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Welcome to the California Public Utilities Commission (CPUC) website for the California Environmental Quality Act (CEQA) review of the proposed construction of the Southern California Gas Company (SoCalGas) Aliso Canyon Turbine Replacement Project (Aliso Canyon Project, or project). The CPUC, through its Environmental Review Team, has conducted an environmental review of the Aliso Canyon project. An application for this project was submitted to the CPUC on September 28, 2009, and the applicant’s request was granted by the Commission on November 14, 2013 (Decision D-13-11-023). Subsequently, the Commission also approved the applicant’s Petition For Modification of the project on December 22, 2014 (Decision D-14-12-058). This site provides access to public documents and information relevant to the CEQA review process.

Construction of the project began the week of March 10, 2014. Information about the CPUC’s monitoring of construction activities for environmental compliance is provided here.


The CPUC is the CEQA lead agency. The environmental review of the project was conducted pursuant to the provisions of CEQA and CPUC procedures. The Final EIR prepared for the project was certified by the CPUC on November 14, 2013.

The Aliso Canyon Project, as proposed by SoCalGas, includes the removal from service of the existing gas turbine-driven compressor (TDC) station located at the Aliso Canyon natural gas storage field (storage field) in unincorporated Los Angeles County and the City of Los Angeles, California. The TDC station will be replaced with three variable frequency compression trains installed in a new compressor station (Central Compressor Station). Other on-site and off-site associated facilities will be upgraded as part of the project. Under Section 851 of the Public Utilities Code, an existing Southern California Edison (SCE) electrical easement on SoCalGas property will also be enlarged.

SoCalGas' application for constructing the Aliso Canyon Project was required in order to meet the terms of a Settlement Agreement (SA) between SoCalGas and parties to Phase 1 of the 2009 Biennial Cost Allocation Proceeding (BCAP) in D.08-12-020. The SA requires that SoCalGas replace the TDCs and expand the overall injection capacity at the storage field by approximately 145 million cubic feet per day (MMcfd), an increase of almost 50 percent.

The project involves coordination between SoCalGas and SCE. Components of the proposed project that will be constructed and operated at the storage field by SoCalGas include:

  1. A new, electric-driven Central Compressor Station at the Plant Station site to replace the existing compressors, including three variable frequency drive compressor trains, compressors, piping, coolers, and other required equipment;
  2. Relocated office facilities. The existing trailers at the Plant Station site will be replaced by new, permanent office and crew shift buildings at a location in proximity to the proposed Central Compressor Station;
  3. Relocated guardhouse. The new guardhouse will be located 200 feet north of the existing guardhouse to relieve traffic congestion at the facility entrance. The existing guardhouse will not be removed as part of the project; and
  4. A new, four circuit, approximately 1,800-foot, 12-kV Plant Power Line that will provide dedicated electric services to the proposed Central Compressor Station. The Plant Power Line will be interconnected from the proposed SCE Natural Substation to the Central Compressor Station, and will be owned by the applicant.

Components of the proposed project that will be constructed and operated by SCE at and in the vicinity of the storage field will include:

  1. A new, 56-megavolt-ampere, 66/12-kV substation (Natural Substation), which will be constructed and operated at the storage field on an approximately 1-acre site. This project component will be constructed and owned by SCE;
  2. Upgrades of up to 8.2 miles of electrical subtransmission lines in the area of the proposed project, along segments of SCE’s Chatsworth–MacNeil–Newhall–San Fernando 66-kV Subtransmission Line and MacNeil–Newhall–San Fernando 66 kV Subtransmission Lines. Upgrades will consist of reconductoring (conductor wire replacement), and tower/pole replacement.
  3. Installation of up to 34 miles of telecommunications cable on existing structures in the area of the proposed project; and
  4. Upgrades (installation of new equipment) at several existing SCE substations (including the Newhall, Chatsworth, and San Fernando Substations) that support the two existing SCE 66-kV subtransmission lines.

The main project site (storage field) is approximately 3,600 acres in size. Project components pass through unincorporated Los Angeles, the City of Los Angeles, the City of Santa Clarita (in Los Angeles County), the City of Mission Hills (in Los Angeles County), and unincorporated Ventura County.

Application and Proponent's Environmental Assessment (PEA)

The application and PEA for the Aliso Canyon Project may be viewed here (39 MB). The application was deemed complete by CPUC on March 24, 2010.

Other Documents Available

Environmental Impact Report (EIR)

The Draft Environmental Impact Report (Draft EIR) and Final Environmental Impact Report (Final EIR) for the project are available here. If you are unable to download these documents please see the contact information provided in the For Additional Information section below.

Addendum to Final EIR

Final EIR

Draft EIR

The public review and comment period for the Draft EIR commenced April 4, 2012 and ran through May 22, 2012. This period was extended by two weeks, to June 5th, so that comments submitted to the CPUC after the public review period could be considered.

