Resilience: Posturing for the Unknown
Resilience is replacing protection as a new risk management framework that balances robust design and flexibility in order to sustain military and civilian communities through emergencies as well as long-term change.
By Col. Paul E. Roege, P.E., M.SAME, USA (Ret.), Zachary A. Collier, James W. Mancillas, Ph.D., John A. McDonagh, J.D., Igor Linkov, Ph.D., M.SAME
Recent and memorable events such as Hurricane Sandy and the tsunami that hit Fukushima, Japan, highlighted our vulnerability to prolonged loss of energy systems and other essential services. In the aftermath, resilience has emerged as the risk management approach of choice to posture for change and recover from the unexpected.
The concept took center stage in 2013 as President Obama issued Executive Orders prescribing resilience for critical infrastructure, cybersecurity and climate change adaptation, and even declared November as Resilience Month. Furthering this transition, the Department of Homeland Security is integrating resilience into the National Infrastructure Protection Plan and the Air Force has adopted resilience as the first priority in its new energy strategy. These and many other initiatives bring into focus a clear challenge: "How do we know whether we’re resilient?" Answering this question will help us identify novel courses of action, establish objectives, clarify resource needs, and guide future adaptations.
Many activities have been undertaken within Department of Defense (DOD) and civilian communities to “increase” resilience. Unfortunately, traditional risk assessment tools still guide many of these initiatives, as they focus primarily upon evaluating known (or predictable) stresses to physical infrastructure and systems. This protective approach allows for a (pre-determined) degree of variation in the severity of these conditions, then addresses the potential variation through increased design robustness and redundancy. Predictably, the resulting assessments recommend additional investments to harden existing systems. This is a “fighting the last war” strategy.
This retrospective approach has proved inadequate to ensure continuity of essential outputs and functions such as energy in the complex real world of uncertain threats and dynamic change. Furthermore, traditional risk assessment methodologies fail to evaluate the array of possible approaches (beyond the existing system structure) for maintaining community function and security—i.e., to identify alternative system configurations that might provide the same desired essential system outputs at lower cost or risk. Thus, in today’s funding constrained environment, military leaders are using tools that inevitably place mission security in conflict with desired cost reductions.
Hence, to fully adopt and evaluate resilience, new tools need to be employed, tools that are rooted in social-ecological system (SES) resilience theory and principles. As the name suggests, SES theory leads us to look beyond our engineered systems. The corresponding tools will need to explore engineering performance beyond failure; to consider alternatives to steady-state system design and operations; and to examine system interactions that include degraded operations, alternate uses, and recovery. This journey begins by defining “resilience” and describing the metrics used to quantify resilience in the energy system context.
Resilience, in the SES context, is not an inherent system characteristic; rather, it is a property that becomes evident when a particular system interacts with its wider environment, and the forces that act on both.
Specific definitions of SES resilience differ, but they converge upon a common theme: the ability of a focal system to successfully deal with disruptive risks. Resilience can be defined as the capacity of a system to absorb disturbance and reorganize while undergoing change so as to still retain essentially the same function, structure, identity and feedbacks. Notice the requirement is not to survive a design basis event intact. Instead, a “resilient” SES must possess capacities both to cope with current known risks and to adapt to uncertain, unknown, or unpredictable future risk scenarios.With respect to the systems involving essential social functions, the National Academy of Sciences (NAS) defines “resilience” in terms of four system functionalities: plan/prepare, absorb, recover and adapt to anticipated and unanticipated conditions. In this context, the focus is on sustaining critical community functions, such as life support and security, under any changing conditions.
IMPLEMENTATION IN ENERGY SYSTEMS
Resilience thinking requires a reexamination of basic system design. Especially in the digital age, we have become focused on optimization—leading to remarkable performance improvement, but under limited conditions for very specific activities. As a result, our energy systems and other infrastructure have become brittle and therefore increasingly vulnerable to the debilitating impacts of cascading failures. Resilience thinking transcends traditional risk management approaches that attempt to predict changes and incorporate protective or backup design measures. Instead, a resilience-based paradigm seeks ways to reduce inherent dependencies, to increase flexibility or, ultimately, to adapt to inevitable changes. Sometimes, we can substitute pencil and paper for computers, and public shelters can help mitigate water and power outages, especially if we prepare for these options ahead of time.
It is also important to recognize that SESs have multiple interactive scales of operation, and that resilience is relevant at each level—from single organisms or devices up to the scale of communities. Systems operate and interact at multiple scales, for example, organizations, facilities, communities and regional energy systems. This phenomenon forms a “panarchy” wherein larger, slower scales and smaller faster scales may both impact the desired outputs. This broader focus often also reveals previously unrecognized system interdependencies and thresholds, providing system designers and operators additional options for the larger community. The narrower system design focus is “engineering resilience” versus the more flexible “ecological resilience” that favors community survival and adaptation.
Resilient SES thinking does not preclude responsible protection against anticipated events, but engineering resilience can extend our thought process beyond traditionally static design standards. Codes that consider wind and seismic loads are essential to provide robust designs, not only to withstand those anticipated stresses, but more generalized conditions previously unconsidered. The concept of SES resilience simply leads us to think differently about such measures, as a consequence, yielding different solutions to satisfy the same ultimate goal. Instead of optimizing performance then protecting the design, SES resilience-based approaches look for ways to achieve balance with acceptable performance under varying conditions. This often leads to more cost-effective solutions that substitute, for example, enhanced information feedback loops for costly enhancements in structural robustness and redundancy.
We need measurement techniques and metrics if we hope to increase resilience. As we all know, “what gets measured gets done.” Recognizing the complexity of resilience, a 4x4 resilience matrix is proposed. The columns are based upon the four NAS critical functionalities (plan/prepare, absorb, recover, and adapt), and rows represent the four domains identified by Network Centric Operations doctrine: physical, information, cognitive, and social. To use the matrix, stakeholders and designers would collaborate to identify specific, relevant metrics to populate each cell using the question: “how can the system’s ability to [plan/prepare, absorb, recover, adapt] to a change be improved by measures taken in the [physical, information, cognitive, social] domain?” Building this resilience matrix can help identify gaps and inform areas to allocate scarce resources to better plan/prepare for adverse events, as well as means to respond to change by better absorbing, recovering, and adapting to the environment.
The engineering community must deliberately move beyond traditional risk assessment tools to explore and exploit the advantages of SES resilience. Invoking broader definitions of performance and cultivating capabilities to manage uncertainty and change are essential in today’s world.
However, this shift in thought from optimized but brittle systems to ones that are more risk-informed and fault-tolerant will require education and new tools. The presented resilience matrix approach provides an example of a systematic framework useful to identify complete solutions. And, when used in combination with inclusive, holistic analysis techniques (e.g., stakeholder-participative scenario analysis), it can identify solution portfolios and initiate resource reviews. Happily, many of the insights may simply guide activities/solutions that would be required anyway (e.g., utility upgrades). Others may be relatively low-cost (e.g., public communication).
At the very least, resilience based analyses provide us with a far more comprehensive and detailed understanding of cross-scale and cross-domain interdependencies and thresholds, thereby allowing us to target investment dollars on energy system improvements or other initiatives that most effectively posture us for changing conditions. Given the vital national interests at stake, we should avail ourselves of the unique insights and adaptive management opportunities provided by SES resilience science. We are waking up to the fact that change is inevitable and we cannot predict it.
[Permission was granted by the U.S. Army Corps of Engineers, Chief of Engineers, to publish this material. The views expressed in this article are solely those of the authors and do not reflect the official policies or positions of the Department of Army, the Department of Defense, or any other department or agency of the U.S. government.]