The floating solar proposition
When land is at a premium it makes sense to use the ‘free’ space on lakes and dams for solar panel installations. Paul Skelton reports.
By the year 2017 an estimated 3.5 million rooftop photovoltaic panels had been installed on Australian homes and business premises.
However, such panels are not always suitable: there may not be enough space, or a roof may not have the necessary structural integrity, pitch and orientation.
In response to this, ground-mount arrays – commonly known as solar farms – have found a strong following, making use of vacant land close to electrical infrastructure.
In fact, Australia is home to more than 20 large-scale solar farms that generate more than 50MW. Solar now accounts for 3.8% of the nation’s electrical energy production, responsible for generating 10,131MW.
But what can you do when land is at a premium? For owners of properties that feature dams, ponds or lakes, the answer could come in the form of floating solar islands.
Floating solar systems are designed to use the surface of an irrigation dam. They generate renewable energy to offset electricity consumption while reducing water evaporation and algae growth.
FloatPac chief executive Gavin Hodgins contends that water is a relatively lazy asset.
“Realistically, if you’re not using it, it’s probably costing you money – it’s like a boat,” he says.
“In recent times the floating solar industry has moved very, very quickly. Holistically, it’s fairly easy to understand why.
“But today the industry is in that limbo area between start-up and commercialisation.
“In Australia, we’re talking about 1-4MW projects. Overseas, where the adoption rate has been a lot higher, the small side is 50MW and the large side is 200MW.
“There is so much potential.”
The story of floating solar in Australia is brief and begins in 2015 in South Australia.
In addition to hosting the first application of floating solar in the country, that state is also home to the nation’s largest solar farm – Bungala in Port Augusta.
(SA leads the nation in the adoption of renewable power, with 48% of its electricity coming from sources such as solar panels.)
In August 2015 Infratech Industries unveiled a $17.5 million island that it had built, with assistance from Flinders University, at a large wastewater treatment plant at Jamestown, 200km north of Adelaide.
The system, which comprises 112 panels, uses the body of water to prevent overheating of the panels, and specialised concentrating and tracking technology to further improve output.
“With ground-mount solar installations you need a huge investment in the purchase of land,” Infratech Industries director Rajesh Nellore says.
“But there are so many water bodies just doing nothing, for which you don’t need large up-front capital investments. That’s what got us interested in water-based solar solutions.”
Four years before the installation at Jamestown, Suntrix – also of South Australia – was steadily making a name for itself in the increasingly crowded residential rooftop solar sector.
In order to expand its offering, the company recruited former Tyco Thermal Controls executive Geoff Fussell as chief project officer.
“When I joined the solar industry in 2011, I was appalled at the quality of work being performed in Australia – the lack of standards and the lack of training,” Geoff says.
“Looking at Suntrix, the first thing I said was that in order to be successful we needed to get out of the residential market and focus entirely on commercial applications.
“From there, I started to investigate what was expected to be the next ‘big’ area of solar, whether it was building-integrated PV or solar on carpark shelters. Whatever it was, I knew that it had to be something other than simply throwing panels on a roof.”
Geoff had spent time looking at product applications around the world and seeing how they could apply in Australia. He realised that Europe would probably hold the answer.
“I came across an article that talked about a floating solar installation on a dam at a winery. I liked the concept and understood that putting solar panels on water would be beneficial to energy efficiency as well as the environment.
“The French company Ciel & Terre was still in the early stages of development. It had recently completed a trial and had a new opportunity in Japan to design and install a floating system.
“I got in touch and soon after signed a distribution agreement. That’s when I started to promote floating solar in Australia.”
Since 2013, Geoff has made presentations at several national conferences to generate awareness and interest in the water-based solution.
“Before I did anything, I first had to find out what the market needed. What are the challenges and hurdles that are unique to the Australian market?
“This meant that when the tender for the Lismore City Council came up I could put forward a proposal that would ultimately be successful.”
Lismore City Council, which has adopted a 100% renewable energy goal, required an innovative solar solution at its highest electricity consumption site, the East Lismore Sewage Treatment Plant (ELSTP).
The ELSTP, which consumes 1577MWh per year, simply did not have the roof or land space to accommodate a solar farm.
As a result, Suntrix presented the council with a proposal to design and construct Australia’s largest floating solar island, based on a modular purpose-built float technology on a secondary water pond.
“Suntrix designed a solution for that site, which was actually quite challenging,” Geoff says.
“It was probably one of the hardest sites to start with from a delivery point of view – a sewage treatment plant with contaminated water in a flood-prone area. In fact, during the construction phase of the project the whole town was under water.”
