An efficiency-first approach to transmission
Transmission lines are critical to our energy system, capable of shuttling electricity vast distances from where it’s generated to where it’s consumed. Over the past 40 years, energy efficiency has helped to avoid the need for new transmission projects. A coming wave of electrification and other load growth that will largely be powered by solar, wind and battery storage projects across the region has put our transmission infrastructure in the spotlight to connect these resources to demand.
Limited transmission capacity is commonly seen as one of the biggest barriers to the clean energy transition and reaching our climate goals. The process to build new projects can take a decade or two to complete, it’s difficult to allocate the mammoth price tag, and should always include early Tribal consultation and robust engagement to engage impacted communities in decision-making.
Energy efficiency has been a lifesaver for our aging transmission system, allowing it to remain relatively unchanged for decades even as our region’s population has boomed. But now, the latest forecast from the Pacific Northwest Utilities Conference Committee (PNUCC) finds electricity demand could grow 30% in the next decade, driven large by data centers, new manufacturing, and the electrification of buildings and transportation.
While the region plans for and works toward building new transmission, we must adopt an efficiency-first approach to transmission upgrades to squeeze more juice out of our existing system to support as much near-term clean energy development as possible. This will take some immediate pressure off the new transmission siting and permitting processes and allow them to be done effectively.
Fortunately, we can increase the capacity of our existing grid with transmission efficiency upgrades, such as installing advanced transmission lines (aka reconductoring) and other grid-enhancing technologies (GETs) for a fraction of the time, money, and impact. While not every GET is appropriate for every line, transmission owners (aka utilities and the Bonneville Power Administration (BPA)) must examine all their power lines, high voltage down to distribution lines, for opportunities to implement efficiency measures that will increase the capacity of our power grid.
The challenges to new transmission
The backlog for new clean energy generation projects is enormous and growing. Across the country, around 1,200 GW of projects, 95% of which are clean energy, between the West and California’s Independent System Operator (CAISO), are stuck waiting in the “interconnection queue.” This process allows transmission system operators to study the impact of new power generation and/or storage projects on the system and determine if new transmission related infrastructure is needed to interconnect the generation and then determine how to allocate the costs for any transmission upgrades needed to safely connect the new project to the grid. The following figure shows the dramatic increase of clean energy resources in the interconnection queue in recent years, particularly in the West and CAISO.
Source: Lawrence Berkeley National Laboratory
In the Northwest, an overwhelming amount of new resources, especially wind, solar and batteries, are seeking to connect to the BPA power grid, which operates about three-quarters of Northwest transmission.
Source: Bonneville Power Administration, May 2024
Even with BPA’s fast-increasing upgrades and new transmission projects under its Evolving Grid initiative, there is far more need from new power generation than there is available capacity.
Another hurdle is deciding who will pay for new transmission projects. When a project spans multiple states and utilities, each entity may benefit from the project and the overall system may benefit, but negotiations around how the costs should be allocated are often very slow and hard to bring to closure.
GETs and reconductoring are the fastest, lowest-cost approaches to increase transmission capacity
The efficiency upgrade that has drawn the most attention recently is reconductoring, which means swapping out a traditional transmission line made of steel (for strength) and aluminum (for conducting electricity) with advanced conductors made from carbon fiber.
All power lines must maintain safety, and traditional lines have an additional safety hazard because steel can sag from thermal expansion, especially on hot summer days when it’s carrying a lot of electricity. This can sometimes force grid operators to lower a line’s capacity to avoid sagging into vegetation below and potentially causing a wildfire. As a Volts podcast breaks down, reconductoring lines with carbon fiber lines provides double the strength of steel at 20% lighter weight – and with no thermal expansion. Thus avoiding any need to reduce usage.
An additional benefit of reconductoring is that it utilizes existing transmission towers to get more out of our existing transmission without the need for new “greenfield” right of way construction. To put the potential in perspective, a study from the University of California, Berkeley and GridLab found that reconductoring typically costs less than half of the price of building new transmission lines. Reconductoring could also add four times the transmission capacity by 2035 compared to a 100% greenfield construction scenario.
