The DER-enabled Future of Outage Restoration
Advanced Distribution Management Systems Necessary With Increased DERs
by Terry Nielsen
Storm-related power outages cost the U.S. an average of $25-75 billion annually. Large-scale mega-storms have regional socio-economic consequences that include the loss of critical infrastructure and long-term health & safety impacts (e.g. the excess mortality months after Hurricane Maria in Puerto Rico).
While utilities are working to improve grid resiliency through their various Grid Modernization efforts, customers are taking advantage of declining costs of solar, batteries, and microgrid technologies to implement their own ‘self-resiliency’ solutions. Self-resiliency is the ability for them to island and be self-sufficient during grid outages using some form of Distributed Energy Resources (DERs – solar PV, backup generators, batteries, electric vehicles, flexible loads, etc.) for temporary power.
Microgrid capacity is expected to triple by 2027 as it grows into a $30 billion market. Solar and microgrid implementation costs have also declined 25-30% since 2014. While solar only made up 10% of installed microgrid capacity in 2014, renewables account for 45% of the growth pipeline.
However, current utility outage management processes, policies, and software systems are blind to this emerging customer self-resiliency. Utilities have limited information about the microgrids on their network past the point-of-interconnection, and essentially no situational awareness into their islanded power status or remaining supply. Outage restoration, after addressing emergency and safety issues, is usually based on a simple prioritization of critical customers and/or number of customers interrupted. They assume de-energized customers are without power. In a rapidly emerging future of widely deployed solar, batteries, microgrids and other DER-enabled resiliency solutions across all customer categories, we believe this traditional approach is becoming increasingly suboptimal.
Back in 2014, GridBright and Berkeley co-authored an IEEE paper “Leveraging Distributed Resources to Improve Resilience”. It discussed how DER-enabled microgrids (homes, buildings, campuses, communities, smart cities, etc) could be used to avoid outages, reduce the time and consequences of outages, or assist in restoration by giving operators more triage flexibility.
It means that we could reduce the regional impact of large-scale grid events by optimizing how crews and equipment are dispatched during outage restoration. The essential idea is that self-resilient ‘locations’ (customers, circuits, communities, or critical infrastructure) with some form of temporary power supply could be reprioritized in favor of other urgently-impacted critical infrastructure locations. As long as the self-resilient locations are re-energized prior to exhausting their self-sufficiency (e.g. sunlight, battery charge, backup generator diesel fuel) their individual event impact is minimal and thus operators can focus on overall service territory restoration priorities.
For example, Seattle City Light is creating a microgrid that includes a battery system, solar panels and emergency generators at the Miller Community center. During a crisis, this stand-alone power grid will keep core emergency services and communication networks operating. Awareness of this self-sufficiency status will allow operators the flexibility to focus on restoring other critical community services like gas, water, and telecom.
While the idea is simple, the implementation will be complex. It requires better utility knowledge of self-resilient microgrid locations, situational awareness of how long they can continue operating independently during an outage event, and a much more intelligent prioritization of locations or damage to repair. Solar PV based resiliency strategies present a special challenge since ‘power supply’ is a function of time-of-day, sunlight, and local storage capacity.
Reducing the socio-economic consequences of large storms by even a small percentage has a huge national impact. We believe the current traditional approach is sub-optimal, and will become increasingly anachronistic as solar, batteries, and microgrids provide more customers with their own resiliency solutions.
To this end, GridBright is actively working with the DOE on a variety of projects related to power systems optimization research , high-penetration solar integration, and DER-enabled microgrids . Additionally, we have co-authored several reports with CEATI on the topic of reducing operational impacts when integrating DERs. These reports are an excellent source for further details of how grid operations must evolve to help mitigate the negative DER effects, and present opportunities like this to further optimize our future control room processes to leverage the growing DER penetration. A summary of the distribution utility report is available here – gridbright.com/derms-presentation.d