Warehouse scheduling that balances SLA, throughput and energy cost
Scheduling a large automated warehouse on turnover alone ignores how much equipment dynamics and tariff structure move the actual cost.
The problem
We led the control-system design for a large automated storage and retrieval facility. Compared with a simple warehouse, it had many dynamic access points, equipment shared across tenants, wide variation in the physical energy cost of each movement, and goods with awkward handling properties.
The brief was to hold a strict SLA while maximising operational efficiency and minimising energy cost — three goals that conventional scheduling logic tends to trade off against each other.

Energy is not a fixed overhead. It is a variable the scheduler can actively optimise.
What we built
- 01An energy and path optimisation modelRather than ranking slots by turnover, we built an energy model incorporating the drive characteristics of the equipment, measuring the real difference between horizontal travel and vertical lift, and replacing a single reference point with multiple dynamic access nodes so every retrieval picks the lowest-energy, shortest-path slot.
- 02Off-peak tariff arbitrage and overnight stagingTime-of-use pricing is written into the scheduler. Overnight, when tariffs are lowest and equipment is idle, pallets for the next day are moved to staging, cutting daytime peak demand and contracted capacity pressure while speeding up the morning shift.
- 03Multi-tenant SLA protection and predictive maintenanceMaintenance windows are scheduled against each tenant's historical inbound and outbound peaks, so servicing shared hardware never lands on someone's busiest hours.
- 04Physical exclusion constraintsGoods carry physical and chemical property tags; strongly aromatic items and odour-absorbing items are kept apart by a dynamic safety-distance rule, so the optimiser never trades storage quality for a shorter path.
- 05Elastic capacity and yield managementBorrowing from cloud resource scheduling, the system continuously computes tenant throughput and seasonality, releasing surplus reserved slots for existing customers to expand into at peak, or offering idle capacity to the market on short high-rate terms.
The business case
Higher yield per square metre and better operating margin, with no additional hardware investment.
Once a scheduler can reason about energy, the ceiling on what the same hardware can return is redrawn — a layer conventional warehouse management systems do not touch.