Source: UC Berkeley and GridLab
Reconductoring must be applied in the right circumstances and is typically most effective and useful in shorter distance lines, regardless of the voltage.
Alongside reconductoring, GETs is an umbrella term to describe a range of potential hardware and software upgrades to our transmission system, including dynamic line ratings, power flow controls, and topology optimization.
A recent report from RMI analyzed GETs’ potential to add capacity to new and existing transmission for PJM, a regional transmission organization that covers 13 states in the Eastern and Southern US. The report found that GETs could add an additional 6.6 gigawatts of clean energy capacity by 2027, delivering $1 billion in annual benefits for a fraction of the cost.
Dynamic line ratings (DLRs) compile an array of sensors and collect data on wind speed, temperature, and solar irradiance to calculate the operating capacity of a transmission line at any given moment. RMI’s report found that on average this increases a line’s capacity by 17% in the summer compared to traditional static ratings. This granular monitoring also improves resiliency, alerting operators to reduce capacity during extreme weather events.
Source: RMI
Power flow controls (PFCs) work like traffic controllers, rerouting power from crowded lines to those with extra capacity. This hardware provides utilities and transmission operators with increased flexibility to send power where it’s most needed on the system. The figure below shows how PFCs can balance power across multiple transmission lines, increasing the capacity of the system.
Source: Canary Media
Topology optimization (TO) is a software upgrade that models the entire grid and where power is flowing within it and redirects power to relieve any lines that become overly congested. TO works to shift these power flows as needed by switching high voltage circuit breakers on or off. Once programmed, this process happens automatically, helping grid operators diffuse a potentially overloaded line before it becomes a problem.
Source: RMI
Taken together, reconductoring and GETs have enormous potential to modernize our transmission system at the pace needed to help interconnect new solar, wind, and battery storage projects in a timely manner. Despite these clear benefits, utilities and BPA have fallen behind other countries in implementing these beneficial technologies.
As Canary Media reports, Australia, some countries in South America, and Europe have all been quicker to adopt GETs over the past decade. In one example in 2021, UK transmission operator National Grid added 2 gigawatts of new capacity using new power flow controls. This avoided the need for new infrastructure, reduced congestion costs and is expected to deliver £390 million ($494M) in benefits over a seven-year period.
Policies and regulations could go further to prioritize transmission efficiency in the US
One roadblock to implementing efficiency upgrades to our transmission system is the traditional cost-of-service regulation. Traditional regulation tends to support regulated investor-owned utilities prioritizing the larger cost of building new transmission assets over more efficient and economical solutions like reconductoring and GETs. Additionally, risk-adverse utility and BPA grid operators focused on maintaining a reliable grid may also be hesitant to adopt new technologies they aren’t familiar with. Public utilities do not face the same regulatory hurdles as private utilities, access to capital and prioritizing how it is spent can be equally challenging.
The US Department of Energy is working to unleash the potential of GETs and reconductoring with billions of dollars worth of investments in pilot projects around the country. This investment infusion can further showcase the value of efficiency upgrades to regulators, policymakers, and grid operators. Federal funding also circumvents the current lack of regulatory incentives to pursue the low-hanging fruit of improving the current system.
Federal regulators are beginning to address the challenges of modernizing our transmission system with a recent ruling from the Federal Energy Regulatory Commission (FERC), Order No. 1920. The ruling requires transmission operators to consider the potential of these efficiency measures to save costs, speed up upgrade timelines, and improve the reliability and capacity of the transmission system.
There is no doubt that new transmission lines will be needed to enable the transition to a fully clean-powered grid, especially for utility scale wind and solar projects that may not sit next to an existing transmission line. At the same time, our existing system has plenty of extra capacity waiting to be realized with proven measures like GETs and reconductoring. These efficiency upgrades can reduce the amount of new transmission that’s needed, saving costs for customers, improving reliability, and more quickly connecting the clean energy resources needed to meet our decarbonization goals.