Hybrid renewable energy with membrane distillation polygeneration for rural households in Bangladesh: Pani Para Village case study

Despite the country´s rural electrification program, kerosene is the predominant source for lighting, and woody biomass is virtually the only the option available for cooking. Aside from this energy service challenges the rural population also struggles with unsafe drinking water in terms of widespread arsenic contamination of well water. Access to electricity, clean cooking gas, and safe drinking water services are genuine needs of the rural poor and are essential to improving welfare. These needs can be addressed individually or using an integrated approach. This study considers a holistic approach towards tackling both of these issues via integrated renewable energy-based polygeneration employed at the community level. The polygeneration unit under consideration provides electricity via a pV array and cow dung-fed digester, which in turn is coupled to a gas engine. Excess digester gas is employed for cooking and lighting, while waste heat from the process drives a membrane distillation unit for water purification. The system is sized to serve a community of 52 households (Pani Para, Faridpur District) with 14 kWe peak demand and 250 kWh/day primary electricity loads. Technical assessments and optimization have been conducted with HOMER. Results show that electricity demand can be met with such a system while simultaneously providing 0.4 m³ cooking fuel and 2-3 L pure drinking water per person per day. Cost estimates indicate that this approach is highly favorable to other renewable options.