California’s New Solar and Storage Bill Savings Requirements: Residential Installers Need to Act Now

On March 13, 2025, the California Public Utilities Commission (CPUC) quietly adopted Resolution E-5364 (“the Resolution”), which is about to change how residential solar and storage installers quote projects.

Starting November 1, 2025, interconnection applications in Pacific Gas and Electric (PG&E), Southern California Edison (SCE), San Diego Gas and Electric (SDGE), Liberty Electric, Pacific Power, and Bear Valley Electric service territories will require the updated California State License Board (CSLB) Solar Energy System Disclosure Document, filled out using new standardized bill savings inputs.

This means that if you’re talking with leads, quoting projects, or even signing contracts this week, those projects may be interconnected after November 1 — and they’ll need to comply.

This isn’t a policy footnote. If your disclosure package isn’t filled out properly, your customer’s interconnection may be delayed or rejected by the utility. That means cash flow issues, customer frustration, and lost jobs. But don’t worry, with the right tools and processes in place, complying with the Resolution’s requirements isn’t that burdensome.

What’s Changing Under the Resolution

Here are the key updates, in plain language:

• One-year savings window. Bill savings must be estimated over the first 12 months after installation, not 20 years.
• Use actual customer interval data. Savings windows must be based on 12 months of interval usage data. If that’s not available, you must explain why and obtain the customer’s approval for your estimate.
• Standardized Utility Rate Escalations. Savings windows must use today’s rates, and rate escalations must match the five-year historical average annual escalation rate published on the CPUC’s website. 
• Current and Net Billing Tariff rates. Apply the customer’s current rate pre-solar, and the eligible NBT rate post-solar — including the new base services charge going into effect this month.
• Standardized solar generation. Solar-only projects must use NREL’s PVWatts® tool. In the Net Billing or NEM 3.0 world, solar-only projects are a rarity, so solar and storage projects can use another calculator, like Aurora Solar or OpenSolar, but installers must name it.
• Required Solar and Storage Project Optimizations. Solar and storage projects must provide customers with a bill savings estimate that assumes the battery is programmed to optimize for bill savings. Self-consumption and home back-up optimizations are optional.
• Digital disclosure only. The CPUC has directed the utilities only to accept typewritten CSLB Disclosure Documents that are consistent with the rest of the interconnection package. 

The Interval Data Challenge

The real sticking point for installers is getting interval data. To generate a compliant savings estimate, you will need 12 months of interval consumption data for every customer.

No more estimates based on the highest bill. No more last 12 bills. Each project now requires a savings estimate based on 8,760 hours of interval data. Fortunately, there are three paths to getting the interval data you need:

1. Customer Downloads & Emails

Asking a lead to log into their utility account, download their data, and email it to you has long been the simplest way for installers to get data. However, in the new world where 12 months of interval data is a must, this process becomes much less reliable. 

Moving forward, installers will need to:

• Explain how to navigate each utility’s confusing and constantly updating portals,
• Explain how to select a 12-month date range for interval data, and 
• Hope they remember to send it back. 

This is a viable solution in a pinch, and might work okay for Bear Valley Electric, Liberty Electric, and Pacific Power utility account holders, but at scale, it’s a recipe for churn and delays.

2. Utility Data-Sharing Platforms 

PG&E, SCE, and SDG&E each operate data-sharing or “Green Button” platforms, where you can register and access the customer’s data with permission.  

This is the official pathway the Resolution envisions that installers will pursue. The data from the big three IOU’s Share My Data Platforms is accurate, somewhat standardized, and free to collect.

However, registering for each platform requires a certain amount of technical understanding and takes time. Collecting interval data is free, but setting up your registration is a sunk cost, and maintaining each registration is an ongoing cost. 

Additionally, while each of the IOU’s platforms is designed to meet the Green Button Connect My Data standard, they each have their own nuances that users must understand.

The data sharing platforms provided by the big three IOUs may be a long-term solution for some providers, but they are not practical if you need to start collecting data right away and require ongoing attention.  

3. Platforms Like UtilityAPI

Data access platforms, such as UtilityAPI, make it easy for technical and non-technical users to obtain customer permission and access the interval data required by the Resolution.

Within minutes, a new company can: 

• Register for an account,
• Receive permission using a branded authorization form, and
• Have 12 months of interval data sharing flowing directly into their tools and processes.  

Unlike asking your customer to download their data or registering for each of the CA IOU’s data sharing platforms, data access platforms are a paid service. But the fees are small compared to the value: they eliminate friction, provide consistent compliance, and scale across multiple utilities.

Platforms like UtilityAPI make interval data accessible for everyone — from large enterprises down to local installers. That accessibility is the difference between scrambling for the next four weeks and being able to act today. 

Why Installers Need to Move Today

Resolution E-5364 is not about paperwork — it’s about transparency and trust. The CPUC wants solar and storage bill savings estimates grounded in real data, not estimates. Using interval data to estimate project savings is good for California utility customers and the industry’s long-term reputation.

But the clock is ticking. Projects you’re quoting, selling, and contracting today will likely be submitted for interconnection after the deadline. If you’re still using 20-year escalated bill savings estimates and basing savings on the most recent bill PDF, you’re setting yourself up for rejected applications in November and December.

With just a month to go, now is the time to determine how you and your company will collect the interval data, calculate the savings, and complete the required disclosure documents.