Module 04
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Capacity Planning

Capacity planning is the process of determining the maximum amount of work that an organization is capable of completing in a given period. In a supply chain context, capacity isn't just about how many widgets a machine can produce; it is also about how many pallets a warehouse can store, how many orders a picker can pack per hour, and how many trailers a carrier can move per day.

Theoretical vs. Actual Capacity

It is a dangerous mistake to confuse these two concepts:

  • Theoretical (Design) Capacity: The absolute maximum output possible under ideal, perfect conditions. (e.g., A machine runs 24/7/365 with zero breakdowns, zero maintenance, and perfectly trained staff). Designing a supply chain based on theoretical capacity guarantees failure.
  • Actual (Effective) Capacity: The realistic output a system can achieve given normal operating conditions. This accounts for preventative maintenance, shift changes, employee breaks, machine setups, and acceptable defect rates. Effective capacity is usually 70-80% of theoretical capacity.

Strategies for Managing Capacity

When demand fluctuates, companies must adjust their capacity to meet it. There are three primary strategies:

  1. Lead Strategy (Aggressive): Adding capacity before the demand actually occurs. A company builds a new warehouse based on an optimistic 3-year sales forecast.
    • Advantage: Ensures you never lose a sale due to a stockout. Captures market share from competitors who can't supply.
    • Risk: Massive financial risk. If the demand never materializes, you are stuck paying for an empty building.
  2. Lag Strategy (Conservative): Adding capacity after the demand has already materialized and proven itself to be stable.
    • Advantage: Zero financial risk of overbuilding. High utilization of existing assets.
    • Risk: You will almost certainly lose sales during demand spikes, and frustrated customers may permanently switch to a competitor.
  3. Match (Tracking) Strategy (Balanced): Adding capacity in small, incremental chunks directly in response to changing demand.
    • Advantage: Balances risk and opportunity.
    • Risk: Operationally exhausting. Requires constantly managing small construction projects, short-term leases, or constantly adjusting contractor shifts.

The Theory of Constraints (TOC)

Popularized by Eliyahu M. Goldratt in his book The Goal, TOC states that any complex system is limited in achieving its goal by a very small number of constraints (bottlenecks).

  • A supply chain can only move as fast as its slowest node.
  • If your factory can produce 1,000 units/day, but your outbound shipping dock can only load 500 units/day, your actual system capacity is exactly 500 units/day.
  • Investing a million dollars to upgrade the factory to 2,000 units/day is a total waste of money because the shipping dock (the bottleneck) hasn't changed. TOC dictates that all management focus must be on identifying, exploiting, and elevating the bottleneck.