237 Summary

All facilities require a continuous and adequate supply of utility support to function. Energy security is the process of evaluating utility systems and implementing actions that minimize the impact of unscheduled outages that prevent a facility from operating at full capacity. utility systems are networks with many components. Loss of a few, or in some cases one, critical components is sufficient to disable a network or leave it operating at partial capacity. Additionally, utility networks are not independent. They support each other in a symbiotic manner. The collapse of one network can lead to a domino effect that causes other networks to fail.

The critical components of a utility network can be identified by using risk analysis techniques. The inductive methods make assumptions about the status of in dividual components and then determine what impact is felt on the entire system. Deductive methods, notably fault tree analysis, use an opposite approach. Fault tree analysis assumes the system is in some undesired condition and proceeds to determine what combinations of failed components will result in that condition. The combinations of failed components are called cut sets. The component failures can be caused by equipment failure, natural disaster, accident, or sabotage.

Countermeasures are actions that prevent or minimize the impact of utility disruptions. Three counter-measures that should not be neglected by any facility manager are physical protection, redundancy, and stockpiling of critical spare parts. Coupled with contingency planning, these counter measures will greatly enhance the energy security of any installation. Contingency plans should be exercised for maximum effectiveness.

utility disruptions can cause a wide range of impacts on the affected facility. in most cases, this impact can be expressed as a dollar value. This financial impact is useful in evaluating the economics of implementing countermeasures. The most common economic analysis tools are payback and cost/benefit ratio. Many coun-termeasures can be made more cost effective by linking them to energy conservation projects.


1. Bracher, Bradley L., Utility Risk Analysis, Proceedings of the 8th World Energy Engineering Congress, 1989, p. 601.

2. U.S. Nuclear Regulatory Commission, Fault Tree Handbook, p. II-4.

3. Billinton and Allan, Reliability Evaluation of Engineering Systems: Concepts and Techniques, p. 113.

4. Broussard, Peter A., Energy Security for Industrial Facilities - Contingency Planning for Power Disruption, PennWell Publishing Company, 1994, pg. 111.

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