Frugal Optimization in the Design of a Shea Butter PV Transformation Center in Burkina Faso

Abstract

The design and sizing of a transformation centre based on frugal innovation techniques are presented for an association of women producing shea butter in the Bobo-Dioulasso region of Burkina Faso. The design is aimed at preserving ancestral production methods as much as possible. Regarding the sizing of the electrical supply system, which is based on a solar photovoltaic system, in addition to the standard sizing method (worst-month method), an analytical development methodology has been applied to ensure reliability (Loss of Load Probability). To guarantee the project\'s sustainability, economic, energy, and environmental sustainability indicators are applied. The results are expected to serve as a replicable model for other communities facing similar challenges, providing a sustainable and adaptable solution.

Introduction

Context and Problem

• Shea butter, extracted from Vitellaria paradoxa, is economically and culturally important in West Africa, especially for women.

• Traditional processing methods are labor-intensive and time-consuming.

• Industrialization, often led by foreign investors, threatens local control, reducing economic and food sovereignty.

2. Project Objective

• Design a local shea butter processing center for the NDIA producers' association in Burkina Faso.

• Use frugal innovation and solar-powered systems to:

  • Preserve traditional knowledge

  • Increase efficiency and autonomy

  • Enhance sustainability and reduce reliance on external markets

3. Processing and Energy Demands

Traditional Process Overview

• Includes fruit harvesting, drying, boiling, roasting, grinding, kneading, and storage.

• Significant consumption of firewood and water (up to 75 liters per 25 kg batch).

Energy Needs

• Traditional tasks integrated with semi-industrial equipment.

• Daily energy demand: ~199.26 kWh

• High energy processes: roasting (80 kWh), kneading (38.4 kWh), refrigeration (50.4 kWh)

4. Solar System Design

Energy Source

• Off-grid photovoltaic (PV) system, optimized for the tropical climate of Bobo-Dioulasso.

• Utilizes 550Wp solar panels, a 23.4 kWh battery bank, and a 93% efficient inverter.

Sizing Approaches

• Worst-Case Month (WCM): Ensures reliability in low-radiation months (e.g., September), but risks over-sizing.

  • Requires 86 PV panels and 9 batteries

• Loss of Load Probability (LLP): More analytical; balances reliability and cost.

  • Guarantees 99.99% reliability (LLP = 0.01)

  • Suggests battery size could be reduced while maintaining reliability

5. Sustainability Optimization

Key Metrics Used

• Energy Payback Time (EPBT)

• Internal Return Time (IRT)

• Climate Change Impact (IMPcc)

• Evaluated using a Sustainability Index (SusInd)

Optimal Configuration

• Prioritizes expanding solar capture area over increasing storage

• Leads to:

  • 16% lower cost

  • 59% less CO? emissions

  • 11% longer EPBT

• Final design includes emergency load factor of 1.37 to ensure operation during rainy periods and degradation

6. Broader Impact

• Empowers women producers through self-managed, energy-autonomous infrastructure

• Reduces environmental impact compared to firewood-based methods

• Creates a replicable model for other communities facing similar industrial pressures

• Future work includes utilizing excess solar energy, such as for pumping potable water

