Save water – Produce green energy – Think big. These guiding principles have led Siemens' KACO new energy GmbH and its local partner, Altitude, to supply Israel’s largest floating solar park with power equipment. The Virtual Central system design is perfectly made for a power plant like this: it reduces investment costs, increases yields and makes maintenance easy.
Water evaporation and an unused reservoir surface
The Habonim water reservoir is located in the coastal region south of Haifa. The reservoir contains 3.3 million cubic meters of water, covering an area of 112,50 acres. The water is used for regional agriculture activities. During hot days, some of the water evaporates from the reservoir and cannot be used for agriculture anymore.
Fortunately, Israel has committed itself to a high use of renewable energy. This goal comes with new challenges. Israel is facing space constrains, for example. Solar energy competes with other important infrastructure projects.
Solar system stops water evaporation and provides new space
Since September 2021, the Habonim water reservoir has been covered by 51,500 solar modules, with a total power of 23 MW. This floating PV plant generates clean energy for 3,000 households. The system was constructed using the innovative Virtual Central design.
The solar module strings are collected in dc-combiner boxes, which also manage the string monitoring. The dc-combiner boxes are located on the floating structure on the reservoir. From there, dc cables transport the energy to the designated inverter hubs, which are land-based next to the reservoir. This eases the operation and maintenance activities on the 120 blueplanet 150 TL3 string inverters from our German production facility, which are available in Israel through our distribution partner, Altitude.
The solar modules prevent water from evaporation, so that more water can be used for agricultural purposes. Another major benefit of a floating solar system is the fact that often ground-mounted solar systems frequently face space competition with other important infrastructure projects, like schools or hospitals. Floating solar systems are free from such conflicts; setting them up on water leaves more space for other projects.
Innovative Virtual Central approach reduces costs and increases yield
The Virtual Central design offers a host of other advantages for floating solar systems. Since the inverters can be installed next to the reservoir, there is no need for extensive cabling. Only single-MPPT inverters by Siemens can be deployed in this fashion. Furthermore, power losses stay on the dc side and a highly efficient energy transport from the reservoir to land at 1500 Vdc can occur. Thanks to this, and due to the efficiency of up to 99.2%, the single-MPPT inverters can provide higher yields than conventional system designs with multi-MPPT inverters.
This has been confirmed recently by independent research institutes. Since less cables are required for this design, the investment costs for the balance of system can be reduced by up to 10%. This leads to overall reduced investment costs.
In summary, the Virtual Central approach reduces investment costs, ensures higher yields and is very advantageous for operating and maintenance activities, especially on floating PV systems. Other floating PV systems that rely on the Virtual Central approach are in development and will be deployed soon.
Details about the superior yield of single-MPPT inverters have recently been published by the Fraunhofer Institute for Solar Energy Systems.