Four solar floats spent about a year off Brouwersdam, and their submerged surfaces became home to 72 forms of marine life, including a “glass-caged forest” filled with tiny jellyfish breeders

Floating solar installations at the Brouwersdam have transformed into homes for marine life.

Global coastal regions are becoming increasingly crowded, raising the need for clean energy options.

While offshore wind capacity has significantly expanded, photovoltaic infrastructure is also being deployed.

Approximately 11% of the identified species were non-indigenous, underscoring floating solar’s risk of increasing invasive organisms.

Now, these structures are attracting a variety of marine species, but are also raising the risk of biofouling.

Will these colonizing organisms affect the long-term performance and stability of these offshore installations?

How dense coastal regions are experiencing a rise in energy needs

In one century, the world has undergone major changes.

In 1926, the world’s coastal regions were less populated, sea levels remained stagnant, and industrial development was limited.

Today, shorelines are packed with dense megacities featuring advanced concrete defenses.

Additionally, the oceans have become warmer and more acidic, rapidly depleting marine life.

Wild nature had to make way for booming tourism, which triggered a rise in huge resorts and hotels.

Only 15% of coastlines worldwide remain ecologically undeveloped.

As more small fishing villages transform into concrete jungles, a bigger supply of electricity is needed to maintain daily operations.

This is driven by the surge in people attracted to these regions, as well as ongoing industrialization and urbanization.

Consequently, land scarcity has become severe.

Sectors are fiercely competing over viable land, driving up real estate costs.

For the renewable energy sector, growth meant moving toward the ocean instead.

Boosting offshore clean power capacity

Initially, the development of offshore wind farms became key in meeting rising electricity demand.

By installing giant turbines in the ocean, strong, uninterrupted maritime winds could be harnessed.

Furthermore, it immediately addressed the spatial constrictions faced onshore.

Global capacity has surpassed 80 GW thanks to the technology’s high and rapid scalability.

Despite the distinct benefits, these turbines still experience intermittency.

Major atmospheric changes have made weather more volatile, directly impacting wind speeds.

This unpredictability often results in lower output during calm summer months when coastal demand peaks.

Consequently, energy providers now need complementary offshore green power sources.

Offshore floating solar installations are becoming more popular as a result.

These photovoltaic arrays produce maximum energy during sunny, low-wind periods.

Their co-location alongside existing offshore turbines optimizes subsea transmission cables, which maximizes the total renewable output.

However, the primary challenge to these floating structures is the direct overlap with marine life.

The pilot solar farm at Brouwersdam

Floating solar technology is being tested in the Netherlands.

Researchers particularly examined a pilot installation off Brouwersdam in the Dutch North Sea to understand biofouling risks.

The solar floats are deployed in shallow waters roughly 1,600 to 3,300 feet from the shoreline.

Four floats were sampled over one year to analyze the colonization of marine life on the submerged surfaces.

Discovering 72 distinct marine species colonizing the floats

These colonizing marine wildlife included:

• amphipods
• barnacles
• blue mussels
• tube worms
• colonies of hydrozoans

The hydrozoans created a dense “glass-caged forest” consisting of small branching hydroids.

The hydroids produce tiny jellyfish breeders.

Approximately 11% of the identified species were non-indigenous, underscoring floating solar’s risk of increasing invasive organisms.

Over time, the community transitioned from several small organisms to fewer, much larger specimens.

The rise in biomass increases offshore solar biofouling risks.

Heavy and dense marine layers add extra weight to the structure, elevating hydrodynamic drag.

Consequently, mooring lines become stressed, mechanical wear accelerates, and maintenance costs increase.

It is important to manage this marine growth to ensure offshore floating solar scales globally.

The researchers suggest using advanced, non-toxic anti-fouling coatings, such as Intersleek.

Additionally, long-term environmental monitoring models must be established.

Specifically focusing on offshore wind and solar co-location is also key.

Ultimately, biofouling must be addressed to boost the reliability of sustainable, offshore power infrastructure.

The full study can be accessed at APA CITE: Mavraki N, Bos OG, Vlaswinkel BM, Roos P, de Groot W, van der Weide B, Bittner O and Coolen JWP (2023) Fouling community composition on a pilot floating solar-energy installation in the coastal Dutch North Sea. Front. Mar. Sci. 10:1223766. doi: 10.3389/fmars.2023.1223766