RTE (Electric Transmission Network Operator)

In France, the strategic role of balancing the national electricity system is entrusted to RTE, the Electric Transmission Network Operator. As the public transmission network operator, RTE provides a 24/7 public service at national and European level, thanks to interconnections that make the system more robust. This article explains RTE‘s status and missions, how the transmission network works, the central role of data, and illustrates how players such as Altsis leverage RTE data for supervision and decision support.

Ensuring the power supply of an industrialised country requires extremely precise mechanics: every second, production and consumption must be balanced, electricity flows must be delivered to the right place at the right time, and infrastructure must be maintained in perfect condition.

This orchestration is all the more complex given that the French electric system is interconnected with its European neighbours, which requires cross-border coordination and constant anticipation of variations in consumption, climatic hazards and network constraints.

RTE’s missions and statutes

RTE is the operator of the public electricity transmission network in mainland France. Entrusted with a public service mission, RTE guarantees access to electricity at all times by operating, maintaining and developing the high-voltage network (HTB – voltage level above 50 kV), as well as ensuring a permanent balance between supply and demand.

Legally speaking, RTE is a public limited company and a subsidiary of the EDF Group. It was created in 2000 to meet European requirements for the separation of energy production and transmission. RTE has an Executive Board and a Supervisory Board. 

Its statutes and organisation are based in particular on the decree of 30 August 2005 approving the statutes of “RTE EDF Transport” and on the laws relating to the modernisation of the public electricity service. RTE is functionally independent from its parent company, as required by the European framework.

Its monopoly activity is regulated by the Energy Regulatory Commission (CRE), in particular through the network access tariff (TURPE), which guarantees transparent and non-discriminatory treatment of all users.

RTE is at the heart of the energy transition: it helps to optimise the French electric system, plans and invests in infrastructure (reinforcement of lines, substations, interconnections), and informs public decision-making through its analyses (assessments, development plans). The company regularly publishes reports (forecast balance sheet, network development plan, winter outlook) that structure network planning in a context of high electrification of uses.

Operation of the electric transmission network

The RTE transmission network transports electricity from production sites (nuclear, hydroelectric, wind, solar, geothermal, bioenergy) to distribution system operators (DSOs) and large consumers connected to High voltage (HTB) networks (voltages above 50 kV, generally 63 kV, 90 kV, 225 kV and up to 400 kV).

Network architecture and European interconnections

The RTE network covers more than 100,000 kilometres of lines and relies on thousands of pieces of equipment (overhead and underground lines, substations, circuit breakers, switches, etc.), organised into meshes to ensure operational safety.

High voltage levels limit losses and enable large amounts of energy to be transported over long distances.

The French system is interconnected with neighbouring countries: these cross-border connections (Spain, Italy, Switzerland, Germany, Belgium, etc.) improve security of supply and economic efficiency through electricity exchanges.

Trade flows at borders are published in real time via éCO₂mix, illustrating the European and synchronised nature of the operation.

Real-time control and congestion management

Operationally, RTE manages the supply/demand balance in real time by using several levers: detailed forecasts, balancing reserves, capacity and adjustment mechanisms, and congestion management when certain branches of the network reach their thermal or stability limits.

The Services Portal displays available capacities, reserves and balancing signals (programme data, balancing data, losses, etc.), while dedicated APIs provide detailed time series (imbalances, balancing prices, activated volumes).

Role of stakeholders and coordination of the system

On a daily basis, the link between producers, transport, distribution and consumers operates via network codes, connection rules and electricity markets. Suppliers aggregate the consumption of their portfolios, distribution system operators (DSOs) provide low and medium voltage distribution, and RTE ensures the physical consistency and balance of the system, relying on control centres that monitor the status of the network 24/7.

RTE data accessible to third parties

Data is at the heart of RTE’s activities. The company provides a vast array of real-time and historical data that is useful to other players in the chain (distribution system operators, suppliers, producers), manufacturers, design offices, researchers and citizens.

The éCO₂mix portal

The éCO₂mix portal is RTE’s interactive platform. It is accessible to everyone: professionals, local authorities and citizens, via a website and a free mobile application.

