Coffee producers depend on reliable power for processing and irrigation, yet many rural farms remain off-grid and exposed to volatile diesel prices. A master’s project at ETH Zurich’s Power Systems Laboratory explores this challenge through the world’s first large-scale agriphotovoltaics concept for coffee cultivation. Focusing on Angola, the research shows that installing solar panels above coffee plants can deliver affordable electricity and climate resilience in one system. The findings highlight how integrating energy and agriculture can open new pathways for sustainable production in tropical regions.
A new concept for two problems
Coffee farmers in Sub-Saharan Africa face two persistent problems. The first problem is access to reliable and affordable electricity. Many agricultural operations depend on diesel generators, which cause high carbon emissions and expose farmers to fluctuating fuel prices. In rural areas of Angola, where this study is based, electrification rates are estimated at less than 10 percent. Grid-connected electricity, where available, remains heavily subsidised and often costs below USD 0.02 per kWh compared with about USD 0.20 per kWh in Switzerland. As a result, for most rural communities lacking grid access, the main options remain either decentralized solar investments or reliance on subsidised fossil fuels.
The second problem is increasing climate stress. Rising temperatures of 2 to 2.5 degrees Celsius projected by 2050, combined with more erratic rainfall, threaten agricultural productivity across the region. Shade-grown crops such as coffee are highly sensitive to heat and water stress, making them especially vulnerable to these changes.
Consequently, farmers depend on subsidised fossil fuels and their crops face increasing resilience challenges as climate impacts intensify. This study conducted at ETH Zurich’s Power Systems Laboratory explores how combining solar energy generation and coffee cultivation within a single dual-use system, known as agriphotovoltaics (APV), can address both challenges simultaneously.
Why coffee and solar panels fit together
APV systems place solar panels above crops rather than on separate land, enabling the simultaneous use of the same area for energy generation and cultivation. The panels produce electricity while providing partial shading that moderates temperature and humidity. For shade-adapted crops such as coffee, which have traditionally been grown under tree canopies, this shading can reduce heat stress, lower water loss from both soil and plants (a process known as evapotranspiration), and alter microclimatic conditions (see Figure 1), ultimately improving both yield and bean quality while generating renewable power directly on-site.
In collaboration with Companhia de Café de Angola’s off-grid coffee plantation in southern Angola, the ETH Zurich Power Systems Laboratory team developed the world’s first large-scale APV concept specifically designed for coffee production. The study integrates field measurements, ray-traced shading simulations, and techno-economic modelling to evaluate the technical and economic feasibility of such systems under real local conditions. While the results indicate that APV could be both technically and economically viable, it is important to note that full real-world feasibility can only be confirmed once the system is actually implemented, as certain hurdles remain. While high upfront investment costs remain a major challenge and will require foreign investment, the dual-use nature of APV creates an additional value stream through improved crop yields under beneficial shading. This added agricultural benefit increases overall competitiveness and makes APV a financially attractive alternative, even compared to strongly subsidized diesel.
Policy shifts and new opportunities
Recent developments in Angola illustrate how rapidly diesel subsidy policies can change. In 2024, the government reduced diesel subsidies by more than half. This decision triggered public protests but also marked an important correction of long-standing price distortions and a step towards a more competitive energy market. Within one year, diesel prices more than doubled. Although they remain low by international standards, the increase has made self-generated solar electricity far more attractive for agricultural operations.
Such policy changes can transform APV from a visionary concept into an economically sound investment. For governments, APV offers a practical pathway to advance rural electrification and climate adaptation simultaneously.
From feasibility to pilot
At the coffee farm site in Angola, no full-scale APV plant has yet been built, but the study provides a blueprint ready for implementation. The design prioritises structural simplicity, the use of locally available materials, and agronomic suitability over complex “optimal” engineering solutions. For example, older PV panels with lower peak watt ratings were considered to increase the shaded area for the crops, demonstrating that the main objective of this APV concept was not maximum land-use efficiency, as often emphasised in European projects, but rather the creation of favourable growing conditions for coffee and providing off-grid energy solutions.
The next step is a pilot installation that will collect long-term data on coffee growth, energy yield, and maintenance under real operating conditions. Ongoing discussions with local engineering offices are underway to prepare the implementation.
Personal reflections
Working on this project taught me that feasibility is defined very differently in Sub-Saharan Africa than in Europe. In Zurich, I was used to thinking in terms of efficiency, cost optimisation and model accuracy. In rural Angola, I quickly realised that success depends on far more fundamental questions: will someone be there to maintain the system once the project ends, how can we manage diurnal and seasonal load variations caused by changing harvesting routines between the rainy and dry seasons, and how might such a technology affect daily work or even create fear among local farm workers?
