Battery storage

In plain terms

A battery can absorb power when there is too much (e.g. midday PV feed-in) and return it when it is needed, smoothing the load the grid sees. eDisGo supports both a simple self-consumption reference operation and full optimisation, and storage can be added manually anywhere in the grid (see Adding and modifying components).

Data

Storage units live in topology.storage_units_df with the key attributes p_nom (nominal power), max_hours (energy capacity / p_nom), efficiency_store / efficiency_dispatch (charge/discharge efficiencies) and, for home batteries, the associated building_id. Home-battery potentials can be imported from the OEP with import_home_batteries().

Reference operation

apply_reference_operation() implements a self-consumption strategy for home batteries: charge when local generation exceeds demand, discharge when demand exceeds generation, exchanging power with the grid only when the battery is full or empty.

The state of energy evolves as

\[\text{SOE}(t+1) = \text{SOE}(t) + \Big(P_\text{in}(t)\,\eta_\text{store} - \frac{P_\text{out}(t)}{\eta_\text{dispatch}}\Big)\,\Delta t , \qquad 0 \le \text{SOE}(t) \le p_\text{nom}\cdot \text{max\_hours},\]

where the efficiencies account for conversion losses on charging (\(\eta_\text{store}\)) and discharging (\(\eta_\text{dispatch}\)).

Optimised operation

Storage units passed to pm_optimize() via flexible_storage_units are dispatched by the OPF to minimise grid expansion, subject to their state-of-energy dynamics and capacity limits. (The OPF models the battery losses with a resistance-based model rather than the efficiency_store/efficiency_dispatch factors of the reference operation — see Multi-period optimal power flow.) Storage units not marked flexible keep the self-consumption reference operation.

Note

Storage time series are not generated automatically. For a time-series study you must either provide a series (e.g. via add_component()), let the OPF schedule the unit, or use a worst-case analysis.

A heuristic that automatically sizes and places storage to relieve the grid exists but is currently unmaintained — see Experimental & legacy features.