GHG quantification

General

General GHG reduction quantification rules can be found in the Riverse Standard Rules.

Calculations of GHG emissions for the baseline and project scenarios shall follow the method detailed below, based on

Battery second-life projects are only eligible for avoidance Riverse Carbon Credits.

Battery second-life projects serve two functions: waste treatment from a battery’s first life (Battery A), and the provisioning of a “new” battery in its second life (Battery B). Both of these functions are included in the project and baseline scenario.

The baseline scenario represents the functionally equivalent set of activities that would occur in the absence of the project. Therefore, the baseline scenario is the average waste battery treatment of Battery A, and the market mix for production of a new Battery B.

The distribution, packaging, use, and waste treatment of Battery B are not included in the calculations because they are assumed to be the same in both scenarios. Therefore, the downstream system boundary is Battery B at the factory gate.

Calculations and data collection are based on annual project operations.

Functional unit

Battery second-life projects are multifunctional so the functional unit is twofold:

• production of one battery (Battery B), plus

• treatment of the corresponding amount of battery waste treated (from Battery A) to generate this one Battery.

Data sources

All data shall be provided per battery type and chemistry type because different battery types and chemistries use distinct materials and production processes, leading to varying environmental impacts, particularly during production and end-of-life waste treatment. This ensures accurate assessment of emissions across the lifecycle.

The required Primary data for GHG reduction calculations from projects are presented in Table 2:

Table 2 Summary of primary data needed from projects and their source. Asterisks (*) indicate which data are required to be updated annually during verification (see Monitoring Plan section). Data are for a battery of type i and chemistry c.

Parameter	Unit	Source proof
Percentage of mass of all collected battery packs that fail initial quality control and are sent directly to waste treatment.*	%	Battery second-life project tracking system
Percentage of collected battery units (BU) by individual units that fail quality tests after initial quality control and are sent to waste treatment.*	%	Battery second-life project tracking system
Percentage of collected auxiliary components that fail quality test after initial quality control*	%	Battery second-life project tracking system
Percentage by mass of BU within a battery pack (optional)	%	Battery second-life project tracking system
Number of battery packs that were sold in a functioning state in the monitoring period.*	unit	Battery second-life project tracking system
Average BU weight.	kg	Battery model technical document Direct measurements made by the project
Number of BUs in a battery pack.	Unit	Battery model technical document Direct measurements made by the project
Distance traveled for collecting battery packs per sourcing country/city.	km	Battery second-life project tracking system
Distance in km to the batter waste treatment facility used by the project.	km	Battery second-life project tracking system Assumption based on the recycling facility location and the project’s site
Average percentage of BUs in sold battery packs that are new, as number of new BUs divided by total BUs used.*	%	Battery second-life project tracking system
Average percentage of auxiliary components in sold battery packs that are new, as mass of new auxiliary components divided by total auxiliary components used.*	%	Battery second-life project tracking system
Average percentage of BMS in sold battery packs that are new, as mass of new BMS divided by total BMS used.*	%	Battery second-life project tracking system
Average percentage of electrolyte solutions in sold battery packs that are new, as mass of new electrolyte solutions divided by total electrolyte solutions used.* For the regeneration of lead acid batteries only	%	Battery second-life project tracking system
Electricity amount and type for inspection and testing of BUs.	kWh/BU	Battery second-life project tracking system
Electricity amount and type for recharging the battery pack before sale.	kWh/Bat	Battery second-life project tracking system

Secondary data taken from the literature are used to define default values for the following elements:

• Battery’s expected lifetime (first and second life)

• Battery unit (cells and modules) percentage, by mass, in a battery pack (if not provided by the Project Developer)

The (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in Appendix 1.

Assumptions

1. Batteries (including battery packs, BUs, and auxiliary components) are evaluated in categories of battery types and chemistries rather than specific battery models to facilitate data collection. It is assumed that batteries in the same battery type category and chemistry have similar characteristics (component percentages, emission factor, lifetime), as defined in Appendix 2.

2. A battery pack consists of several essential components, which vary depending on the battery end use, manufacturer, and chemistry. To facilitate data collection, the battery pack is divided into three main components:

   1. Battery units: The battery unit (BU) is responsible for the battery's primary function—energy storage and delivery. It contains potentially hazardous materials and heavy metals, making it a critical focus for environmental and safety considerations. The structure and design of these units vary depending on factors such as the battery type, manufacturer, intended application, and chemical composition. In this methodology, it is assumed that the BU shape (e.g. cylindrical or prismatic) does not influence its environmental impacts.

      • lithium-ion and NiMH batteries are assembled from individual cells or modules (groups of cells combined to create standardized units of capacity and voltage).

      • lead-acid batteries are typically constructed as single units rather than separated into distinct cells. In this methodology, lead-acid batteries are considered a single BU.

   2. BMS: the Battery Management System (BMS) is the second most impactful component of a battery in terms of GHG emissions, due to its complex manufacturing process. Additionally, the integration of the BMS in the battery pack can affect recycling processes, further influencing its overall environmental footprint.

   3. Battery auxiliary components: other components that are not classified as BU or BMS. e.g. thermal management components, protective elements, internal wiring, busbars, connectors, and terminals.

3. The BMS weight per kg of the battery pack may vary depending on multiple factors such as the battery type, chemistry, and manufacturer. For simplifying the calculations and due to the lack of precise data per battery type and chemistry, it is assumed that the BMS rate is 0.02kg/kg of the battery pack based on the ecoinvent process for Li-ion battery production.

