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: (1) waste treatment from a battery’s first life (Battery A), and (2) 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.

Figure 1: Representation of Battery Units (BU), Battery Management System (BMS) and Auxiliary Components (AC) within a battery pack.

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 because they use distinct materials and production processes, leading to varying environmental impacts, particularly during production and end-of-life waste treatment. This ensures an 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, by mass, of all collected battery packs that fail initial quality control and are sent directly to waste treatment, with no parts recovered to reuse.*	%	Battery second-life project tracking system
Percentage, by mass, of collected battery units (BU) that pass initial quality control but are later sent for waste treatment, because they are later deemed unsuitable for refurbishment or regeneration*.	%	Battery second-life project tracking system
Percentage, by mass, of collected battery management systems (BMS) that pass initial quality control but are later sent for waste treatment, because they are later deemed unsuitable for refurbishment or regeneration*.	%	Battery second-life project tracking system
Percentage, by mass, of collected auxiliary components (AC) that pass initial quality control but are later sent for waste treatment, because they are later deemed unsuitable for refurbishment or regeneration*.	%	Battery second-life project tracking system
Percentage by mass of BUs within a battery pack per battery type and chemistry (optional).	%	Battery second-life project tracking system
Total number and type of battery packs that were sold in a functioning state during the monitoring period.*	unit	Battery second-life project tracking system or invoices
Weight of sold battery packs per battery type and chemistry.*	kg	Battery second-life project technical documentation or direct measurements
Distance traveled for collecting used battery packs.*	km	Battery second-life project tracking system
Distance in km to the battery waste treatment facility used by the project (optional).	km	Battery second-life project tracking system Assumption based on the recycling facility location and the project’s site
Total number of BUs collected and tested during the monitoring period.*	unit	Battery model technical document Direct measurements made by the project
Amount of any new components (e.g., BUs, BMS, casing plastic, electrolyte) in sold second life battery packs that are new (i.e. not reused spare parts recovered from other collected batteries).*	selection	BU, BMS: identification numbers with source proof, purchase records, battery second-life project tracking system AC: may be based on project estimates.
Electricity amount for inspection and testing of BUs.	kWh/BU	Battery second-life project tracking system
Electricity amount for the regeneration of BUs.	kWh/BU	Battery second-life project tracking system
Electricity amount for recharging the second life battery before the sale.	kWh/Bat	Battery second-life project tracking system
Second life battery SoH*.	%	Measurement from project.
Second life battery lifespan (optional).	years	Assumption based on technical documentation from the project. If not available, the most conservative choice will be considered.

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

• Battery’s expected lifetime (first and second life), when real-life data from the project is inaccessible.

• Battery unit (cells and modules) percentage, by mass, in a battery pack, when real-life data from the project is inaccessible.

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 packs, units, management systems, and auxiliary components) are evaluated in categories of battery types and chemistries rather than specific battery models. 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 type, manufacturer, and chemistry. To facilitate data collection, the entry battery pack is divided into three main components (see Figure 1 for a depiction of a battery pack with the following breakdown):

   1. Battery unit (BU): 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. Its structure and design 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.

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

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

   2. Battery management system (BMS): the second most impactful component of a battery in terms of GHG emissions, due to its complex manufacturing process.

   3. Battery auxiliary components (AC): other components that are not classified as BU or BMS. e.g. casings (e.g. aluminum, steel), connectors, and electronic control systems. It is assumed that all mass of the battery pack that is not BU or BMS is AC.

3. The BMS weight per kg of the battery pack may vary depending on multiple factors such as the battery type, chemistry, and manufacturer. Due to the lack of precise data per battery type and chemistry, it is assumed that the BMS rate is 2% by mass 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 for all battery chemistries under this methodology except Pb-acid. For Pb-acid, this value is assumed 500 km. The considered distances reflect the maximum distance between existing battery recycling facilities in Europe. These values 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 project scenario, in the absence of project data, it is conservatively assumed that 100% of the BMS and AC from collected waste batteries (Battery A) are not reused and, therefore, recycled.

7. The distribution of Battery B 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. Second-life batteries are assumed to have shorter lifetimes than new batteries. 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. See the Substitution section and Appendix 2 for details and examples.
10. It is assumed that when any battery component fails, the entire battery pack becomes non-functional, because the failure of even a single component—such as a cell, module, or critical part like the BMS—renders the whole battery pack inoperable. Therefore the input battery is assumed to be true waste, and no residual value is allocated from its first life. This means that new, unused batteries obtained from overproduction are not eligible under this methodology.

