The flex offer is a buy order or sell order for electricity.

If the supply of or demand for electricity is greater than the electricity network in a specific region can handle (congestion), the grid operator asks large market parties (such as CSP) to place bids to use or generate more or, on the contrary, less electricity compared to their previously planned production / consumption.

If these companies can temporarily reduce (or increase, depending on the grid operator's request) their consumption or production, they then indicate how much flexible capacity they have available and at what price they sell it, called the flex bid