4. The waste collection and transport distance for Battery A in the baseline scenario is determined using bounding analysis to identify the most conservative value. A distance of 1800 km is assumed, reflecting the maximum possible distance between existing battery recycling facilities in Europe. This value can also be applied to the Project scenario if no project-specific data are available.

5. The waste collection for Battery A is assumed to be done 100% by truck within Europe .

6. In the baseline scenario, for the fraction of waste Battery A that are separately collected by specialized waste battery programs (e.g. ), it is assumed that 70% of batteries will be reused and 30% will be recycled. This assumption is based on projections provided by industry experts.

7. The distribution of batteries in the baseline and project scenarios is assumed to be the same and is therefore excluded from quantifications. This is a conservative assumption because new batteries in the baseline scenario are , and transported long distances. In contrast, the project scenario consists of mostly inter-EU shipping of batteries across much shorter distances.

8. Packaging, use, and waste treatment of Battery B are assumed to be the same in the baseline and project scenarios and are therefore excluded from quantifications.

9. Refurbished or regenerated batteries are assumed to have shorter lifetimes than new batteries, depending on the battery type and chemistry, as outlined in the Substitution section and Appendix 2. It is assumed that the battery State of Health (SoH) can be a proxy for remaining battery performance, and that the amount of battery production avoided in the baseline scenario is proportional to the ratio of new and second-life battery lifetimes and second-life SoH.

10. It is assumed that when any battery component fails, the entire battery pack becomes non-functional, as the failure of even a single component—such as a cell, module, or critical part like the BMS—renders the whole battery pack inoperable. This means that for this methodology the input battery is considered true waste, and no residual value is allocated from its first life.

11. The battery cleaning process involves (a) degreasing to remove oils and grease applicable to all battery types (100 ml degreaser per kg of battery pack), and (b) for lead-acid batteries, neutralizing residual electrolytes using baking soda solution (50 ml solution per kg of battery pack). These assumptions are based on estimates by the Project Developers.

12. It is estimated that the electrolyte in a lead-acid battery constitutes approximately of the total battery weight.

13. The lead-acid batteries electrolyte solution is assumed to be made of 38% sulfuric acid and 62% water.

14. There are two main types of battery waste treatment: pyrometallurgy and hydrometallurgy. Each battery chemistry is assumed to have the following repartition of the waste treatment process:

    • Li-ion: .

    • NiMH: assumed to be 100% through pyrometallurgical treatment. Even though hydrometallurgy is the most common process for recycling NiMH batteries, .

    • Pb-acid: 100% through

15. In the absence of the project, the battery end-of-life would have been treated according to the current market shares in Europe, which are detailed per battery type and chemistry in Table 3.

Table 3 .

Battery type	Chemistry
	: : 60% : 30% : 10% NiMH	collection schemes: 51% (separate collection) Outside schemes: 49% (assumed mix of some separate collection, some general battery fate)	PRO collection schemes: Battery second life: 7 % Recycling: 93% Outside PRO schemes: Battery second life: 13.3% Recycling: 80.7% Landfill and incineration: 6%
V	Li-ion NiMH	Separate collection 100%	Battery second life: 17.5% Recycling: 82.5%
	Pb-acid	Separate collection 100%	Recycling 100%
Industrial	Li-ion Pb-acid	Separate collection 100%	Recycling 100%

• LMT: The PRO collection scheme target for 2028 is set at 51% from the EU regulation. Therefore, the collection targets are assumed to be 51% for separate collections through PRO schemes and 49% for batteries collected outside of PRO schemes.

• EV/HE, SLI, and industrial: These batteries do not have a collection target because the Extended producer Responsibility (EPR) systems are required to separately collect all batteries that become waste. Therefore, none will go to incineration or landfilling, and they will all be recycled.

• In the End-of-Life (EOL) scenario, it is assumed that 70% of the batteries entering the second-life stream will be reused or refurbished, while the remaining 30% will be recycled. Accordingly, the EOL scenarios have been adjusted. Refer to Appendix 3 for detailed information.

Project scenario

Figure 1 system boundary and scope of the project scenario are shown

The project scenario consists of preparing used batteries for a second life, which serve two functions: 1) waste treatment of the battery after its first life (Battery A) and 2) preparation for reuse to produce a “new“ battery (Battery B). This process is broken down into 3 life cycle stages, and displayed in Figure 1:

• Battery A waste collection

• Battery A waste treatment

• Battery B preparation for reuse

Battery waste collection

The mass of waste battery (Battery A) collected equals the total mass of input used batteries collected at the battery second-life project annually.

The total mass of batteries collected shall be back-calculated based on the quantity of battery packs that were successfully prepared for reuse and sold, and the rate of parts that could not be reused and were recycled (see Eq. 2). This approach is preferred as tracking the battery packs that were successfully prepared for reuse and sold is more reliable and accurate than tracking input collected batteries.

Project Developers may provide more precise information on the mass of collected batteries if it is available.

For calculating transport distance, Project Developers shall provide the country and/or city where used battery packs are transported from, and provide the distance from the collection source to the battery second-life project site.

Calculations project battery collection

This step calculates the GHG emissions from transporting used batteries during the collection process ($Total\ E_{P.collection}$).