11. In the project scenario, the battery cleaning process involves (a) degreasing to remove oils and grease applicable to all battery types (2 ml degreaser per kg of battery pack), and (b) for Pb-acid batteries, neutralizing residual electrolytes using baking soda solution (0.08 ml solution per kg of battery pack). For cleaning, cloth is used (17g of cloth per kg of battery). These assumptions are based on estimates by the Project Developers. Only sold second-life batteries are assumed to be cleaned.

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

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

14. In the regeneration of Pb-acid batteries, the electrolyte waste from Battery A (if present), is assumed to be neutralized using lime (CaO). The required amount of lime for neutralization is determined based on the chemical reaction between lime and sulfuric acid.

15. The Pb-acid battery lead content is assumed to be . This value is used to calculate the impacts related to the Pb-acid battery waste treatment. Lead recovery process has efficiency.

16. There are two main types of battery recycling 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 remelting.

17. In the absence of the project, the Battery A 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.

18. In the baseline scenario, for the fraction of waste Battery A that is separately collected by specialized waste battery programs (e.g. ), it is assumed that 70% of batteries will be refurbished or regenerated and 30% will be recycled. This assumption is based on projections provided by industry experts and is already accounted for in the "Europe EOL market share" in Table 3. Check Appendix 3 for detailed market share information.
19. In the baseline scenario, the lithium-ion battery market share for NMC is assumed to be evenly distributed across two specific compositions: NMC811 and NMC111. Although other NMC compositions may exist, these are used due to the limited data availability.

20. It is assumed that a rather small amount of new battery purchases come from existing refurbishing activities due to the novelty of the technology . The market share of the project technology currently in use is assumed to be zero.

21. In the baseline scenario, a portion of both separately collected and non-separately collected batteries will be repurposed for second life use. The environmental impacts associated with processing these batteries for second life applications are excluded from the baseline impact assessment due to the application of cutoff criteria.

Table 3 .

Battery type	Chemistry	type
	: : 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%
	Li-ion Pb-acid	Separate collection 100%	Recycling 100%

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

• EV/HE, SLI, and ESS: These batteries do not have a collection target because the Extended Producer Responsibility (EPR) systems are required to separately collect 100% of waste batteries. Therefore, none will go to incineration or landfilling, and they will all be recycled.

• For waste treatment of the batteries entering the second-life stream, it is assumed that 70% will be successfully regenerated/refurbished, and the remaining 30% will be recycled. This is already accounted for in the waste treatment breakdown provided in the last column of Table 3. Refer to Appendix 3 for detailed information.

Project scenario

Figure 2 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/repurpose to produce a “new“ battery via refurbishment/regeneration (Battery B). This process is broken down into 3 life cycle stages, and displayed in Figure 2:

• Battery A waste collection

• Battery A waste treatment

• Battery B preparation for reuse or repurpose

Battery waste collection (project)

The mass of waste battery collected (Battery A) equals the total mass of input used batteries collected by the battery second life project annually. The total mass of batteries collected is back-calculated based on the number of battery packs that were successfully prepared for reuse or repurpose and sold, and the rate of parts that could not be reused/repurposed and were recycled (see $Eq. 2$).

To calculate the transport distance, Project Developers must provide the distance from the collection source to the battery's second life project site. Additionally, for better project understanding, the country and/or city from which the used battery packs are transported can be included in the project's risk assessment.

Calculations project battery collection

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

\begin{align}\textbf{(Eq.1)}\ Re_{\%.i_A.c} = \ &ReBP_{\%.i_A.c} \\+\ &ReBU_{\%.i_A.c}\times BU\%_{i_A.c} \\+\ &ReBMS\%_{i_A.c} \times BMS\% \\+\ &ReAC_{\%.i_A.c} \times (1 - BU\%_{i_A.c}-BMS\%)\end{align}​​

where,

• $Re_{\%.i_A.c}$ represents the percentage of all collected batteries and battery components (Battery $A$) of type $i_A$ and chemistry $c$, that could not be successfully refurbished/regenerated by the project, and are recycled.

• $ReBP_{\%.i_A.c}$ represents the percentage of battery packs (BP) of type $i_A$ and chemistry $c$ that fail initial sorting and are sent directly to waste treatment. This rate is expected to be close to zero for most projects, but it is included here as a conservative measure.

• $ReBU_{\%.i_A.c}$ represents the percentage, by mass, of input used BUs of type $i_A$ and chemistry $c$ that pass the initial sorting but are recycled after failing the first or last tests.

• $BU\%_{i_A.c}$ represents the percentage, by mass, of BUs within a battery pack of type $i_A$ and chemistry $c$. This value should ideally be provided by the PD or selected from Appendix 2 if the exact value is unknown.
• $ReBMS\%_{i_A.c}$ represents the percentage, by mass, of collected BMS of type $i_A$ and chemistry $c$ that are recycled. In the absence of project data, this is conservatively assumed 100%.

