Project Overview

BPUB is undertaking a comprehensive transmission infrastructure upgrade program to meet the demands of unprecedented load growth. With projected increases of 200+ megawatts over the next five years, BPUB is implementing strategic substation upgrades and new construction to ensure reliable electric service for residential and commercial customers.

Current System Status

Existing Infrastructure:

• 15 substations operating at 138 kV
• 50 miles of transmission lines
• Ring system configuration for enhanced reliability
• Peak historical load: 334 megawatts

Service Area:

All infrastructure serves the Brownsville city limits with connections to adjacent transmission service providers.

Load Growth Drivers

The rapid expansion of Brownsville’s electrical demand is expected to increase over the next five years and is driven by:

Residential Development

• 124 MW of new load from subdivision developments concentrated in northern Brownsville
• Multiple large-scale residential projects

Industrial/Commercial Growth

• 90 MW of new industrial load commitments
• Significant expansion near Port of Brownsville
• Large individual loads ranging from 50-300 MW

Projected Total Impact

• ~500-600 MW total system peak load anticipated by 2030
  Nearly double current peak capacity requirements
  Sustained 2% annual growth rate plus new development

Strategic Solution: North Transmission Loop

To address concentrated growth north of the city, BPUB is developing a North Transmission Loop strategy that mirrors the successful ring system currently serving southern Brownsville.

Key Features:

• New 138 kV transmission lines forming northern ring
• Multiple new substation locations
• Redundant power sources for all stations
• Ability to tap into transmission for future growth
• Enhanced system reliability and load flexibility

This infrastructure will enable BPUB to serve new loads efficiently while maintaining the redundancy standards that ensure continuous service even during equipment failures.

Project Stages

Stage 1: Loma Alta/Cipher Substation (Already Underway)

The Loma Alta rebuild serves as the critical first phase of the north loop strategy. Originally planned with two 28 MVA transformers, the project scope is being increased to accommodate two 50 MVA transformers (100 MVA total capacity) due to emerging large load opportunities. Some individual loads at the port exceed 100 MW, making this enhanced capacity essential.

• Timeline: Quarter 3, 2028
• Status: Design phase, equipment procurement initiated
• Board Action Required: Approval to procure larger transformers

Future Stages

The complete north loop buildout will occur in phases as load materializes, and funding is secured. The presentation noted that a comprehensive implementation plan is under development, including:

• Detailed cost estimates
• Resource requirements
• Phased construction timeline
• Integration with overall system planning

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Current Mitigation Projects

While the full north loop is in planning, BPUB is actively addressing immediate capacity constraints:

Ocelot Substation (New Construction)

• Capacity: 60 MVA
• Timeline: Energization Q2 2026
• Status: Construction underway

New 138 kV substation serving the northern growth corridor. The first major component of the North Transmission Loop strategy.

Palo Alto Substation Upgrade

• Capacity Addition: 28 MVA transformer
• Timeline: Completion Q1 2027
• Status: Design and procurement phase

Adding transformer capacity to existing station serving northern Brownsville residential areas. Critical for near-term subdivision development.

Waterport Substation Upgrade

• Capacity Addition: 28 MVA transformer
• Timeline: Completion Q1 2027
• Status: Design and procurement phase

Expansion dedicated to Port of Brownsville industrial development. Supports logistics and manufacturing facilities.

Loma Alta Rebuild (Cipher Substation)

• Capacity Addition: Up to 250 MVA (two 125 MVA transformers)
• Timeline: Completion Q3 2028
• Status: Design phase, equipment procurement approved

Complete rebuild of existing station with substantially increased capacity. Renamed “Cipher” upon completion. Located near Port of Brownsville to serve large industrial loads. Equipment specifications upgraded during design process to accommodate potential 50-100+ MW individual customers.

Airport Substation Rebuild

• Capacity Addition: 56 MVA
• Timeline: Ongoing through 2026
• Status: Demolition in progress

Full rebuild of existing substation infrastructure. Current loads temporarily served by Strand mobile substation to maintain system flexibility during construction.

System Reliability Enhancements

Strand Mobile Substation

Temporary mobile unit providing operational flexibility during Airport rebuild. Enables construction without stressing remaining system infrastructure or compromising service reliability.

Ring System Architecture

All new substations designed with dual-source capability. If any transmission line fails, affected stations can be served from adjacent facilities without service interruption.

Compliance & Planning

NERC Standards

All projects designed and modeled in accordance with NERC TPL-001-4 transmission planning standards. BPUB conducts annual power flow studies and system stress analysis to ensure compliance.

Regional Coordination

North Loop design submitted to ERCOT Regional Transmission Planning (RTP) study process. Ensures alignment with regional grid planning and ERCOT standards. Study completion expected late 2025.

Next Steps

Immediate Actions (2025-2026)

• Continue power flow modeling and system studies
• Finalize comprehensive cost estimates and timelines
• Develop resource allocation plans
• Complete grant application processes
• Establish internal transmission project committee

Strategic Planning (2026-2027)

• Present comprehensive North Loop implementation plan to Board
• Request Capital Improvement Plan (CIP) funding for FY 2027
• Prioritize projects based on load commitment timelines
• Coordinate with economic development for customer planning

Long-Term Vision (2027-2030)

• Complete all active substation projects
• Construct North Transmission Loop infrastructure
• Add additional substations as growth continues
• Maintain system reliability during rapid expansion

Funding Strategy

Current Project Budget: Funded through existing CIP allocations.

Future Funding Approach:

• Federal infrastructure grant applications (submitted)
• Annual CIP budget requests beginning FY 2027
• Coordination with economic development incentives
• Potential bonding for major transmission corridor construction

Community Impact

These substation upgrades ensure:

• Reliable electric service for new residential developments
• Adequate capacity for industrial and commercial expansion
• Economic development support through available utility infrastructure
• Reduced risk of service interruptions during peak demand
• Foundation for sustainable long-term community growth

Last Updated: November 2025