Storage Discharge Granular Certificate (SD-GC) Issuance

Introduction

The Storage Discharge Granular Certificate (SD-GC) represents energy that has been stored and subsequently discharged, maintaining the original environmental attributes of the energy source while accounting for storage efficiency losses. Additionally, this methodology introduces a novel approach to tracking the net marginal carbon impact of energy storage, providing users with a more accurate carbon footprint assessment of their time-shifted energy use.

SD-GCs are issued through the conversion of Storage Allocation Records (SARs), which are created by linking Storage Charge Records (SCRs) and Storage Discharge Records (SDRs) using a First-In, First-Out (FIFO) allocation method. This ensures the integrity of the stored energy lifecycle while accurately attributing the carbon intensity impact.

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Prerequisites for SD-GC Issuance

Before an SD-GC can be issued, the following conditions must be met:

1. A SAR must exist – A valid Storage Allocation Record (SAR) must be available in the registry.

2. GC Allocation to SAR – A user must allocate CFE Granular Certificates (CFE GCs) from their account to a SAR, canceling the original GCs in exchange for an SD-GC.

3. SCR-SDR Linkage Complete – The SAR must correctly link one or more SCRs and SDRs, ensuring that energy is properly accounted for.

4. Carbon Impact Calculation Applied – The registry calculates the net marginal carbon impact of the SAR and applies it to the GCs being shifted using the following formula:

$$SD\text{-}GC_{impact} = GC_{impact} + SAR_{impact}$$

Where:

• GC_impact = Carbon impact of the original GC before storage.

• SAR_impact = Carbon emissions associated with energy storage, accounting for grid charging mix and losses.

• SD-GC_impact = Adjusted carbon impact of the discharged energy.

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Step-by-Step Process for SD-GC Issuance

Step 1: User Selects SAR for GC Allocation

• The user navigates to the Storage Projects Page in the registry.

• Available SARs are displayed with key attributes, including:

  • Storage Asset ID

  • Charging and Discharging Time Intervals

  • Available Capacity for Allocation

  • SAR Carbon Impact Estimate

• The user selects a SAR and allocates CFE GCs from their account.

Step 2: Validate GC Allocation

• The registry verifies the following conditions:

  • The allocated CFE GCs are valid and unallocated.

  • The GC’s generation timestamp precedes the charging timestamp of the SAR.

  • The GC volume matches or is proportionally allocated to the SAR’s available capacity.

• If the validation is successful, the system cancels the allocated GC(s) and marks the SAR as "Pending SD-GC Issuance."

Step 3: Calculate SD-GC Volume and Carbon Impact

• The carbon impact adjustment is calculated:

$$SD\text{-}GC_{impact} = GC_{impact} + SAR_{impact}$$

• This ensures that the adjusted carbon impact of the discharged energy is correctly recorded.

Step 4: Issue SD-GC to User’s Account

• The registry creates and issues an SD-GC with the following attributes:

  • Unique SD-GC ID

  • Original GC Source (Energy Type, Production Device, Location)

  • Storage Asset Details

  • Charging Timestamp (from SCR)

  • Discharge Timestamp (from SDR)

  • Final SD-GC Volume (Wh)

  • Net Carbon Impact Adjustment

• The issued SD-GC is deposited into the user’s account, where it can be retired, transferred, or used for compliance claims.

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Example SD-GC Issuance Workflow

Step	Action	Registry Interaction
1	User selects SAR for GC allocation	User picks available SAR from the Storage Projects Page
2	System validates GC allocation	Ensures the GC is valid and meets allocation rules
3	GC is canceled, and SAR is marked pending	Registry cancels the original GC and confirms allocation
4	Net carbon impact calculated	SD-GC impact is adjusted using SAR carbon impact
5	SD-GC is issued	User receives an SD-GC reflecting the time-shifted energy

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Compliance & Data Integrity

• Time-Based Integrity – The SD-GC maintains a clear link to its original generation source while shifting its availability based on storage activity.

• Preventing Double Counting – The registry ensures that once an SD-GC is issued, the corresponding original GC is permanently canceled.

• Carbon Transparency – The new methodology ensures users receive an accurate carbon footprint for their time-shifted clean energy.

• FIFO Enforcement – The registry enforces a first-in, first-out (FIFO) allocation, ensuring energy is time-shifted in chronological order.

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Summary & Key Benefits of SD-GC Issuance

Feature	Description
Enables Time-Shifting of Clean Energy	Allows users to store and later retrieve energy while maintaining its original attributes.
Accounts for Storage Carbon Impact	Adjusts the carbon footprint of shifted energy based on storage grid interaction.
Supports 24/7 CFE Strategies	Helps organizations match clean energy consumption with storage-backed renewable supply.
Ensures Compliance with EnergyTag	Prevents double counting and maintains accuracy in clean energy reporting.