• $BMS\%$ represents the percentage of BMS, by mass, in a battery pack. This is assumed to be 2% for all battery types $i_A$ and chemistries $c$ as defined in the assumptions section.
• $ReAC_{\%.i_A.c}$ represents the percentage, by mass, of input auxiliary components (AC) of type $i_A$ and chemistry $c$ that are recycled (e.g. damaged cooling systems that cannot be reused). In the absence of project data, this is conservatively assumed 100%.

• $(1 - BU\%_{i_A.c}-BMS\%)$ represents the percentage of ACs by mass in a battery pack, which are assumed to be everything that is not BU and BMS.

The weight of collected batteries may be directly reported by PDs, or may be back-calculated from the amount of sold battery packs, and the rate of parts that could not be reused/repurposed and were recycled.

$\textbf{(Eq.2)}\ W_{i_A.c.\ collected} = N_{i_B.c.sold} \times W_{i_B.c.sold}/\ (1 - Re_{\%.i_A.c})$

where,

• $W_{i_A.c.\ collected}$ represent the total weight of input battery packs (Battery A) of type $i_A$ and chemistry $c$ collected by the project in the monitoring period, in kg of batteries.

• $N_{i_B.c.sold}$ represent the number of battery packs (Battery B) of type $i_B$ and chemistry $c$ that were sold in a functioning state, and shall be provided by the PD for each monitoring period.

• $W_{i_B.c.sold}$ represent the weight of sold battery pack (Battery B) of type $i_B$ and chemistry $c$ that was sold in a functioning state. In the case of battery repurposing (e.g. from EV to LMT) the sold battery weight may differ from the input collected battery weight, thus PDs are required to provide the mass and amount of sold functioning batteries.

• $Re_{\%.i_A.c}$ is calculated in $Eq.1$.

$\textbf{(Eq.3)}\ Total\ E_{P.collection} = \sum_{(i_A,c)}(W_{i_A.c.collected} \times D_{i_A.c}) \times \ EF_{transport}$

where,

• $Total\ E_{P.collection}$ represents the total greenhouse gas (GHG) emissions, in kgCO₂ equivalent, from transporting waste battery packs collected by the project.

• $W_{i_A.c.\ collected}$ is calculated in $Eq.2$.

• $D_{i_A.c}$ represents the average distance traveled, in kilometers, for collecting battery packs (Battery A) of type $i_A$ and chemistry $c$, as provided by the PD.

• $EF_{transport}$ 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 (project)

Battery packs and/or parts 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, BMS and auxiliary components

Project Developers shall provide the percent of collected BUs, BMS, and ACs 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 ACs such as the battery casing, cables, and cooling system, may be removed from batteries destined for recycling, and kept onsite to harvest spare parts in the future. If limited project data is available on this topic, they are conservatively assumed to be 100% recycled.

Calculations project battery waste treatment

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

$\textbf{(Eq.4)}\ W_{c.recycling} = \sum_{i_A}(Re_{\%.i_A.c}\ \times \ W_{i_A.c. collected})$

where,

• $W_{c.recycling}$ represent the total weight, in kg, of batteries of chemistry $c$ that are unsuitable for reuse or repurpose and are therefore recycled.

• $Re_{\%.i_A.c}$ is calculated in $Eq.1$.

• $W_{i_A.c. collected}$ is calculated in $Eq.2$.

$\textbf{(Eq.5)}\ E_{c.recycling} = \ W_{c. recycling} \times \ CF_{Pb} \times \ EF_{recycling.c}$

where,

• $E_{c.recycling}$ represents the total GHG emissions, in kgCO₂eq, resulting from the recycling of batteries with chemistry $c$ that are unsuitable for reuse or repurpose.

• $W_{c.recycling}$ is calculated in $Eq.4$.

• $CF_{Pb}$ represents the conversion factor for Pb-acid batteries. remelting with lead recovery as presented in Appendix 1. For this, it is assumed that the lead recovery process has 98.8% efficiency and the battery lead content is 0.61kg of lead/kg of battery as presented in the Assumptions section. For other battery chemistries, consider this equal 1.
• $EF_{recycling.c}$ represents the emission factor for recycling a battery of chemistry $c$, in kgCO$_2$eq per kg battery. For details on the ecoinvent processes used, refer to Appendix 1.

For Pb-acid batteries, it is assumed that the waste treatment used is the

$\textbf{(Eq.6)}\ E_{\text{transport}} = \sum_c (W_{\text{c. recycling}} \times D_{\text{c.scrap}} ) \times EF_{\text{transport}}$

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.

