How Grid Enhancing Technologies Are Expanding Electric Power Transmission System Capabilities

It’s no secret that power grids around the world need to expand to accommodate more renewable energy and the so-called “electrification of everything.” The latter, of course, refers to the growing trend of using electricity to power various sectors and applications that have traditionally relied on fossil fuels, such as natural gas or petroleum-based products. The electrification of everything includes the push toward electric vehicles; the transition from fossil fuel–based heating and cooling systems to electric alternatives, as well as the adoption of electric appliances; and the shift to more electric motors, furnaces, and other electric-powered equipment in manufacturing processes. Add to that the expected power needed to supply data centers and the growth of artificial intelligence-related computing, and current estimates of 50% load growth by 2050 could be vastly understated.

Yet, getting new transmission lines planned, approved, and constructed is a daunting task, often taking a decade or longer to complete. So, how can the world more quickly add transmission capacity to the system without investing enormous time and money in the process? The answer: grid enhancing technologies, or GETs.

“GETs are exciting to us because they are technologies that help us unlock quickly the additional headroom or additional capability of the grid to carry energy across the system,” Alexina Jackson, vice president of Strategic Development with AES Corp., said as a guest on The POWER Podcast. “This is something that is very important, because today, we are not making the fullest use of the electricity system as it’s built.”

The system is operated below its maximum capacity for very good reasons, specifically, to maintain reliability, but by implementing GETs, it can be operated closer to its true limits without risk of failure. “Once we have these technologies, such as dynamic line rating, which helps us visualize the dynamic and full headroom of the electrical grid, and then technologies like storage as transmission, advanced power flow control, topology optimization—they all allow us to operate the grid in its dynamic capability. By doing both these things—visualization and operation dynamically—we’re able to start making fuller use of that carrying capacity for energy, which will allow us to add additional energy more quickly, serve our customer needs more efficiently, and ultimately decarbonize faster,” Jackson said.

Understanding the Possibilities

AES published a white paper in April titled “Smarter use of the dynamic grid: Accessing transmission headroom through GETs deployment.” The 20-page document goes into much greater detail on the four items Jackson mentioned—dynamic line rating (DLR), storage as transmission (SAT), advanced power flow control (APFC), and topology optimization.

DLR. The paper explains: “Traditionally, TOs [transmission owners] use static or seasonal line ratings based on worst-case assumptions—for example, the hottest time and day of the season under low wind speeds. This often results in conservative ratings that do not accurately reflect the true thermal capacity of a line at a given point in time. In contrast, DLR provides real-time visibility into line capacity and customized rating profiles on lines that are otherwise identical.”

DLR can be particularly beneficial in high wind areas because wind can cool conductors and enable them to carry more current. Similarly, lines can carry more current in lower temperatures, so utilities with transmission constraints during winter peaks could benefit greatly from DLR.

And deploying DLR technology can be done relatively quickly. AES partnered with LineVision on a project that went very smoothly. “We were able to deploy in a series of months from the idea of wanting to deploy dynamic line rating to actually getting it on the grid,” Jackson said. “That’s a really quick turnaround—doing anything on the grid in less than a year is really significant when it comes to transmission.”

SAT. Again, the white paper explains: “In operations, Storage as Transmission (SAT) can absorb excess generation during periods of low load and store it near load to dispatch during peak periods when transmission lines risk congestion. Using storage in this way reduces system costs from congestion pricing and can reduce harmful pollutants and overall carbon emissions by avoiding use of peaking thermal power plants.”

“Storage as transmission is just another evolution in storage’s capabilities,” said Jackson. “I like to say that it would be great to let storage bring its full self to work, because it has a lot of talents that we’re currently under-using.”

Jackson suggested that many people see storage as either an energy asset or a transmission asset, but the truth is it can do both from the same device. “One way to think about that might be as an effective warehousing and logistics solution, or you might also think about it as an Airbnb for the grid, where you can make sure that the resources that we have in the system are being used effectively,” she said.

APFC. Advanced power flow control (APFC) controls the magnitude of power flows along specific transmission paths, and can mitigate thermal and stability issues that arise by changing the flow to alternative paths, the white paper says. Without getting too technical, Jackson explained that APFC alters the impedance on lines to encourage flow via a desired route.

“If you imagine energy, like water, will flow where there’s less resistance to it flowing,” she said. “And so, you can actually change the impedance to say, ‘Flow on this less-constrained line. Don’t flow on this more-constrained line.’ And so, it allows you to ‘push’ or ‘pull’ energy in certain directions through its physical properties, so that it goes in the direction that you prefer to see it go.”

Topology Optimization. The AES white paper explains: “Topology optimization refers to the strategic reconfiguration of the power grid’s structure by switching the status of circuit breakers, switches, or other controllable devices. This process involves switching transmission lines in or out and/or splitting bus sections. For example, if load is growing rapidly and stressing one feeder, grid operators can transfer all or part of the load to adjacent feeders through switching actions at substations and minimize the risk of equipment failure and outages. Studied topology optimization solutions can be applied quickly to mitigate unexpected events like equipment failures or demand changes.”

Although the actual process is more complicated than this, Jackson said a person could imagine turning on or off a light switch, so that you can allow energy to flow or not flow across the line. “If we’re seeing constraints on a line, or we’re seeing certain potential for overloading other lines, we can make decisions to actually change the flow of energy across lines to make better use of them,” she explained.

Education and Scaling Solutions

The solutions Jackson talked about are not pie-in-the-sky ideas, they are tools being demonstrated and used commercially today. Yet, a lot of people are still not aware of the possibilities. That’s why AES published the white paper: to help spread the word.

“One key thing we need to do is education,” said Jackson. “We’re sharing our insights at a system level. We want to make sure that we’re breaking down barriers to people’s understanding of these technologies.”

Yet, to make a real difference, deployment of these tools is necessary at scale. “Deployments are going to help people understand, not only conceptually, but actually in the field, how these technologies can be done, how they perform, things to watch out for, things to make the most of, so that we can move from those early deployments into scale,” Jackson said.

To hear the full interview with Jackson, which contains more about the benefits of GETs and some of AES’s projects, listen to The POWER Podcast. Click on the SoundCloud player below to listen in your browser now or use the following links to reach the show page on your favorite podcast platform:

For more power podcasts, visit The POWER Podcast archives.

Aaron Larson is POWER’s executive editor (@AaronL_Power, @POWERmagazine).

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