Energy curtailed at the POI limit

What this step does

When the system has a grid power limitation, the grid injection with the battery is held to it and the energy above it is curtailed. It acts on the grid energy. The solar chain already holds its own output to the limit, so the row appears only when a discharge pushes the injection above it.

The math

1. The row on the running total
2. The curtailed energy

$$E_{after} = E_{before} - \frac{E_{curt}}{P_{DC}} \tag{1}$$ $$E_{curt} = \sum_i \max\!\big(0,\ p'_i - \max(P_{POI},\ p_i)\big)\,\Delta t \tag{2}$$

where

Symbol	Meaning	Unit
$E_{after}$	the running total after this row	kWh/kWp
$E_{before}$	the running total before this row	kWh/kWp
$E_{curt}$	the curtailed energy	kWh
$P_{DC}$	the system DC nameplate	kWp
$p'_i$	the system's grid injection with the battery at timestep $i$	kW
$P_{POI}$	the system's grid power limitation, unbounded without one	kW
$p_i$	the system's grid injection before the battery at timestep $i$	kW
$\Delta t$	the length of one timestep	h

Reading the number

A loss, negative, and omitted when zero. It is usually zero on utility and rooftop systems, and appears when the AC-coupled battery's interconnect target is set above the grid power limitation. With DC coupling the inverters already hold the limit, so it stays near zero. With the grid power limitation switched off on the Model tab (ac_losses.use_grid_limit false) the battery ignores the limit and the row does not appear.

API

storage.curtailed

Symbols follow the symbol registry.