• $W_{c.recycling}$ is calculated in $Eq.4$.

• $D_{c. scrap}$ represents the distance in km for transporting battery chemistry $c$ scrap to the specialized battery waste treatment facility. If this value is not provided by the PD, it is conservatively assumed to be 1800 km for Li-ion and NiMH batteries, and 500 km for Pb-acid batteries, as described in the assumptions section.
• $EF_{transport}$ represents the emission factor for truck transport, in kgCO₂eq/kg.km. 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.

• $E_{c.recycling}$ is defined in $Eq.5$.

• $E_{transport}$ is defined in $Eq.6$.

Battery preparation for reuse/repurpose

This life cycle stage is composed of some shared common steps across all battery second-life projects, plus different steps depending on the battery's second life technology implemented: refurbishing or regeneration.

Common steps

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

Pieces that remain in good condition are prepared for reuse or repurposing through processes such as refurbishing or regeneration, and used in new second-life batteries.

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

Refurbishing steps

The refurbishing process typically includes electricity use for testing and charging, and may also involve replacing used, non-functional BUs, BMS or ACs 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, paper 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) or low means of transport (LMT).

For replacement of non-functional parts such as BUs and BMS, Project Developers shall select items/materials used among the options in Appendix 1. If the relevant input is not listed, it may be added/considered on a case by case basis, and approved by the Riverse Certification team. For each material, Project Developers shall provide the item it corresponds to and the amount used in the item. Items may be composed of multiple materials, or only one main material.

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 steps, and in some cases the refurbishing steps, regeneration involves sending controlled high-frequency pulses of electricity through the battery unit, and may include desulfation and the replacement of chemicals/electrolytes (for Pb-acid batteries).

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

In the first verification period, carefully tracked electricity data is used to calculate the project’s average kWh consumption per battery type or process step (e.g., inspection, testing, recharging). This average is then applied to all future monitoring periods.

For example, if the first validation reports an electricity usage of 10 kWh per battery for recharging, and in Year 2 the project sells 100 batteries, the estimated electricity consumption for recharging would be 10 kWh/battery × 100 batteries = 1000 kWh.

Calculations project battery B preparation for reuse/repurpose

This step calculates the GHG emissions from the preparation for reuse or repurpose process$({Total\ E}_{P.\ refurbishing}$ and/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 is disassembly of the battery pack into BUs, followed by inspection and testing to assess its SoH, which uses electricity.

$\textbf{(Eq.8)}\ E_{sorting} = \sum_{(i_A,c)}(\ N_{BU.i_A.c} \times \ Electricity_{kWh/BU.i_A.c}) \times EF_{electricity}$

where,

• $E_{sorting}$ represents the sum of GHG emissions due to the electricity consumption needed for sorting (inspecting and testing) incoming BUs (cells/modules), in kgCO$_2$eq.

• $N_{BU.i_A.c}$ represents the number of battery units of type $i_A$ and chemistry c entering the preparation for reuse or repurpose process after the first quality control and sorting process. This value shall be provided by the PD.

• ${Electricity}_{kWh/BU.i_A.c}$ represents the amount of electricity needed in kWh/BU for inspection and testing per battery unit (cells or modules). The PD must provide this value along with supporting evidence for the data, such as documentation of the test machine's usage time and power consumption, details of the tracking system, or the software used in the project.

• $EF_{electricity}$ represents the emission factor of grid electricity in the given project country. Refer to Appendix 1 for the ecoinvent process used.

After evaluating the battery, any BU, BMS, or damaged auxiliary components that are not suitable for refurbishing or regeneration are removed for recycling and are 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. It is assumed that only sold batteries will undergo the cleaning process.

$\textbf{(Eq.9)}\ E_{cleaning} = \sum_{(i_B,c)}(N_{i_B.c.sold} \times W_{i_B. c.sold} \times (\sum_j(Chem_{j}\times EF_{chem.j})\ + \ Cloth \times EF_{cloth}))$

where,

• $E_{cleaning}$ represents the sum of GHG emissions due to the battery components cleaning. This includes chemicals and cloth, in kgCO$_2$eq.

• $N_{i_B.c. sold}$ is defined in $Eq.2$.

• $Chem_{j}$ represents the amount of chemical product $j$ used for cleaning the battery. This includes baking soda solution and degreaser as detailed in the assumptions section.
• $EF_{chem.j}$ represents the emission factor of chemical $j$. Refer to the assumptions to Appendix 1 for the ecoinvent processes used.
• $Cloth$ represents the amount of cloth used for cleaning a battery, by battery weight. This amounts were assumed from data provided by Project Developers and is considered 17g of clothing per kg of battery.

