Contribution project

Generating energy from waste water

Bulgaria, Sofia

ClimatePartner ID: 1236

Project details

Gas RecoveryGet to know the project

Sofiyska Voda provides water supply, sewerage and waste water treatment services to over 1.4 million citizens in the Municipality of Sofia. The company operates the Kubratovo waste water treatment plant, processing about 400,000 cubic metres of water per day. The plant is located close to the village of Kubratovo, 20 km outside of Sofia, near the Iskar river.

In order to reduce greenhouse gas emissions the company implemented a system for anaerobic sludge treatment and combustion of biogas for power generation. Methane is captured in common tanks and then supplied to the newly installed combined heat and power (CHP) gas engines for electricity and heat production. This substitutes the plant’s electricity purchases from the grid and also diesel fuel usage. Excess electricity is supplied to the grid. The project reduces the volume of sludge by up to 50 percent. It saves methane emissions from open anaerobic sludge tanks, drying beds and landfill disposal sites and reduces CO₂ emissions from fossil fuel-based energy generation.

70,276 t CO₂Estimated annual emissions reductions

Project Standard

The project contributes to the the United Nations' Sustainable Development Goals

How does gas recovery contribute to climate action?

Methane is a greenhouse gas emitted by many processes including livestock farming, waste management, sewage treatment, oil production, and coal mining. When released into the atmosphere, it oxidises first to carbon monoxide and then to carbon dioxide, making it a major contributor to global warming. Climate projects avoid these emissions by capturing the gas and using it to generate heat or electricity, or by processing the gas into dry and liquid gas. In this way, the gas is not released into the atmosphere and is used to generate energy instead. Gas recovery projects in the ClimatePartner portfolio are registered with international standards.

The project aims to contribute to these United Nations’ Sustainable Development Goals (SDGs).

Project facts

Type
Reduction

Climate projects generally fall into one of three groups: carbon reduction, carbon removal, or carbon avoidance. Carbon reduction projects reduce the amount of greenhouse gas emissions produced by a specific activity (e.g., improved cookstoves). Carbon removal projects remove carbon from the atmosphere by sequestering it in carbon sinks (e.g., reforestation). Carbon avoidance projects avoid greenhouse gas emissions entering the atmosphere (e.g., protecting forests from deforestation with REDD+ projects).

Location
Bulgaria, Sofia

Standard
Gold Standard

All climate projects are based on international standards. They set processes and requirements which carbon projects must fulfill to be recognised as a proven method of reducing carbon emissions.

Technology
Gas Recovery

Climate projects demonstrably reduce, remove, or avoid greenhouse gas emissions. This is achieved with various technologies, ranging from nature-based solutions to social impact projects and renewable energies.

Registry ID
4238

Most standards on the voluntary carbon market list their projects in public registries. The registries are used to store project data and track issuances and retirements of verified emission reductions. The registry ID can be used to identify projects in the standard registry.

Check out this project

Verified by
RINA Services S.p.A. (RINA)

Climate projects go through third-party validation and verification. Verification happens regularly after each monitoring period. A validation and verification body checks and assesses whether the values and project activities stated in the monitoring report are correct and verifies them. As with validation, visits to the project site are often part of the process.

Validated by
RINA Services S.p.A. (RINA)

Climate projects go through third-party validation and verification. Validation happens early in the project life cycle and ensures that the project design is in line with current processes and requirements. This phase often also involves field visits with on-site interviews and analyses. Auditors are accredited, impartial assessors who have to be approved as a validation and verification body (VVB) by the standards body.

Estimated annual emission reductions
70,276 t CO₂

This figure shows the estimated annual emission reductions calculated before the project started. The actual number of emissions saved in each monitoring period may differ. The background to this process is that in order to be registered as a climate project, the project operator must submit the calculation of the estimated emissions savings using the ex-ante methodology in a Project Design Document (PDD), which is similar to a business plan. This calculation is validated by an independent auditor. The values determined in the PDD are recalculated during regular monitoring periods based on actual project performance, documented in a monitoring report, and verified again by independent auditors at the end of the monitoring period to ensure a robust process. Independent verification thus provides ex-post verification of actual emission reductions. Verified emission reductions are not distributed until the savings have actually been made.

Four criteria for projects to meet quality thresholds

01. AdditionalityA project must lead to lower carbon emissions than would have occured without the project. Additionality also means that a project relies on financing from the sale of emission reductions, as the project would otherwise not be feasible and the upfront investment would be too high for project developers.

02. Exclusion of double countingThe carbon reduction may only be counted once and may not be counted again elsewhere, so a Verified Emission Reduction is retired once it has been used. This process is recorded in official registries.

03. PermanenceThe criterion of permanence ensures that carbon reductions or removals are ongoing and do not occur just once. This guarantees a long-term benefit for the climate. The minimum duration of a project depends on the underlying project technology.

04. Audit by independent third-partiesClimate projects must be audited regularly by independent auditors such as TÜV Nord. These auditors verify that the project is in compliance with the relevant standards. They also determine the volume of carbon emissions that have actually been avoided or removed.

The life cycle of a climate project

A climate project has a set life cycle consisting of various phases, from the feasibility assessment to the retirement of Verified Emission Reductions (VERs).

Project planning phase

The project developer reviews the general feasibility of the project, the project design, and the financing. Then, the Project Design Document (PDD) is prepared, which contains all the basic information about the project, such as the objective, location, timeline, and duration.

Validation

In this phase, independent auditors examine the PDD and the information it contains. This phase often also involves field visits with on-side interviews and analyses. Auditors are accredited, impartial assessors who have to be approved by the relevant standard as a validation and verification body (VVB). TÜV Nord/Süd, S&A Carbon LLC., and SCS Global Services are examples of VVBs."

Registration

Once validated, the project can be registered with a standard such as the Verified Carbon Standard or the Gold Standard. All high-quality climate projects are based on international standards. They provide the framework for project design, construction, carbon accounting, and monitoring. Recognised standards make the climate project system and the projects themselves resilient, traceable, and credible.

Monitoring

After the climate project has been registered, the monitoring begins. Here, the project developers monitor and document the data of the project activities and progress. The duration of the monitoring phase varies from project to project: it can cover two years, but documentation over five or seven years is also possible.

Verification

At the end of each monitoring phase, a VVB checks and assesses whether the values and project activities stated in the monitoring report are correct. As with validation, visits to the project site are often part of the verification process.

Issuance of Verified Emission Reductions

Once verified, the emission reductions that were confirmed in the verification phase can be issued as VERs. The steps of monitoring, verification, and issuance of VERs are repeated regularly and are therefore considered as a cycle.

Retirement of Verified Emission Reductions

Once a VER has been used, it must be retired. This process is also reflected in the registry. If the financing of a climate project is done through ClimatePartner, the VERs are bundled in a system certified by TÜV Austria and then retired on a regular basis. This ensures that each VER can no longer be sold and is only used once, preventing double counting.

* The information on this page was last updated 15 April 2024.* For certified projects only: the project-related information on this page is based on the documents in the register.

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