As of November 1, 2025, every residential solar interconnection application in California must include 12 months of the customer's hourly energy consumption tracking data. This fundamental shift, established under CPUC Resolution E-5364 and implemented through the updated Solar Energy System Supporting Information document: represents more than just a compliance requirement. It's reshaping how solar providers approach energy project modeling, system design, and customer trust.
While some installers view this as another regulatory hurdle, forward-thinking professionals recognize it as an opportunity to deliver more accurate solar performance optimization and build stronger customer relationships through data-driven transparency.
What the New Rule Requires
The updated CSLB Supporting Information document mandates that all interconnection applications include:
Essential Data Requirements:
• 12 months of energy consumption tracking data (Green Button format)
• Machine-typed inputs only: handwritten entries face immediate rejection
• Accurate, auditable entries covering consumption patterns, solar production data, rate schedules, battery storage data, and modeling assumptions
• Compliant first-year bill savings estimates based on standardized CPUC inputs
Alternative Documentation:
If hourly data cannot be obtained, contractors must document:
• Why energy data analytics weren't available from the utility
• How consumption was estimated without interval data
• Customer-signed attestation confirming reasonable efforts were made to obtain actual usage patterns
The California Public Utilities Commission will conduct semiannual audits to ensure accuracy and consistency across all submissions. This means every solar provider must now build proposals and interconnection packages on real intelligent energy insights, not monthly estimates or assumptions.
Why Hourly Data Is Essential for Modern Solar Design
Under California's Net Billing Tariff (NBT), solar production data value varies dramatically by hour. This creates significant implications for both system sizing and energy independence calculations:
Critical Performance Factors:
• Two customers with identical monthly usage can achieve completely different savings based on their hourly consumption patterns
• Battery storage data optimization depends entirely on when customers use energy: not just total consumption
• Accurate true-up meaning solar calculations require precise load profiles aligned with time-of-use rates
• Solar inverter monitoring becomes meaningless without corresponding consumption context
Hourly energy consumption tracking reveals essential patterns that monthly bills cannot capture:
Consumption Intelligence:
• Peak evening demand during high-cost utility rate periods
• Seasonal HVAC patterns affecting both summer and winter energy independence
• EV charging habits that impact battery storage data optimization strategies
• Weekend versus weekday differences in energy usage
• Opportunities for load shifting and advanced solar performance optimization
This granular energy data analytics approach explains why the CPUC now mandates hourly data: it's the only method that produces accurate first-year bill savings calculations and enables proper system sizing for long-term customer satisfaction.
Why Smart Installers Use Hourly Data Early in the Sales Process
Most installers approach interval data as an end-stage compliance requirement needed only for interconnection submissions. However, the most successful solar providers integrate intelligent energy insights at the beginning of their sales cycle.
Strategic Early Implementation Benefits:
• Design systems with accurate load assumptions rather than utility bill estimates
• Eliminate costly upsizing and downsizing corrections during project development
• Provide customers transparent insights into their actual consumption behavior
• Demonstrate genuine battery storage data value during evening peak rate periods
• Build trust through recommendations based on real energy data analytics, not industry assumptions
This approach transforms the CPUC requirement from a compliance burden into a competitive differentiator that strengthens customer relationships and improves project outcomes.
How SolarFax by Solar Data Pros Simplifies Compliance
Our SolarFax platform was engineered to deliver comprehensive energy consumption tracking years before regulatory mandates required it. This foresight means meeting the new CPUC standards becomes seamless rather than disruptive for our clients.
Platform Capabilities:
✓ Instant Interval Data Retrieval
Secure, rapid access to PG&E, SCE, and SDG&E energy data analytics with full 12-month historical coverage.
✓ Validated, Continuous Hourly Files
Clean data streams with no missing intervals, formatting issues, or manual cleanup requirements for reliable energy project modeling.
✓ Advanced Analytics Integration
Combine consumption and solar production data to model savings scenarios, battery storage data behavior, and NBT export value with precision accuracy.
For Solar Professionals: SolarFax transforms complex regulatory requirements into streamlined, scalable workflows that enhance both compliance and customer experience.
The Competitive Advantage of Accurate Data
The CPUC's mandate represents more than regulatory compliance: it's establishing a new standard for industry professionalism and customer protection. Installers who embrace intelligent energy insights as a foundation for every customer interaction will differentiate themselves in an increasingly competitive market.
Professional Benefits:
• Enhanced credibility through data-driven recommendations
• Reduced project change orders and customer disputes
• Improved energy independence outcomes through precise system sizing
• Stronger customer relationships built on transparency and accuracy
• Streamlined interconnection processes with consistent compliance
Customer Benefits:
• Realistic expectations based on actual consumption patterns
• Optimized solar performance optimization for their specific usage
• Better energy project modeling that reflects real-world conditions
• Enhanced energy independence through properly sized systems
Moving Forward with Confidence
California's new interval data mandate is reshaping solar industry standards, but it's creating opportunities for installers who view accurate energy data analytics as a strategic advantage rather than a compliance burden.
Solar Data Pros provides the technology infrastructure that transforms regulatory requirements into competitive differentiation. Our SolarFax platform enables installers to leverage intelligent energy insights not just for compliance, but as a foundation for trust, accuracy, and superior customer outcomes.
Ready to streamline your compliance process? Join other California installers who rely on our platform for accurate, compliant, ready-to-submit interval data that enhances both regulatory compliance and customer satisfaction.
Learn more about SolarFax capabilities or contact our team to discuss how we can support your transition to the new CPUC requirements.
