Estimating SSS from Public Sources

As a renewable energy technical expert advising Clean Incentive, Inc., which owns and operates the Granular Registry and Marketplace, this methodology outlines a standardized, transparent process for estimating (i) the volume of Renewable Energy Certificates (RECs) and other zero-carbon attributes retired on behalf of SSS customers and (ii) a supplier-specific emission factor (SSEF) for market-based Scope 2 reporting. This approach is applied when a Load-Serving Entity (LSE) or utility does not submit structured data directly to the Granular Registry. It leverages publicly available sources to generate a defensible proxy bundle (retired RECs paired with SSEF), aligned with the draft GHG Protocol SSS guidance as a "credible third-party dataset." The process is conducted annually per energy-market region (e.g., U.S. state + ISO, Canadian province, EU Member State, etc.), with adjustments for local data transparency.

This methodology focuses on annual baselines; hourly extensions are addressed in Section 8 for regions with time-stamped data availability.

1. Scope and Definitions

• Standard Supply Service (SSS): Default electricity service with costs recovered via regulated tariffs or universal service obligations, including mandated clean energy (e.g., from Renewable Portfolio Standards or RPS).

• Proxy Bundle: Paired dataset of estimated retired RECs (MWh) and SSEF (kg CO₂e/MWh) derived from public sources when direct supplier allocation is unavailable.

• Energy-Market Region: Jurisdictional footprint for retail load service and REC retirements (e.g., California ISO, PJM Interconnection, or Ontario province).

• REC: Renewable Energy Certificate, representing 1 MWh of renewable generation; extended here to include other zero-carbon attributes (e.g., from nuclear or large hydro under certain programs).

Estimates adhere to GHG Protocol Scope 2 Quality Criteria, ensuring no double-counting and alignment with market-based accounting.

2. Data-Source Inventory

Public sources are prioritized based on availability and reliability. Key information needs and representative sources include:

Information Need	North America Examples	Europe Examples	Other OECD/Emerging Markets Examples
Utility Retail-Sales Volumes	EIA Form 861 (U.S.); Statistics Canada CANSIM 127 (CA)	Eurostat "Retail electricity sales"; Ofgem CCA data (UK)	AEMO NEM "Retail sales" (AU); IEA country energy balances
Mandated RPS/CES Targets & REC Retirements	State compliance reports; PJM GATS "RPS Retired"; M-RETS "Compliance"; WECC WREGIS	AIB Disclosure "Residual Mix & Cancelled GOs"; National regulator reports	I-REC Public Reports; National renewables agency filings
Publicly Owned Hydro/Nuclear Attributes	Utility IRPs; Power Content Labels (CA); FERC Form 1 fuel mix	National statistical offices; ENTSO-E TSO disclosures	Provincial/state utility annual reports; Government asset registers
System/Supplier Emission Factors	EEI "Carbon Emissions & Mix"; Climate Registry "Utility-Specific EF"	AIB "Residual Mix EF"; RE-DISS	Gov’t GHG inventories; Utility sustainability reports
Plant-Level Emission Factors	EPA eGRID & Form 923; Canada NIR	E-PRTR; EU ETS verified data	National PRTRs; UNFCCC CRF tables

Data catalogs are maintained in the Granular Registry repository (/data/catalogue/), with source links, refresh cadences, and version stamps.

3. Workflow (Per Market-Utility Pair)

Follow these steps sequentially, documenting assumptions and sources in a Jupyter notebook attached to the Registry entry.

Step 1: Define Market Boundary

• Identify the balancing authority/ISO or regulated franchise area (e.g., PG&E service territory in California).

• Record LSE legal entities (e.g., Pacific Gas & Electric).

Step 2: Extract Retail-Sales Volumes

• Fetch latest calendar-year MWh from sources in Section 2 (e.g., EIA Form 861).

• Flag partial-year or estimated values.

Step 3: Quantify Compliance REC Obligations & Retirements

• Retrieve statutory RPS/Clean Energy Standard (CES) percentage or absolute MWh obligation (e.g., from state regulator reports).

• Pull actual MWh retired (by technology tier) from certificate-tracking systems (e.g., WREGIS reports).

• Calculate Obligation Gap = Obligation – Actual Retired; document if non-zero (e.g., due to banking or penalties).

Step 4: Identify Non-RPS Zero-Carbon SSS Resources

• Scan public filings for regulated or publicly funded zero-carbon assets not in RPS (e.g., legacy hydro, nuclear under ZEC programs).

• Record annual MWh from sources like utility IRPs or FERC Form 1 (e.g., large hydro output).

Step 5: Assemble SSS-Retired REC Volume

• SSS_REC_MWh = RPS_Retired + Public_Asset_Zero-Carbon_MWh – RECs_Sold_Externally

• Subtract external sales evidenced in tracking-system voluntary market reports to avoid double-counting.

