EDP Piauí Transmission Project Energised 34 Months Early
Project Background: Aneel Auction 01/2024 and the Piauí Transmission Project
On 16 September 2026, Portuguese energy group EDP announced the energisation of its Piauí transmission project — Lot 2 — 34 months ahead of the regulatory deadline** set by Aneel, Brazil’s national electric energy regulatory agency. The Piauí transmission project includes EDP’s longest transmission line and largest substation built in Brazil to date, marking another above-schedule delivery under the South American transmission concession model.
EDP’s Brazil Transmission Footprint
EDP Brasil has used Aneel transmission auctions as its primary vehicle for entering the transmission sector, securing multiple lots including Lot 5, Lot 7, Lot 13 and the now-energised Lot 2. The Lot 2 project sits entirely within Piauí state, comprising 522 km of transmission line and the São João do Piauí 2 substation.
Lot 2 Concession Timeline
The lot was awarded in **Aneel Transmission Auction 01/2024**. Annual permitted revenue (RAP) is released in stages as line sections are energised. With the line sectioning connection now in service, the project unlocks an incremental R$154 million of permitted annual revenue.
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What Drove the 34-Month Early Delivery
Three factors converged to push this Piauí transmission project past the deadline: aggressive renewable energy connection targets in northeast Brazil, Aneel’s regulatory push to relieve transmission bottlenecks, and EDP’s project execution experience carried over from Portugal and the wider South American portfolio.
Engineering Parameters: 522 km Line and 730 MVAr Substation
Transmission Line Design
The Lot 2 line stretches **522 km** in a single corridor — EDP’s longest single-line build in Brazil. The route crosses semi-arid Caatinga highlands and several environmental protection zones, requiring elevated tower foundation, insulation coordination and lightning protection standards.
São João do Piauí 2 Substation Capacity and Footprint
The São João do Piauí 2 substation occupies roughly **21 hectares** (around 210,000 m²) and delivers a total capacity of **730 MVAr**, dominated by shunt reactor banks that provide reactive compensation and voltage support. With high renewable penetration feeding the northeast grid, large centralised substations are the critical nodes for voltage stability and reactive management.
R$154 Million RAP Release Mechanism
For broader industry coverage of substation build-outs and transmission upgrades, see our archive on substation project engineering.
Annual permitted revenue is unlocked in tranches tied to line-section energisation, the standard design under Aneel concession contracts designed to incentivise early completion. The R$154 million tied to Lot 2 corresponds to the capacity and mileage released by the sectioning connection.
Lot 13 and Adjacent Lot Coordination
Lot 13 First Section: 230 kV Delivered 42 Months Early
In **December 2025**, EDP had already energised the first 95 km, 230 kV section of Lot 13 between Ribeiro Gonçalves and Balsas, **42 months ahead of the regulatory deadline**. This lower-voltage corridor serves industrial load and wind export in Maranhão state.
Lot 13 Second Section: 500 kV Backbone Still Under Construction
The Lot 13 second section runs 366 km at **500 kV** from Ribeiro Gonçalves to Colinas and remains under construction. This backbone handles the bulk transfer of northeast renewable generation into SIN, the Brazilian interconnected grid, and demands higher insulation levels and tighter engineering tolerances.
Lot 5 and Lot 7: Geographic and Voltage Mix
EDP is also progressing Lot 7, spanning **390 km plus a 230/138 kV substation across Bahia, Piauí and Tocantins, and Lot 5 in Goiás, with 285 km and a new substation. Together with Lot 2 and Lot 13, these lots consolidate EDP’s central–northeast transmission footprint.
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Renewable Curtailment and the SIN Backbone
Piauí Renewable Build-out
The northeast region, where Piauí sits, is one of the fastest-growing wind and solar clusters in Brazil. BNDES and EPE capacity figures show northeast wind capacity has crossed 30 GW, with annual additions running at 2–3 GW — far above local load growth and dependent on new export corridors.
Curtailment: An Engineering View
ONS, the Brazilian system operator, has previously reported northeast renewable curtailment above 10%. Daniel Sarmento, EDP’s South America transmission director, noted that Lot 2 would “ease network bottlenecks and address curtailment” — a position aligned with northeast renewable operators.
Reinforcing the SIN Interconnection
Through the 500 kV backbone, 500/230 kV substations and shunt reactor stations, SIN’s north–south transfer capability is strengthened. Although Lot 2’s 730 MVAr substation is largely reactor banks, the sectioning connection still delivers local voltage support and fault-ride-through capacity.
Investment Scale and Forward Roadmap
R$3.7 Billion Three-Year Plan
EDP plans to invest approximately R$3.7 billion in Brazilian transmission between 2026 and 2028, averaging roughly R$1.23 billion per year. In absolute terms, this approaches the annual transmission capex of a Chinese provincial grid company, signalling EDP’s shift from “auction participant” to “regional consolidator” in Brazil.
From 2,032 km to 3,001 km: Share Implications
EDP currently operates 2,032 km of transmission line; with projects under construction, total mileage rises to 3,001 km, a 48% increase. The growth lifts EDP from “mid-tier independent operator” toward “regional backbone operator” status in the Brazilian market.
Comparing South American Concession Models
Unlike Argentina (state-led Transener) or Chile (Transelec-led private model), Brazil uses an “auction + RAP” concession framework that awards 30-year RAP revenue by awarded capacity. Aneel 01/2024’s early-completion incentives are the policy lever behind Lot 2’s 34-month early delivery — a model worth examining for other regulators.
Closing Thoughts
EDP’s Piauí transmission project — Lot 2 — is one of the few “two-years-plus early” deliveries in South American transmission in 2026. Against the backdrop of sustained Brazilian renewable build-out and chronic northeast export congestion, ahead-of-schedule delivery has real operational value for curtailment relief, SIN interconnection stability and regional price stability. For transformer and transmission equipment suppliers, demand for 500 kV power transformers, 230/138 kV distribution transformers and large MVAr-class shunt reactors will scale further as Lot 5, Lot 7 and other lots progress.