Can we ensure energy resilience after a disaster?

Today’s research is tomorrow’s design. We’re asking researchers within Arup and beyond to describe their work and its potential applications. Russell Carr, an electrical engineer in our San Francisco office, spoke with us about his work on sustainable emergency power.

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What are you studying?

How can we make cities more resilient by maintaining continuity of essential services when disaster strikes — in a sustainable manner? This is the focus of a two-year research project.

Arup is the prime consultant to the City and County of San Francisco Department of the Environment for this effort, which is funded by the U.S. Department of Energy.

Viewing disaster preparation and resiliency through the lens of sustainability is fairly new in the emergency response arena. Portable diesel generators have historically been used to power buildings critical to disaster plans (e.g., churches, schools, and libraries used to shelter displaced residents). These generators are not the most sustainable choice for several reasons. First, they’re used only for backup power. When the grid is operational (99.9% of the time) they’re an unused asset — a waste of resources. Second, they burn fossil fuels, which cities around the globe are committing to eliminate. Finally (and most pertinently for people affected by disasters), diesel fuel tends to be scarce during emergencies, meaning that many generators are unable to run for extended periods — defeating the purpose of having backup energy equipment in the first place.

Diesel fuel tends to be scarce during emergencies — defeating the purpose of having backup energy equipment.

Like other cities working at the intersection of sustainability and emergency preparation, San Francisco wants to transition to renewable energy sources as its backup when the grid goes down. But daunting technical and financial barriers stand in the way: a lack of technical expertise among emergency response planners (specifically around renewable energy); a paucity of non-grid-dependent equipment, including energy storage equipment; funding shortages; and competition for other emergency response priorities, such as robust postdisaster communications networks.

Snapped power lines after a hurricane in Florida

There is a clear path ahead, though — solar generation coupled with energy storage. For the first time, all the pieces needed to implement a solution are now available in the marketplace. Solar manufactures are starting to offer combined generation and storage. Building-energy-storage providers are using innovative aggregation to allow small building-scale batteries to operate together as one larger resource in grid-services markets and earn revenue. Utilities are beginning to understand the potential of microgrids.

No one has created a comprehensive plan for incorporating solar plus storage into urban disaster planning, however. We’re stepping in to fill the gap.

There is a clear path ahead — solar generation coupled with energy storage.

Why is this important?

Large natural disasters severely damage energy infrastructure, while minor storms regularly disrupt power networks around the world.

Each US region faces a different threat, from earthquakes in the west to tornadoes in the central states and hurricanes in the east. Climate change–induced shifts in weather patterns will likely heighten the risk of disaster-induced power outages.

Recent events such as Superstorm Sandy clearly showed that inadequate backup power can often be traced back to fuel shortages. Renewable technologies like solar provide a near-constant supply of fuel that won’t run out in a disaster. (While solar levels vary throughout the year, they’re almost always high enough to generate some electricity.)

What are the potential implications for the future?

Our team reviewed emergency operation and hazard mitigation plans for several US cities to find opportunities to incorporate resilience-focused solar-plus-storage plans.

service restoration timeframes

When a major earthquake disrupts San Francisco’s power supply, the electricity-distribution system should recover in around a week, while gas will likely be unavailable for many months.

We found that current urban emergency response plans provide little guidance for ensuring energy resilience in mission-critical buildings. Most cities don’t track building-specific operations plans or emergency electrical loads, nor do they include provisions for power restoration or temporary generation. None provide concrete plans for using renewable technologies for emergency energy provision.

Awareness of these gaps is growing, however. Each plan we studied clearly identifies a need to provide electricity in the wake of disasters. San Francisco, Baltimore, and Portland all expressed the desire to incorporate solar-plus-storage capabilities.

Our research aims to provide a road map for achieving this goal. By determining the optimal placement of solar-plus-storage facilities in San Francisco and exploring ways to overcome hurdles to implementation, we hope to create a system that can be replicated in other jurisdictions.

As part of this effort, we created a web-based map showing each building identified in San Francisco’s disaster preparedness plan. This tool will aid city planners in developing disaster-relief strategies.

Potential microgrid zones identified in San Francisco (developed in ArcGIS software)

The project also explores issues that affect solar-plus-storage efforts in general — for example, regulatory hurdles, electricity distribution to multiple stakeholders and across public rights-of-way, and energy dispatch and grid control across noncontiguous property boundaries to many stakeholders.

By the end of the project in December 2016, we will have developed a framework for cost-effectively integrating solar plus storage into disaster preparedness plans and provided a blueprint for implementing them, using San Francisco as a case study. This could improve the speed of a given city’s recovery from electrical disruption by 100% in some areas. It could also support emergency response goals such as postdisaster communications by providing solar-plus-storage systems for mission-critical facilities like Department of Homeland Security office trailers.

This work has benefits beyond disaster planning as well. It could potentially drive down costs for widespread adoption of solar power and facilitate the creation of plans for renewable energy and storage systems that are able to operate independently of the grid within cities.

What are the next steps?

We’re launching a solar-plus-storage sizing tool to the public in the coming months. This will allow average citizens to understand what size solar-plus-storage system is required to maintain power in any given building in the United States after an emergency. Users will be able to easily upload their building’s energy data to create a customized emergency profile. They can also see how outages of different durations and electric loads of different amounts (e.g., with refrigerators turned on or off) would affect sizing requirements.

 

Questions or comments for Russell Carr? Email russell.carr@arup.com.

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