Step 6: Construct Supplier-Specific Emission Factor (SSEF)

• Preferred (6A): Use published SSEF integrating REC retirements (e.g., EEI, California Power Content Label, or AIB Residual Mix).

• Fallback (6B): Bottom-up calculation: a. Build generation mix = Owned Generation + Contracted + Net Purchases (from fuel mix disclosures). b. Subtract volumes matched to RECs retired in Step 5 (zero-carbon adjustment). c. Multiply residual fossil MWh by fuel-specific CO₂ intensity (e.g., from eGRID). d. SSEF = (Total tons CO₂e) / Retail Sales MWh.

• Include CH₄ and N₂O if required by local protocols.

Step 7: Allocate Pro-Rata Entitlement to Reporting Customer

• For customer load L_customer (MWh): Claimable_REC_MWh = (SSS_REC_MWh / Retail_Sales_MWh) × L_customer

• SSEF applies directly to the customer's SSS-supplied load.

Step 8: Optional Hourly Proxy

• Where hourly residual-mix factors (H-RMFs) exist (e.g., GB, Nordics): H_SSS_EF_t = H_Residual_EF_t – (H_SSS_CFE_MWh_t × 0 / H_Load_MWh_t) (Zero-carbon volumes nullify emissions in matching hours.)

• If no H-RMF, disclose approximation using annual factors and flag uncertainty.

Step 9: QA/QC & Documentation

• Cross-verify REC volumes against multiple sources (e.g., regulator + registry).

• Ensure no double-counting between compliance and voluntary retirements.

• Version-stamp datasets with retrieval dates.

• Attach calculation notebook to Registry entry.

4. Data-Quality Hierarchy

Prioritize sources as follows:

1. Supplier-attested, verified data (preferred).

2. Regulatory compliance filings (e.g., RPS reports, Power Content Labels).

3. Certificate-tracking system/residual mix reports.

4. Bottom-up generation-mix reconstruction.

5. If unavailable, assign average grid EF and mark as high-uncertainty.

5. Region-Specific Adaptations

Region	Key Quirks	Additional Data Pointers
PJM (U.S.)	Hourly REC timestamps available; includes ZEC nuclear schemes.	State ZEC dockets; PJM-EIS Bulletin Board.
California	Power Content Label publishes SSEF per supplier.	CPUC PCL database (released year +1).
EU	AIB Residual Mix and GO cancellations; public hydro assets.	ENTSO-E production; Eurostat ownership tagging.
Australia NEM	No federal RPS; LRET/SRES RECs and state targets.	Clean Energy Regulator "REC Surrenders"; AEMO Generation Info.
Latin America	Widespread I-REC; limited retail transparency.	I-REC Public Reports + utility annual reports.

6. Limitations & Future Work

• Annual estimates may under- or over-allocate clean energy hourly; transition to time-stamped certificates planned.

• Assumes dispatch parity; may mis-estimate if curtailment occurs.

• Public hydro data approximate in some markets; incorporate confidence scores.

• Methodology updated annually or on policy changes via stakeholder review.

Example Calculation: PG&E (California, 2022 Data)

Assume a hypothetical customer with 10,000 MWh annual SSS load from Pacific Gas & Electric (PG&E) in California. Using public sources (e.g., CPUC Power Content Label, WREGIS reports, EIA Form 861).

Step 1-2: Market = CAISO (PG&E territory). Retail Sales = 78,000 GWh (EIA Form 861, converted to MWh).

Step 3: RPS Obligation = 44% (CPUC report). Actual Retired = 34,320,000 MWh RECs (WREGIS compliance, including eligible renewables).

Step 4: Non-RPS Zero-Carbon = 38,220,000 MWh (nuclear 49% + large hydro 7% from PCL; total ~37.4 GWh, but adjusted for SSS inclusion).

Step 5: SSS_REC_MWh = 34,320,000 + 38,220,000 – 0 (no external sales evidenced) = 72,540,000 MWh.

Step 6: Published SSEF = 206 lbs CO₂/MWh (PCL; converted to 93.4 kg CO₂/MWh), reflecting REC retirements and zero-carbon assets (96% GHG-free mix).

Step 7: Claimable_REC_MWh = (72,540,000 / 78,000,000) × 10,000 ≈ 9,300 MWh (93% zero-carbon share). SSEF applies as 93.4 kg CO₂/MWh to full load. Market-Based Scope 2 = 10,000 MWh × 93.4 = 934 tCO₂e.

QA/QC: Verified against PCL and WREGIS; no double-counting as RPS RECs are retired for SSS. Hourly proxy: Use CAISO H-RMF if available; otherwise, annual approximation flagged.