Addressing the three key challenges in keeping floating PV afloat

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Gian Schelling's picture
Business Development Manager, Renewables, Hitachi Energy

Having started his career with Vestas Wind Systems 13 years ago, Gian dedicated his entire career to the energy transition for Wind, Solar, BESS and Energy Efficiency in mostly global Business...

  • Member since 2022
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  • Jun 29, 2022

This item is part of the DER and Management Systems - June 2022 SPECIAL ISSUE, click here for more

In many areas of the world, renewable energy project developers and owners are increasingly looking to floating photovoltaic (PV) as the next long-term growth market in utility-scale solar. In fact, global floating PV (FPV) capacity is expected to grow by 33.7% between 2021 and 2026.

Floating PV: The Next Offshore Wind?

To gain perspective, consider the trajectory of offshore wind. The first commercial offshore wind farm was built in Denmark in 1991. At that time the price per megawatt (MW) was more than five times higher than onshore wind, and further investment languished. Cumulative global capacity did not top 1 gigawatt (GW) until 2007. Today, just 15 years later, global capacity is about 40GW – representing a CAGR of about 27.9% over that span – and is forecast to increase steadily throughout the decade.

Just like offshore wind in 1991, the potential of floating PV is often overlooked today. For FPV to see the same type of growth trajectory, project stakeholders must learn from the offshore wind pioneers and focus on three key challenge areas to avoid common pitfalls and sustain investor confidence to foster long-term growth.

Challenge No 1: Corrosion and Wear and Tear

Corrosion and wear and tear are the top concerns in offshore renewable energy projects. Floating PV system owners can reduce risks of corrosion and wear & tear by focusing on the two most known vulnerabilities: cables and mooring systems.

Cables. As cables are most exposed to wear and tear (and in the case of copper cables, corrosion), offshore wind owners and operators seek to eliminate cables, including communications cables, where they are not critically needed. Particularly, copper- but also fiberoptic communication cables have been massively reduced with the help of wireless communication technologies in more than 20 offshore wind farms globally – and first floating PV plants like the Lac des Toules project in Switzerland. Where cables cannot be eliminated, floating PV parks can minimize the use of copper, which is highly susceptible to corrosion and can directly impact power yield losses. Digital substations, like ENEL’s 500 MW onshore PV plant in Brazil where copper cables were replaced with fiber optics, are also emerging.

Mooring systems. With floating offshore wind in its infancy, mooring systems have not been proven and floating PV site managers cannot leverage learnings from offshore wind just yet. However, a known weak point of all mooring systems occurs at the water surface where constant exposure to both air and water makes components more susceptible to corrosion. Therefore, avoidance of copper in mooring systems as well as stringent 24/7 monitoring of the latter is a must!

Challenge No 2: Asset Health Management

Given the coat and complexity asset maintenance, managing the health of floating PV systems must focus on downtime and unscheduled repair. This is especially true for tracker-based PV systems that have many moving parts. Wireless communications systems, like the one in place at the Lac des Toules project mentioned above, can enable sustained, high-quality asset management capabilities through ultra-reliable data transmission while also eliminating communication cables. Industrial-grade wireless communications are at the heart of SCADA and APM systems that track component health, enable detailed monitoring, and control of system components, allowing operators to prognosticate failures in substations, which are the single most important system component for avoiding total system downtime.

Challenge No 3: Reaching Utility Scale

As more renewable energy projects of all types are integrated into utility operations, the need to provide true utility-scale service is critical to ensure reliable uptime. For floating PV projects to perform at utility scale in already advanced energy transition power systems, a set of core capabilities may be required: black-start capability, ramp-rate control, virtual synchronous machine (VSM) capability and proven offshore ruggedness. Special battery energy storage systems (BESS) that demonstrate the core capabilities outlined above can help improve reliability and enable operation at utility scale. Existing offshore BESS systems, like the one deployed by Australian Woodside on its Goodwyn offshore platform, provide valuable insights that can be applied to large-scale FPV projects.

Rely on experience to keep floating PV afloat!

Even with large-scale installations already online, major hurdles exist for sustained operations of floating PV in most areas of the world as the industry aims to match the 20-30 year lifetimes of onshore PV assets. Bankability, insurability and the appetite of large owners and operators to pursue utility-scale floating PV are yet to be proven. According to the World Bank Group, conservative estimates see a potential of 400 GW of floating PV globally. Similar to the wind industry’s global trajectory, moving offshore will likely be essential for sustained utility-scale PV growth. Leveraging proven offshore wind technologies and experience from leading offshore wind players is a must for the World Bank Group’s forecasts to turn into reality.

Julian Jackson's picture
Julian Jackson on Jul 7, 2022

Floating PV is clearly a next step in the carbon transition. I expect, as you say, it to follow the path of prior renewables like wind. Firstly, how much are governments getting behind this? Most renewables need financial support to reach the large-scale pilot stage before they become commercially viable.

Is there an argument for hybrid systems, for example deploying floating solar and wind together, would that be better or simply add complexity for no purpose?

Gian Schelling's picture
Thank Gian for the Post!
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