Accumulator

The Accumulator is a rechargeable energy storage building used in electrical networks. It stores excess power and releases it back into the grid when production is insufficient, making it a core part of solar power setups and a useful buffer for factories with fluctuating demand. It also produces light while charging and discharging.

An accumulator stores 5 MJ of energy and charges or discharges at up to 300 kW, so a full cycle takes about 17 seconds at maximum rate. Because of that output limit, accumulators are best understood as a way to smooth power flow rather than as a source of unlimited burst power. They can support the factory through the night when paired with solar panels, provide emergency power during a blackout, and help cover short spikes in demand when a machine or group of machines briefly consumes more than the current generation can supply.

For solar grids, a common balancing rule is that 21 accumulators should be supported by 25 solar panels. Another practical guideline is that 20 accumulators can sustain 1 MW through the night, though accumulators do not begin discharging immediately at dusk, so real performance depends on the timing of the day-night cycle. If power is being distributed above the accumulator’s maximum rate through multiple unconnected poles, the load is not always shared evenly; some consumers may receive full power while others receive none.

Accumulators can also be used as a controlled energy link between separate power networks. Since their delivery priority is lower than that of other entities, they only charge after higher-priority consumers are satisfied. If two networks are connected only through shared accumulators, either network can charge them and either network can draw from them, while the transfer remains capped at the total output of the accumulators involved. This is useful for isolating critical and non-critical systems. For example, lasers, ammo production, or other priority loads can be kept on one network, while labs, electric furnaces, miners, or beacons are placed on another network that only receives surplus power.

This isolation method can effectively limit consumption in low-power situations: the non-critical network only receives electricity when the main grid has excess, and even then it cannot exceed the accumulator transfer limit. It is especially helpful early in the transition to solar power, when building large dedicated solar and accumulator farms is not yet practical. If the goal is only to prevent throughput from being limited, a power switch can be used instead.

In short, accumulators are flexible tools for smoothing demand, bridging day and night cycles, and separating power priorities within a factory. They are most valuable when used as part of a planned electrical layout rather than as standalone batteries.