Aquasol: hydro-solar synergy at Urrá

The Aquasol pilot installation is situated at the 340MW Urrá hydropower plant in the Sinú River basin in Córdoba

What motivated Noria Energy to develop the Aquasol project at Urrá Dam, and what are the main objectives of the project?

We saw an amazing opportunity to deploy an innovative solution at a site that demonstrates the complementarity that exists between generating power from a floating photovoltaic system and a hydroelectric power plant. The benefits are many: generating clean energy, preserving water, leveraging existing infrastructure, minimizing land-use conflicts, and creating overall awareness of the potential of clean energy. 

Can you provide more details about the design and technology used in the floating solar system? How does it withstand water-level fluctuations of up to 120ft?

Many hydroelectric dams face specific challenges — including deep water, significant water level variation, swells, and strong winds. For the Aquasol project at Urrá Dam, conditions include water depths up to 100 meters, 35+ meters of water-level variation, swells, and seasonal high-speed winds. 

Noria’s technology uses state-of-the-art materials and innovative optimizations among anchors, mooring lines, floats and modules to adapt to challenging conditions. We knew that we needed to partner with industry experts to design a safe, advanced, and cost-effective Floating PV solution.

Noria chose to work with Isigenere from Spain and Seaflex from Sweden. Isigenere developed Isifloating, a very versatile high-density polyethylene (HDPE) Floating PV mounting structure. Seaflex has been developing mooring solution for over 40 years, and developed the first elastic mooring system.

What are the key advantages of pairing floating solar with hydroelectric operations, particularly in terms of energy reliability and increased production?

Advantages include: 

• The ability to leverage the existing infrastructure (interconnection, roads, resources, security, etc.), thus reducing the overall capital investment required
• Co-location and optimization of water surface area so that valuable land space can be used for other purposes 
• Additional clean energy generated from the FPV to power pumped-storage hydropower plants 
• More efficient solar energy generation from water’s cooling effects and higher sunlight reflection provided by the water itself 
• Reduced algae growth, water evaporation, and improved water quality from the shading provided by PV panels on the water 
• Floating solar provides resiliency, reduces power fluctuations, and optimizes dispatch
• Minimizes the impact of seasonal water cycles 
• Serves as a “virtual battery” — FPV can generate power during the day while the reservoir stores up water and energy for release during peak demand periods

How does the Aquasol project contribute to Colombia’s renewable energy goals, and what impact does it have on reducing carbon dioxide emissions?

Colombia’s energy transition policy is at a crucial turning point, as the government targets the gradual shift to net zero. Colombia is shifting away from an extractive industry model heavily dependent on oil and coal exports, and toward a more diversified clean energy economy based on investments in renewable energy.

Colombia has the third largest installed hydropower capacity in South America, at 11,726MW. The sector makes up 70% of national installed energy capacity. In 2017, hydropower produced 86% of national electricity generation, exceeding both the 70% average generation of the previous four years, which were marked by continuous droughts, and the 79% recorded in 2012.

Aquasol is a benchmark in the sector, demonstrating the real complementarity that exists between generation by a floating photovoltaic system and generation by a hydroelectric power plant. In the same way, the project wants to reconcile all the economic, social, technical and environmental aspects of this type of facility, and generate valuable information for future deployments. 

Aquasol is expected to avoid over 1,540 tons of carbon dioxide emissions every year, and generate over $1.2 million in additional electric power revenue over 20 years.

What were the main challenges faced during the development and installation of the floating photovoltaic system, and how were they overcome?

The main challenges were related to: 

1. Logistics and risk (cost) associated with deploying a system in a developing country and in a very remote area
2. The uncertain/unknown regulatory framework that could have been imposed on this type of project.

We were keen to find the right local partner with proper knowledge and technical expertise that would help us navigate the local environment, and that was willing to take on local logistics, procurement and construction risks.

What lessons have been learned from the Aquasol pilot project, and how will they inform the development of future Aquasol projects in Colombia and globally?

Key lessons learned extend from the challenges listed above. Due to the complexity of the project as well as the remote location of the site, commercial and business decisions took more collaboration and endured more delays than expected. More contingencies, more time, and more resources should be planned for in the execution of future projects. 

How will Noria Energy compare the production and efficiency of the Aquasol system to that of a ground-mounted solar system installed on the shore, and what are the expected outcomes of this comparison?

We are partnering with Urrá to analyze and publish energy production data collected from newly installed ground-mounted and floating solar panels as part of the Aquasol project.

FPV plants on bodies of water reduce the impact of the thermal coefficient through the cooling effects of evaporation and wind ventilation. This can result in a slightly higher yield compared to land-based PV systems. The temperature of FPV modules can be 5–10 °C lower than that of ground-based installations. Hydroelectric dams operating in conjunction with FPV have been proven to optimize energy generation and increase system reliability compared to land-based PV systems due to the cooling effect of water.

In addition to improved yields, the PV module can provide shading (depending on the module’s design) and limit water evaporation from wind. Evaporation represents a significant loss factor of managed water resources worldwide, with reported values as high as 40% of the total volume of water storage.

In terms of scaling up, what are the considerations and challenges in implementing larger-scale floating solar systems in combination with hydroelectric dams?

In part due to competition for land for solar systems, deployment, and the associated costs derived from licensing and land preparation, developing solar plants has become increasingly challenging. This is especially true in densely populated areas, land-scarce countries, or regions with high land prices.

Coupling FPV and hydropower plants offers a way to share existing hydropower infrastructure such as transmission extensions and substations. It also eases time and siting constraints, such as land acquisition.