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Solar panels floating on water
In this area of renewable energy the photovoltaic array is situated on a body of water. We look at the various methods used with this interesting system.
What is it?
- A photovoltaic solution that covers a body of water
- Usually a commercial size
- Largest to date is Sungrow Huainan Solar Farm capacity of 40(MW)
- Plans in Indonesia are underway to build a 200MW FPV system
Closer to home, floating PV has been appearing in Australia, but usually quite small projects.
These include an installation at a wastewater treatment facility at Jamestown in South Australia, a 100kW system at Happy Valley Reservoir in Adelaide and a 99kW installation in Lismore, New South Wales.
Where do they go?
- Large inland waterways
- Lakes, natural and man made
- Water treatment facilities
In most cases these systems are best located in still water situations where wave action is minimal.
Floatovoltaics have some water saving advantages:
- Part coverage can reduce the water evaporation
- This depends on local conditions and
- The percentage of the covered surface
- In Australia a decided advantage since about 80% evaporation is saved
- Really important in regards to irrigation
The main advantage of floating PV plants is that they do not potentially displace arable land.
Floating PV plants are more compact than land-based plants, their construction and decommissioning is straightforward. The main point is that no fixed structures exist like the foundations used for a land-based plant so their installation can be totally reversible.
What are some other advantages?
The containment of algae bloom is a real problem in many countries and by partially covering the water surface this reduces the amount of light hitting the water surface which translates into less algal blooms.
This is only a part of the more general problem of managing a water basin generated by industrial activities or polluted by them.
A solar panel’s output is related to the temperature:
- Passive cooling due to proximity to the water’s surface
- Can also be active by spraying the PV modules
- Can use a submerged PV modules
- Potential gain in energy harvesting up to 8-10%.
What about solar tracking?
A floating platform can be rotated and this can be done without wasting energy and no complex mechanics. There is an increased cost but the energy gains can range from 15 to 25%.
What about the methods of solar tracking?
- Central mooring. The tracking is generated by bow thrusters
- Mooring in the centre, ropes with winch
- Platform inside a reference frame and turns thanks to a rolling wheel
- System with a submerged support moored in a triangular way
- The platform rotates in respect to the submerged support
Things to consider with a FPV project
Costs incurred vary from project to project and they are highly site-specific.
Water level variation, depth, quality and salinity all play a huge role in determining the best possible anchoring and mooring system as do wind loads
Other factors to consider include:
- Distance to the shore
- Site accessibility
- Local infrastructure, proximity to the grid
Projects tend to require a more comprehensive technical due diligence.
- Water bodies are subject to increased scrutiny measures
- Imposed by relevant governmental authorities
- Conduct comprehensive environmental impact assessments (EIA)
In general, the CAPEX of FPV systems is currently around 5–15% higher compared to a ground-mounted PV system, but in some European countries, a 20+ MW system is already considered competitive.
Water catchment areas
Amongst OECD nations Australia is ranked fourth-highest in water use and this water is derived from catchments that cover an area of almost 16,000 square kilometres.
The potential of floatovoltaics in Australia is just fully being recognised now.
- Floatovoltaics involves PV projects installed on water catchment and treatment areas
- The advantages include the non displacement of valuable land and increases in output
- The increased cost over ground mount systems is around 5 -15% higher
This is an incredibly interesting area with certain technical and engineering challenges to come and Greenwood looks forward to being involved in our own floatovoltaic project soon!
If you’d like to see more of what Greenwood Solutions get up to in the real world of renewable energy, solar, battery storage and grid protection check out the following pages: