Grid-Edge Resources Can Be Resiliency Game Changer
Written by Hao Zhu and Robert Hebner
The rising occurrence of extreme weather events is placing an increasing amount of operational challenges to the resiliency of the electricity sector. Thus far in the year of 2021, North America (NA) has experienced a variety of weather disasters including winter storms, wildfires, and hurricanes. These disasters have indicated a clear pattern of climate change and caused significant impact on the electricity delivery infrastructure. Various sizes and durations of wide-area emergency conditions and even power outages have happened in different regions of the NA power grid, due to physical asset failures or generation resource insufficiency.
But these are not new types of problems. Rather climate change is making seasonal problems more intense and causes the problems to occur in areas they never occurred before. These are problems the engineering community has solved, but the public only wants to pay for the solutions where they are needed. And those areas are changing in unanticipated ways.
The stakes are high because electricity is becoming increasingly critical to the functioning of society. Blackouts are becoming less of an annoying inconvenience and more the trigger that can collapse the interconnected infrastructures on which modern society depends.
We need innovation to achieve critical continuity of electricity supply at a lower cost. Consequently, there is growing recognition that energy resources and information technologies at the grid edge can play an increasingly important role to mitigate the impacts on localized areas and enhance the overall resilience of the electric energy infrastructure.
Sensing for Situational Awareness
If one searches the internet, it is easy to see that “Build Back Smarter” is a mantra across many industries and countries. While there are ways to do so, the electric power industry’s commitment to Smart Grid makes it challenging not to build back smarter in response to climate-induced grid failures. The small size and low cost of computing and communication resources are making the grid smarter every day.
In the immediate aftermath of a disaster, the appropriate response is to become operational as quickly as possible. Then the more deliberate process of minimizing the chance of a similar event begins. This is when smart designers, smart regulators, and smart engineers build back better. And there are plenty of tools becoming available.
For wildfires, the preferred current solution is to put the power in underground cables not overhead lines, a decades-old approach. The reason it was not adopted decades ago is cost, not technology. As the wildfire problem became more critical, engineers invented a substation-based system that could detect incipient wildfires. It was good, but not good enough. Today the U.S. Department of Energy is funding the development of what is likely the smartest online sensor by virtue of being the newest with the newest technology. These can be mounted on the power line wherever there is concern. They are affordable enough that they can be applied redundantly for reliability. They show a path to rapid identification of a fire potential. Will the smart approach be reliable and less costly than a buried line? We don’t yet know, but when we bury the line, we lock in the high cost.
Control for Flexibility
Alongside the sensing upgrades, distribution utilities are also investing more on the equipment and new solutions for improving the controllability within feeder systems. Distribution feeders can now proactively respond to a disaster by actively configuring the network topology and connectivity and its connected energy resources. Individual customers may be able to do the same with their residences as well in coordination with utility operators.
Flexible feeder topology reconfigurations through the seamless coordination of distributed sectionalizing devices are a key technology to future-proof the power grid from the climate crisis. One lesson learned from the 2021 Texas blackout is that the level of load shedding requested by the transmission operators can be unprecedentedly high. It is critical for utilities to be able to have rolling outages among the non-critical feeders when being asked to disconnect half of total demand. Otherwise, certain communities might have to endure the outage for several days, causing huge economic losses and human suffering.
Can businesses and individuals support their utility companies in developing the emergency plan for extreme weather induced outages? The answer is most definitely yes. Advanced technologies of smart buildings and smart homes not only enable normal grid operation support like frequency/voltage regulation, but also can empower certain functionalities for emergency conditions. If designed for emergency use, they can potentially automatically disconnect non-essential electricity uses for a multi-level load shedding during wide-area power shortages.
Today, the load shedding is assigned to a utility as a percentage of the desired load. The utility then meets that requirement by giving some consumers no power. Research in Europe and the US, however, is showing it is possible to assign the percentage to the customers. This requires operating a smart meter so it only provides power when the demand is below a dynamically preset value. This emergency response would permit consumers to maintain some refrigeration or heating or other services. This is a smart extension of demand-side management in which consumers can decide during emergencies what load shedding makes sense in their particular situation while meeting overall system requirements.
Emerging Resources and Technologies
The path to decarbonization calls for the electrification of multiple sectors, transportation, manufacturing, agriculture, and food production, to name a few. The electricity infrastructure can possibly welcome these electrification efforts as additional resources for emergency planning. Can electric vehicles act as mobile storage when the grid is in such need? Can electrified chemical plants power a small community using its installed resources?
The emerging technology focuses on a facility having rooftop solar panels and battery storage and is being highlighted by the U.S. Secretary of Energy Granholm following hurricane Ida. The concept works, but studies have shown it to be among the most expensive solutions. Transportation electrification may well provide a disruptive technology to this emerging technology.
Research and demonstrations of the research concepts have shown that electric and hybrid vehicles can power a home or business during an outage. The situation has matured so that an electric Ford F150 is advertised as being able to power a house for three to ten days, depending on the situation. Electrified transportation is showing a path to resilience without the investment in solar panels or dedicated batteries. A “smart” challenge is to have this flexibility so that it is both safe and beneficial to grid stability when millions have readily accessible backup power in their driveway. This will likely required enhanced communication.
The answer may well be in the better connectivity enabled by the up-and-coming 5G/6G wireless technology to further empower the active participation of customers. It is time for the electric utilities to harness these emerging opportunities to prepare their systems for the future operational paradigm. Transportation electrification may well provide a disruptive technology to an emerging technology.
Finally, a different type of smart system is being made available via hydrogen. A significant fraction of the world’s population lives in cities without direct access to wind or solar power. To solve that problem in Texas, for example, the State authorized the Competitive Renewable Energy Zones (CREZ) transmission lines to connect areas with abundant wind and solar power with population centers. This project had a CapEx of about $7B. Recent studies have shown that the same amount of energy could have been transmitted the same distance in a hydrogen pipeline for about 20% of the power line cost. In addition, the global manufacturers of utility generators are marketing units that operate on a mixture of hydrogen and natural gas. This provides dual-fuel resilience. Moreover, a smart distribution system connected to smart transmission lines and dual-fuel generators can provide operational options that are impossible today.
The evolution to a smarter, more resilient grid at lower costs seems to be on the path of being inevitable technically. The biggest risk is that inappropriate laws, regulations and/or subsidies may limit us to 20th century technology.
This article edited by Jose Medina
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