Green Energy from Solid Coffee Wastes

Research on green energy sources of energy is a crucial field calling for concerted efforts and this will help in curbing global energy crisis. Biomass could serve as an excellent source of alternative energy substituting fossil fuels and thus not compromising stringent environmental requirement of using clean energy with little or no pollution but can lead to deforestation. Thus commercial use of biomass as a source of green energy requires a systematic study of the most suitable procedures for their handling, storage, use and combustion properties. The project characterizes energy content in solid coffee wastes, determines the amount of solid coffee wastes generated annually in Kenya and the potential of green energy production nationally from solid coffee wastes.


Analysis of solid coffee wastes samples were prepared for their specific analysis which involved drying in an oven and subsequent removal of the solid coffee wastes. It was then taken to the bomb calorimeter to analyze the calorific content as well as ash content. Data showed that the annual solid coffee waste was 1,141,900 tonnes from coffee milling plants in the country which translates to high energy if utilized. The coffee pulp and beans covered with husks had a moisture content of approximately 82% and 57% respectively. The ash content for the coffee husks, pulp and a 1:1 mixture of the two was found to be 5.7, 6.4, and 3.5 % respectively. Solid coffee wastes gave high calorific values of 4826, 4397, 5225 cal/g for husks, pulp and a 1:1 mixture respectively which is viable enough to start a green energy power plant. Recommendations necessary in achieving energy freedom as a nation include:

Solid coffee wastes should be utilized for green energy production in the country.

Thorough research on the combustion behaviour of the wastes.

The water obtained from the processing of coffee cherries to be utilized in biogas production. While the ash produced can be used in soil and landscape management.

Study of the chemical composition of the ash from solid coffee wastes should be done.


Key Words: green energy, energy crisis, solid coffee wastes, high calorific value, and conversion technologies.

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