Electricity availability of remote areas is a key bottleneck for development of these areas. Increasing electricity availability of remote areas has previously been severely constrained by connection conditions to a main electricity grid, including line distance, geographical conditions for construction, and size and pattern of loads. Increasingly cost-effective renewable energy, together with fast development of distributed energy production technologies, provides opportunities for tackling this challenge. However, due to the unique characteristics of energy supply and demand sizes and patterns of remote areas, design of distributed energy systems in these areas pose great challenges compared with existing ones for urban areas. In this paper, we propose a modelling and optimization framework for design of distributed energy systems in remote areas, featuring residential, small industrial, commercial and agricultural power loads, off-grid network, and solar, wind, and biomass as primary energy sources. We then implement the optimal design framework in HOMER, and illustrate the capability of the proposed framework via a case study of a village in West China. Results show that a hybrid distributed energy system comprising solar, wind, biomass energy is a cost effective, sustainable and environmentally friendly option for remote areas.