Conclusion

This study aimed at designing, optimizing, and implementing a standalone photovoltaic (PV) system for a transformation center, ensuring a balance between system reliability, energy supply, and sustainability. The system sizing was approached using two primary methodologies: the worst-month method and the loss-of-load probability (LLP) method. These methods were applied to determine the best configuration to ensure the system could meet the energy demands of the center while considering variability in consumption patterns, especially seasonal fluctuations. Sustainability indicators, including economic, energy, and environmental metrics, were incorporated to ensure the system operated responsibly and economically, while minimizing its environmental footprint.The key findings of the study include the following: 1) Sizing Methodology: The system was sized using the worst-month method, for a first estimation. Additionally, the Loss of Load Probability (LLP) method and a sustainability index were introduced to further optimize the sizing process. This resulted in the installation of 104 photovoltaic panels (550 Wp each), estimated to generate 100.7 MWh annually. Although this output meets the center\'s energy needs, seasonal fluctuations in demand still result in surplus energy. Although the panels\' output and stationary batteries system of 23,4 KWh meet the center\'s energy needs, seasonal demand fluctuations still result in surplus energy, assuring an emergency load of 1,37. 2) Energy Surplus: Despite the optimized sizing, energy overproduction remains a significant challenge, particularly during periods of low energy demand, such as in the summer months. The seasonal variability in consumption creates a mismatch between supply and demand. Monthly energy surpluses were calculated, with values ranging from 213,2 kWh during high-demand months to 55,98 kWh during low-demand months. These surplus energies represent a critical issue in terms of resource utilization and waste. 3) System Costs and Emissions: The total cost of the PV system was estimated at 10877,15 €. Of this, 80% was allocated for the photovoltaic panels, and 20% was designated for the batteries. The estimated emissions reduction over the system’s lifetime is significant, with projected CO2 emissions amounting to 1688,14 tons, compared to traditional fossil fuel-based energy sources. Furthermore, the energy payback period for the system is approximately 3,76 years, which highlights the system’s ability to recover its energy costs in a relatively short period. 4) Sustainability Index: The sustainability index for the system was calculated to be 0.43, indicating a solid balance between energy generation, environmental impact, and costs. This value is relatively close to the optimal level, suggesting that the project’s design and implementation have prioritized sustainability, energy efficiency, and minimal environmental harm. 5) Utilization of Surplus Energy: To address the challenge of energy overproduction, the surplus energy is effectively utilized by powering a deep-well water pumping system. This innovative solution ensures that the excess energy generated during low-demand periods is used to meet another critical need: water access for the community. The deep-well water pumping system, which operates seasonally, can pump water at a flow rate of 226.8 liters per hour, ensuring a daily water flow of 1,134 liters, which is sufficient to meet the daily needs of the population, including shea butter production, crop irrigation, and other basic requirements like hydration, hygiene, and cooking. In conclusion, the combination of these methodologies resulted in a well-optimized photovoltaic system, addressing both energy overproduction and excess capacity issues. The surplus energy that would have otherwise been wasted is now used effectively to power a water pumping system, which enhances the project\'s sustainability by utilizing all available energy resources. This approach not only reduces waste and lowers emissions but also helps meet critical community needs, improving both the environmental and social impact of the system. Future research may explore other uses for excess energy and assess potential optimizations for similar systems in different contexts.

References

[1] FAO/WHO/UNU. Human energy requirements. Inf. téc. Food and Agriculture Organization Report, oct. de 2001 [2] Swiss contact Benin y Helvetas Benin. Le guide practique de la production du beurre de karite: manuel de l’apprenant. Inf. téc. url: https://www.doc-developpement-durable.org/file/Fabrications-Objets-Outils-Produits/Huiles-vegetales-noix/Fiches_plantes/karite/guide_pratique_de_la_production_du_beurre_de_karite.pdf R. E. Sorace, V. S. Reinhardt, and S. A. Vaughn, “High-speed digital-to-RF converter,” U.S. Patent 5 668 842, Sept. 16, 1997. [3] Holtzman, J. “La chaîne de valeur du beurre de karité. Synthèse d’étude et recommandations pour WATH”. Rapport Technique WATH NO. 2004 [4] Muñoz Muñoz, C. “Shea butter transformation center in Burkina Faso”. Universidade de Santiago de Compostela, Master thesis, 2025. [5] Delgado E, Peralta J., Arboleda J., López-Agüera, A. “Design and analysis of a Hybrid Drying Using Renewable Technologies” ICREPQ´12. 2012. [6] Weather Spark. [Online]. Available: https://es.weatherspark.com/y/35126/Clima-promedio-en-Bobo-Dioula. 2025. [7] Atersa [Online]. Available: https://atersa.shop/panel-solar-580w-a-580m-atersa-gs-mono-n-type-topcon-144-medias celulas/?srsltid=AfmBOooV3HZqrKftV50DjiwdIx_Ki9Nelb5ArsgeLznjb8WIGbYik. 2025. [8] Leroy Merlin [Online] Available: https://www.leroymerlin.es/productos/bateria-solar-estacionaria-traslucida-uopzs-u-power-24v-975ah-23-4-kw-82510892.html. 2025. [9] Victron [Online] Available : https://autosolar.es/inversores-cargadores-24v/inversor-victron-multiplus-24v-3000va-7050a.2025. [10] Lorenzo Pigueiras, E. et al. (1992). “The sizing of stand alone PV-system: A review and a proposed new method”. Solar Energy Materials and Solar Cells 26 (1992) 51-69. [11] IRENA. “The Global Atlas for Renewable Energy – A Decade in the Making, International Renewable Energy Agency,” Abu Dhabi. 2024 [12] Bechir, M. H., Martínez, D. F., & Lopez-Agüera, A. “Energetic Sustainable Transition Process Optimization in Terms of LCA Using CLEWs Tools”. In International Conference on Water Energy Food and Sustainability (pp. 147-157). Cham: Springer International Publishing.2022 [13] Ferreira-Martínez, D., Bechir, M. H., & López-Agüera, A. “Effect of the sustainability indicators within OSeMOSYS optimization transition scenarios”. Energy Strategy Reviews, 54, 101448. 2024. [14] Electrobombas. [Online] Available: https://www.electrobombas.es/bombas-para-pozos/. 2025

Copyright

Copyright © 2025 Munoz Munoz, C., Lopez-Aguera, A.. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.