The CPUC held two public meetings to explain the Aliso Canyon Project, discuss the identified impacts that would result from the project, and receive comments on the Draft EIR from the public. The public meetings were held at the following days, times, and locations:

Wednesday, May 2, 2012 (6:30 to 9:00 PM)
Wiley Canyon Elementary School
24240 La Glorita Circle
Newhall, CA 91321

Thursday, May 3, 2012 (6:30 to 9:00 PM)
Porter Valley Country Club
19216 Singing Hills Drive
Northridge, CA 91326

Copies of the Draft EIR were made available for review at the following public libraries:

San Fernando Library
217 North Maclay Avenue
San Fernando, CA 91340

Newhall Library
22704 West Ninth Street
Santa Clarita, CA 91321

Simi Valley Library
2969 Tapo Canyon Road
Simi Valley, CA 93063

Commission Decisions

The Commission approved the project on November 14, 2013, in Decision D-13-11-023.

The Commission approved the applicant’s Petition For Modification of the project on December 18, 2014 (Decision D-14-12-058).

Construction Progress and Mitigation Monitoring

The CPUC developed a Mitigation Monitoring, Compliance, and Reporting Plan (MMCRP) in coordination with SoCalGas and SCE to provide guidance and procedures for environmental monitoring during project construction. The MMCRP is a tool to ensure compliance with the applicant proposed measures (APMs) and mitigation measures approved in the Final EIR.

The MMCRP can be viewed here (2 MB).

The CPUC issues Notices to Proceed (NTPs) to the applicant for each phase of construction activity, after confirming that SoCalGas and/or SCE have complied with pre-construction environmental requirements. Each NTP for the project is listed in the table below.

Notices to Proceed

The CPUC issues Notices to Proceed (NTPs) to the applicant for each phase of construction activity, after confirming that SoCalGas and/or SCE have complied with pre-construction environmental requirements. Each NTP for the project is listed in the table below.

NTP No. Project Components/Phase SoCalGas or SCE? Date NTP Approved
1 Guardhouse relocation and entry road widening SoCalGas February 24, 2014
2 Crew-shift office buildings, removal of existing offices, temporary office trailers and staff parking, and development of fill sites P-41 and P-43 SoCalGas May 27, 2014
3 Construction of new Central Compressor Station, grading and paving activities related to the Natural Substation, and installation of five tubular steel poles (TSPs) and associated conductor stringing SoCalGas July 18, 2014
A 66-kV subtransmission work and upgrades at five existing substations SCE October 28, 2014
B Partial installation of Telecommunications Route #3 SCE February 24, 2015
C Construction and telecommunication installation activities associated with the 66-kV subtransmission work SCE April 14, 2015

Construction Monitoring Reports

Monthly reports issued on construction progress as part of mitigation monitoring and compliance are listed here. If you would like more information, please see the contact information provided in the For Additional Information section below.

Construction Month Associated Notice to Proceed
April 2014 1
May 2014 1, 2
June 2014 1, 2
July 2014 1, 2, 3
August 2014 1, 2, 3
September 2014 1, 2, 3
October 2014 1, 2, 3
November 2014 1, 2, 3, A
December 2014 1, 2, 3, A
January 2015 1, 2, 3, A
February 2015 1, 2, 3, A, B
March 2015 1, 2, 3, A, B

Minor Project Refinements

SoCalGas and/or SCE may submit Minor Project Refinements (MPRs) for project changes that are not major enough to warrant potential revision of the certified CEQA document. The CPUC will review any MPRs submitted by the applicant or SCE per the process described in the MMCRP. Each MPR request submitted for the project is listed in the table below.

MPR No. Associated NTP Description Date CPUC Approved
1 2 Relocation of glycol and lube oil storage tanks May 27, 2014
2 2 Addition of the PS-42 fill site October 20, 2014
3 2 Temporary relocation of portable containers July 11, 2014
4 3 Kiewet parking and office trailers August 14, 2014
5 2, 3 Use of additional staging areas at the Aliso Canyon Storage Field January 29, 2015
6 3 Installation of drainage devices associated with the new Natural Substation February 23, 2015
7 2, 3 Installation of utility lines for the new Central Compressor Station and office buildings March 24, 2015
A A Additional undergrounding work at San Fernando Substation October 28, 2014
B A Relocation of TSP 49 November 6, 2014
C B Installation of a temporary San Fernando Substation tap February 24, 2015
D C Use of additional staging area along the 210 Freeway March 20, 2015

For Additional Information

To request additional information or to be added to the project mailing list, please contact us by email, fax, or phone, as follows:

Project email: AlisoCanyonNG@ene.com
Project fax: (415) 398-5326
Project voicemail: (877) 676-8678

The CPUC Project Manager is:

Andrew Barnsdale, CPUC Project Manager
California Public Utilities Commission
505 Van Ness Avenue
San Francisco, CA 94102
Tel. (415) 703-3221
Fax (415) 703-1758
Email: andrew.barnsdale@cpuc.ca.gov