In March 2017 between 500mm and 740mm of rain was recorded in the Lismore region, where the Wilsons River peaked at 11.6m. More than 20,000 people had to move out.
Today, the ELSTP solar island generates 12% of the facility’s energy requirements. The council has since set a target of 100% renewable power for the facility, indicating an expansion of the island from 99kW to 400kW to offset consumption from an estimated 12% to 44% respectively.
“Even though we weren’t the first to install floating solar in Australia, we are the first to develop a solution that is scalable and largely repeatable for large projects,” Geoff says.
Benefit of the drought
The case for floating solar is substantial and ranges from performance enhancements to environmental benefits.
“When you install solar panels over water you are putting them in a cooler environment, which leads to better efficiency,” Geoff says.
“For every degree over 25ºC a solar panel loses 1% of its output. So you’re not actually going to get 300W from a 300W panel, for example, once you go over 25ºC.
“If you put a solar panel on an iron roof and the ambient temperature is 45ºC and you’ve got raging heat reflecting off the roof, you’re talking about a cell temperature up around 65ºC or even 75ºC. This means you’ve lost a lot of output from the panel.
“However, water temperatures are typically around 25ºC, even in summer, so you don’t experience the same losses.”
Floating covers for bodies of water are effective but also expensive.
Such covers provide a physical barrier to reduce solar radiation, trap water vapour and decrease wind speed over the water.
Studies indicate that floating covers provide an evaporation efficiency of greater than 60%, along with a likely reduction of algae.
The introduction of floating solar essentially acts as a cover, mitigating the issue of evaporation.
“Because the solar island shades the water, you’re reducing the evaporation rate,” Geoff says,
“If you are covering, say, 75% of the water surface, you’re going to reduce water evaporation quite dramatically.
“In Australia, we lose something in the order of 2m of water out of a dam each year due to evaporation. If you can save that much each year, it’s far better for conservation.”
Algae multiply rapidly if there are ample nutrients, particularly when direct exposure to sunlight is heating the water.
“By covering water and shading it you’re also reducing algae growth,” Geoff says.
“By reducing algae growth, you’re reducing your filtration requirements.”
There are many suppliers of solar panels around the world, and Australian companies will never be able to compete with the Chinese and German manufacturing giants.
For Gavin Hodgins of FloatPac, it’s the float itself that differentiates solar islands. He believes his company’s history in supplying Australian-made floatation systems puts it in a prime position to best service the market.
“FloatPac was established in 1983 when it started manufacturing inflatable lift bags for the Australian Navy,” Gavin says.
“We still have the contract for the Defence Department and have expanded into other inflatables, marker buoys and the like.
“Then in the mid-1990s the company started experimenting with live fish transport systems.”
Gavin says there was an opportunity in the live fish industry. Coral trout caught in Cairns had to be shipped to Hong Kong efficiently and affordably. The FishPac live air transport system was created as an alternative to outdated water-filled plastic bags packed in Styrofoam boxes, and air pump systems.
“When it came to floating solar, we modified our FishPac system. We were able to ‘Frankenstein’ it into something well suited to floating solar islands.
“FishPac has a lot of history behind it and a lot of success. It’s not just plucking an idea out of thin air. There’s plenty of science and technology behind it.”
FloatPac is working on its first installation – a 20kW system in regional Victoria, just outside Healesville.
“In our system, with regard to attaching the pods, we’ve eradicated any sort of thread or locking nuts,” Gavin says.
“When you put things on water and you get movement, locking nuts love to undo. The clipping concept that we’ve developed is a pretty novel idea.
“And the racking system we’ve designed borrows a lot from a roof rack design for solar panels.”
Every FloatPac Solar flotation pod is 100% recyclable, UV stabilised, and rot and mould resistant.
“The unique design of FloatPac Solar ‘floatovoltaics’ means that our packing density for all forms of transport is superior to other flotation offerings. This not only reduces transport costs, it also affects your carbon footprint.
“Other systems, despite being very good, are expensive to transport. You’re essentially transporting air. That’s really what we focused on: how do you get rid of the air?”
FloatPac is looking at floating projects that would mean the cumulative generation of 15-20MW, and a couple of interesting export opportunities have come up.
Floating solar installations must be anchored, and that presents many challenges.
Geoff Fussell says a system in a cyclone region is subject to prevailing wind from one direction, and cyclonic wind from the other direction.
“This turns your floating solar island into a sail, so wind loads are critical in the design phase. It’s not just taking a float, putting it out on the water and saying ‘she’ll be right’.”
