The Arañuelo III plant, the first large-scale solar PV power plant integrated with an energy storage system in Spain, has been inaugurated.

The 40MW solar PV is located in the district of Almaraz in Extremadura and comprises a 3MW/9MWh battery energy storage.

The project is part of Iberdrola’s Arañuelo 1, 11 and 111 solar systems with a total capacity of 143MW.

Technology firm Ingeteam was selected by Iberdrola for the supply and installation of the lithium-ion battery systems, solar PV inverters, transformer stations, power plant controllers and SCADA monitoring system.

The digital control and SCADA systems enable the system to be monitored and controlled in near real-time to optimise energy generation and storage.

Digital protection and control systems which include 30/132KV step-up transformers and collector and connection circuits were installed to develop a renewable energy control center with real-time information and access to various aspects of the system. The system also enables protection and control of the line that delivers capacity to the grid, according to Ingeteam.

The project offers a novel feature with the inclusion of the battery storage system within the solar PV plant as a distributed system with a DC-Coupling configuration. In this mode, the batteries are installed within the solar array and the battery converters share the DC connection with the PV inverters, offering advantages including:

Possibility of utilizing the extra power from the solar panels that is not used in the peak production hours (Clipping Recapture).

This makes it possible to minimize the losses by charging the batteries from the PV array, given that the connection between the panels and the batteries only passes through the DC/DC converter. The discharge is also more efficient, due to the fact that no power transformer is required, in contrast to the AC connected solution.

The Campo Arañuelo complex is part of Iberdrola’s strategy to expand its portfolio of renewable energy for decarbonisation and use of energy storage to optimise renewables projects.

By coupling renewables with storage, the utility will be able to shift capacity to when it is most required, as well as leverage use cases such as energy flexibility for grid reliability.

The project is already producing clean energy to supply a population equivalent to 65,000 homes a year and avoiding the emissions of 41,000 tons of carbon dioxide per year.