• $EF_{cloth}$ represents the emission factor of cloth. Refer to the Appendix 1 for the ecoinvent process used.

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

where,

• $E_{common\ impacts}$ represents the sum of GHG emissions due to battery preparation for reuse/repurpose common processes, in kgCO$_2$eq. This includes the impacts of sorting (inspection and testing) and cleaning.

• $E_{sorting}$ is defined in $Eq.8$.

• $E_{cleaning}$ is defined in $Eq.9$.

Refurbishing impacts

Some components, such as BUs, BMS, or ACs may be replaced with new ones to substitute non-functional parts. Additionally, if the incoming battery is repurposed and the resulting battery type is intended for a different use than the original, additional ACs—such as a new casing—might be used. These changes are accounted for only if the process involves using brand-new parts.

$\textbf{(Eq.11)}\ E_{component, total} = \sum_{(i_A.k)} (\text{Amount}_{material.i_A, k}\times EF_{material, k})$

where,

• $E_{component, total}$ represents the total emissions from one new replacement battery component, in kgCO$_2$eq.

• $Amount_{material.i_A, k}$ represents the amount of the material of type $k$ used in the component replacement battery for the second life battery $i_A$, in the same units as the emission factor described below. This amount shall be provided by the PD for each monitoring period.

• $EF_{material,k}$ represents the life cycle emission factor/s for the material of type $k$ in kgCO$_2$eq (e.g. BMS, plastic for casing, aluminium, steel, etc) per given unit from ecoinvent. Refer to Appendix 1 for the ecoinvent process used.

$\textbf{(Eq.12)}\ E_{charging} = \sum_{(i_B,c)}(N_{i_B.c.sold}\times{Electricity}_{kWh/Bat.i_B.c})\times EF_{electricity}$

where,

• $E_{charging}$ represents the sum of GHG emissions, in kgCO$_2$eq, associated with charging battery B before it is sold, in kgCO$_2$eq.

• $N_{i_B.c. sold}$ is defined in $Eq.2$.

• ${Electricity}_{kWh/Bat.i_B.c}$ represents the amount of electricity in kWh/battery needed for recharging the second life battery (Battery B) of type $i_B$ and chemistry c. This recharge usually accounts for 60% of the battery capacity.

• $EF_{electricity}$ is defined in Eq.8.

$\textbf{(Eq.13)}\ Total\ E_{P.refurbishing} = E_{common\ impacts\ } + \ E_{item, total} + E_{charging}$

• ${Total\ E}_{P.refurbishing}$ represents the sum of GHG emissions, in kgCO2eq, associated with battery refurbishing, in kgCO$_2$eq.

• $E_{common\ impacts}$ is defined in $Eq.10$.

• $E_{component, total}$ is defined in $Eq.11$.

• $E_{charging}$ is defined in $Eq.12$.

Regeneration impacts

Regeneration includes both the common impacts, refurbishing impacts (optional), and additional impacts associated with regenerating.

$\textbf{(Eq.14)}\ N_{BU.i_A.c\ sorted} = {N_{BU.i_A.c}}\times(1 - ReBU\%_{i_A.c})$

where,

• $N_{BU.i_A.c.sorted}$ represents the number of BUs from the collected battery (Battery A) suitable for regeneration after sorting.

• $N_{BU.i_A.c}$ defined in $(Eq.8)$

• $(1 - {ReBU\%}_{i_A.c})$ represents the percentage by mass of collected BUs that are suitable for regeneration after quality control. ${ReBU\%}_{i_A.c}$ is defined in $Eq.1$.

$\textbf{(Eq.15)}\ E_{electricity\ regen} = \sum_{(i,c)}(N_{BU.i_A.c\ sorted}\times{Electricity}_{regen. kWh/BU.i_A.c})\times EF_{electricity}$

where,

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

• $N_{BU.i_A.c\ sorted}$ is calculated in $Eq.14$.

• ${Electricity}_{regen. kWh/BU.i_A.c}$ represents the amount of electricity in kWh needed to regenerate a BU.

• $EF_{electricity}$ is defined in Eq.8.

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. In such cases, the addition of a new electrolyte should be included in the regeneration process calculations, as described in Eq. 16.

$\textbf{(Eq.16)}\ E_{electrolyte, new} = \text{Amount}_{electrolyte}\times F_{electrolyte\ in \ battery} \times EF_{new\ electrolyte}$

where,

• $E_{electrolyte,new}$ represents the sum of GHG emissions associated with the production of new Pb-acid battery electrolyte, in kgCO$_2$eq.

• $Amount_{electrolyte}$ represents the amount, in kg, of new electrolyte used for the regeneration of Pb-acid batteries during the monitoring period, provided by the Project Developer.

