CORPORATE STRUCTURE
Transmission
Snam Rete Gas takes charge of natural gas at delivery points. These are located at interconnections with import lines from Russia, Northern Europe and North Africa, with LNG regasification plants, and with domestic gas production and storage centres situated throughout Italy. The gas is then transmitted, on the basis of instructions provided by the customers, to the delivery points connected to local distribution networks and to major industrial users and power stations.
The gas transmission system is comprised of a network of gas pipelines extending for 31,531 km throughout most of Italy, 11 gas compressor stations, and 567 plant areas containing pressure reduction and regulation plants.
Control and management of the system are carried out by the Dispatching Centre in San Donato Milanese in cooperation with the local Operating Centres distributed throughout Italy. These Operating Centres, comprising 8 districts and 55 maintenance centres, are responsible for ensuring the operation, maintenance and control of the entire system.
The volume of gas put into the transmission network totalled 76.90 billion cubic metres, with a reduction of 8.74 billion cubic metres (-10.2%) over 2008 levels. The reduction is due to the lower demand for natural gas in Italy, which is mainly associated with the lower consumption of the thermoelectric sector (-15.5%) and the industrial sector (-14.6%) as a result of the difficult economic climate, the effects of which have in part been absorbed by the increase in consumption of the residential sector (+4.9%).
NATURAL GAS INJECTED INTO THE TRANSMISSION NETWORK
Regasification
GNL Italia is the company that takes charge of its customers’ liquefied natural gas (LNG) at the Panigaglia facility, located in Fezzano di Porto Venere (La Spezia), regasifies it and injects it into the transmission network. This regasification is the last phase of the LNG chain which begins in the exporting country, where the natural gas is brought to a the liquid state (by cooling it to -160°C at atmospheric pressure) and loaded on ships (called “methane tankers”) for transportation by sea.
The convenience of transforming the natural gas, which in nature is present in its gaseous phase, to liquid form lies in the fact that its volume is reduced by a factor of around 600, both facilitating and making economic its transport by ship as an alternative to transmission via pipeline. This becomes particularly interesting when the need arises to diversify sources of supply, especially considering the increase in distance between the regions of production and the regions of consumption, thus enabling gas to be imported from producer countries that cannot be connected by pipeline.
The Panigaglia facility occupies a productive area of around 45,000 square metres and it is made up of two storage tanks of 50,000 cubic metres each, steam plants, and a berth for ships. In 2009, 38 tankers of different types were unloaded and around 1.32 billion cubic metres of natural gas were injected into the national transmission network.
LNG REGASIFIED
Storage
Stogit is the biggest operator in Italy and in Europe in the natural gas storage service activity; by means of eight storage fields, located in Lombardy (four), Emilia Romagna (three) and Abruzzo (one) the company puts its storage capacities at the disposal of the market according to technical and economic efficiency criteria. The company does that using an integrated system (gas fields, gas treatment plants, compressor plants and a dispatching system) that is capable of providing the required modulations of performance, compatibly with the available storage capacities.
The natural gas storage activity acts to compensate for the fluctuating needs between supply and consumption of gas. Actually supply is an essentially constant activity throughout the year, while the demand for gas has a strongly seasonal variability, with wintertime demand being significantly higher than summertime demand.
The activity is essentially divided into two phases. The injection phase, when the natural gas coming from the national transmission network is injected into the gas field (between April and October), and the supply phase, in which the natural gas is withdrawn from the gas field (between November and March), treated and delivered to the customers, again through the transmission network. For the storage, gas fields are used that have already been exploited for production, located at depth of around 1,000 - 1,500 metres.
In 2009 around 16.52 billion cubic metres of natural gas were handled (8.7 supplied and 7.8 injected), an increase of 4.95 billion cubic metres over 2008 (+42.8%). This increase can be attributed to the major withdrawal of gas during the Russian supply crisis in January 2009, and to the consequent increased injection to restore the volumes supplied and to progressively fill the additional capacity made available for the 2009-2010 thermal year.
NATURAL GAS MOVED THROUGH THE STORAGE SYSTEM
Distribution
Italgas, together with its subsidiary Napoletana Gas, provides a natural gas distribution service, under concession, for the selling companies authorised to sell on the gas (local public bodies). The activity is conducted by means of an integrated system of infrastructures (cabins for withdrawal, pressure reduction plants, distribution networks, delivery points), for the most part directly owned, which allow the companies to withdraw the gas from the national transmission network and deliver it to the end customers (domestic and industrial). At the withdrawal points, the gas (actually the gas itself is odourless) is also odorized to make its presence noticeable in the event of leaks. Of no lesser importance is the metering activity, which is carried out both at the withdrawal points and at the delivery points.
An integral part of the infrastructure is the Integrated Supervision Centre, which constantly monitors the plant remote control systems, to ensure rapid response in the event of anomalies and also in the event of limitations or interruptions to the service. The data coming from remote control and remote reading is made available immediately throughout Italy by telematic means, so as to allow the operating units to have a picture of the status of the distribution system that is always up-to-date.
In 2009 the volume of gas distributed in the distribution network was 7,537 million cubic metres, an increase of 106 million cubic metres over 2008 (+1.4%), basically as a result of the effect of climate and the development of the network. At the end of the year the gas distribution service was provided in 1,441 municipal concessions and with 5,770,672 active meters installed at end customers’ premises.
NATURAL GAS DISTRIBUTED
