Renewable Generation Interconnection Ken Brunkenhoefer Distributed Generation Consultant

Oncor Electric Delivery’s goal is to insure the safe and reliable interconnection of distributed resources that connect in parallel to the distribution system. Renewable interconnection process requirements are subject to changing rules and regulations. Potential impacts from multiple facility interconnections or other impact concerns could cause process changes to occur without notice (check periodically for process changes). Disclaimer !

The PUCT in Project adopted requirements for pre- certification of DG equipment by a NRTL including labeling requirements indicating compliance with § and § Pre-certification, as described in this requirement, was never initiated by any market participant. As a result, Oncor Electric Delivery recognizes UL 1741 utility-interactive certified inverters as meeting the intent of the PUCT pre- certification rules and accepts them as being pre-certified. However, Oncor Electric Delivery does not require UL 1741 certification for inverter based systems. Interconnections Utilizing Inverter Based Technology

The Energy Policy Act of 2005 defines Net Metering Service. “Net Metering Service means service to an electric consumer under which electric energy generated by that electric consumer from an eligible on-site generating facility and delivered to the local distribution facilities may be used to offset electric energy provided by the electric utility to the electric consumer during an applicable billing period.” This definition could imply that net metering is accomplished by the use of a single meter which spins forward and backwards allowing offsets. The use of multi-channel metering normally implies that consumption is valued at retail and exporting energy is valued at wholesale pricing. With this assumption “offsets” are not one for one. Customer Information Customer’s of Oncor are provided information giving a general explanation of: 1) how a customer can be paid for exported energy; 2) the process to request Net Metering. Customers are told that if they want to be paid for excess energy ERCOT market model rules apply and their REP needs to specify the type of metering (multi-channel, etc.). This information should be specified in the customers interconnection application.

PUCT rules require that all distributed resources that electrically operate in parallel with the distribution system of the utility must compete and submit an Application for Interconnection with the local distribution utility. (§ and §25.212) PUCT Interconnection Rules --Utility Notification--

Receive and review completed application, one-line diagram and layout sketch Verify pre-certification to UL-1741 Utility Interactive Obtain REP concurrence for Net Metering requests Verify facility metering for Net Metering requests Prepare and secure Interconnection Agreement Basic Steps for Inverter Based Interconnections requesting Net Metering:

Basic Steps for Non-Inverter UL-1741 Based Interconnections Interconnection requests which are not precertified under UL Utility Interactive must follow the standard interconnection rules described in the Public Utility Commission’s Substantive Rule § and §

Renewable Interconnection Requests 1)Completed Application 2) One-line diagram 3) Layout sketch

Control Strategy - 59N Relay Inverter Utility Visible disconnect in close proximity to meter Not a breaker PV panels or Wind Turbine General Loads Utility Meter Inverter Based One-Line Diagram Example Main Service Panel Utility Visible Lockable Disc.

Utility Source Utility Meter Customer Main Breaker Panel Visible lockable (labeled) Disconnect Fence PV Panels Sample Layout Sketch Within ~10 feet Comments: 1) Layout sketch is to show the relationship between the meter and visible disconnect. The goal is to have the visible disconnect located within 10 feet from the meter or within visible sight and in a readily accessible location. 2) The visible lockable disconnect switch is not a breaker. These switches have a visible air gap for a utility lineman to verify the alternate source of power is “open” and should be labeled something like Alternate Power Source Disconnect. Address: Account #:

Negative Meter Readings Oncor customers with REP approved Net Metering have the capability for negative end-of-month meter readings. If end-of-month meter readings are negative (meaning more was exported to the grid than was consumed from the grid) then the monthly consumption reading will be set to zero. Annualized or multi-month net metering is not available meaning that you cannot "bank" excess production in one month and apply it to the consumption of another month.

Private bilateral energy transactions Scheduling Entities Balanced schedules of loads and resources; and information and transactions required to support reliability. Retail Customers ERCOT Bilateral Market Load Serving Entities ERCOT Resources Electricity sellers Electricity buyers Deregulation Model DG sales into the market TDSPs are prohibited from buying or selling energy in the market

ERCOT Market Model

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