Seaflex is a Swedish supplier of elasticised mooring solutions for floating applications such as docks/pontoons, wave attenuators, buoys and solar islands.
Sales executive Vasile Bazarschi says the company has more than 1,700 installations in 85 countries.
“About 10 years ago, when the floating solar industries started to develop in Europe, we saw great potential. So we took the products we were using in marinas and adjusted them to the new market.
“Today we have seven floating solar installations around the world. There are three in South Korea, one in India, one in the UK, one in Portugal and one in the US.
Every Seaflex unit is composed of rubber hoses. The length and number of hoses in each unit changes depending on the project.
“Every one of our mooring systems is custom made,” Vasile says.
“To develop the best possible system for a project, we require a range of environmental data such as water depth, water level variations, wave height and wind speed. We then design the units to handle those forces.”
The company’s confidence in the product is demonstrated by a 20-year warranty.
“Of course, there are mooring systems that have been used for hundreds of years, such as chains, ropes and metal wire.
“Seaflex is different in that our system is elastic. When there is water level variation or high winds, the length of our mooring line will adapt.
“With chains, if you have water level variation of, say, 3m, you will get slack in the mooring line at the lowest water level.
“With slack, high winds will move the floating platform from side to side. That can result in failure of the mooring line.
“You will have the same problem with ropes and metal wire, because they don’t have any elasticity.
“Our system is always under tension. During these variations, it will dampen the big loads and will not let the mooring line fail.”
Floating solar requires not only product compliance but also an engineer-designed and constructed system that meets Australian regulatory requirements.
“Don’t think that floating solar is just another application of ground or rooftop solar,” Geoff Fussell says.
“There are so many other challenges involved in this application that it’s very high risk and will send you broke if you get it wrong.
“I wouldn’t attempt to do it as a subcontractor without properly researching the market.
“You need to be very careful about how you approach the whole exercise, because it’s fraught with huge dangers.
“Floating solar systems have to be designed for a particular site, and there are lots of challenges on every site. It’s not a quick solution that you can deliver without a lot of pre-engineering.”
Of course, success attracts imitators, many of whom are simply looking for a cash grab.
“Following on from the success of Suntrix and Ciel & Terre globally, we’re starting to see other manufacturers enter the Australian market. But they lack the knowledge to build a solution that is appropriate to our market.
“Even Ciel & Terre didn’t have the right knowledge of Australian Standards and conditions for the Lismore City Council project. It was only thanks to Suntrix knowledge and product development capabilities that the solution was successful.”
Floating solar installations in Australia require adherence to strict and stringent requirements.
“We’re talking electricity and water, so it’s a high-risk application. And installation requires compliance with more Standards than AS/NZS 3000. There are all sorts of little traps that most people won’t even consider.
“The build phase itself is quite quick. It’s the engineering phase that requires a lot of time.
“For the Lismore City Council project, for example, the actual construction of the 100kW island took a week including civil works, anchoring and assembly.”
Geoff says the installation of 100kW on a roof might be a two-week job for a fairly large team.
“Construction-wise, floating solar is relatively quick because it’s like a big Meccano set.
“But there are lots of challenges. Again, looking at Lismore, we had to allow for at least 7m in rise and fall thanks to flooding. And the actual construction of the project was delayed because of the 2017 floods.”
Gavin Hodgins says there’s not much going on in Australia at the moment, but it’s only a matter of time.
“In the past few months we’ve seen a 150MW plant installed in China. The Japanese have somewhere in the vicinity of 200MW installed across different properties.
“The Indian government has started tendering on 1GW of installations over the next 10 years.”
Charles Gery, worldwide sales manager at Seaflex, says people are predicting terawatts of floating solar installations.
“The potential is immense. There are quite a few advantages in the floating solar industry versus ground-mount systems.”
Rajesh Nellore of Infratech Industries says the environmental benefits of floating solar far outweigh any possible cost premium.
“Actually, water-based solar may be a bit cheaper than land alternatives. It all depends on scale.
“But it’s not just about cost. With floating solar you’re getting better returns compared with ground-mount systems. You can have as much as a 57% higher yield.”
The final word goes to Geoff Fussell, who says the technology will be accepted ‘en masse’ in future, but it is still early days. He strongly advises contractors to do their homework before attempting to install a floating system.
“With any release of a new product, if it’s done wrong you can destroy the reputation of the product and the application.
“What I’m doing at the moment is proving the methodology, the application and the product. Once I’m happy with all of that and we’ve got established reference sites, I will be looking to work with skilled subcontractors.”
Until that time, everybody just needs to avoid making waves.