3.2.3. Economic Appraisal of the Business Model

For the case scenario considered in the study to be financially viable, Abbood et al. [15] reported that an NPV of a positive value and an IRR greater than the present interest rate (14% for the case study) should be targeted. The variation of the NPV and IRR over the operation period is presented in Figure 10. Economic analysis of the case scenario revealed that, at a discount rate of 14% over a projected 10-year lifespan of the drying system, an NPV and IRR of \$1633 and 71%, respectively, can be achieved at a payback period of 1.41 years after operations begin. The economic indicators' values prove the viability of the case scenario where a farmer can invest in owning and running the column dryer as a business in the study area. The study results agree with studies by Adams et al. [14] and Mensah et al. [27], who worked on the financial feasibility of a mango-chip processing and small-scale meat production, respectively, in Ghana. In their studies, the authors reported the economic viability of their case studies in Ghana, where there were similar trends in NPV and IRR for the operational period of the individual startups.

**Figure 10.** Variation of NPV and IRR over the 10-year operation period.

#### 3.2.4. Sensitivity Analysis

The effect of price variations for maize drying (\$/bag of maize) on the economic outlook of the case scenario is presented in Table 5. The analysis of the results shows that at a constant discount rate of 14%, the NPV, IRR, and BCR values increased considerably at an increased cost of drying. For instance, at 20% increase in drying charge from \$0.94 to \$1.13, the NPV increased by 33% (from \$1633.00 to \$2174.00). A similar increasing trend was observed for the other economic indicators as IRR and BCR increased by 24% and 20%, respectively. However, the PBP decreased by 20% when the drying price was

increased by 20%. This indicates that an investor will regain his investment in a relatively shorter time as the price charged for drying maize is raised, and more revenue is expected. However, a reduction of the drying price also showed a reverse effect on the economic indicators seen in Table 4. Similar results have been reported by Abbood et al. [15], who worked on the financial analysis of a 1 MW PV plant, and observed that NPV and IRR increased considerably with an increase in the selling price of electricity. The result shows that variations in the cost of maize drying using the drying system can affect the economic potential of the business model.


**Table 5.** Variation of NPV, IRR, PBP, and BCR with drying price charged per bag (130 kg) of maize.

The effect of discount rate on the economic indicators at a constant drying price of \$ 0.94 per bag of maize was also investigated, and the result is presented in Table 6. The analysis shows that when the discount rate increases, the economic viability of the business model tends to be affected negatively with respect to the NPV and BCR and vice versa. For instance, with a 50% increase in the discount rate, from 14% to 21%, NPV and BCR decreased by 31% and 17%, respectively. On the other hand, PBP and IRR were not affected by variations in the discount rate. This is attributed to the independence of both economic indicators on the discount rate reported by Abbood et al. [15].

**Table 6.** Variation of NPV, IRR, PBP, and BCR in relation to the discount rate.


The final sensitivity analysis was done in anticipation of manufacturers, investors, and/or distributors who may sell or distribute the drying system. The study considered a situation where an operator tends to buy the column drying system from a manufacturer or an investor at a cost that is 20%, 50%, and 80% more than the actual manufacturing cost (investment cost). The profit margins on the investment cost of the dryer were simulated at a drying charge of\$ 0.94/bag and using a discount rate of 14%. The reflection in the economic indicators is presented in Table 7 to see their effect on the economic indicators. NPV, IRR, and BCR tend to decrease as the profit margin on the investment cost increases, although PBP increases. This is justified since a higher investment cost means an extended period to break even on an investment. Although the economic feasibility of the case scenario tends to decline in values, even at a higher profit margin of 80% increase on the investment cost, the economic indicators demonstrate a viable case with a positive NPV and IRR of \$1100 and 37%, respectively.


**Table 7.** Variation of NPV, IRR, PBP, and BCR in relation to increasing dryer cost.

#### **4. Conclusions**

The techno-economic performance of a half-tonne capacity crossflow column dryer with a biomass burner heat source was successfully assessed. Maize at 22.30% was dried to a final moisture content of 13.25% within a period of 5 h. The average drying rate recorded during the study was 1.81%/h with a drying efficiency of 64.65%. The economic viability of a case study was assessed to be viable for a smallholder maize farmer or an investor who operates a unit to provide drying services to maize farmers. The economic analysis over a 10-year lifespan operation of the dryer resulted in an NPV of \$1633 and IRR of 71%. At an assumed drying charge of \$0.94/bag, which is one-third lower the drying charges of a typical commercial drying facility in Ghana, an investor is expected to recoup his investment in the shortest possible time at a PBP of 1.48 years with a BCR of 2.55. Finally, the positive performance indicators provide confidence for scale-up and adoption by smallholder maize farmers in Ghana. It is recommended that manual mixing of grains should be incorporated in the unloading of maize from the drying system to minimize the difference in moisture content between the grains at the inner and outer sections. Smallholder grain farmers should adopt portable and mobile, low-cost grain drying systems in Ghana and sub-Saharan Africa. In order to facilitate this adoption, smallholder farmers should be brought the knowledge of the technical and economic performance of these systems. In addition to this, smallholder farmers should be equipped with entrepreneurial skills to better utilize such technologies for economic benefits and provide on-time drying services to mitigate the substantial loss of grain in most rural grain-growing communities in sub-Saharan Africa.

**Author Contributions:** The following authors contributed to the work: Conceptualization, D.E.M., J.O.A., A.A.; methodology, G.O.-A., J.O.A. and D.E.M.; software, G.O.-A.; formal analysis, G.O.- A.; investigation, G.O.-A.; resources, D.E.M., J.O.A. and A.A.; writing—original draft preparation, G.O.-A.; writing—review and editing, J.O.A. and D.E.M.; supervision, J.O.A., A.A. and D.E.M.; project administration, D.E.M.; funding acquisition, D.E.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study is based on research supported by the Post-Harvest Engineering and Feed Technology Group, Department of Agricultural & Biosystems Engineering, Iowa State University.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

