Rhondda Cynon Taf (RCT) council's carbon emissions have fallen over the last six years and compared with the previous year, according to data submitted to the Welsh Government.
The carbon dioxide equivalent emissions for 2025-26 were 18,437.8 tonnes in scopes one and two and 93,085.2 tonnes in scope three, totalling 111,523 tonnes. This is a decrease of 5,020.19 tonnes compared with 2019-20 and a decrease of 11,037 tonnes compared with 2024-25.
Emissions breakdown
Scope one emissions are direct emissions from an organisation, including fuel combustion and unintended emissions. Scope two emissions are indirect emissions, including purchased electricity and heat. Scope three emissions cover other indirect emissions such as supply chain, transport and distribution, business travel, commuting, product use, waste, investments, and leased assets or franchises.
Of the council's carbon footprint, 74.62% is accounted for by the supply chain, 10.19% by natural gas, 5.38% by electricity, 3.82% by business travel, commuting and homeworking, 4.23% by fleet and equipment, 0.96% by waste, 0.6% by street lighting, 0.1% by water and 0.1% by other fuels.
Operational emission changes
Natural gas emissions for 2025/26 were 11,360.67 tonnes (CO2 equivalent), down 16.41% from 2019/20 and down 2.39% from 2024/25. Electricity emissions were 5,996.7 tonnes, down 13.43% from 2019/20 and down 11.6% from 2024/25. Waste emissions were 1,075.8 tonnes, down 75.8% from 2019/20 but up 33.15% from 2024/25.
Street lighting emissions were 667.8 tonnes, down 21.31% from 2019/20 and down 9.87% from 2024/25. Fleet and equipment emissions were 4,717.8 tonnes, up 25.79% from 2019/20 but down 2.98% from 2024/25. Water emissions were 143.6 tonnes, down 41.03% from 2019/20 but up 63.61% from 2024/25.
Other fuels (Liquefied Petroleum Gas) emissions were 77.88 tonnes, up 730.28% from 2019/20 and up 33.2% from 2024/25. Business travel, commuting and homeworking emissions were 4,260.9 tonnes, with no comparison to 2019/20 but down 3.93% from 2024/25. F-Gases (refrigerant gases) emissions were 2.75 tonnes, with no comparison to 2019/20 but down 83.97% from 2024/25.
Total emissions from these areas were 28,303.9 tonnes (CO2 equivalent), down 5.07% from 2019/20 and down 3.84% from 2024/25. Supply chain emissions for 2025/26 were 83,219.2 tonnes, down 4.05% from 2019/20 and down 10.64% from 2024/25.
Data quality and methodology
Overall, the council's emissions have reduced compared with the baseline year and the previous reporting year. A report to the council's energy efficiency and decarbonisation cabinet sub-committee says this helps to show the impact of the council's ongoing energy efficiency measures and planned approach to decarbonising areas of operation.
Supply chain emissions make up the majority of scope three emissions and represent the largest proportion of the council's overall carbon footprint. The calculation uses a combination of spend-based emission factors and, where available, supplier-specific carbon data. Under the spend-based method, emissions are estimated using factors that allocate a nominal carbon value to each pound spent within a particular spend category.
Reported supply chain emissions have decreased compared with the previous reporting year, but the committee report says this reduction should not be attributed solely to changes in spend or operational activity. During 2025/26, spend data was reviewed and reclassified into more appropriate spend categories, which influenced the resulting emissions calculations. There has also been increased use of supplier-specific emissions data, providing a more representative estimate of emissions associated with the council's supply chain.
The report says that where robust supplier-specific emissions data is available, it supersedes the generic spend-based approach, resulting in a “more accurate estimate of supply chain emissions.” As a result, the reduction reported this year “reflects improvements in the quality of data and reporting methodology as well as any actual changes in supply chain activity.”
The report says the council's ability to compare changes and trends is hindered due to new categories being added to the annual submission and changes in carbon emission factors or coefficient values. From 2021/22, three more carbon emission reporting requirements on staff business travel, commuting and home working were added. The report says that while staff business-travel-related emissions are relatively straightforward to calculate using data from business travel mileage claims, the calculation of emissions related to staff commuting and staff homeworking is more challenging and means the council has to make informed assumptions.
From 2022/23, an extra category was added for 'F-Gas', the group name for refrigerant gases used in cooling and air conditioning systems. The introduction of the extra reporting categories for business travel, commuting, homeworking and F-Gases added a total of 4,263.65 tonnes CO2e to the council's reported emissions for 2025/26.