$\textbf{(Eq.1)}\ Re_{\%.i.c} = \ ReBP_{\%.i.c} + ReBu_{\%.i.c}*BU\%_{i.c} + ReBc_{\%.i.c}*(1 - BU\%_{i.c})+ReBMS\%_{i.c}*BMS\%_{i.c}$​​

• $Re_{\%.i.c}$ represents the percentage of collected battery packs of type $i$ and chemistry $c$, that could not be successfully refurbished/regenerated by the project, and are recycled.
• $ReBP_{\%.i.c}$ represents the percentage of battery packs of type $i$ and chemistry $c$ that fail initial sorting and are sent directly to waste treatment. In battery second-life projects, this rate is typically close to zero, as the goal is to maximize the reuse of battery units and components. However, it is included here as a conservative measure.
• $ReBu_{\%.i.c}$ represents the percentage of input used BUs of type $i$ and chemistry $c$ that pass the initial sorting but are recycled after failing the first or last tests.
• $BU\%_{i.c}$ represents the percentage, by mass, of BUs within a battery pack of type $i$ and chemistry $c$. This value should ideally be provided by the PD or selected from Appendix 2 if the exact value is unknown.
• $ReBc_{\%.i.c}$ represents the percentage of input auxiliary components that are recycled, e.g. damaged cooling systems that cannot be reused.
• $ReBMS\%_{i.c}$ represents the percentage, by mass, of collected BMS that are recycled.
• $BMS\%_{i.c}$ represents the percentage of BMS, by mass, in a battery pack. This is assumed to be 2% as defined in the assumptions section.

$\textbf{(Eq.2)}\ N_{i.c.\ collected} = \sum_{1}^{i}(N_{i.c.sold}/\ (1 - Re_{\%.i.c}))$

• $N_{i.c.\ collected}$ represents the amount of input collected from battery packs of type $i$ and chemistry $c$ collected by the project, in a number of batteries.
• $N_{i.c.sold}$ represents the number of battery packs of type $i$ and chemistry $c$ that were sold in a functioning state, and shall be provided by the Project Developer for each monitoring period.

$\textbf{(Eq.3)}\ W_{i.c} = W_{BU.i.c}*N_{BU.i.c}/BU\%_{i.c}$

• $W_{i.c}$ represents the weight in kilograms of battery pack type $i$ and chemistry $c$, which can be calculated here if it is not directly provided by project developers.
• $W_{BU.i.c}$ represents an average BU weight as defined in the Assumptions section.
• $N_{BU.i.c}$ represents the number of BUs in a battery pack type $i$ and chemistry c. This value shall be provided by the PD.

$\textbf{(Eq.4)}\ Total\ E_{P.collection} = \sum_{1}^{i}(N_{i.c.collected}*W_{i.c}*D_{C.i.c}*R_{C.i.c})*\ EF_{transport}$ where,

• $Total\ E_{P.collection}$ represents the total greenhouse gas (GHG) emissions, in kg CO₂ equivalent, from transporting waste battery packs collected by the project.
• $D_{C.i.c}$ represents the distance traveled, in kilometers, for collecting battery packs of type $i$ and chemistry $c$, as provided by the PD for each sourcing country/city (C) and battery type/chemistry ($i$ and $c$).
• $R_{C.i.c}$ represents the fraction of the battery packs collected per sourcing country/city (C).
• $EF_{transport}$ represents the emission factor for transport in kgCO$_2$eq/kg.km according to the ecoinvent database and includes truck. Refer to Appendix 1 for the ecoinvent processes used.

Battery waste treatment

Battery packs collected by the project that cannot be successfully prepared for reuse are processed through recycling.

Battery second-life projects typically partner with certified recycling companies that are equipped to handle hazardous materials. These companies must be capable of managing BU and auxiliary components

Project Developers shall provide the fraction of collected BUs, BMS and auxiliary components that are recycled.

Battery recycling is modeled using either hydrometallurgical or pyrometallurgical treatment depending on the battery chemistry (see ecoinvent processes in Appendix 1).

Some auxiliary components such as the battery casing, cables, and cooling system, may be kept onsite to harvest spare parts in the future, but due to limited project data on this topic, they are conservatively assumed to be recycled.

Calculations project battery waste treatment

This step calculates the GHG emissions from transporting and recycling the used battery components that are unsuitable for being reused ($Total\ E_{P.waste\ treatment}$).

$\textbf{(Eq.5)}\ E_{c.recycling} = \sum(Re_{\%.i.c}\ *\ N_{i.c.collected}*\ W_{i.c}*\ EF_{recycling.c})$

• $E_{c.recycling}$ represents the total GHG emissions, in kgCO₂eq, resulting from the recycling of batteries with chemistry $c$ that are unsuitable for reuse.
• $Re_{\%.i.c}$ is defined in (Eq.1).
• $N_{i.c.collected}$ is defined in (Eq.2).
• $W_{i.c}$ is defined in Eq.3
• $EF_{recycling.c}$ represents the emission factor for recycling a battery of chemistry $c$, in kgCO$_2$eq per kg. For details on the ecoinvent processes used, refer to Appendix 1.

