The resiliency of the nation’s electric power grid is at the forefront of the minds of many in the public, utility, and political arenas. State legislatures are enabling power companies to focus funds to harden their systems against storms, and to modernize their infrastructure. Even the White House has published a report titled the Economic Benefits of Increasing Electric Grid Resilience to Weather Outages. These efforts typically focus on downed trees and damage from high winds. However, there is a lesser publicized risk that can be more costly and more negatively impactful to utilities: flood risk. Those of us in the flood risk community know that if you live or have infrastructure in a high-hazard area, the question is not if you will flood, but when. Most people outside of this flood risk community tend to believe it won’t happen to them, until it’s too late. The damage and destruction of Superstorm Sandy brought this to the forefront for the areas impacted, and utilities such as PSE&G are now making it a high priority to protect their infrastructure from the catastrophic damage flooding can bring. Despite the nationally publicized damage caused by Sandy, many people and utilities outside of the impacted area still believe they are safe from flooding.
Many electrical substations were built before flood hazards and risks were known or fully understood at these sites. Due to this and ongoing urbanization, a significant number of substations in the country are located in areas that are considered flood prone, putting the electrical grid at risk. Often, flood risk is unknown to the utility or believed to be far less severe than what it actually is. In April 2013, one Midwest utility experienced flooding at a substation, which was surprising because the substation had not experienced past flooding. The utility was aware that some of their substations flooded occasionally, and took measures to sandbag or use other means of flood fighting. However, at this particular substation, the flood risk was more difficult to recognize because the substation was built behind a levee. Levees provide a sense of security and protection to many, but when they fail, it’s often catastrophic. In this scenario, the levee failed, and the substation was significantly flooded, causing well over $1 million in damages.
Could this flood have been prevented? No – no matter how hard we try, we can’t stop Mother Nature. Could the damage have been prevented? Possibly. Could the severity of the damage have been minimized? Absolutely – and this is the purpose of a flood mitigation program.
Since this event, Primera has worked closely with the Midwest utility to develop their own flood mitigation program. Programs like this focus on three areas common to flood mitigation for utilities, communities or individuals:
- Understand your risk
- Plan for mitigation
- Mitigate your risk
Understand Your Risk
There are two elements that comprise risk: probability and impact. In the flood world, probability is about looking at the variety of flood hazards – from the events that occur often with a low flood elevation, to infrequent events with higher flood elevations. The industry standard for defining a high flood hazard area is the “100-year flood,” a flood that has a 1% chance of occurring in a given year. This is the standard used by the Federal Emergency Management Agency (FEMA) to identify hazard areas for the National Flood Insurance Program, and has been evaluated in multiple forums such as the Gilbert F. White National Flood Policy Forum 2004 Assembly “Reducing Flood Losses: Is the 1% Chance (100-year) Flood Standard Sufficient?”
To transform the hazard into risk, you need to understand the impact of the flood in terms of the amount of damage and impact potential within the hazard area. In the Midwest utility scenario described above, Primera performed a risk assessment that categorized each of their 800+ substations into a risk level of High, Moderate to High, Moderate, and Low. This gave the utility a starting point of what the risk was, and the data needed to effectively communicate to executive levels on the need to address the risk. When there is a need, there is a funding request.
Plan for Mitigation
So now you understand your risk. While knowing is half the battle, there are several more struggles to overcome. You will need a business case and funding scenarios to get the program off the ground. Then there will be engineering, construction, operations and maintenance, oversight and the ability to prove that what you set out to do is actually providing the intended benefit. To address these, good planning is needed. Primera is assisting the Midwest utility with refining the original risk assessment based upon the severity of the flood risk to the substation components and the impact the loss of that substation has on the utility. We are using additional internal factors about the criticality of each substation to the utility and to customers to help produce a prioritized, ranked list of the substations. This then leads to the ability to make high-level plans for funding and establish the overall timeframe for the program’s need.
Next, you need to know what is viable to address the flood conditions at each site targeted for mitigation. Feasibility studies of the at-risk substations will help identify what will work, what the regulatory constraints are, and what a project-level cost estimate will be. A cost-benefit analysis as part of these studies will also help further the business case for the mitigation project and the overall program. For example, in one feasibility study performed, the substation was located in the floodway, the area of highest velocities and highest likelihood of damage. Significant mitigation measures are needed to address this site. At other sites, a more thorough review revealed that the flooding was limited to the perimeter of the substation, where no critical equipment existed. This will result in a lower cost solution, and in some cases acceptance of the risk and flood fighting may make more sense than engineering a solution.
Mitigate the Risk
Now it’s time to make things happen. Full engineering and design of the mitigation solutions, work planning, material ordering and construction take place in line with the funding schedules. As the engineering and design are in process, a critical component is the need to coordinate with regulatory authorities early in the design process. Floodplains and floodways are strictly regulated by local, state and federal agencies. Wetlands are often associated with floodplain areas, adding additional complexity to permitting and regulatory issues. Extensive coordination with the appropriate agencies, as well as ensuring that all requirements are understood, will minimize any disruptions.
Floods affect us all; they impact people, property, communities and businesses. A key to making our communities more resilient, and utilities more sustainable, is having a program in place to mitigate risk. We mitigate a variety of risks each day through the decisions we make, purchase of insurance and avoidance of certain situations. It is essential that utility companies do the same for natural hazards, especially flooding, in order to protect their investments and their customers. For additional information on flood mitigation, please contact Mary Jo Mullen.