Utah Rocky Mountain Power Schedule 136 Export Credit Guide

Key Takeaways

• Rocky Mountain Power Schedule 136 governs solar export compensation in Utah through a net billing system.
• Residential solar and storage installations can claim a 30% federal income tax credit under Section 25D.
• All grid-tied inverters must meet UL 1741-SB and IEEE 1547-2018 anti-islanding standards.
• Operating a solar system without written Permission to Operate from the utility is strictly prohibited.

Understanding Utah's Schedule 136 Export Credit Plan

Rocky Mountain Power Schedule 136 outlines the transition export credit plan for solar energy systems in Utah. This plan operates under a net billing incentive architecture, which includes hourly netting and fixed export compensation. The governing docket for these regulations is Utah Public Service Commission (UPSC) Docket No. 17-035-61.

How Net Billing Works with Schedule 136

Net billing means that the electricity you generate and export to the grid is credited against the electricity you import. Under Schedule 136, this process involves hourly netting. This means that your electricity consumption and generation are reconciled over one-hour periods. Any excess generation during an hour is exported to the grid and compensated at a fixed export rate, rather than a one-for-one credit against retail rates.

Federal Tax Credits for Solar and Storage in Utah

Residential solar and energy storage systems in Utah may qualify for federal tax incentives. These incentives are designed to encourage the adoption of clean energy technologies.

Federal Clean Energy Tax Credit

Qualified residential clean energy expenditures are eligible for a 30% federal income tax credit. This credit is applied against your total federal tax liability under Section 25D of the Internal Revenue Code (IRC). This includes the costs associated with installing solar photovoltaic systems.

Energy Storage Qualification

Energy storage property also qualifies for these federal credits. To be eligible, the energy storage system must have a capacity of 3 kilowatt-hours or greater. This applies whether the storage is installed alongside a new solar system or as a standalone addition.

Technical Requirements for Grid-Tied Systems

Connecting a solar generating facility to the grid in Utah under Schedule 136 requires adherence to specific technical and safety standards. These standards ensure the reliability and safety of both the solar system and the wider electrical grid.

Inverter Standards

Grid-tied solar inverters must comply with UL 1741-SB and IEEE 1547-2018 anti-islanding parameters. These standards are critical for ensuring that an inverter safely disconnects from the grid during a power outage, protecting utility workers.

Safety and Disconnects

A lockable utility-accessible AC disconnect switch is required. This switch must be located within 10 feet of the revenue meter, allowing utility personnel to safely isolate the solar system from the grid. Rooftop PV systems must also incorporate rapid shutdown devices complying with NEC 690.12 specifications, enhancing fire safety.

Electrical Code Compliance

Dedicated overcurrent protection devices must be sized according to NEC 705.12 120% busbar rules. Equipment grounding conductors must be bonded directly to the main building service grounding electrode. Connection of generating sources to panelboards must follow the 120% ampacity calculation in NEC 705.12. Additionally, photovoltaic systems operating at 80 volts DC or greater require certified Type 1 AFCI protection.

Interconnection and Approval Process

Before your solar system can begin operating and exporting power, you must complete an interconnection process and receive formal approval from Rocky Mountain Power.

Mandatory Pre-Approval

Operating the generating facility prior to receiving written Permission to Operate is strictly prohibited. This pre-approval filing gate ensures that all technical and safety requirements are met before the system is energised.

Interconnection Service Agreement

Execution of an Interconnection Service Agreement is a mandatory step. This agreement formalises the terms under which your solar system will connect to and operate with the utility grid.

What you can check yourself, and what you cannot

As a homeowner, you can review your utility bills to understand the net billing credits applied under Schedule 136. You can also verify that your system's documentation confirms compliance with UL 1741-SB and IEEE 1547-2018 standards, and that your energy storage capacity is 3 kilowatt-hours or greater if claiming federal credits.

However, you cannot modify your inverter's anti-islanding parameters or other grid-protection settings yourself. These settings are configured by an accredited installer to comply with utility requirements and changing them can breach your connection agreement and compromise safety. Similarly, any work involving the AC disconnect switch, main panel busbar, or rapid shutdown devices should only be performed by qualified, certified electricians or solar professionals.

What the published sources do not tell you

The provided published guidance does not specify the exact fixed export compensation rate under Schedule 136; it only states that net billing includes "fixed export compensation." It also does not detail the specific non-bypassable basic charges that may apply to customers with solar systems. Furthermore, while it mentions the need to verify whether battery storage is AC-coupled or DC-coupled for correct export measurement, it does not provide guidance on how this verification impacts the compensation or measurement process. The annual credit expiration timeline for any unused export credits is also not specified.