From Duck to Turtle: 2040's Synchronized Demand Response Reshapes Distritubion Grid Load

Several jurisdictions now require dynamic pricing so that households adjust consumption to time-varying prices and supply demand-side flexibility (Directive (EU) 2019/944). Most analyses treat this price as exogenous and households as price takers, a reasonable description of individual behavior, but a questionable one once dynamic pricing is adopted at scale, when synchronized responses to a common price signal may feed back on the price itself.

We develop a household-level optimization framework and apply it to Luxembourg under ENTSO-E’s 2040 TYNDP scenarios, varying technology adoption and flexibility participation. Taking prices as given, we isolate how synchronized flexibility reshapes load at the transformer level. We find that identical price signals drive households to respond in lockstep, inverting the conventional "duck curve" into a pronounced, midday-peaking "turtle curve": rather than relieving the grid, coordination concentrates stress, and at high flexibility shares transformer overloads rise sharply and require substantial reinforcement.