Baseline assessment of fuel consumption and thermal efficiency of conventional biomass cookstoves: A case study

Abstract

Conventional biomass cookstoves are the predominantly utilised household cooking method in rural Sri Lanka. Nevertheless, the in-use performance is under-quantified. This study adopted a baseline experimental approach combined with field surveys to produce the first initial integrated efficiency and fuel demand baseline for Maskeliya, Nuwara Eliya District. Fifty households were enrolled in 5-day Kitchen Performance Tests (KPT) to measure the amount of wood utilized during cooking, while 25 households were in Water Boiling Tests (WBT) under controlled cold-and hot-start conditions. A systematic survey was conducted to analyse socio economic determinants of stove choice. The average wood demand was 2.56 kg cap⁻¹ day⁻¹, which was equivalent to 0.93 T cap⁻¹ yr⁻¹, with an inter-household coefficient of variation of 0.35. Cold-start thermal efficiency varied from 6.69 % to 10.79 %, while hot-start efficiency varied from 9.33% to 13.71%. The baseline overall efficiency of conventional stoves was 10.62 %. In cold- and hot-start conditions, the average boiling times were 20.3 min and 17.4 min, respectively. Households served a mean of 5.1 persons per meal across 772 recorded cooking events, indicating substantial aggregated fuel pressure on local wood supply. Affordability, cultural orientation and limited resources were identified as the main barriers to improve stove adaption. Replacing conventional stoves with high-efficiency alternatives can mitigate CO2 emissions. These findings provide a platform for targeted clean-cooking approaches, tracking future impacts, and for informing evidence-based policy design and programming at the regional scale throughout rural Sri Lanka.