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Floating solar offers revenue boost to water

Tuesday, 18 August 2020

Pumping up water assets with solar power

Around the world, policies promoting increased use of renewable energy are driving utilities to explore options for increasing clean generation capacity. As a result, the owners of water assets like reservoirs have a route to new revenue streams - floating solar.

Although still a relatively new concept (the world’s first floating solar project was installed in Aichi, Japan, in 2007) numerous trials and pilot installations have now proven the technical and business case.

Developers are looking to scale-up installations to large and fully commercial power plants.

For example, the largest floating solar project in Europe was commissioned last year in France at the site of an old quarry. At 17 MW, the OMega1 project was developed by Akuo Energy in the Rhone valley.

Exponential growth expected

Asia is also taking the lead on deploying floating solar, with one project in China having a peak output of some 150 MW.

Meanwhile, in Japan, where they are looking to promote clean and renewable energy, there are some very significant developments of floating solar.

There is certainly considerable scope for floating solar. According to the SolarPower Europe trade group, if just 1 per cent of the world’s artificial reservoir surfaces were used for solar, the global capacity would be around 400 GW.

A World Bank study also notes that the capacity for floating solar is already growing exponentially.

At the end of 2014, the total global installed capacity for floating solar stood at 10 MW. Less than four years later that figure had grown more than 100-fold to 1.1 GW.

This is expected to grow to around 10 GW by 2030, according to Statkraft which is currently developing a floating solar project in Albania.

The benefits for water asset owners

Considering floating solar, aside from extreme weather events such as typhoons, engineering risks are not significantly greater than for their land-based equivalents. There are a number of technical advantages in terms of the performance too.

For instance, bodies of water are largely free from obstructions that may shade the solar panels. In addition, the water may be used to cool the panels which boosts their conversion efficiency and increases output.

However, perhaps the biggest commercial benefit comes from alternative land use.

While there are considerable additional costs associated with the floating platform these must be offset against land costs that would be required for conventional terrestrial solar PV development.

In high density urban areas land values are at a premium, likely making traditional PV plants economically unviable.

Conversely, the surface of a reservoir may be considered an asset of almost zero commercial value unless it is used for this kind of development.

“Given the value of land in places like Hong Kong it would never be cost-effective to take up large areas with solar,” says Justin Searle, director of projects at Black & Veatch.

Speaking to Aquatech Online, he adds: “The prime benefit is in not utilising land for these kinds of developments. In many cities, floating solar is really the only viable option.”

Secondary benefits

For water asset owners there are secondary benefits too, such as the reduction of evaporation and also a reduction in the amount of algae growth due to curbing the amount of sunlight reaching the water column.

Searle says: “Reservoir operators may enjoy some of these secondary benefits, which are probably relatively small given that many projects only cover a fraction of the total water surface, but there will be a proportional reduction in evaporation and in algae growth.”

Another advantage of solar development on reservoirs comes from the location and the proximity of the electric utility’s infrastructure.

Such sites are often close to urban populations which also coincide with energy demand hot spots. Locating the solar power plant close by saves on transmission and distribution costs.

“A World Bank study notes that the capacity for floating solar is already growing exponentially.”

Adding up the advantages

For the owners of reservoirs or similar bodies of water, floating solar potentially represents an attractive additional revenue stream depending on conditions such as feed-in tariffs, local energy policy and other relevant factors.

Certainly, policies to promote renewable energy capacity support the business case beyond potential earnings or offsetting existing energy costs for pumps, air blowers or other necessary equipment.

As Searle concludes: “Development of renewable energy is a prime driver for the floating solar market and there is a huge potential for further development.”

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