The energy objectives set at the national level and broken down by territory, notably through the voluntary initiatives of local authorities and local documents such as the SRCAE and the PCET, lead to a necessary reflection on the organisation of all local energy distribution networks (power, gas, electricity), those found at the level of agglomerations, towns and districts.
Planning and energy networks: two subjects at the heart of the local energy transition
Energy distribution networks and urban planning (planning, operational development, observation and evaluation of the city) are the subject of increasingly intertwined problems:
- the question of the choice of network development or reinforcement in order to optimise the costs of urban development for a community
- the question of the choice of energy sources and the best means of energy distribution by the local authority, for the benefit of residents and businesses, in a context of strong changes in energy prices
- the question of public action strategies between financing networks and financing energy demand management actions
- the parallelism between the development of smart grids and the smart city
The emergence of local governance of the energy transition requires a good knowledge and territorial control of the infrastructures that support energy distribution. More and more local production sources are being mobilised at city, district or building level (renewable energies, recovery energies), with variable characteristics (intermittent regimes, power regimes, preferential uses, etc.). The economic and environmental pressure is increasing, so it is necessary to be vigilant about possible network redundancies, particularly gas and heat, and about the impact of energy efficiency measures on consumption.
Thus, for a community, knowing and controlling its energy networks is not limited to improving energy policy and controlling energy prices, but also contributes to improving urban policies.
Constitution of energy distribution networks
The energy distribution networks are the local networks that deliver energy directly to consumers; upstream of the distribution networks are (for gas and electricity) the transmission or collection networks. The distribution networks are the most capillary, those most closely linked to the cities, generally following the route of the roads, serving all points of consumption in the territory. They are comparable to the local telephone loop.
For electricity and gas, the distribution networks are generally connected to the national/regional transmission networks, from which most of the energy in the current, highly centralised system comes. For heat networks, interconnection on scales far larger than those of agglomerations is not relevant, because unlike gas and electricity, heat cannot be transported over distances of several hundred kilometres. An entire heating network and its production points are therefore located at the scale of cities.
Overview of gas networks
In France for example, 98% of natural gas is imported. The transport of gas in the pipelines managed by GrDF on behalf of local authorities is not competitive (see next section “Organisation of the players and interactions”); on the other hand the gas and power trading is competitive (GDF in competition with other gas suppliers: Altergaz, Poweo, EDF…). In addition to GrDF, there are a number of other companies (e.g. SOREGIES in the Vienne region). Similarly, transmission is under the monopoly (with geographical breakdown) of GRTgaz and TIGF in south-western France.
The transmission systems
They allow gas to be imported from onshore interconnections with adjacent countries and LNG terminals. They are also an essential link in the integration of the French market with the rest of the European market.
- 31,000 km of GRTgaz transmission pipeline and 4,900 km of TIGF pipeline
- high-pressure gas, steel pipes
The distribution network
They enable gas to be transported from the transmission networks to final consumers who are not directly connected to the transmission networks.
- 186,000 km of pipeline
- medium and low pressure gas, polyethylene pipeline
- the transport/distribution interface is generally located on the outskirts of towns and cities
Approximately 11 million consumers in 9200 municipalities are connected to the natural gas distribution networks. These customers are supplied by 25 natural gas distribution system operators (DSOs) of very different sizes.