The ability of an infrastructure system including its governance, material assets and human resources, to serve business-as-usual as well as adjust to shocks/stresses.


1. In planning for service continuity for infrastructure systems, flexibility includes rearrangement of management structures and decision-making to mitigate or manage crises.

2. The flexibility of a system is intended to secure core functions, sometimes at the expense of ancillary/non-core functions/components of the system.

3. See also “Organizational learning”, “Disaster resilience”, and “Prospective disaster risk management”.


Adapted from Woods, D. D. (2006). Essential characteristics of resilience. Resilience Engineering: Concepts and Precepts, Aldershot: Ashgate,21-34 and Jackson, S. (2010). The Principles of Infrastructure Resilience. CIP-R, 17 February 2010.

Case of German solar power grid during the 2015 solar eclipse

The International Energy Agency's (IEA) definition of power system flexibility highlights its capacity to adapt to changes in electricity production or consumption. Renewable energy technologies such as biogas, hydroelectric, and geothermal can provide a fully dispatchable and flexible power supply, which can balance residual load variations. Similarly, demand response refers to the flexibility on the demand side, where factories can be retrofitted, or control systems redesigned to accommodate residual load flexibility.

A notable instance of such flexibility occurred during the solar eclipse in Germany in March 2015, which witnessed a drop in solar power production from 21.7 GW to 6.2 GW. This event acted as a stress test for Germany's solar power grid, the largest in Europe by capacity, and demonstrated the need for alternative power sources to manage such variability in supply. During this event, four aluminium factories in Germany reduced their power consumption during the eclipse, allowing the solar-powered grid to manage the event without incident. This highlights the growing importance of flexible power supply systems in managing a renewable energy-driven world.