The renewable energy market is rapidly growing amid the increasing interest of international society in sustainable development. Meanwhile, research and development in photovoltaics (PV) continues to raise the generating efficiency of a leading renewable energy source: solar power generation.
Measures to efficiently expand the surface area that sunlight reaches are emerging, alongside ways to improve the performance of solar modules. The recently covered BIPV (building integrated photovoltaic) could be seen in the same context. These days, ‘floating PV’, which actively utilizes the surface of lakes, rivers and oceans, is receiving new attention beyond land-based solutions. Remember, the earth’s surface is 70% water after all.
According to a 2019 floating solar market report by World Bank Group, the potential capacity of floating solar power if installed on 1% of the surface of all reservoirs worldwide is 404 GW. In terms of annual energy production, approximately 521 TWh of electricity could be generated, a huge quantity equivalent to 16% of the 3,446 TWh of electricity consumed across Europe in 2019. World Bank Group forecasted that floating PV systems will become the third pillar of photovoltaics after ground-mounted PV and rooftop PV.
Demand for floating PV is expected to continue to rise. A research study estimated that US floating solar panel market demand will reach 4,690.8 MW by 2027, reflecting a 28.9% CAGR (compound annual growth rate).
Many countries around the world have already taken action, including preparing institutional support measures, to meet potential demand. For example, the US state of Massachusetts is offering an ‘incentive program’ that supports unit price according to generating capacity when installing a floating PV system, and the Taiwanese government is applying a higher *FiT (Feed in Tariff) subsidy for floating PV systems compared with land-based PV.
China is another country that is active in floating PV development. The floating PV plant installed in Anhui, China, consists of 166,000 solar panels and produces 40 MW of electricity, which supplies about 15,000 households.
The Netherlands, known as the ‘land of water’, has numerous inland waterways measuring about 7,650 km2, a geographical advantage to installing floating PV systems. In 2018, the largest Dutch commercial floating PV plant was constructed on a reservoir in Lingewaard, The Netherlands. At the plant, 6,100 Q.PEAK 300W monocrystalline solar modules produced by Q CELLS were installed on a surface area of 15,800m2. The annual eco-friendly energy production of the power plant is approximately 1,800 MW, equivalent to the power demand of about 400 four-people households.
Meanwhile, in Korea, the world’s largest floating PV system, at 300 MW, has been under construction in the Saemangeum region since November 2019. Floating PV plants will be established in various phases at 31 dams nationwide by 2022.
The reason why the ‘floating PV system’ is the center of attention is not simply for efficient space utilization but also for the increase in generating efficiency. Compared to land-based PV systems, solar irradiance is not affected by shading, and the sometimes deep water under the solar modules plays the role of coolant, helping to increase energy production by about 10%. The additional effect of light interruption can suppress the growth of green algae that seriously degrades the water quality. The floating PV system is like killing three birds with one stone.
Going into detail, a floating PV system combines renewable energy and maritime technology (shipbuilding and mooring). The method of generating power is not that different from ground-mounted solar panels. However, there is a difference in facility structure, as the floating modules are installed on the water. The floating system consists of solar modules, buoyant body, mooring device and various electric installations (cable, inverter, etc.) The floating PV modules are installed on a buoyant body that is generally anchored with a mooring device and the generated electricity is supplied via underwater cable.
Current domestic and overseas markets mainly feature two types of buoyant body. The ‘frame’ type has buoyant bodies on the bottom and solar panels on the top of a manufactured floor frame made of metallic material like aluminum. It is structurally stable and offers high system utilization, but the installation cost is high. On the other hand, the ‘all-in-one buoyant’ type is constructed by directly connecting buoyant bodies to modules at a 15-20% lower installation cost than the frame type, but its less stable structure decreases system utilization by about 3-3.5%.
Despite the timeliness and importance of the floating PV plant business, misunderstandings and misperceptions exist related to floatovoltaic installation and operation in Korea. We will go over the main issues based on *research data provided by Korea Environment Institute.
Regarding water quality issues, there are reports saying that floating PV systems deteriorate the water quality, quoting overseas cases and studies. However, four analyses conducted at Hapcheon Lake in Korea revealed that measurements of water quality around the system didn’t show any meaningful difference compared to that of a comparison target point.
There was a study reporting the possibility of algal bloom, but the experiment in that study was based on a man-made environment and excessive installation area and did not reflect the actual conditions of domestic floating power plants. An analysis of the biological components in the Hapcheon Lake power system area found a stable plankton community index and didn’t show a significant difference from a comparison target point. The system rather has a fish attraction effect as small fry and other fish species that eat the fry, as well as legally protected species, were found under the structure.
According to a comparative analysis of Hapcheon Lake sediment samples of an area under the influence of the system and target areas from a point near where the system is installed, no significant differences were found. The results stem from the fact that major solar facilities in Korea use only environmentally-safe equipment that does not contain hazardous heavy materials.
Most of the items in the material solubility test were not detected in the Hapcheon Lake system, and the few detected items were below their regulatory thresholds. Specially, based on the precautionary principle, ‘Hygiene and Safety Standards’ under the Enforcement Decree of the Water Supply and Waterworks Installation Act, the most strict standard, which is about ten times stricter than ‘the quality standards for drinking water’ were applied, so there is no concern about dissolved hazardous substances.
Floating PV systems have various advantages, although considering the characteristics of the area where the system is installed, there are some constraints, such as wind load, wave height and waves based on weather conditions. Hence, floating PV plant installers require a high level of understanding and experience with location-allocation and installation, along with advanced technology.
Q CELLS is constructing the world’s largest dam floating PV plant, ‘Hapcheon Dam Floating PV Plant’ project. The plant will produce enough electricity to meet the annual power needs of about 60,000 households, which is more than the actual 44,434 population of Hapcheon county. Q CELLS is building the floating PV plant in a design inspired by the symbolic flower of the region.
Q CELLS is leading the floating PV business, as evidenced by landing a 63 MW floating PV plant construction contract on Goheung Lake after having started the construction of the Hapcheon Dam Floating PV plant. The Goheung Lake floating PV plant will be constructed in a moon-shape design to symbolize Goheung country where the nation’s Naro space vehicle was launched. This power plant will generate enough electricity to meet the annual power needs of about 90,000 households, which is more than the 63,922 population of the county.
‘Q.PEAK DUO Poseidon,’ an exclusive floating solar module by Q CELLS, is being installed for the floating PV plants. The Q.PEAK DUO Poseidon is specialized to withstand harsh aquatic environments as proven through the salt-attack corrosion test, while its excellent damp-proof eco-friendly materials allow it to endure high temperatures and high humidity conditions. Q CELLS has achieved sales of 100 MW of the Q.PEAK DUO Poseidon thanks to the Goheung Lake floating PV plant.
The floating PV system, one of the pillars of the solar power market, is evaluated as having the potential to lead the future energy industry. For long-term growth of the floating PV market, it is necessary to improve safety and efficiency as well as to make considerable efforts for maintenance. Q CELLS will continue to develop product technology based on world-class quality and performance and to lead the industry in innovation.