• $F_{electrolyte\ in \ battery}$ represents the average fraction of electrolyte in a Pb-acid battery. Electrolytes typically constitute 27% of the battery's total weight, as described in the assumptions section.
• $EF_{new\ electrolyte}$ represents the emission factor of the new Pb-acid battery electrolyte, in kgC kgCO$_2$eq/kg. Lead-acid batteries electrolyte is assumed to be a solution made of 38% sulfuric acid $(H_2SO_4)$ and 62% water. Details of the ecoinvent process used can be found in Appendix 1.

If new electrolytes are used, it is assumed that an equivalent amount of the used electrolyte undergoes waste treatment. During the regeneration of lead-acid batteries, the used electrolyte can either be regenerated or neutralized and then treated as wastewater. To neutralize this electrolyte solution, various chemicals can be used, with lime being the most commonly applied. For 1 kg of the electrolyte solution, approximately s required. For a conservative approach, it is assumed that the used electrolyte will be neutralized, as described in $(Eq. 17)$.

$\textbf{(Eq.17)}\ E_{\text{electrolyte treatment}} = W_{\text{electrolyte,new}}\times CaO \times EF_{\text{lime}}$

where,

• $E_{electrolyte\ treatment}$ represents the sum of GHG emissions associated with the chemicals needed for treating the battery's used electrolyte, in kgCO$_2$eq.

• $W_{electrolyte, new}$ represents the weight of any new electrolyte used for regenerating a battery of type $i$ and chemistry $c$, in kg, provided by the PD if relevant.

• $CaO$ represents the amount of lime needed to neutralize the electrolyte in kg of CaO per kg of used electrolyte.

• $EF_{lime}$ represent the emission factor of lime, in kgCO$_2$eq/kg. Refer to Appendix 1 for the ecoinvent process used.

Next, BUs are tested to verify the effectiveness of regeneration, which requires electricity consumption. This is calculated by applying Eq. 8 again (E_$E_{testing}$). 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 $Eq.11$.

Finally, the battery is charged, following $Eq. 12$.

The impacts of regeneration are, therefore:

$\textbf{(Eq.18)}\ E_{P.regeneration} = E_{sorting} + E_{common\ impacts} +E_{item,total}+E_{charging} + E_{electricity\ regen} + E_{electrolyte,new} + E_{electrolyte\ waste}$

where,

• $E_{P. regeneration}$ represents the sum of GHG emissions associated with the battery regeneration process, in kgCO$_2$eq.

• $E_{sorting}$ is calculated in $Eq.8$. It is used again here because the battery undergoes the same inspection and testing process at the end of regeneration as when it is first received by the project and sorted.

• $E_{common\ impacts}$ is defined in $Eq.10$

• $E_{item, total}$ is defined in $Eq.11$.

• $E_{charging}$ is defined in $Eq.12$.

• $E_{electricity\ regen}$ is defined in $Eq.15$.

• $E_{electrolyte, new}$ is defined in $Eq.16$.

• $E_{electrolyte\ waste}$ is defined in $Eq.17$, and may be zero if the project doesn't work with lead acid batteries.

Baseline scenario

Figure 3 The system boundary and scope of the baseline scenario are shown.

The baseline scenario is composed of two main functions, to represent the same functions as the project scenario: 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 3. This is broken down into 3 life cycle stages, which are detailed in the following sections:

• Battery A collection

• Battery A waste treatment

• Manufacturing of Battery B

The baseline scenario shall be reviewed annually by the Riverse climate team to account for any potential 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 (baseline)

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 in the monitoring period.

Calculations baseline battery collection

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

$\textbf{(Eq.19)}\ Total_{B.collection} = \sum_{(i_A,c)}W_{i_A.c.collected} \times D \times \ EF_{transport}$

where,

• ${Total\ E}_{B.collection}$ represents the total greenhouse gas (GHG) emissions, in kgCO$_2$eq, due to battery waste transport.

• $W_{i_A.c.collected}$ is calculated in $Eq.2$ and represents the weight of battery type $i_A$ and chemistry $c$ collected by the project, in kg of batteries.

• $D$ represents the distance traveled, in kilometers, for collecting battery packs. In the baseline scenario this is assumed 1800 km for Li-ion and NiMH batteries and 500 km for Pb-batteries as described in the assumptions section.
• $EF_{transport}$ represents the emission factor for truck transport in kgCO$_2$eq/kg.km. Refer to Appendix 1 for the ecoinvent processes used.

Battery waste treatment (baseline)

Separately collected battery waste is assumed to undergo waste treatment based on the targets set by the . Most of this battery waste either undergoes specialized recycling, or repurposing for second life applications. Specialized recycling treatment is further divided into pyrometallurgical or hydrometallurgical processes, depending on the battery chemistry, as detailed in the assumptions section.

