Flexibilities: a challenge for the power system

A tool to respond to the evolution of the constraints of the power grid

At any given moment in France, the electrical power injected into the grid, whether imported or generated locally, must be balanced with the electrical power withdrawn, whether consumed within France or exported. To avoid widespread power cuts, the power grid must be maintained at 50 Hertz at all times: this is the supply-demand balance.

While the French energy mix’s sizing capacity, based on controllable means of production (nuclear or thermal generation), has in the past always been able to accommodate increases in consumption during periods of grid stress, the growing development of renewable energies motivated by the objectives of the PPE (Pluriannual Energy Programming) is challenging its overall operation.

Additionally, other factors may affect the balance of the power grid:

• the thermo-sensitivity of the French generating fleet: 1°C less in winter is equivalent to 2.4 GW more consumption,
• the electrification of use, such as the use of electric vehicles or the production of green hydrogen.

Renewable energies, whether wind or solar, depend on weather conditions and are therefore, by their very nature, variable and uncontrollable. This is why they are defined as “intermittent” energies.

To encourage the development of renewable energies, while at the same time helping to balance the power grid, flexibilities are proving to be an ingenious solution for the grid, thanks in particular to tools such as dispatchable generation plants, interconnections, electricity storage and consumption curtailment through process modulation or self-generation.

Where and how are flexibilities organized?

These flexibilities can operate at several levels: generation resources, consumption

Flexibility in electricity consumption enables customers to earn revenue from their ability to stop, reduce, modulate or substitute their electrical consumption. This is known as load shedding: a customer who accepts a load shedding offer shifts consumption to a time when there is less pressure on the power grid. The customer is then compensated for the service rendered, and the flexibility obtained in this way is valorized on the energy markets.

Production flexibility enables producers to reduce or increase their production volume. This flexibility is then valued on the electricity markets, enabling producers to respond to a need in the power system and/or to generate profits from existing or additional power plants.

Customers with storage assets such as a stationary batteries can also enhance the flexibility of their batteries, thereby optimizing their profitability by offering them on all the markets and mechanisms for which they are eligible.

Through the mobilization of all elements of the power system, whether individual consumers or professionals, and thanks to the flexibility tools and offers adapted to their interests and those of the power system, that the French grid is currently able to balance itself and cope with the intermittent nature of renewable energy.