Mining & Remote Power Engineering Guide

How to Size BESS for Mining & Remote Sites

Why mining BESS sizing is different

Mining and remote industrial sites often combine large motors, crushers, pumps, ventilation, accommodation loads, diesel generators, solar PV and an unreliable or absent grid. Loads can change by shift, production stage and season. A system sized only from monthly energy bills may miss short power peaks; a system sized only from maximum demand may carry unnecessary battery capacity.

The engineering study should therefore define the operating modes first. Common modes include peak support while generators remain online, generator-off operation during low-load periods, solar energy shifting, spinning-reserve replacement, black start, critical-load backup and complete microgrid operation.

1. Build a usable load profile

Start with 15-minute data where possible; one-minute or higher-resolution data is valuable when large motors and process steps create rapid changes. Separate the following:

• Base load: the demand that remains present across most operating hours.
• Critical load: equipment that must continue during an outage or generator transition.
• Process peaks: crushers, conveyors, pumps, compressors and other intermittent loads.
• Motor starting: starting method, inrush current, start duration and allowable voltage dip.
• Daily energy: kWh consumed by shift and by operating mode, not only monthly totals.

If measured data is not yet available, prepare a load list with rated power, expected loading factor, operating hours, diversity and start sequence. Mark estimates clearly so that the final design can be checked against logged site data.

2. Determine the required BESS power

PCS power is driven by the largest duty the battery must support. For peak shaving, calculate the difference between site peak demand and the power that the grid or generators should supply. For backup, add the simultaneous critical loads. For motor starts, confirm whether the PCS can provide the required short-duration overload and reactive-power support.

This is only a screening calculation. Protection coordination, transient response, power factor, harmonics, short-circuit level and the overload curve of the selected PCS must be reviewed before equipment selection.

3. Determine usable and nominal battery energy

Energy capacity depends on the load to be carried and the required duration. A simple backup screen is critical load multiplied by autonomy. Nominal nameplate capacity must then account for the usable state-of-charge window, discharge efficiency, reserve and expected degradation.

For solar shifting or diesel optimization, use an energy-balance model across a representative day. Confirm how much surplus PV is available, when the load occurs, the generator minimum-loading limit and the state of charge required before the evening peak or a possible outage.

Worked screening example

Consider a remote site with a 650kW average operating load, a 1.2MW short peak, 400kW of critical load and a two-hour backup target. If the design assumes 90% usable depth of discharge, 94% discharge efficiency and a 15% planning reserve, the initial energy screen is:

400kW × 2h ÷ 0.90 ÷ 0.94 × 1.15 ≈ 1,087kWh

This suggests a starting point around 1.1MWh of nominal energy before degradation, temperature and project-specific margins are finalized. PCS selection is a separate decision. If the BESS only limits generator loading during the 1.2MW peak, the required continuous PCS rating may be based on the peak reduction rather than the full site load. Motor-start and contingency studies can increase the short-duration requirement.

For comparable configurations, review the 1MWh BESS product guide and the 1MW/2MWh sizing example.

4. Model diesel generators, solar PV and EMS control together

A hybrid plant should not be sized as three independent assets. The EMS must coordinate generator start/stop thresholds, minimum generator loading, PV curtailment, battery state-of-charge reserve and recovery after an outage. Important questions include:

• How many generators operate at each production level?
• What minimum loading prevents inefficient operation or wet stacking?
• Can the BESS carry low-load periods so that one or more generators can stop?
• How much PV energy is actually available after serving the daytime load?
• What reserve must remain for motor starts, faults or grid loss?
• Who has control priority during abnormal operating conditions?

See our Diesel + BESS systems and Microgrid & Backup Power pages for the relevant system architectures.

5. Apply environmental and project constraints

Remote mines can impose high temperature, altitude, dust, humidity, corrosion and logistics constraints. These conditions affect HVAC demand, PCS derating, enclosure selection, fire-protection design and maintenance access. The RFQ should state ambient temperature range, elevation, dust or corrosive exposure, available footprint, road or container restrictions, grid voltage and frequency, local codes and required certifications.

Availability targets also influence architecture. A site that cannot tolerate a single-point failure may require modular PCS blocks, battery isolation zones, redundant auxiliary power and defined spare-parts support. These decisions should be agreed before comparing supplier prices.

Mining BESS RFQ checklist

• Project country, mine type, project stage and required delivery date.
• Interval load data, maximum demand, critical loads and largest motor.
• Existing generator kW/kVA, quantity, minimum load and operating schedule.
• PV capacity, expected production profile and curtailment limits.
• Grid availability, outage history, voltage, frequency and interconnection constraints.
• Target BESS power, autonomy, daily cycles and reserve requirement.
• Preferred supply boundary: battery, PCS, transformer, switchgear, EMS and commissioning.
• Ambient temperature, altitude, enclosure, fire protection and communication protocol.

Use the BESS Sizing Calculator for an initial estimate, then send verified site data for engineering review.

Frequently asked questions

Important sizing limitation

These examples are screening guidance, not a final electrical design, safety study or performance guarantee. Final equipment selection requires verified project data, applicable standards, equipment ratings, protection studies and project-specific engineering.