Navigating the CEC AB 205 Opt-In Certification Process

By Lexi Beebe, PE  | Civil Engineering Discipline Manager | Bay Area

On May 26, 2026, the California Energy Commission (CEC) approved the Potentia-Viridi Battery Energy Storage System (BESS) in Alameda County through its AB 205 Opt-In Certification program. Developed and owned by Clearway Energy Group, the project is currently planned as a 400 MW battery energy storage facility with up to 3,200 MWh of storage capacity. As only the third project to successfully complete this new and rigorous process, Potentia-Viridi highlights both the opportunities and challenges associated with California’s emerging permitting pathway for clean energy infrastructure.

The AB 205 process is designed to streamline approvals, but success requires significant upfront engineering, detailed environmental and technical analyses, and close coordination with regulatory agencies. For project teams, understanding these requirements early can be critical to maintaining the project schedule and achieving certification.

Construction for Potentia-Viridi is estimated to start in 2027 and last approximately 18 months. Once built, the project will charge and store excess energy from the grid and dispatch up to 3,200 megawatt-hours (MWh) during peak demand periods, supporting California’s grid reliability and moving toward its clean energy and climate goals.

Coffman played a central role in securing this approval, working alongside Clearway Energy Group, Dudek, and the broader project team to provide multidiscipline engineering support from early conceptual design through final permit certification and helping guide the project through one of California’s most demanding permitting pathways.

Navigating the CEC AB 205 Opt-In Certification Process

The AB 205 Opt-In Certification program introduces a fundamentally different permitting model, shifting authority to the CEC and establishing an accelerated approval timeline up to a maximum of 270 days for the permit and 270 days for resolution of any court appeals. While designed to streamline delivery, the process presents unique challenges, including:

• Greater level of design development and documentation required at the application stage
• Compressed, highly structured review timelines with limited flexibility
• Expanded technical scope, including detailed environmental and engineering analyses
• Intensive coordination with multiple state agencies and stakeholders

Successfully navigating this process requires early technical alignment, advanced design development, and disciplined project execution beyond traditional entitlement efforts.

Coffman’s Role

Coffman provided comprehensive engineering and permitting support, with civil engineering leading overall design integration and application readiness. Coffman also engaged our multidiscipline team, bringing experience from hundreds of utility-scale battery storage projects, to support fire protection, electrical, structural, and acoustical design. This experience helped advance a coordinated, constructable, and code-compliant early-stage design.

Laying the Foundation with Civil Engineering

Coffman’s civil engineering team served as the foundation for the project’s permitting strategy, leading development of the site configuration and grading approach to meet both regulatory and constructability requirements.

Key contributions included:

• Developing site layout and configuration to support permitting and constructability objectives
• Leading preliminary grading design and earthwork balancing strategies
• Preparing site profiles and elevation drawings to progress coordinated design
• Advancing stormwater design to support environmental compliance

Civil engineering leadership helped the project achieve the level of design maturity required by the AB 205 process, while enabling a coordinated and defensible application package under accelerated timelines.

Close collaboration with environmental consultants and the broader design team allowed Coffman to optimize infrastructure placement within a challenging topographic envelope, aligning site constraints, environmental considerations, and permitting requirements into a cohesive design.

Supporting Disciplines

Coffman’s multidiscipline team supported the project with experience across energy storage, interconnection, and fire protection, including:

• Development and optimization of ESS yard configurations and supporting electrical infrastructure
• Preparation of engineering documentation required for the CEC application
• Ongoing coordination with project partners and authorities having jurisdiction (AHJs)

Fire protection engineering provided critical input to address regulatory requirements for battery energy storage systems, including coordination with the Fire Marshal and preparation of key documentation including the Fire Protection Basis of Design (BOD), Fire Master Plan (FMP), and Emergency Operations Plan (EOP).

Considerations for Success

Coffman’s experience supporting the Potentia‑Viridi project highlights several key success factors:

• Early Layout / Configuration Development: Establishment of a well-defined site layout early in the design process is critical to maintaining project schedule targets.
• Advanced Level of Design: The CEC process requires a higher level of engineering design than traditional entitlement efforts.
• Proactive Agency Engagement: Early and continuous engagement with regulatory agencies, particularly fire authorities, helps align expectations and minimize late-stage design revisions.
• Strong Teaming Strategy: Partnering with experienced environmental consultants and technical specialists is essential to delivering the breadth of required documentation.

Delivering High-Stakes Energy Projects

The successful approval of Potentia-Viridi demonstrates how early engineering alignment, proactive regulatory engagement, and strong multidiscipline coordination can position projects for success under the AB 205 Opt-In Certification program. By combining technical experience leading complex multidiscipline engineering efforts through emerging high-risk permitting pathways, Coffman helps clients advance critical energy infrastructure that strengthens reliability, resilience, and decarbonization goals.

Rendering provided by Clearway Energy Group