$\textbf{(Eq.6)}\ E_{transport} = \sum({Re_{\%.i.c}*N_{i.c.collected}*\ W_{i.c}}_{})*D_{scrap}*\ EF_{transport}$

where,

• $E_{transport}$ represents the sum of GHG emissions due to the transport of batteries not suitable for reuse that are sent to recycling, in kgCO$_2$eq.
• $D_{scrap}$ represents the distance in km until the waste treatment facility. If this value is not provided by the Project Developer, it is conservatively assumed 1800 km as described in the assumptions section.
• $EF_{transport}$represents the emission factor for truck transport, in kgCO₂eq. As battery waste is considered hazardous, it cannot be exported for treatment. Therefore, it is assumed that transport occurs locally by truck, as outlined in the assumptions section. For details on the ecoinvent processes used, refer to Appendix 1.

$\textbf{(Eq.7)}\ Total\ E_{P.waste\ treatment} = \ E_{c.recycling} + E_{transport}$

where,

• $Total\ E_{P.waste\ treatment}$ represents the sum of GHG emissions in the project scenario battery waste treatment treatment of non-reusable parts, in kgCO$_2$eq.

Battery preparation for reuse

This life cycle stage is composed of different main processes depending on the battery's second life technology implemented: refurbishing or regeneration.

Common steps

Both refurbishing and regeneration processes involve the disassembly of the battery packs into their BUs. Next, the BU undergoes inspection and testing to assess its and performance, including evaluations of voltage, performance, and charge retention. Any faulty BU or auxiliary components that cannot be refurbished or regenerated are removed and recycled.

Final testing and validation consume electricity and ensure the battery’s safety and functionality before it is partially charged (60%), packaged, and distributed for reuse.

Refurbishing steps

The refurbishment process typically includes electricity use for testing and charging, and may also involve replacing used BUs or auxiliary components with new ones. All components are cleaned and reassembled into a "new" refurbished battery pack. This pack undergoes strict quality control checks to ensure compliance.

Cleaning involves inputs of cleaning chemicals and cloth, modeled after assumptions presented in the assumptions section.

Refurbished batteries are frequently repurposed for new applications, such as transitioning from their original use in electric vehicles (EVs) to energy storage systems (ESS).

Regeneration steps

The regeneration process is only suitable for some BUs with specific chemistries (e.g., NiMH and Li-ion).

In addition to the common and refurbishing steps, regeneration involves a battery or charger sending controlled high-frequency pulses of electricity through the battery, and may include desulfation and the replacement of chemicals/electrolytes (for Pb-acid batteries).

kgCO$_2$eq

Once regenerated, the battery is often reused in its first life application as regeneration can achieve similar performance as for a new battery.

Calculations project battery B preparation for reuse

This step calculates the GHG emissions from the preparation for reuse process$({Total\ E}_{P.\ refurbishing}$ or $Total\ E_{P.regeneration}$) broken down into three main processes: 1) common steps, 2) refurbishing steps, and 3) regeneration steps.

Common steps

Battery refurbishment and regeneration processes are conducted on a battery unit (cells/modules) level. Thus, the first step of both processes starts with the disassembly of the battery pack into BUs, followed by inspection and testing to assess its SoH, which uses electricity.

$\textbf{(Eq.8)}\ E_{sorting} = \sum(N_{i.c.collected}*\ N_{BU.i.c}*\ Electricity_{kWh/BU})*EF_{electricity}$

• $E_{sorting}$ represents the sum of GHG emissions due to the electricity consumption needed for sorting (inspecting and testing) incoming battery units (cells/modules), in kgCO$_2$eq.
• $N_{i.c.collected}$ is defined in Eq.2 and represents the amount of input collected battery packs of type $i$ and chemistry $c$ collected by the project, in number of battery packs.
• $N_{BU.i.c}$ is defined in Eq. 3 and represents the average amount of battery units in a battery pack type $i$ and chemistry c. This value shall be provided by the PD.
• ${Electricity}_{kWh/BU}$ represents the amount of electricity needed in kWh for inspection and testing per battery unit (cells or modules).
• $EF_{electricity}$ represents the emission factor of electricity in the given project location. Refer to Appendix 1 for the ecoinvent process used. The ecoinvent process might change depending on the project's geography.

After evaluating the battery, any BU or damaged auxiliary component that are not suitable for refurbishing or regeneration is removed for recycling and is considered in the Project battery waste treatment calculation section. The remaining components are then cleaned.

The cleaning process typically includes (a) external cleaning to remove dirt and dust; (b) degreasing to eliminate oils and grease; and (c) neutralizing any residual electrolytes. Default amounts of cleaning product per kilogram of each battery type are assumed.

$\textbf{(Eq.9)}\ E_{cleaning} = \sum(N_{i.c.sold}*(Chem_{i}*EF_{chem.i}\ + \ Cloth*EF_{cloth}+\ Paper*EF_{paper}))$

• $E_{cleaning}$ represents the sum of GHG emissions due to the battery components cleaning. This includes chemicals, paper and cloth, in kgCO$_2$eq.
• $Chem_{i}$ represents the amount of chemical product $i$ used for cleaning the battery. This includes baking soda solution and degreaser as detailed in the assumptions section.
• $EF_{chem.i}$ represents the emission factor of chemical $i$. Refer to the assumptions to Appendix 1 for the ecoinvent processes used.
• $Cloth$ and $Paper$ represent the amount of cloth and paper used for cleaning a battery, by battery weight. These amounts were extrapolated from the on refurbishing of electronic devices.
• $EF_{cloth}$ $EF_{paper}$ represents the emission factor of cloth and paper respectively. Refer to the assumptions to Appendix 1 for the ecoinvent processes used.

