Acciona Energía is testing a hybrid storage architecture that combines lithium-ion batteries with ultracapacitors at renewable-energy sites in Navarra, Spain. The design assigns longer-duration energy delivery to batteries while ultracapacitors handle rapid power changes and short peaks.
From 250 kW to 1.25 MW
The first phase at the Barásoain wind farm operated at 250 kW before being expanded to 1.25 MW. The original 250 kW system was then moved to the Tudela solar facility for testing with photovoltaic generation.
The project targets fast frequency response, virtual inertia and voltage support—services historically associated with conventional synchronous plants. For solar-plus-storage buyers, the pilot illustrates why system design increasingly depends on matching each storage technology to a specific duty cycle. Hybrid architectures may reduce battery stress, but procurement must evaluate controls, warranties, interface responsibility and lifecycle cost at system level.