LEARN / REINDUSTRIALIZATION
Transmission and Why It Is Not Built
High-voltage transmission construction has fallen by roughly eighty percent per year over a decade, during the same period in which demand forecasts quadrupled. The obstacle is that nobody has agreed who pays, and that the authority to approve a line is split across every state it crosses, which leaves the engineering as the easy part.
Key points
- New high-voltage transmission averaged 1,700 miles a year from 2010 to 2014, 925 miles from 2015 to 2019, and 350 miles a year from 2020 to 2023.
- A line delivers benefits across a region and imposes costs on specific ratepayers, which makes cost allocation the central dispute rather than a procedural step.
- Siting authority sits primarily with the states a line crosses, and a state gains little from approving a line whose benefits accrue elsewhere.
- FERC Order No. 1920 requires 20-year regional planning and ex ante cost allocation methods; Order No. 1977 sets out federal backstop siting.
- The rules were adopted over a 77-page dissent arguing FERC exceeded its statutory authority, so the legal foundation is itself contested.
The construction record
Data1,700 → 925 → 350 miles
Average new high-voltage transmission miles built per year, 2010 to 2014, 2015 to 2019, and 2020 to 2023. Reported by Americans for a Clean Energy Grid, an advocacy organisation, in its July 2024 Fewer New Miles report.
Series and provenance
- Agency
- Americans for a Clean Energy Grid
- Program
- Fewer New Miles, July 2024
- Series
- Average annual new high-voltage transmission miles
- Measure
- U.S. high-voltage transmission construction rate
- Units
- Miles per year, averaged over each period
- Period
- 2010 to 2014, 2015 to 2019, 2020 to 2023
- Latest
- 1,700 miles per year falling to 925, then to 350
- Source tier
- Advocacy organisation compilation; not reconstructed by the Institute from underlying filings
- Retrieved
- August 9, 2026
The publisher has a stated interest in more transmission being built, and this figure is marked at lower confidence than an agency data release. It is used because no federal series publishes annual high-voltage miles constructed in comparable form, and the alternative is to leave the trend unquantified.
The direction is the point, and it runs opposite to every demand forecast published over the same period. NERC raised its ten-year peak growth projection from 55 GW to 224 GW across four assessments while transmission construction fell to roughly a fifth of its early-decade rate.
Measurement noteThis series comes from an advocacy organisation with a stated interest in more transmission being built, and the Institute has not reconstructed it from underlying utility filings. It is marked at lower confidence than an agency data release. The figure is used because no federal series publishes annual high-voltage miles constructed in a comparable form, and the alternative is to leave the trend unquantified.
Why cost allocation is the obstacle
A long transmission line typically benefits a wide region: it lowers congestion, improves reliability and lets cheaper generation reach load. Those benefits are diffuse and partly probabilistic. The costs are concrete, large and charged to identifiable ratepayers, usually in one or two states.
That asymmetry is the whole problem. A state commission asked to approve costs for its ratepayers must justify them against benefits that accrue substantially to people it does not regulate, and it has no mechanism to charge those beneficiaries. Refusing is the defensible position for each commission individually, which is why interregional lines are proposed frequently and built rarely.
FERC Order No. 1920, issued May 13, 2024, attempts to address this by requiring transmission providers to conduct long-term regional planning on at least a 20-year horizon and to adopt one or more ex ante cost allocation methods agreed before projects are selected rather than negotiated afterward. Order No. 1920-B subsequently strengthened the role of state regulators, requiring that a cost allocation formula agreed among the states in a region be filed even where the transmission provider prefers a different one.
Who can approve a line
Siting authority for transmission has historically belonged to the states. A line crossing four states needs approval in four states, each applying its own standard, and any one of them can stop it. Congress created a limited federal backstop in the Federal Power Act, expanded by the Infrastructure Investment and Jobs Act of 2021, under which FERC may permit lines in corridors the Department of Energy designates as being in the national interest.
Order No. 1977 sets out how FERC will exercise that authority. Its practical reach is narrow: it applies only within designated corridors, and FERC declined to eliminate the existing one-year delay between the filing of state siting applications and the start of its own prefiling process, so the federal route does not run in parallel with the state route.
Institute analysisTransmission is the clearest case in industrial capacity where the binding constraint is institutional rather than physical. The engineering is well understood and the equipment is manufacturable. What is missing is a mechanism to charge the beneficiaries of a line for the costs it imposes, and a rule for approving something whose benefits and costs fall in different jurisdictions. Those are design problems in the rules, not shortages in the world.
Common misconceptions
That transmission is blocked mainly by environmental review. Review adds time. The reason lines are not proposed and financed in the first place is that cost responsibility is unresolved.
That FERC can approve interstate lines the way it approves pipelines. Natural gas pipelines have a federal certificate process. Electric transmission does not, beyond a narrow backstop confined to designated corridors.
That new rules have settled the question. Order No. 1920 was adopted over a lengthy dissent contesting FERC’s authority to issue it, and challenges to the rule and to individual allocations are expected.
What the evidence says, and where it is contested
ContestedThe legal foundation is genuinely disputed inside the agency that built it. Order No. 1920 passed with two votes of three, over a 77-page dissent from Commissioner Mark Christie arguing that the rule claims statutory authority the Commission does not have, that the Federal Power Act leaves transmission siting and generation development to the states, and that FERC was acting as a national resource planner without congressional authorisation. Supporters hold that regional planning and ex ante cost allocation are squarely within FERC’s ratemaking authority and are the only workable route to lines that cross jurisdictions. The disagreement will be resolved in court rather than by further analysis, and until it is, the planning rules rest on contested ground.
Related Institute research
The Interconnection Queue
What the studies keep identifying as necessary.
What Is the Electric Grid?
Why interregional transfer is limited in the first place.
Permitting and the Administrative Path
Separate approval clocks that do not coordinate.
Sources
- Americans for a Clean Energy Grid, Fewer New Miles, July 2024. cleanenergygrid.org
- Federal Energy Regulatory Commission, Order No. 1920, Building for the Future Through Electric Regional Transmission Planning and Cost Allocation, May 13, 2024, and Orders 1920-A and 1920-B. ferc.gov
- Federal Energy Regulatory Commission, What State Regulators Need to Know About Order No. 1920-B. ferc.gov
- Federal Energy Regulatory Commission, Order No. 1977, Applications for Permits to Site Interstate Electric Transmission Facilities, under Federal Power Act section 216. ferc.gov
- North American Electric Reliability Corporation, 2025 Long-Term Reliability Assessment. nerc.com
Reference entry maintained by the Institute for American Manufacturing & Technology. Figures are drawn from primary sources and cited above. Where the Institute states a position rather than a finding, it is marked as such.