Imagining the unimaginable: Examining future climate change scenarios
This author no longer works for DNV GL.
Superstorm Sandy, although not the most expensive hurricane to make U.S. landfall (Katrina holds that distinction), caused $65 billion in economic damages and was responsible for the death of 117 people in the United States. More than 8 million people were left without power in its aftermath. The havoc it wreaked on New York, New Jersey, and 20 other states was due to its immense size, its slow movement, and the fact that it made a direct hit on the coast of New Jersey.
While forecasters knew Sandy was going to be a significant storm, it was hard to imagine the damage it would do. The impacts of Sandy were exacerbated by the fact that it made landfall during a high tide and was trapped over the mid-Atlantic by a cold front from the northwest and a high pressure ridge over Greenland. Even so, Sandy wasn’t the most severe storm imaginable. In fact, it had been downgraded from a Category 1 hurricane to a tropical storm before making landfall.
Whether looking backward or looking forward, it is possible to imagine an even more severe storm hitting the East Coast. The Great New England Hurricane of 1938 was a Category 3 storm at landfall, causing electrical outages in Connecticut, Massachusetts, New York, New Hampshire, and Vermont that took weeks to repair. If such a storm were to hit the area today, the consequences would be staggering.
We’ve all heard that climate change is expected to lead to more frequent and more intense extreme weather in the future. We also know that attributing a particular storm today to climate change is fraught with uncertainty. But what if we tried to imagine a future in which climate change had taken place, and the same conditions that led to Sandy were to reoccur?
DNV GL, working with the National Center for Atmospheric Research (NCAR), did just that in a post-Sandy study to determine the vulnerability of electrical infrastructure to climate change. In our study, NCAR recreated Superstorm Sandy using its Weather Research and Forecasting (WRF) model. In this so-called “control simulation” NCAR was able to match the path and intensity of the actual storm with substantial accuracy. The computer model was then used to look at several scenarios of future climate change, where atmospheric, sea surface, and soil temperatures were increased to mimic scientists’ expectations for climate change in 2020, 2050, and 2090. These scenarios are representative of an atmospheric climate change of 1 degree, 2 degrees, and 4 degrees C.
We modeled the impact of a future Superstorm Sandy on the electrical infrastructure of Long Island, NY, an area hard hit by the storm. Sandy caused damage to 51 substations of the Long Island Power Authority (LIPA) and required the repair or replacement of nearly 2,500 transformers, more than 4,400 distribution poles, and more than 400 miles of wire. This damage caused a loss of electric service to more than 90% of LIPA’s 1.1 million customers, and it took days and in some cases weeks or longer to restore their power. LIPA’s repair costs in the immediate aftermath of Sandy approached $1 billion.
In all of the scenarios, NCAR found that the simulated Sandy storms had a more northerly path before making landfall, with the extent of northward travel corresponding to the increase in temperature. More precipitation occurred in the simulated Sandy cases as well. During Sandy, 12 LIPA substations were flooded due to a combination of precipitation and storm surge. Based on NCAR’s WRF simulations, DNV GL used a hydrodynamic model to determine how the future Sandy cases would affect coastal substations. The results were significant. Flood heights at the substations were two to three feet higher in the future simulations and it was estimated that 27 substations would potentially be affected by flooding under the 2050 scenario and 30 under the 2090 scenario. Under these scenarios, more than twice the number of substations would be affected compared to the 12 substations that were engulfed in 2012.
Electricity companies impacted by Sandy are spending billions of dollars making their systems more resilient to future storms. Solutions include hardening infrastructure to withstand hazards such as wind and flooding by installing stronger poles and thicker wires, and by raising the elevation of substation equipment. Other solutions are designed to make electrical systems smarter so that outages can be located and repaired more quickly, as well as making the grid more flexible through installation of distributed energy resources.
DNV GL has created a risk management framework—called ADAPT—that can help utilities and their regulators determine how much to spend on enhancing resilience to extreme weather, and what measures provide the greatest reduction in vulnerability under a range of future scenarios.
SlideShare presentation: ADAPT Framework for Grid Resiliency
Probabilistic risk-based modelling tool for the power industry
Enhancing resilience to severe weather and climate change
How utilities can prepare for the bigger, badder storms of the future
Continued lessons learned from Superstorm Sandy
Is your strategy for responding to extreme weather events up to the challenge?
DNV GL: Adaptation To A Changing Climate (Video)
Adaptation to a Changing Climate Report
One year later: Superstorm Sandy underscores need for a resilient grid
When the Bough Breaks: Managing Extreme Weather Events Affecting Electrical Power Grids, IEEE P&E, Sept/Oct 2014
Assessing Climate Change Hazards to Electric Power Infrastructure – A Sandy Case Study, IEEE P&E, Sept/Oct 2014