Interconnection Standards

Summary

Interconnection in New Mexico is governed by New Mexico Public Regulation Commission (PRC) Rule 570 and Rule 571. Rule570 applies to all qualifying facilities (QFs) under PURPA, which generally includes all renewable-energy systems and combined-heat-and-power (CHP) systems up to 80 megawatts (MW) in capacity. All utilities subject to PRC jurisdiction must offer net metering and must comply with certain interconnection standards. (Municipal utilities, which are not regulated by the commission, are exempt.) Rule 571, adopted in September 1999, applies to small renewable-energy systems and CHP systems up to 10 kilowatts (kW) in capacity. The purpose of Rule 571 is to simplify the interconnection requirements for QFs up to 10 kW and to encourage the use of small-scale, customer-owned renewable or alternative-energy resources. The rule includes a standard interconnection agreement. Systems must comply with all local and national standards, including the NEC, IEEE and UL, and must also meet any additional requirements approved by the PRC. Net metering is accomplished using a single, bi-directional meter. A manual external disconnect device is required unless the customer and utility agree that the meter can be used to disconnect the system in the case of a power outage. While it is not mandatory, the PRC strongly recommends that a customer purchase liability insurance, and may require the customer to do so at the utility's request. As a practical matter, PV interconnection in New Mexico is a straightforward process. Most utilities allow the meter to serve as the external disconnect. The only testing required is a simple shut-down test to ensure that systems recognize when the power grid is down. Rule 570, established to comply with PURPA for QFs up to 80 MW in capacity, addresses the legal, technical and buy-back rate issues for these larger systems. The PRC extended the availability of net metering to QFs up to 80 MW in January 2007. As part of its January 2007 revisions to Rule 570, the PRC developed a standard interconnection agreement for systems up to 100 kW. Systems must meet utility safety standards, and system owners must pay appropriate "interconnection costs," as defined in the rule. All QFs are "strongly encouraged to obtain liability insurance." A utility may require QFs larger than 50 kW to obtain general liability insurance not to exceed $1 million. Customers must pay demand charges and other charges in accordance with applicable tariffs, and for any incremental costs associated with installing necessary metering equipment and facilities. Furthermore, an additional customer charge to cover the added costs of billing and administration may be included in a utility's tariff if supported with evidence of need for such a charge. In January 2007, the PRC initiated a proceeding to consider new interconnection standards and procedures for QFs, with the IEEE 1547 standard forming the basis of the commission's technical interconnection standard. The PRC also will consider a standard set of procedures to streamline the interconnection process between a utility and all customer-owned generation facilities.