Installing Generating Equipment

Important Update and FAQs

Here are our latest updates to the TIIR. Be sure to check our FAQs for more information.

• DER Technical Interconnection & Interoperability Requirements

DER FAQs

What's DER mean?

DER, or distributed energy resources, are sources of electric power that aren't part of the main power system. This includes generators such as solar panels as well as energy storage facilities that operate alongside the main power system, also known as the power grid. Typically owned by customers, DER are primarily used to meet the energy needs of customers' home or business property. Any un-used power can be moved to the grid, if the DER is interconnected.

What are the requirements for me to add a DER?

Before anything is installed, it's important to go through the interconnection application process.

To connect your devices, like solar panels, battery storage systems, or generators, to the grid, we require you to have a valid tariff option and follow the DER Interconnection Process.

This process isn’t just about meeting utility requirements and state laws, it ensures the safety and reliability of the grid. It’s also an opportunity to uncover any hidden issues and make sure your DER works effectively.

Before committing to any vendor or contractor, we strongly recommend getting an approved interconnection application to understand any necessary upgrades, costs, or mitigations.

• Submit an interconnection application

Make sure to install DER equipment that is IEEE 1547-2018-certified.

Starting January 1, 2024, make sure you have the right equipment that meets the IEEE 1547-2018 Standard or its equivalent to connect with us. This is important because as more DERs join the grid, they become crucial interconnected components, and we need to trust their reliable performance. For more information, check out the TIIR (our technical requirements document).

Don't forget to give PSO a heads-up whenever you make changes to your DER.

Before making any major changes to your installation, like adding more solar panels, upgrading or removing your generator, reach out to us. You can send an email to our coordinator or contact your customer account manager. This is a requirement of your Interconnection Service Agreement, and we're here to help ensure that your changes align with your current grid connection. We'll even give you advice on possible adjustments to support your updated DER.

What's the process to apply for interconnection of a DER?

Start your application through the on-line portal.

Once you've provided all the necessary information, paid any fees and signed your application, we'll start the technical review process. After conducting a Technical Analysis and agreeing on any required mitigations, we’ll provide you with the Interconnection Service Agreement (ISA) and if needed, a cost estimate that includes approved items and necessary upgrades. Once you've signed the ISA and submitted payment for the interconnection equipment, you're good to go. Construction can move forward, as long as there’s no further changes to your project.

After completing the installation, including required upgrades or meter updates, conducting all necessary testing and commissioning, and ensuring all payments associated with your DER Facility interconnection have been made, we’ll give you a Permission to Operate letter.

• Submit an interconnection application

Do I need to upgrade any equipment for my DER installation?

You might, it depends on the capacity of the DER device(s) you're installing and how it's integrated into your existing electric service panel. We highly recommend connecting with a licensed electrician who has experience sizing panels for this kind of technology. Keep in mind that certain locations may have specific codes or requirements. For more info, you can refer to the National Electric Code (NEC 705.12) with your electrician.

Don’t forget, all customers must have a visible lockable disconnect switch for their DER interconnection.

Does PSO need to upgrade any equipment due to my DER interconnection?

During the technical evaluation of your application, we'll determine and document any necessary system upgrades. These upgrades might include replacing service transformers, meters, or adding additional meters, depending on the DER and program you're interested in.

What does PSO need to test/verify before I can energize my DER?

Depending on the nature and size of your DER, you'll need to provide proof of local inspections and testing. We’ll check meter functionality, placards, disconnects, and safe ingress/egress plans. It's important to have a qualified technical expert available to coordinate with our staff as needed. Your installer should conduct thorough testing to ensure device settings and communications capabilities meet PSO interconnection requirements.

When testing larger DERs, we review third-party testing results and PSO may come onsite to verify them with your DER technical representative. We also check meter functionality, placards, disconnects, and ensure safe ingress/egress plans are in place.

If your project doesn't meet the technical specs, it can lead to delays, disconnections, and extra costs. However, if your application is approved and your system is installed according to TIIR requirements, getting Permission to Operate should be straightforward.

What happens after my DER is in-service?

Make sure to keep your interconnected equipment in good working order by following the technical requirements, so it won't cause any issues with your electric service or other customers.

If we determine that your DER is not performing as expected or causing issues for the grid, we may ask you to temporarily shut down your device. If this happens, we can send someone to safely disconnect your service. You may need to work with your equipment provider or installer to investigate and resolve your device’s operational issues. Once you’re ready to restart your DER device, we'll make sure everything is in order and quickly reconnect your service after verifying normal operations.

We'll monitor your DER equipment and may send it commands.

We'll stay connected with your device to stay informed about your DER's performance. Verifying its effectiveness with the grid is important to us. If grid conditions require a change, we can provide instructions to your device.

If you need to take your DER out of service for anything other than routine maintenance, please reach out to our coordinator. We may request testing or other verifications to ensure your DER is set up and working correctly.

Other info

Do I need to have an Interconnection Service Agreement for my home backup generator?

You don’t need our approval for home backup generators that are only activated during outages. However, if you plan to connect it at the PSO meter you will need to get our approval and help. We may require certain information about your backup generator and there may be other local inspection or code requirements. We encourage you to reach out to a local qualified licensed electrician.

What is an aggregation for DERs?

These programs, created by the Federal Energy Regulatory Commission (FERC) and the Electric Reliability Council of Texas (ERCOT), allow third-party providers to contract with customers (like you) who own DERs to collectively offer services in the wholesale electric market. Aggregated DERs will be used by third-party aggregators, who respond to signals from the grid operator.

What happens if I want to join an aggregation?

Before connecting your DER (such as solar PVs or battery energy storage systems [BESS]) to an aggregation, make sure you have a valid Interconnection Service Agreement with PSO.

Your aggregator will then request permission from us to aggregate your devices, and we'll evaluate the feasibility of these devices responding to aggregation signals.

Additional information on Aggregation will be provided in a separate document as aggregation rules are developed by the wholesale energy entity and state commissions in the PSO markets.