Network structure

1. Metrics associated to LV network