$\textbf{(Eq.10)}\ E_{common\ impacts} = E_{sorting} + \ E_{cleaning}$

• $E_{common\ impacts}$ represents the sum of GHG emissions due to battery preparation for reuse common processes. This includes the impacts of sorting and cleaning.

Refurbishing impacts

After the common steps, the battery pack is reassembled. Some new pieces might be used to replace old non-functioning pieces, notably BUs or BMS. This is only accounted for if the PD uses new pieces instead of only recovered pieces from other waste batteries.

$\textbf{(Eq.11)}\ E_{new\ BU} = \sum (BU\%_{new}*N_{BU.i.c}*\ N_{i.c.sold}*W_{BU.i.c})*EF_{BU.i.c}$

• $E_{new\ BU\ }$ represents the total GHG emissions, in kgCO$_2$eq, associated with the production of new battery units, if applicable.
• $BU\%_{new}$ represents the percentage of new battery units in the battery pack type $i$ and chemistry $c$ sold.
• $N_{BU.i.c}$ and $W_{BU.i.c}$ are defined in Eq. 3.
• $N_{i.c.sold}$ is defined in Eq. 2.
• $EF_{BU.i.c}$ represents the emission factor for producing a battery unit of type $i$ and chemistry $c$, in kgCO2eq/kg. Refer to Appendix 1 for the ecoinvent processes used.

$\textbf{(Eq.12)}\ E_{new\ AC} = \sum({Bc\%}_{new}*W_{i.c}*(1 - BU\%_{i.c})*N_{i.c.sold})*EF_{AC}$

• $E_{new\ AC}$ represents the total GHG emissions, in kgCO$_2$eq, associated with the production of new auxiliary components for battery of type $i$ and chemistry $c$, if applicable. This includes, for instance, the production of battery casing and electronic components.
• $Bc\%_{new}$ represents the percentage of new battery components in the sold battery pack of type $i$ and chemistry $c$
• $BU\%_{i.c}$ is defined in Eq. 1.
• $W_{i.c}$is defined in Eq.3.
• $EF_{AC}$ represents the emission factor of the auxiliary components, in kgCO$_2$eq/kg. Refer to Appendix 1 for the ecoinvent processes used and the Assumptions section for the considerations made.

$\textbf{(Eq.13)}\ E_{new\ BMS} = \sum({BMS\%}_{new}*{BMS\%*N}_{i.c.sold}*W_{i.c})*EF_{BMS}$

• $E_{new\ BMS}$ represents the total GHG emissions, in kgCO$_2$eq, associated with the production of a new battery management system.
• $BMS\%_{new}$ represents the percentage of new battery management systems implemented per sold battery pack.
• $BMS\%$represents the percentage of a battery management system in a battery pack per weight, which is 0.02kg per kg of battery pack, see the Assumptions section.
• $EF_{components}$ represents the emission factor for producing a battery management system, in kgCO$_2$eq/kg. Refer to Appendix 1 for the ecoinvent processes used and the Assumptions section for the considerations made.

$\textbf{(Eq.14)}\ E_{charging} = \sum(N_{i.sold}*{Electricity}_{kWh/Bat.i.c})*EF_{electricity}$

• $E_{charging}$ represents the sum of GHG emissions, in kgCO$_2$eq, associated with battery B final charge before it is sold, in kgCO$_2$eq.
• ${Electricity}_{kWh/Bat}$ represents the amount of electricity in kWh needed for recharging a battery B of type $i$ and chemistry c. This recharge usually accounts for 60% of the battery capacity.
• $EF_{electricity}$ is defined in Eq.8.

$\textbf{(Eq.15)}\ Total\ E_{P.refurbishing} = E_{common\ impacts\ } + \ E_{new\ BU} + E_{new\ BMS} + \ E_{new\ AC} + E_{charging}$

• ${Total\ E}_{P.refurbishing}$ represents the sum of GHG emissions, in kgCO2eq, associated with battery refurbishing, in kgCO2eq.

Regeneration impacts

Regeneration includes both the common impacts, refurbishing impacts (optional), and additional impacts associated with regenerating. After the common processes described in Eq. 10, BUs that are suitable for regeneration undergo specialized treatment.

$\textbf{(Eq.16)}\ N_{BU.i.c\ qualified} = \sum(N_{i.c.collected}*\ N_{BU.i.c})*(1 - ReBU\%_{i.c})$

• $N_{BU.i.c.qualified}$ represents the number of BUs suitable for regeneration after qualification.
• $(1 - {ReBU\%}_{i.c})$ represents the rate of collected BUs that are suitable for regeneration after quality control.

$\textbf{(Eq.17)}\ E_{electricity\ regen} = \sum(N_{BU.i.c\ qualified}*{Electricity}_{kWh/BU})*EF_{electricity}$

• $E_{electricity\ regen}$ represents the sum of GHG emissions associated with the electricity consumption for battery regeneration, in kgCO$_2$eq.

Lead acid battery regeneration may also include the replacement of the BU's electrolytes, where fresh sulfuric acid is used to replace the old, degraded electrolyte in the BU.

