Castellón green hydrogen plant has reached 90% completion in latest update from developers BP and Iberdrola. The 25-MW green hydrogen plant located at BP’s refinery in Castellón and is expected to become the largest operational green hydrogen facility in Spain. The project is being developed through the 50/50 joint venture Castellón Green Hydrogen S.L., with all major equipment, including a 25-MW electrolyzer system supplied by Plug Power, already installed at the site. The facility is scheduled to begin testing in May 2026 ahead of full commercial operation in the second half of 2026. Once operational, BP and Iberdrola’s 25-MW green hydrogen plant in Castellón will produce around 2,800 tons of renewable hydrogen annually. Additionally, this will replace part of the grey hydrogen currently used in refinery operations.

Castellón Green Hydrogen Plant Project Factsheet

Location: Castellón in Valencia region, Spain

Developers: BP & Iberdrola (via Castellón Green Hydrogen S.L.)

Electrolyser Capacity: 25 MW

Technology: PEM electrolyzer system

Electrolyzer Supplier: Plug Power

Investment: €70 million

EU Funding: €15 million through NextGenerationEU program

Renewable Power Supply: 200 GWh/year via Iberdrola wind and solar PPAs

Annual Hydrogen Production: 2,800 tons

CO2 Emissions Reduction: 23,000 tons per year

Target Commissioning: H2 2026

Construction Workforce: Up to 500 jobs. 25 Spanish companies also involved in construction and supply chain.

Project Team Behind Castellón Green Hydrogen Plant

BP

Project co-developer and host of the facility at its Castellón refinery. Also responsible for integrating green hydrogen production into refinery operations.

Iberdrola

Co-developer and renewable electricity provider supplying approximately 200 GWh annually from wind and solar generation under a PPA.

Castellón Green Hydrogen S.L.

50/50 JV established to develop, construct and operate the hydrogen facility.

Plug Power

Supplier of five containerized 5-MW PEM electrolyzer units with 25 MW total capacity.

Imefy

Spanish manufacturer selected to supply the main transformer for the hydrogen plant.

NextGenerationEU

Provided €15 million in funding under Spain’s Recovery, Transformation and Resilience Plan.

Instituto Tecnológico de la Energía

Technical collaboration supporting the hydrogen value chain development and innovation.

Project Financing

Castellón green hydrogen facility represents an investment exceeding €70 million, jointly financed by BP and Iberdrola. The project has also received €15 million in funding from the European Union’s NextGenerationEU program, distributed under Spain’s national recovery and resilience plan to focused on industrial decarbonization and renewable hydrogen deployment.

The hydrogen plant also forms part of BP’s broader HyVal initiative, which aims to develop a large-scale green hydrogen cluster around the Castellón refinery with up to 2 GW of electrolysis capacity by 2030. This is with an aim of supporting the refinery’s transformation and wider industrial decarbonization across the Valencia region.

Why is Castellón Green Hydrogen Plant Important

Castellón project represents the first green hydrogen development jointly undertaken by BP and Iberdrola. It is also a show of how renewable electricity can be integrated into industrial energy systems.

Additionally, by replacing grey hydrogen derived from natural gas, the plant will significantly reduce emissions from refining processes. It is also expected to strengthen Spain’s emerging hydrogen economy with other projects like Andalusia Green Hydrogen Valley and Lhyfe 15 MW green H2 plant in Vallmoll.

The project also serves as a pilot phase for potential expansion, with future phases potentially scaling electrolysis capacity beyond the initial 25 MW as part of the wider HyVal hydrogen hub strategy.