Publicly available toolkits for cost calculation in renewable energy projects were reviewed, and their main characteristics, strengths and weaknesses identified. An original Life-Cycle Cost (LCC) modelling toolkit was developed to address some of the identified shortcomings, and to facilitate the calculation of costs of electrical and thermal energy from biomass-based processing pathways. The toolkit was used to compare the Levelized Cost of Energy (LCOE) for electricity and/or heat generation for a ‘Bioenergy Case’, after the adoption of bioenergy technology, and compared with equivalent costs under a business-as-usual ‘Base Case’, for selected commercial demand sectors in Sub-Saharan Africa, within a 10 kW to 5 MW scale range. Case Studies of the toolkit’s application are described for a smallholder tea factory in Kenya, a wood processing enterprise in Tanzania and an oil palm mill in Ghana, which illustrate its ability to model energy production based on both combustion and anaerobic digestion, under various heat, power and combined heat and power configurations. Sensitivity analysis was carried out to determine the effect on LCOEheat and LCOEelectricity of adjustments in key operating parameters, such as biomass feedstock cost, feed-in tariff for export of surplus power to the grid or on-site energy demand. The versatility of the LCC toolkit enables bioenergy projects to be modelled from different perspectives (biomass feedstock diversification, conversion pathways or business models) and for different users (plant managers, project developers or potential investors), and it can be customised and adapted as prices, legislation and technical aspects evolve with time.