Battery waste that is not separately collected is assumed to eventually be sent for specialized battery waste recycling through pyrometallurgical or hydrometallurgical processes. This assumption is based on the , which requires specific treatment technologies. Improperly managed battery waste that is not separately collected typically undergoes incineration or landfilling.

A portion of both separately collected and non-separately collected batteries will be repurposed for second life use. The environmental impacts associated with processing these batteries for second life applications are excluded from the baseline impacts due to the cutoff criteria for recycling (the impacts would instead be included in the second-life battery).

A detailed breakdown of battery waste treatment shares can be found in the assumptions section and Appendix 3. Table 3 summarizes the battery treatment market shares.

Calculations baseline: battery waste treatment

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

$\textbf{(Eq.20)}\ E_{B\ recycling} = \sum_{(i_A,c)}(W_{i_A.c.collected}\times (C\%_{i_A.c} \times RR\%_{i_A.c} + (1-C\%_{i_A.c}) \times nRR\%_{i_A.c}) \times CF_{Pb} \times EF_{recycling.c}$

where,

• $E_{B.recycling}$ represents the sum of GHG emissions due to the recycling of batteries (Battery A) of chemistry $c$, in kgCO$_2$eq, in the baseline scenario.

• $W_{i_A.c.collected}$ is calculated in $Eq.2$.

• $C\%_{i_A.c}$ represents the percentage of battery waste separately collected in Europe for battery type $i_A$ and chemistry $c$. In Figure 3, this is represented by C%. This percentage is presented in Table 3 and detailed in Appendix 3.
• $RR\%_{i_A.c}$ represents the percentage of collected batteries of type $i_A$ and chemistry $c$ that are recycled after separate collection. In Figure 3, this is represented by RR%. This percentage is presented in the Assumptions section and Appendix 3. The specific recycling treatment used varies according to the battery chemistry (pyrometallurgy or hydrometallurgy), as described in the assumptions section 16.
• $(1-C\%_{i_A.c})$ represents the non-separately collected battery percentage in Europe for battery type $i_A$ and chemistry $c$. In Figure 3, this is represented by (1-C%). This percentage is presented in the Assumptions section and Appendix 3.
• $nRR\%_{i_A.c}$ represents the percentage of non-separately collected batteries of type $i_A$ and chemistry $c$ that are eventually recycled. In Figure 3, this is represented by nRR%. This percentage is presented in the Assumptions section and Appendix 3.
• $CF_{Pb}$ is defined in $Eq.5$ and it is only considered for Pb-acid battery chemistry.

• $EF_{recycling.c}$ represents the emission factor for treating battery of 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.

$\textbf{(Eq.21)}\ E_{residual\ waste} = \sum(W_{i_A.c.collected} \times (C\%_{i_A.c}\times RW\%_{i_A.c} + (1-C\%_{i_A.c}) \times nRW\%_{i_A.c})) \times EF_{residual\ waste}$

where,

• $E_{residual\ waste}$ represents the sum of GHG emissions due to residual waste battery treatment (landfill and incineration), in kgCO$_2$eq. This regards especially LTM batteries of NiMH chemistry as described in Appendix 2.
• $W_{i_A.c.collected}$ is calculated in $Eq.2$.

• $C\%_{i_A.c}$ is defined in $Eq.20$.

• $RW\%_{i_A.c}$ represents the percentage of separately collected batteries that become residual waste and are treated through either landfill or incineration. In Figure 3 this is represented by (RW%). Refer to Appendix 1 for the ecoinvent process used.
• $(1-C\%_{i_A.c})$ is defined in $Eq.20$.

• $nRW\%_{i_A.c}$ represents the percentage of non-separately collected batteries that become residual waste and are treated through either landfill or incineration. In Figure 3 this is represented by (nRW%). Refer to Appendix 1 for the ecoinvent process used.
• $EF_{residual waste}$ represents the emission factor for treating residual battery waste that is neither recycled nor reused, in kgCO$_2$eq/kg. This is assumed 50% incineration and 50% landfill. Refer to Appendix 1 for the ecoinvent processes used.

$\textbf{(Eq.22)}\ Total\ E_{B\ waste\ treatment} = E_{B.\ recycling} + E_{residual\ waste}$

where,

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

• $E_{B \ recycling}$ is calculated in $Eq.20$.

• $E_{residual \ waste}$ is calculated in $Eq.21$.

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 the 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. Precise data on this topic are unavailable, but it is assumed that a rather small amount of new battery purchases come from existing refurbishing activities due to the novelty of the technology (<1%). The market share of the project technology currently in use is assumed to be zero.

