Harnessing the sun at sea: the promise of offshore floating solar

Global energy demand is rising rapidly, with energy consumption set to grow by 50% by 2050, according to the Energy Information Administration. Against this backdrop, there’s not only a pressing need for radical innovation in sustainable energy solutions — but also solutions that use already available technology to combat climate change in new ways.

Solar photovoltaic (PV) power stands as a crucial pillar in this transition. While land-based systems such as solar farms and household solar panelling have long been the focus, a new solution is showing plenty of promise: floating solar.

As part of our “Ask the Pioneer” podcast series, we recently spoke to Don Hoogendorn, CTO of ambitious floating PV company SolarDuck, about the benefits of offshore solar power and how it might transform the world. In this article, we build on his insights to explore why floating solar is fast emerging as a powerful new addition to an increasingly diverse global energy mix. 

Rapid urbanisation and economic development, especially in densely populated developing nations, are contributing to the rise in energy demand. But the current energy system still heavily relies on fossil fuels.

Added to this, nearly 20% of the global population still lacks access to basic electricity and other energy sources. As the global economy transitions to one that is largely decarbonised and electrified, there is an urgent need for affordable and sustainable solutions. These solutions must minimise land use as populations grow, while simultaneously maximising access to untapped renewable energy resources.

Traditional land-based solar installations, while absolutely necessary in their own right, may not be able to meet these pressing needs on their own, with challenges such as land costs, land availability, conflicting land use, and environmental concerns all making expansion difficult.

In contrast, offshore locations, which are typically unused spaces, offer both expanses of potential sites and better exposure to sunlight. And by strategically positioning floating platforms near coastal megacities, in combination with offshore wind power, transmission losses and intermittency can be mitigated.

Floating solar farms therefore make for a highly scalable solution. But for them to become as established as land-based solutions, innovative engineering tailored to specific maritime environments will be needed.

There are meticulous engineering considerations that go into designing floating PV panels to achieve reliability, optimisation, robustness, and cost-effectiveness. But as floating solar becomes more viable, challenges remain, including safety concerns, risks associated with electricity-water interactions, standardisation issues, and national policy considerations.

Currently, there are several shapes for offshore floating solar structures, and new designs may emerge in the future. Some of these designs include raft-like platforms commonly used in inland freshwater bodies such as lakes and reservoirs, or rotating platforms that follow the sun’s trajectory. Another shape is the triangular platform used by SolarDuck.

According to Don, the main advantage of this design is that thanks to its three-axis rotation, compared to a square design’s two, structural load is diminished as the platform is allowed to move more freely with waves. It also simplifies connections between platforms, reduces the need for long, buckling-prone couplings. Their elevation above the water lessens drag and shields panels from damaging seawater, allowing use of more affordable solar panels without special seawater-resistant features.

Additionally, the raised structure deters marine growth, which cling to submerged surfaces and necessitate frequent cleaning. By avoiding such growth, energy output is maximized with significantly lower upkeep. These platforms present a compelling solution for offshore solar energy, marrying cost-effectiveness with durability.

As ambitions scale to gigawatt levels, interconnected plants with robust mooring systems will be needed to ensure safety and stability.  Offshore deployment also demands robust standardisation – akin to the automotive industry – to minimise maintenance costs.