NDC assessment, implementation and tracking can be a daunting task. However, a number of guides and tools are available to help countries navigate the challenges. One of these is the Greenhouse Gas Abatement Cost Model (GACMO), an excel-based tool developed by UNEP-Copenhagen Climate Centre, and updated for ICAT.

GACMO allows countries to carry out rapid, comprehensive evaluations of the GHG impacts of a variety of mitigation options. It calculates GHG reductions resulting from specific mitigation actions, allowing for the effect of mitigation actions to be compared to a business as usual scenario. 

GACMO can be used to estimate expected and achieved GHG reductions of policies and measures. Thus, it can be used for NDC tracking purposes, and in the preparation of biennial transparency reports, the main reporting vehicle under the Paris Agreement.

One of the many compelling features of GACMO is that countries need very little data for their initial calculations, as GACMO includes a series of default values, that are already pre-loaded in the tool and that the user does not have to update unless the user has better inputs and wants to make more precise estimates. When more country-specific data becomes available, it can be inputted to the platform and values will automatically adjust.

After more than 20 years of research at UNEP Copenhagen Climate Centre, GACMO now contains 40 sheets covering sectors such as agriculture, biomass energy, energy efficiency in households, forestry, and solar and wind energy. It has been successfully used in multiple countries across the globe. In this article, we provide examples from two countries, Viet Nam and Sri Lanka, both of which were supported by ICAT’s implementing partner, UNEP-Copenhagen Climate Centre.

Sri Lanka: Updating NDCs

In Sri Lanka, GACMO was used to successfully update not only NDC targets, but also the number of NDCs for the energy sector. In its updated NDC (2021), Sri Lanka stated its intention to reduce greenhouse gas emissions from the energy sector by 20 per cent by 2050. It identified seven related NDC mitigation options to do so.

The ICAT project aimed to assess greenhouse gas impacts of the proposed mitigation measures so policy makers could make informed decisions on amending the NDCs (among other aims). The project’s initial scoping study identified two additional potential mitigation measures, bringing the total mitigation measures assessed to nine.

Applying available data to GACMO produced results which allowed Sri Lanka to prioritize and revise its energy-related NDCs. Importantly, it found that the country could reduce its greenhouse gas emissions from energy by 25 per cent by 2030 (see graph below).

Above: Graph showing Sri Lanka’s projected decrease in greenhouse gas emissions (Project Scenario), compared to business as usual (Baseline Scenario), following assessment with GACMO.

GACMO also produced data on costs, indicating the cost of reducing greenhouse gas emissions would be USD 68 per ton of CO2e, as at May 2020 (see table below for the marginal abatement costs). This indicated the magnitude of climate finance Sri Lanka would need to mobilize to achieve its NDC targets in the energy sector.

Above: Table showing Sri Lanka’s nine energy NDCs and the marginal abatement costs for potential emission reduction. Data as at May 2020

The results of the ICAT Sri Lanka project can be reviewed in full on the ICAT website. At the same link, visitors can access all the reports related to the ICAT project in Sri Lanka.

Assessing emissions in Viet Nam’s agriculture sector

Viet Nam used GACMO to assess the greenhouse gas mitigation potential of its agricultural sector. In its updated NDC (2022), Viet Nam committed to reducing emissions from the sector by over 63 million tons CO2-equivalent (CO2e) by 2030. 

Viet Nam identified 11 areas in which mitigation activities were needed, and put all available information into GACMO. For its baseline, Viet Nam used expected growth in GDP, population and energy consumption. Using the energy balance for the ‘start year’ GACMO then developed a business as usual scenario (see table below), by calculating the greenhouse gas emissions with growth factors applied for each sector covering three periods of time.

Above: Table showing a business as usual scenario in Viet Nam over three time periods

GACMO provides users with 119 pre-defined emission reduction options sorted by sector with the goal of determining the total CO2e emission reduction for each option. One of Viet Nam’s 11 mitigation measures  was the use of biogas instead of firewood, as shown in the table below. GACMO provided default data for each of the required inputs, and Viet Nam was able to amend the numbers with locally-relevant data, where it was available. 

Above: A graphic overview of an example of the inputs that countries can provide in GACMO to achieve a set of outputs. This example covers the increased use of biogas for cooking.

GACMO then calculated the total investment needed for this mitigation option, the CO2e emission reduction, as well as the cost per ton of CO2e reduced. A snapshot of the GACMO spreadsheet related to Viet Nam’s mitigation action of increased biogas use for cooking is shown below. 

Above: Screenshot of GACMO output related to Viet Nam’s plans to increase the use of biogas as a greenhouse gas emission reduction measure. The figures highlighted in green show the total investment required, the total annual cost, and the total CO2e emissions reduced. Figures highlighted in yellow indicate those entries that are provided as a standard option in GACMO, but can be adjusted by the country in question.

Read the full report of Viet Nam’s use of GACMO for the agriculture sector on ICAT’s website. At the same link, visitors can see how the country applied GACMO to its energy sector too, as well as read all the other reports related to the ICAT project in Viet Nam.