$\textbf{(Eq.18)}\ E_{electrolyte\ regen} = \sum(N_{BU.i.c\ qualified}*W_{i.c}*Electrolyte\%_{i.c}\ *Electrolyt{e\%}_{new.\ i.c})* (EF_{electrolyte.i.c} + EF_{electrolyte\ treatment})$

• $E_{electrolyte\ regen}$ represents the sum of GHG emissions associated with the chemicals needed for battery regeneration, in kgCO$_2$eq.
• $W_{i.c}$ is defined in Eq. 3 and represents the weight of the battery pack in kg.
• $Electrolyte\%_{i.c}$ represents the percentage of electrolytes in battery type i and chemistry c. For lead-acid batteries, this is assumed to be 27%.
• $Electrolyt{e\%}_{new\ i.c}$ represents the percentage of new electrolyte solution for the regeneration of a battery of type $i$ and chemistry $c$. This value might vary depending on the BU state, design, and manufacturer.
• $EF_{electrolyte.i.c}$refers to the emission factor of the production of electrolyte for battery type $i$ and chemistry c. Refer to Appendix 1 for the ecoinvent process used. For lead-acid batteries, it is assumed that the electrolyte is a solution made of 38% sulfuric acid (H2SO4) and 62% water.
• $EF_{electrolyte\ treatment}$ represents the emission factor of the old electrolyte (which was replaced by a new electrolyte) waste treatment. When regenerating lead-acid batteries, the used electrolyte can be either regenerated or neutralized and then water treated. It is conservatively assumed that the electrolyte will be neutralized.

Next, BUs are tested to verify the effectiveness of regeneration, which requires electricity consumption. This is calculated using Eq. 8 (which will be referred as $E_{testing}$ below). Any BUs that fail this test are sent for recycling, which is covered in the Project Battery waste treatment section.

The battery is then reassembled (except lead-acid batteries, which are here considered as BUs), which may require new components. If applicable, refer to Eq. 11 through Eq. 13.

Finally, the battery is charged, following Eq. 14.

The impacts of regeneration are, therefore:

$\textbf{(Eq.19)}\ E_{P.regeneration} = E_{common\ impacts}+E_{electricity\ regen}+E_{electrolyte\ regen} +E_{testing}+E_{new\ BU}+E_{new\ BMS}+E_{new\ AC}+E_{charging}$

Baseline scenario

Figure 2 The system boundary and scope of the baseline scenario are shown.

The baseline scenario consists of two main functions: 1) waste treatment of the battery after its first life (Battery A) and 2) provisioning of a new battery (battery B). The system boundary of the baseline scenario is shown in Figure 2. This is broken down into 3 life cycle stages, which are detailed in the following sections:

• Battery A collection

• Battery A e-waste treatment

• Manufacturing of Battery B

The baseline scenario shall be reviewed annually by the Riverse climate team to account for any changes in regulations. Additionally, it shall be updated using project data to reflect the functional equivalent of the project's annual operations, considering the number and type of batteries collected and prepared for reuse.

The structure of the Baseline scenario is the same whether the project consists of ongoing operations or an expansion. In the former, project data from all annual site operations is considered, and the baseline scenario is defined as the functional equivalent of all annual operations. For an expansion project, only project data related to the expansion is considered, because the normal annual operations would be the same in the baseline and project scenario, and can therefore be excluded.

Battery waste collection

It is assumed that battery waste is transported by truck 1800 km to its waste treatment center.

The mass of battery waste collected in the baseline scenario equals the total mass of input used batteries collected by the battery second life project annually.

Calculations baseline battery collection

This step calculates the GHG emissions from transporting used batteries during the collection process ($Total\ E_{B.collection}$).

$\textbf{(Eq.20)}\ Total_{B.collection} = \sum(N_{i.c.collected}*W_{i.c})*D*\ EF_{transport}$

• ${Total\ E}_{B.collection}$ represents the total greenhouse gas (GHG) emissions, in kgCO$_2$eq, due to battery waste transport.
• $N_{i.c.collected}$ is defined in Eq. 2 and represents the battery packs of type $i$ and chemistry $c$ collected by the project, in a number of batteries.
• $W_{i.c}$ is defined in Eq.3 and represents the weight in kilograms of battery pack type $i$ and chemistry c.
• $D$ represents the distance traveled, in kilometers, for collecting battery packs. In the baseline scenario this is assumed 1800 km.
• $EF_{transport}$ represents the emission factor for transport in kgCO$_2$eq/kg.km according to the ecoinvent database and includes truck. Refer to Appendix 1 for the ecoinvent processes used.

Battery waste treatment

The treatment of battery waste is split between pyrometallurgical or hydrometallurgical processes depending on the battery chemistry as described in the assumptions section. Additionally, part of the waste may be treated through incineration or landfilling, see Appendix 2.

The proportion of battery waste recycled is based on European regulation targets and estimates from real projects operating in Europe. Detailed information is in the assumptions section and Table 3.

First, the fraction of battery waste that is not separately collected through PRO schemes is assumed to eventually be sent for specialized battery waste treatment. This assumption is based on the hazardous nature of battery waste, which requires specific treatment technologies. Shredder operators are generally stringent about excluding such batteries from their waste streams and may impose heavy penalties on those who attempt to include them.

Then, the fraction of battery waste that is separately collected and treated through PRO schemes is considered according to the battery type and chemistry as defined in the targets of the European regulation.

The separately collected and treated batteries can be further broken down into the fraction of recycled and second-life batteries that are already occurring in the baseline. The battery regulations are evolving and at this time there are no country-specific fractions. Separately collected batteries through PRO schemes that cannot follow the second-life pathway are assumed to be recycled according to the proportions outlined in Table 3 and detailed in Appendix 2.

