Council briefing: New approaches to transmission planning aim to ease bottlenecks, prioritize existing rights of way

Transmission lines near Fairfield, Idaho.

The Pacific Northwest's system of transmission and distribution wires, which transport power from where it's generated to where it's consumed, is grappling with bottlenecks in key areas like the Portland-Hillsboro area and in the Puget Sound region. Additionally, expanding the transmission system to accommodate new energy development faces lengthy planning and construction times - sometimes spanning a decade or more. Drivers who've ever eagerly awaited a project to ease rush hour traffic on a highway or major road in the Northwest can certainly relate.

During its November meeting in Portland, the Council heard briefings on new regional, West-wide, and national planning efforts underway that aim to address this congestion, get new transmission line projects built faster, and help states and utilities meet upcoming clean energy goals in the 2030s and 2040s. Presenters included Paul Wetherbee, Advisor for Regional Energy System Planning with Pacific Northwest National Laboratory; Matthew Tisdale, Executive Director of Gridworks; Jennifer Galaway, Senior Manager, Regional Transmission Development and Interconnection Services for Portland General Electric; and Kyle Kohne, Manager of Transmission Planning for Bonneville Power Administration. (Read presentation | watch video)

Under the Northwest Power Act, the Council's power plans give priority to conservation and generation resources that are cost-effective - meaning they can meet or reduce load at a cost less than other resources - while also being reliable and available when needed. That requires access to the transmission system. Thus, transmission availability is an increasingly important element of the Council's power planning, because load forecasts show potentially dramatic growth and policies and economics are driving greater need for clean, renewable energy.

Before the panel presentation, Senior Power Analyst Tomás Morrissey briefed the Council on how resources like energy efficiency can avoid or delay costs of building and maintaining transmission and distribution lines by lowering load on the Northwest's power system. (Read presentation | watch video) The Council's power plans include a value, called a T&D deferral rate, that helps quantify this benefit. Past power plans have applied this to energy efficiency, demand response, and some natural gas resources located on the west side of the Cascades.

Without energy efficiency, between 2010 and 2022 the Northwest would have needed to build resources generating 3,000 aMW - and their related transmission and distribution infrastructure, Morrissey said. For the upcoming Ninth Power Plan, he said Power Division staff are recommending the Council use three T&D deferral values - a regional version, a west-of-Cascades value, and an east-of-Cascades value. The Council is also in the process of determining how to apply this benefit in cost assumptions for new resource options in the Ninth Power Plan.

BPA owns about 15,000 miles of high-voltage transmission in the Northwest, which is 80% of the regional total. For scale, the Western Interconnection, which covers the Canadian provinces of British Columbia and Alberta, 11 western U.S. states, and part of Baja, Mexico, includes roughly 136,000 miles of transmission. Over the past two years, BPA has committed to building 23 new transmission projects costing $5 billion over the next 20 years, Kohne said. The first phase includes 10 projects worth $2 billion and are all considered "brownfield" developments because they expand or upgrade existing infrastructure using existing rights-of-way. BPA aims to complete these in the short-term to help bring clean energy resources from the east side of the Columbia River Basin to the Portland metro area and Puget Sound region, which will help utilities like Portland General Electric and Puget Sound Energy meet their 2030 clean energy goals. One project in the Portland-Hillsboro area has already been completed.

The next phase entails 13 projects costing $3 billion and will take longer to build - likely between the late 2020s and extending into the late 2030s. Subsequent phases of transmission projects will be needed beyond these first two. Prospective energy developers send BPA requests to hook up to their transmission system and get put into a queue. This queue has grown substantially in recent years. The agency reports having 272 projects totaling 186 gigawatts eligible for an upcoming transmission study, although many requests will be speculative and only a portion of these projects will ultimately reach construction.

New approaches to transmission planning gain momentum

In the latter half of the 20^th century, the Northwest and BPA invested billions of dollars to link with the broader grid in the Western Interconnection. This facilitated resource sharing across the West that continues to play a key role today in safeguarding the Northwest power system's resilience, reliability, and adequacy. For many years after these investments, the Northwest transmission system had capacity to spare. By the 1990s, further buildout began to level off due to lack of need for new energy development because of the success of energy efficiency measures, increased time and cost for permitting and siting, opposition to new transmission line projects in parts of the region, and other factors.

This chart shows miles of buildout by decade for BPA's transmission system as of August 2023. Data credit: BPA

In 2011, the Federal Energy Regulatory Commission issued an order intended to jumpstart new regional transmission development in the U.S. However, this failed to spur construction of any new projects in the Northwest, Galaway said. Further, inter-regional transmission planning has been virtually nonexistent in recent years. The Western Transmission Expansion Coalition, or WestTEC, is a response to that, she said. WestTEC is not a FERC process, although it's proceeding in parallel with a new FERC order issued in spring 2024 that aims to speed up transmission expansion in the U.S.

WestTEC is an industry-led initiative that convenes states, BPA, utilities, tribes, public interest groups, energy providers, and transmission companies, among others. By the end of 2026, it will produce a study looking out over 10- and 20-year time periods. This will include detailed descriptions of required infrastructure, including locations, technologies, and upgrades; comprehensive cost estimates and assessments of benefits for the Western region; preliminary routing options to support permitting, siting, and construction feasibility studies; and transmission alternative review, highlighting trade-offs and reasons for selecting preferred options, according to Galaway.

Tisdale presented findings from a recent study Gridworks commissioned that focused on transmission needs in the West by 2045 under an economy-wide decarbonization scenario that include large-scale build out of clean energy projects and electrification of buildings, transportation, and some heavy industrial sectors. Energy Strategies performed the study, and prioritized existing rights of way, co-locating, and upgrading existing infrastructure. It downgraded "greenfield" development and routes through national parks or culturally sensitive areas like tribal lands. This study didn't identify specific projects, but is intended to highlight key opportunities and inform other processes, such as WestTEC's.

Tisdale said the study recommended adding 20,000 miles by 2045; the existing system has about 136,000 miles. In some scenarios, 85% of the required line miles could be achieved with reconductoring upgrades, co-locating, and using advanced technologies like high-capacity conductors. However, some greenfield development would be unavoidable, depending on the needs of the power system. The study identified a transmission corridor between western Montana, northern Idaho, and southeastern Washington as a path that would potentially need new greenfield development.

Results from Gridworks' new transmission study show large-scale decarbonization in the West doesn't require significant greenfield development, although some would be unavoidable.

Wetherbee presented results of a new national study PNNL produced with the National Renewable Energy Laboratory and the Department of Energy. This study also didn't identify specific projects but identified key corridors that would likely benefit from expanded transmission and is intended to help inform regional and interregional transmission planning efforts.

• Analyzing the trajectories of current energy policies like state renewable and clean energy portfolio standards, the study found the U.S. transmission system is expected to roughly double in size by 2050, and inter-regional transmission will grow between 2 and 2.8 times its current size.
• Under current policies, power system CO2 emissions would decrease by 43-48% by 2050.
• Under a broader decarbonization scenario that achieved a 90% emissions reduction (from 2005 levels) by 2035, expanding the transmission system resulted in lower power system costs and greater resource adequacy. Regions coordinating to achieve resource adequacy would lower system costs $170-380 billion by 2050 in this scenario.

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