Biochemical methane potential of agro-wastes as a renewable source alternative for electrical energy production in Cuba

Abstract

The present Cuban economic model focuses on renewable sources of energy production, according to sustainable development strategies for 2030. However, the strategies do not consider biogas (or methane) due to, among other reasons, a lack of knowledge of its actual potential. Following the methodology of the batch anaerobic digestion process, the study shows the biomethane potential contained in the most critical agricultural solid wastesgenerated in Cuba, i.e., rice straw, cane straw, corn straw, bean straw, banana straw (leaves), coffee husk, and parchment coffee. Biochemical Methane Potential (BMP) was assayed by lab-scale (585 ml) batch reactors, using the pig manure anaerobic sludge as inoculum under mesophilic conditions (35 ± 2 °C). Physicochemical parameters (total volatile solids, pH, alkalinity, volatile fatty acid concentration, and alkalinity ratio) were determined for processstability, quantifying the biogas production daily. Subsequently, the BMP was calculated for all substrates. The results showed that corn straw (0.42 l CH4 per gram of volatile solids) contained the highest biomethane potential. Stability on all systems was obtained, demonstrating the viability of the inoculum used to start digesters that treat this waste.The total potential methane obtained was 1258 106 m3/year, which is enough to generate 3,750 GWh of power per year—equivalent to 18 % of the total annual electricity generation in the country.

Latin America towards Sustainability through Renewable Energies: A Systematic Review

“…In Bolivia, the share of electricity produced domestically is projected to increase to more than 20% by 2040 [67]. In Cuba, it is planned to continue with the modification of its energy matrix to obtain 24% of electricity from renewable energy sources by 2030 [68].…”

“…This country, in turn, has a great potential for obtaining biomass from agro-industrial waste, as the forestry industries in Argentina are the generators of the largest volume of waste in this country [13] This possibility is also observed in countries such as Cuba, which produces a large amount of solid waste from its agricultural activities, including rice straw, sugarcane straw, corn, beans, husks and parchment coffee, among others. These residues can be used in digesters for the production of biomethane, with the potential to supply up to 18% of the total annual energy generation of this country [68].…”