Solar panels to generate energy on water seemed like a dangerous trick to Benedict Ortmann when he first heard the idea.
"Every kid knows that electricity and water don't mix," says Ortmann, chief solar officer at Bayware Munich, one of Europe's largest renewable energy producers.
When Ortmann installed its first floating panel assembly in 2018, Bayware's business was primarily for conventional land-based solar. But five years later, the company is now Europe's leading manufacturer of floating photovoltaics, better known as FPV, or "photovoltaics" in industry parlance. While floating solar accounted for less than 1% of all panels installed worldwide last year, its use has grown by more than 2,000% in the past decade.
They are increasingly being installed in former coal and quarry watersheds and hydroelectric lakes.
One of the factors behind this change is the massive adoption of rooftop solar panels in Europe over the past two decades, which has put pressure on finding new real estate for renewable energy. Further attempts to build in rural areas were hampered by opposition from farmers and local residents, who were upset that the panels obstructed visibility. "Agriculture still sees solar panels as a competitive threat to the same land," says Bayware CEO Matthias Taft.
Photovoltaic floats overcome this problem and can revitalize abandoned spaces. Most of the former gravel and sand pits are no longer in use. "It's low-hanging fruit," Taft said.
Bayware has installed floating panels capable of generating half a gigawatt of power in Europe and is evaluating new sites in Asia and South America. The project's pipeline currently has 28 gigawatts of capacity, equivalent to the peak capacity of a dozen nuclear reactors, which the company aims to triple by 2025.
To meet the growing demand for FPV, European governments, companies and utilities are exploring abandoned industrial sites for available water sources. At the top of the list are ponds and lakes that do not attract many visitors and have a stable water level that does not disappear under a layer of snow in winter.
Access to infrastructure and proximity to population centers are also important. "The main barrier to solar development in Europe today is the lack of sites with easy grid connections and land permits," said BloombergNEF solar analyst Jenny Chase.
According to World Bank estimates, Europe could cover at least 7% of its annual energy consumption with floating solar panels on 10% of the area of man-made lakes. If this figure were to increase globally, electricity generation would increase by 5,211 watt-hours per year, which is more than all the electricity consumed annually by the world's largest economy, the United States.
Austria, central Europe's largest floating voltaic pool, has launched private subsidies for photovoltaic power and other new projects that combine energy production with environmental or agricultural goals. Scientific studies show that FPV improves water quality by reducing algae growth. The panels can also help conserve water during dry periods by reducing evaporation and reducing sunlight penetration.
Austria's climate and energy minister Leonore Goessler said small countries "must be smart" when it comes to innovative solutions to produce clean energy. The Netherlands has installed Europe's largest floating solar system, and interest is growing in Italy, Portugal, Switzerland and the UK.
Austria's first floating power plant in Grafenwürth, an hour west of Vienna, is an example of how he envisions a green future. The former quarry is surrounded by farmland and adjoins a sand and gravel company and is developed by Bayware, local EVN and municipal services. After two years of planning, it took workers just two months to install the 24.5 MW panels, and the site went online in February.
On a cloudy day in July, specially designed buoys and transducers float in 15 meters (49 feet) of water. Tall grass grew along the shore, and lighted kayaks were used on the pier when technicians had to run out to check their equipment. The 45,000 panels covering Grafenwoerth cover an area the size of 20 football fields and produce enough energy to power 7,500 homes on a clear day. Additional potential exists in the hundreds of wells created by the mining of high-quality sand scattered across the Danube alluvial plains.
Developers are also eyeing a nearby former German coal mine with 2.7 gigawatts of floating solar capacity, according to the Fraunhofer Institute. In May, German coal miner LEAG AG announced plans to install floating photovoltaics on an artificial lake southeast of Berlin.
Dominik Gillow of EP New Energies GmbH, which is overseeing efforts to turn the former Cottbuszer-Ostsee coal mine into the center of Germany's fossil fuel economy, said the old coal regions were "ideal" for the technology. Power plant with a capacity of 29 megawatts. When the project is completed in 2024, it is expected to be Europe's largest floating photovoltaic generator.
But while the power generated by FPVs more than doubles every year, Bayware doesn't expect the overall European PV market to take off. There is still a lot of red tape and environmental licenses can take longer to evaluate than ground-mounted solar. But by 2025, the company hopes regulators will have time to catch up with the technology and start accepting more applications to install floating solar panels.
Once permission is granted, things move quickly. It took just 50 workers a day to install 1.5 megawatts of new energy in the water of a former mine in Austria.
"There's a lot to learn the first time," says Benedikt Kammersteiter, who managed the project during the two-month installation.
“But now it's just cut and pasted. It's faster and easier."