Calculations baseline: battery waste treatment

This step calculates the GHG emissions from the baseline e-waste treatment life cycle stage ($Total\ E_{B.waste\ treatment}$).

$\textbf{(Eq.21)}\ E_{recycling} = \sum(N_{i.c.collected}*W_{i.c}\ *(RR_{rate.i.c}\ *C_{rate.i.c} + nC_{rate_{i.c}}))*EF_{recycling.c}$

• $E_{recycling}$ represents the sum of GHG emissions due to recycling of batteries, in kgCO$_2$eq.
• $RR_{rate.i.c}$ represents the proportion of collected batteries of type $i$ and chemistry $c$ that are recycled after separate collection. These rates are presented in the Assumptions section and Appendix 2.
• $C_{rate.i.c}$ represents the battery waste collection rate in Europe for battery type $i$ and chemistry $c$. These rates are presented in the Assumptions section.
• $nC_{rate.i.c}$ represents the non-separately collected battery rate in Europe for battery type $i$ and chemistry $c$. These rates are presented in the Assumptions section
• $EF_{recycling.c}$ represents the emission factor for treating battery type $i$ and chemistry $c$ waste. Specific waste treatment shares per battery type are presented in the Assumptions section. Refer to Appendix 1 for the ecoinvent process used.

$\textbf{(Eq.22)}\ E_{residual\ waste} = \sum(N_{i.c.collected}*W_{i.c}*RW_{rate.i.c}*C_{rate.i.c})*EF_{residual\ waste}$

• $E_{residual\ waste}$ represents the sum of GHG emissions due to residual waste battery treatment, in kgCO$_2$eq. This regards specially LTM batteries of NiMH chemistry as described in Appendix 2.
• $RW_{rate.i.c}$ represents the rate of separately collected batteries that become residual waste and is treated accordingly (landfill and incineration). Refer to Appendix 1 for the ecoinvent process used.

$\textbf{(Eq.23)}\ Total\ E_{B\ waste\ treatment} = E_{waste\ recycling} + E_{residual\ waste}$

• ${Total\ E}_{B\ waste\ treatmen}$ represents the sum of GHG emissions due to battery waste treatment, in kgCO$_2$eq.

New battery production

The number of new batteries to consider in the baseline scenario corresponds to the number of batteries successfully prepared for reuse and sold in a functional state in the project scenario, adjusted by the shorter lifetime consideration for second-life batteries.

Note that this does not necessarily equal the number of used batteries collected, because a fraction of batteries collected can not be successfully prepared for reuse.

To quantify avoided GHG emissions, the baseline scenario must consider the market share of the project technology already in use. Currently, precision on this data is unavailable. It is assumed that a rather small amount of new battery purchases come from existing refurbishing activities (<1%). The market share of the project technology currently in use is assumed to be zero.

The process of manufacturing a new battery is taken from the ecoinvent database, without modifications for the following battery chemistries: lithium-ion, NiMH, and lead-acid.

The difference in lifetime between refurbished and new batteries, detailed in the Substitution section, is accounted for in this life cycle stage. The amount of new battery production avoided in the baseline scenario is proportional to the ratio of the lifetimes of new and second-life batteries, adjusted by the SoH of the second-life batteries in the project scenario.

Calculations baseline: new battery production

This step calculates the GHG emissions from the baseline battery production life cycle stage ($Total\ E_{B.\ new\ battery\ production}$).

$\textbf{(Eq.24)}\ E_{new\ battery} = \sum(N_{i.\ c.\ sold}*EF_{new.i.c})$

• $E_{new\ battery}$ represents the sum of GHG emissions in kgCO$_2$eq due to the production of new batteries, before accounting for the lifetime adjustment.
• $N_{i.c.sold}$ is described in Eq.2.
• $EF_{new.i.c}$ represents the emission factor in kgCO$_2$eq/kg due to the production of the new battery type $i$ and chemistry c. Refer to Appendix 1 for the ecoinvent processes used.

The shorter lifespan of second-life batteries is detailed in the Substitution section and is accounted for in the following adjustment to the avoided emissions from new battery manufacturing:

$\textbf{(Eq.25)}\ F_{lifetime\ adjustment} = (Y_{second - life.i.c}/Y_{new.i.c})*SoH_{i.c}$

• $F_{lifetime\ adjustment}$ represents the new battery lifetime adjustment factor.
• $Y_{second - life.i.c}$ represents the expected lifespan of a second-life battery type $i$ and chemistry $c$ in number of years, as presented in Appendix 2.
• $Y_{new.i.c}$ represents the expected lifespan of a new battery type $i$ and chemistry $c$ in number of years, as presented in Appendix 2.
• $SoH_{i.c}$ represents the SoH of the battery type $i$ and chemistry $c$ prepared for reuse by the project.

$\textbf{(Eq.26)}\ {Total\ E}_{B.\ new\ battery\ production} = \sum(E_{new\ battery}*F_{new\ battery\ adjustment})$

otal GHG emission for this life cycle stage is calculated according to the following equation:

• $Total\ E_{B.\ new\ battery\ production\ \ }$represents the sum of GHG emissions in the baseline scenario new battery production life cycle stage, in kgCO$_2$eq.

Avoided GHG emissions

Avoided GHG emissions are calculated by subtracting the sum of the project scenario GHG emissions from the sum of the baseline GHG scenario emissions.