The process and GHG impacts of manufacturing a new battery are taken from the ecoinvent database.

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 ($Total\ E_{B.\ new\ battery\ production}$).

$\textbf{(Eq.23)}\ E_{new\ battery.i_B.c} = N_{i_B.c.sold} \times W_{i_B.c. sold} \times EF_{new.c}$

where,

• $E_{new\ battery.i_B.c}$ represents the sum of GHG emissions in kgCO$_2$eq due to the production of new batteries of chemistry $c$, before accounting for the lifetime adjustment.

• $N_{i_B.c.sold}$ and $W_{i_B.c. sold}$ are described in $Eq.2$.

• $EF_{new.c}$ represents the emission factor in kgCO$_2$eq/kg due to the production of the new battery of chemistry c. Refer to Appendix 1 for the ecoinvent processes used.

Note that the new battery produced may not be the same type i as the input battery when the project prepares the battery for repurposing. This is why the amount of batteries sold by the project is tracked separately from the amount of input batteries collected.

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:

$\textbf{(Eq.24)}\ L_{adjustment.i_B.c} = (Y_{second\text{-}life.i_B.c}/Y_{new.i_B.c}) \times SoH_{i_B.c}$

where,

• $L_{adjustment.i_B.c}$ represents the new battery (Battery B) lifetime adjustment factor.

• $Y_{second\text{-}life.i_B.c}$ represents the expected lifespan of a second-life battery type $i_B$ and chemistry $c$ in number of years. This value should be provided by the Project Developer (PD) with proof. If no project data are available, a conservative choice will be made according to the values presented in Appendix 2.
• $Y_{new.i_B.c}$ represents the expected lifespan of a new battery type $i_B$ and chemistry $c$ in number of years, presented in Appendix 2.
• $SoH_{i_B.c}$ represents the SoH of the second life battery (Battery B) type $i_B$ and chemistry $c$ prepared for reuse or repurpose and sold by the project. This value shall be presented by the PD.

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

$\textbf{(Eq.25)}\ {Total\ E}_{B.\ new\ battery\ production} = \sum_{(i,c)}(E_{new\ battery.i_B.c} \times L_{adjustment.i_B.c})$

where,

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

• $E_{new\ battery.i_B.c}$ is calculated in $Eq.23$.

• $L_{adjustment.i_B.c}$ is calculated in $Eq.24$.

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.

Avoided GHG calculation

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

$\textbf{(Eq.26)}Project \ emissions= Total\ E_{P.collection} + Total\ E_{P.waste\ treatment} + Total\ E_{P.prep.reuse}$

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

$\textbf{(Eq.27)} Baseline \ emissions= Total\ E_{B.collection} + Total\ E_{B.\ waste\ treatment} + Total\ E_{B.\ new\ battery\ production}$

$\textbf{(Eq.28)}\ Avoided\ emissions\ = \ Baseline\ emissions\ - \ Project\ emissions$

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:

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

• The market share of the project's technology currently in use is assumed to be zero. While this assumption has a strong impact on the estimated avoided emissions, it remains reasonable based on expert opinion, which indicates that less than 1% of new battery purchases come from existing refurbishing activities due to the technology's novelty.

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)

• In the absence of project data, it is conservatively assumed that 100% of the BMS and AC collected are not reused and, therefore, recycled.

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

• The Pb-acid battery lead content is assumed to be .

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

• In the baseline scenario, the Li-ion NMC is assumed to be evenly distributed across two specific compositions: NMC811 and NMC111.

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

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

• The BMS rate is 2% by mass of the battery pack.

• In the baseline scenario, the waste collection and transport distance of Battery A is assumed to be 1800 km for Li-ion and NiMH battery chemistries, and 500 km for Pb-acid batteries.

• 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 are the same.

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

• It is assumed that all second life batteries (Battery B) sold by the project will undergo cleaning with degreaser and electrolytes neutralizer depending on the battery chemistry.

• The Pb-acid batteries electrolyte solution is made of 38% sulfuric acid ($H_2SO_4$) and 62% water.

• In the regeneration of Pb-acid batteries, if the battery's electrolyte is changed, the waste electrolyte is assumed to be neutralized using lime (CaO).

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

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

• The environmental impacts associated with processing second life batteries are excluded from the baseline impact assessment due to the application of cutoff criteria.

The baseline scenario selection has low uncertainty. It accounts for project-specific information regarding the number and type of devices, and fate of devices is based on European 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. 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.
Separate 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 (the environmental impacts associated with processing second life batteries are excluded from the baseline impact assessment due to the application of cutoff criteria).
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 BMS 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. Project Developers are encouraged to provide this lifetime using primary data wherever possible.