How digitizing the transmission grid can enable the energy mix of the future

Transmission grids around the world need major upgrades to support all the new wind and solar power that will be required to decarbonize the electricity supply. A massive investment in new transmission lines will have to be part of that overhaul. But technology to help make better use of the grid we have now could also play a critical role — if it can be scaled up from narrowly focused uses to systemwide applications.

That’s the long-range goal of U.S.-based Smart Wires and Ireland’s grid operator, EirGrid. In July, the partners announced a two-year, 300,000-euro ($356,000) project to design software that can integrate Smart Wires’ SmartValve power flow control devices into how EirGrid operates its nation-spanning electrical grid.

The partners plan to develop an ​“open-source tool that allows the operation of multiple power flow devices on the system at the same time,” said Liam Ryan, EirGrid’s chief innovation and planning officer. ​“The challenge we need to address is the interaction between these devices.”

That’s a big step forward from its first tests of three SmartValve units on a single circuit in west Ireland. Those 2016 tests showed the devices could do what they’re designed to do: modify key variables to increase or decrease power flows along the high-voltage line.

That offers grid operators much greater control over the complex interplay of power flows on a transmission network, with a device that costs less and takes much less time to install than the flexible alternating current transmission system devices now in use on high-voltage grids.

Similar tests of SmartValves in Australia, South America and the U.K. have also returned promising results, according to Ryan. U.K. grid operator National Grid last year expanded early tests of the technology with a plan to deploy 48 SmartValves across five circuits at three substations that had been identified as ​“renewable-power-flow bottlenecks,” meaning that they reach or exceed capacity even as surrounding circuits remain below their limits.

That ability to reduce overloading on bottleneck circuits (and thus increase loading on underutilized circuits) could be a major boon for grid operators. It could be particularly helpful when they are trying to absorb increasing amounts of renewable energy without facing expensive and time-consuming grid upgrades. National Grid expects its Smart Wires deployment to add 1.5 gigawatts of renewable energy capacity to the U.K. grid.

In the U.S., a study released by The Brattle Group in February indicates that combining SmartValve power flow devices with other grid-enhancing technologies could help U.S. grids double their existing clean energy capacity. This approach could also unlock gigawatts’ worth of renewables projects in the Midwest that have been stalled pending long-delayed grid upgrades.

From single power lines to transmission grid control rooms

Getting from these hypothetical benefits to real-world application requires a complex array of supporting systems, however. Individual SmartValves can manage individual circuits with problems, said Mark Norton, Smart Wires’ vice president of European business development. But, he added, ​“It’s the combined effect that really gives you the opportunity to create marked increases in capacity for renewables.”

That’s the goal of the new EirGrid project, which includes the Electric Power Research Institute, a U.S. utility-funded research group. The partners hope to have a simulation running the software by September, and then to complete a product that can be integrated into its control rooms by the end of 2022, Norton said.

The first step is to design an ​“enhanced situational awareness” tool to inform grid operators of the ​“capability the SmartValves have at any point in time,” he said. The devices ​“can redirect power second by second, all the time. It’s very dynamic…and can provide a level of control that you can’t get from most of the other devices on the grid.”

Transmission grid management software platforms built by Siemens, General Electric, Hitachi ABB Power Grids and a few others aren’t yet designed to model second-by-second grid changes. That’s why the Smart Wires-EirGrid project is pursuing an open-source software approach that can integrate into existing platforms, he said.

The second step is an ​“optimization decision support” tool that offers a longer-range view of EirGrid’s system, Norton said. That involves analyzing the shifting levels of capacity of power lines, transformers and other key parts of the grid from hour to hour or day to day, as well as tracking how the power-routing options available from SmartValves will interact with those factors.

Ryan reported that EirGrid is working with other transmission technologies to further hone and optimize these advanced capabilities. Dynamic line rating systems, for example, can capture real-time power line conditions to replace the static measurements used on most grids today, and phasor measurement units can provide sub-second snapshots of grid conditions to identify faults or disruptions to grid stability.

EirGrid is under pressure to increase its renewable energy capacity — mostly wind power — from about 40 percent of its total generation capacity today to about 70 percent by 2030, Ryan said. The grid operator is already being forced to curtail significant amounts of wind power due to its inability to manage all of those megawatts. EirGrid’s ongoing study of its 2030 grid needs calls for investments ranging from 500 million to 2 billion euros ($594 million to $2.37 billion) to reach its goals.

Ryan believes a ​“technology-led approach” to managing this clean energy growth could significantly reduce the number of upgrades needed. Such a strategy could reduce ​“the amount of new build, which is a challenge for grid operators around the world,” he said. ​“One of the key things we need to look at is how we get smart devices on the system to move power around more effectively.”

Ryan hopes EirGrid’s work with Smart Wires will yield a workable set of software tools that other transmission operators can put to use. Ireland’s island grid is in some ways an ideal test bed for managing the challenge of increasing renewables. ​“If we get the right solutions here, we could fast-track the utilization of renewables around the world as well.”

(Lead photo courtesy of Smart Wires)