A recent study by Arnold, et al., (2024) titled “Floating photovoltaics may reduce the risk of hydro-dominated energy development in Africa” published in Nature Energy, examine that floating photovoltaics (FPV) in Africa can significantly complement hydropower, offering sustainable, reliable energy while mitigating environmental and economic risks.
As Africa seeks sustainable solutions to its growing energy needs, Floating Photovoltaics (FPV) have emerged as a promising alternative to traditional hydropower development. This innovative technology could transform the continent’s energy landscape by leveraging existing water bodies for solar energy production, thereby offering multiple advantages over conventional hydropower.
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Floating photovoltaics can significantly supplement planned hydropower in Africa, ensuring stable and sustainable energy production. – Arnold, et al 2024
Advantages of FPV Over Hydropower
FPV systems can generate a significant portion of the electricity anticipated from planned hydropower projects. Unlike hydropower, which is highly dependent on water levels and can fluctuate with seasonal and climatic changes, FPV offers a more stable and predictable energy output. This stability is crucial for maintaining a reliable power supply, particularly as climate change makes hydrological patterns increasingly unpredictable. Strategic investment in FPV can be more cost-efficient than constructing new dams. The initial capital expenditure for FPV installations is generally lower, and the long-term maintenance costs are also reduced compared to those associated with large-scale hydropower infrastructure. Additionally, FPV installations avoid the significant social and environmental impacts that come with building new dams, such as displacement of communities and ecosystem disruption. FPV installations on existing reservoirs can boost overall energy output. By utilizing the surface area of these water bodies, FPV systems can complement existing hydropower facilities, ensuring a more robust and reliable power supply. This is particularly important in the face of climate change, as FPV systems are less vulnerable to variations in water availability and can thus provide a steadier flow of electricity.
A detailed analysis of the Zambezi watercourse underscores the potential of FPV to offset hydropower losses and support sustainable energy development in Africa. The Zambezi River, one of the largest river systems on the continent, is heavily relied upon for hydropower generation. However, the river’s flow is subject to significant seasonal variation, which can disrupt energy production. The study suggests that integrating FPV into the existing hydropower infrastructure on the Zambezi could mitigate these fluctuations. FPV installations on the river’s reservoirs could harness solar energy, providing a supplementary power source that compensates for periods of low water flow. This hybrid approach not only enhances the resilience and reliability of the energy supply but also maximizes the use of existing resources, promoting a more sustainable and efficient energy system.
How the Study was Conducted
The study employed the OSeMOSYS-TEMBA Model, this energy system model is used for long-term capacity planning in Africa. It evaluates cost-optimal trajectories of Floating Photovoltaics (FPV) expansion from 2015 to 2050, considering uncertainties in socio-economic development, energy demand, and emissions policy. The study considers potential FPV deployments at existing and under-construction dams, with FPV system capacities set to incremental multiples of adjacent hydroelectric dam plant capacities. The model includes constraints to avoid overstating physical engineering limits and interference with other reservoir uses. This river basin-scale model explores synergies, tradeoffs, and vulnerabilities within and across hydropower, irrigation supply, and environmental objectives3. It includes existing reservoirs, one run-of-the-river hydropower plant, irrigation districts, and major planned reservoirs.
The study also employed the SAPP Electricity System Model, developed with PowNet, this model simulates the operations of the South African Power Pool’s power systems. It schedules least-cost operations that balance supply and demand over a 24-hour period, accounting for technical and economic constraints. The authors utilized Joint Hydropower–FPV Capacity Expansion Optimization: This optimization process designs alternative reservoir operating rules, irrigation diversion policies, and FPV capacities. It generates Pareto-efficient solutions representing tradeoffs across energy, food, environment, and economic objectives. The study assesses the feasibility of FPV peak capacities and their integration into the grid, considering transmission line capacity and the area required for FPV panels.
What the Authors Found
The authors found that Floating photovoltaics (FPV) could produce 20–100% of the electricity expected from Africa’s planned hydropower, depending on FPV deployment scale and its cost and efficiency relative to land-based photovoltaics. The authors also found that capital investment planned for dams in the Zambezi watercourse could be more efficiently used by building fewer reservoirs and substituting energy supply with FPV, resulting in less variable and more robust energy output. FPV can avoid the environmental, social, and financial risks associated with hydro-dominated energy development, potentially outweighing its impacts on existing reservoir uses. In addition, the authors posit that strategically integrating FPV with hydropower could lead to sustainable, low-carbon energy development, ensuring a stable energy supply robust to hydrological changes.
Why is this Important
Energy Transition: As Africa aims to transition to cleaner energy sources, understanding the potential of floating photovoltaics (FPV) is crucial. FPV can complement existing hydropower infrastructure and provide a more resilient energy supply.
Cost-Effectiveness: By strategically integrating FPV with hydropower, countries can optimize their capital investments. Instead of building numerous dams, they can allocate resources more efficiently by substituting some energy supply with FPV.
Environmental Impact: FPV offers environmental benefits by avoiding the risks associated with large-scale dam construction. It minimizes the impact on ecosystems, local communities, and water resources.
Energy Security: FPV installations on existing reservoirs enhance energy security. They provide a stable power supply even during droughts or changing hydrological conditions.
What the Authors Recommend
- The author recommends that policymakers and energy planners should strategically deploy floating photovoltaics (FPV) alongside existing hydropower infrastructure. This approach can optimize capital investments and enhance energy security.
- When planning new reservoirs, consider the environmental, social, and financial risks associated with large dams. FPV can be a more sustainable alternative, minimizing these impacts.
- Policymakers should integrate energy systems that combine FPV, hydropower, and other renewable sources. Such systems can provide a stable and resilient energy supply while minimizing environmental harm.
- Governments should create policies that incentivize FPV deployment and encourage research and development in this field. This includes addressing regulatory barriers and providing financial support.
In conclusion, the integration of floating photovoltaics (FPV) with existing hydropower infrastructure presents a transformative opportunity for Africa’s energy sector. By leveraging solar energy from water bodies, FPV not only enhances energy security and sustainability but also mitigates environmental and economic risks associated with traditional hydropower development. Strategic deployment of FPV, supported by robust policy frameworks and technological innovation, holds the potential to foster a resilient, low-carbon future for the continent while meeting its burgeoning energy demands.
