Heber 1 HGC Plant Geothermal Expansion Project / IID Relay Upgrades (Project No. 200268)


SCH Number
Public Agency
Imperial Irrigation District
Document Title
Heber 1 HGC Plant Geothermal Expansion Project / IID Relay Upgrades (Project No. 200268)
Document Type
NOE - Notice of Exemption
Document Description
Heber Geothermal Company, LLC (Ormat Nevada, Inc.) proposes to expand the Heber 1 geothermal facility (HGC) located at 895 Pitzer Road, Heber, California, by taking the existing dual-flash steam turbine generator out of service and installing two (2) new Ormat Energy Converter geothermal power generation units as well as storage tanks and an evacuation skid/vapor recovery maintenance unit. As per the IID and the generator’s generation interconnection agreement and the Heber 1/HGC facility final facility study, to accommodate the expansion project, IID will be upgrading the existing 92kV protection equipment for the “P” transmission line at the Perry Substation with dual microprocessor-based SEL relays. The new relays will be two current differential and high-speed distance protection schemes (SEL-411L and SEL-311L), and two SEL-751A relays for breaker failure function with direct transfer trip, and permissive overreach transfer trip function. In addition to the line protection relay upgrades the existing revenue meters at the Heber 1/HGC Substation’s control room are obsolete and will be replaced with SEL-735 metering units. To conclude with the upgrades IID has deemed Heber 1/HGC facility necessary to participate in the Phasor Measurement Unit (PMU) project. As part of IID Energy’s PMU project communication from substation operational technology environment is required to be routed to the corporate network for capturing of relay data. For this implementation, IT is required to install a network firewall to protect operational technology (OT) environment from cyber intrusion. The network firewall will be installed at each site and will require labor to install, configure and test security settings of the network firewall and will also have to commission a telecommunication circuit via IID’s internal telecommunication network. In summary; IID will install four relays inside IID Perry Substation’s control room and two revenue meters and one Phasor Measurement Unit inside the Heber 1/HGC Substation’s control room.

Contact Information

Donald Vargas
Agency Name
Imperial Irrigation District
Job Title
Environmental Compliance Administrator
Contact Types
Lead/Public Agency


Calexico, El Centro
Citywide, Countywide
Other Location Info
The Heber 1 HGC Plant is located on 895 Pitzer Road in Heber, CA (South of El Centro, CA). The Perry Substation is located 1,800 ft. east of Rockwood Avenue on Camacho Road, 2000 ft. south of of East Cole Road and ½ mile east of Highway 111 in Calexico, CA.

Notice of Exemption

Exempt Status
Categorical Exemption
Type, Section or Code
Sec.15301 (Class 1); Sec.15302 (Class 2); Sec. 15061(b)(3)
Reasons for Exemption
The upgrades are exempt under Section 15301 (Class1 exemption) because the work consists of the minor alteration of existing public and private structures, facilities and equipment, involving negligible or no expansion of their existing use, such as interior and exterior alterations involving electrical conveyances used to provide electric power and under Section 15302 (Class 2 exemption) for the reason that they entail the replacement or reconstruction of existing structures; and facilities where the new structure will be located on the same site as the structure replaced and will have substantially the same purpose and capacity as the structure replaced, this exemption includes but is not limited to the replacement or reconstruction of existing utility systems and/or facilities involving negligible or no expansion of capacity. Furthermore, the upgrades are covered by the general rule (Sec. 15061(b)(3)) that CEQA applies only to projects which have the potential for causing a significant effect on the environment. Where it can be seen with certainty that there is no possibility that the activity in question may have a significant effect on the environment, the activity is not subject to CEQA.
County Clerk


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