Comparative GHG assessment calculation

The total baseline GHG emissions, total project GHG emissions, and the project's avoided emissions are calculated as follows.

$\textbf{(Eq.27)}\ Total\ E_P= Total\ E_{P.collection} + Total\ E_{P.waste\ treatment} + Total\ E_{P.prep.reuse}$

where $Total\ E_{P\ prep\ reuse}$ can be either $Total\ E_{P.refurbishing}\$or $Total\ E_{P.regeneration}$ depending on the battery's second-life technology implemented at the project level.

$\textbf{(Eq.28)}\ Total\ E_B= Total\ E_{B.collection} + Total\ E_{B.\ waste\ treatment} + Total\ E_{B.\ new\ battery\ production}$

$\textbf{(Eq.29)}\ Avoided\ emissions\ = \ Baseline\ emissions\ - \ Project\ emissions$

Uncertainty assessment

Uncertainty shall be evaluated at both the methodology level and the project level. The project-level uncertainty assessment must consider the uncertainty in the methodology, which is inevitably passed down to each project.

The uncertainty assessment below must be complemented by a project-specific uncertainty assessment. The outcome of the assessment shall be used to determine the percent of avoided emissions to eliminate with the discount factor.

The assumptions that are estimated to have high uncertainty (i.e. high variability and high impact) are:

• In the baseline scenario, new battery production is adjusted based on the lifespan of both new and second-life batteries, as well as second-life battery SoH. It is assumed that the SoH serves as a proxy for the remaining performance of the battery.

The assumptions that are estimated to have moderate uncertainty are:

• Batteries in the same battery type category and chemistry have similar characteristics (component percentages, emission factor, lifetime)

• The BMS rate is 0.02kg/kg of the battery pack.

• The waste collection and transport distance for Battery A is assumed at 1800 km

• 70% of batteries undergoing a second-life process are reused, while 30% will be recycled.

• The electrolyte in a lead-acid battery constitutes approximately of the total battery weight.

• The lead-acid batteries electrolyte solution is made of 38% sulfuric acid (H2SO4) and 62% water.

• Li-ion battery chemistry is a mix composed of:

  • lithium nickel manganese cobalt oxide (NMC): 60%

  • lithium iron phosphate (LFP): 30%

  • nickel cobalt aluminum oxide (NCA): 10%.

• There are two main types of battery waste treatment: pyrometallurgy and hydrometallurgy depending on the battery chemistry.

The assumptions that are estimated to have low uncertainty (i.e. low variability and low impact) are:

• In the absence of the project, the battery end-of-life would have been treated according to the market shares in Europe.

• A battery pack is divided into three main components: BU, BMS, and auxiliary components.

• The collection of batteries in Europe is done 100% by truck.

• The distribution, packaging, use, and waste treatment of Battery B in the baseline and project scenarios is the same.

• When an auxiliary component fails, the entire battery becomes non-functional, so no residual value is allocated to the collected waste batteries

• After sorting, the battery undergoes a cleaning process using degreasing and neutralizing residual electrolytes.

The baseline scenario selection has low uncertainty. It accounts for project-specific information regarding the number, type and fate of devices, and battery waste management regulations.

The equations used in this methodology consist of basic conversions and have low uncertainty.

Many estimates and secondary data are used in this methodology to enable a reasonable amount of project data collection. These data have varying levels of uncertainty and are assessed in Table 4.

The uncertainty at the methodology level is estimated to be moderate to high. This translates to an expected discount factor of at least 6% for projects under this methodology.

Table 4 Presentation of all secondary data and estimates used, and an assessment of their uncertainty.

Parameter	Reference in document	Uncertainty assessment
Chemistry per battery type	Table 3	Battery types encompass a variety of chemistries. This methodology focuses on the most common chemistries for each battery type, as identified through expert insights and market data. While older systems may still contain small quantities of batteries based on Pl and NiCd, these are assumed to be negligible and are excluded from this methodology. This exclusion introduces a moderate level of uncertainty.
Collection 2024/2025	Table 3	While limited information is available on the separate collection rates of batteries at their end-of-life, this methodology relies on regulatory targets as a reference. Although this assumption introduces moderate to high uncertainty, it is considered a conservative approach.
Europe EOL market shares	Table 3	The EOL market share data for the studied battery types and chemistries is limited. To address this, market share estimates were gathered with support from industry experts, an operational facility in the Netherlands, and individual Project Developers' expertise. While no official documentation validates the chosen market shares, these estimates are considered conservative. This is because the percentages include a large share of second-life batteries, which are expected to be lower in reality.
Battery unit percentage, by weight, in battery pack	Table A2, Appendix 2	The percentage of BUs in a battery pack, by mass, is highly variable and depends on several factors, such as battery chemistry, pack design, and manufacturer. To simplify calculations, data from recent studies were used to estimate this value per battery chemistry, introducing a moderate level of uncertainty. Project Developers are encouraged to provide this percentage using primary data wherever possible.
Lifetime of a new battery and a second life battery	Table A2, Appendix 2	The lifetime of a new battery is highly variable due to factors such as operating conditions, usage patterns, and battery management system efficiency. When available, battery lifetime data were sourced from recent studies or supplemented by project developers' expertise. This introduces high uncertainty, as lifetime is a sensitive and highly variable parameter. However, the assumption is conservative, as it reduces the impacts associated with producing a new battery in the baseline scenario.