This portal provides access to several key indicators. It displays national and regional consumption, production by sector and CO₂ emissions per kWh. It also shows the market price (spot J-1) and cross-border trade. These data sets can be consulted online and via exports or open feeds.

The RTE Data Portal

The RTE Data Portal is the official platform that centralises and displays data from the French electricity system in the form of APIs and downloadable datasets.

The following data types are available:

• Consumption: National and regional curves, day-ahead forecasts, consolidated data.
• Production: By energy source (nuclear, hydro, solar, wind, geothermal), in real time and forecast.
• Balancing and reserves: Imbalances, activated volumes, reserve activation prices
• Market and prices: Spot prices, adjustment signals, capacity mechanisms.
• Cross-border flow: Exchange capacities, interconnection programmes.
• Unavailability & maintenance 

The APIs are REST-based with key and certificate authentication for certain services. The formats supported are mainly JSON, CSV, and XML for integration into third-party systems.

By making this data accessible, RTE facilitates system transparency and monitoring of the energy transition. It also promotes informed decision-making, from the national to the local level.

How Altsis leverages RTE data

Altsis positions itself as an integrator and ‘orchestrator’ of energy data. Its clients include local authorities, suppliers, distribution network operators and industrial companies.

The value proposition of Altsis’ Opéra solution is to aggregate public RTE flows with private customer data: remote meter readings (Linky on the DSO side), load profils from metering, contracts (PU, ARENH, guarantees of origin). This data aggregation is then used to create summary dashboards and propose action scenarios.

Integration of RTE APIs into the Opéra solution

Technical integration is achieved through secure API connectors on RTE’s Data and Services portals.

Some APIs require identity and certificate management (PKI). In addition, the TLS 1.2 protocol encrypts data exchanges.

Finally, the systems perform a Validation Estimation Editing (VEE) process on the data. This processing ensures the consistency and relevance of the time series.

How does Opéra use RTE data?

Altsis’ Opera software connects directly to RTE APIs to:

• Collect real-time data streams (consumption, production, network signals)
• Aggregate this data with your own information (load curves from distribution meters, energy contracts, weather data, etc.).
• Create reports and summary dashboards: consumption, prices, alerts
• Propose action scenarios: load shedding, flexibility management, optimisation of contracted power, choice of tariff bands.

Optimisation of the RTE Turpe with Opera

The Opéra solution also makes it possible to calculate and optimise the Turpe specific to RTE, the Turpe HTB. It thus helps to reduce the transmission bill.

For the TURPE 7 HTB period (1 August 2025 – 31 July 2029), the CRE has confirmed a tariff structure similar to TURPE 6, with:

• A fixed annual component for management, metering, withdrawals/injections, etc.
• A variable portion indexed to the power subscribed and consumption,
• Seasonal modulations (peak/off-peak hours, winter/summer variability).

Use cases for RTE data

Let’s imagine an energy syndicate covering several inter-municipal communities. This syndicate aggregates regional éCO₂mix data to monitor, on an hourly basis, the share of renewable energy injected locally. It also monitors the carbon intensity of the mix. At the same time, it imports detailed load curves for public lighting, administrative buildings and sports facilities.

It cross-references these signals with RTE forecasts and market prices to anticipate peaks. It triggers load shedding and controls the start-up of cooling units or heat pumps outside critical periods.

In one year, the community has the opportunity to achieve:

• Cost reduction through power demand smoothing and contract optimisation (contracted power, modulation);
• A reduction in emissions by aligning consumption with periods of low carbon intensity;
• Greater territorial consistency through shared dashboards, which objectify investment decisions (insulation, photovoltaics, storage, charging stations) in light of network constraints and regional trends published by RTE. (Regional data, interregional flows and consolidated series are available on éCO₂mix and the Services Portal.)

RTE: a strategic player in France’s electric balancing

RTE plays a central role in maintaining France’s electric balance. It transports electricity and ensures real-time security. It develops infrastructure and provides access to a unique data resource, which is key to an efficient and transparent transition.

When used intelligently, this data enables regions and manufacturers to break free from a reactive mindset. It paves the way for proactive oversight and informed decisions.