Energias de Portugal (EDP) and Corporación Masaveu
Asturias, Spain
Overview
Pioneering fuel transition for Spain’s power market
Located in the Asturias region of Spain, the Aboño power station is a two-unit coal-fired power plant with a total capacity of 916 MWe. Commissioned between 1974 and 1985, the plant is owned by Energias de Portugal (EDP) and uses several fuels, including domestic and imported coal, warm-up natural gas, diesel and the excess gases produced by the Arcelor-Mittal de Gijón steel mill.
Aboño’s steam generator was designed by Wood (previously Foster Wheeler) in the 1980s to provide 556 MWe, burning 77% coal and 23% blast furnace gas from the nearby steel mill.
Against the backdrop of a global energy transition, EDP sought to reduce its environmental impact by fuel switching to a purely gas-fired plant. EDP wanted to unlock associated efficiencies and the economic benefits of using gas fuels – such as blast furnace gas (BFG) and hydrogen - to power Aboño.
Scope
In late 2024, EDP selected Wood to execute a boiler conversion project to completely replace coal with natural gas and green H2 in the installed steam generator. The project scope included in-depth feasibility studies, brownfield boiler modifications and commissioning.
The repurposed Aboño plant became operational in July 2025.
Solution
Applying specialist boiler knowledge, built from over a century as OEM
Wood conducted various comprehensive, in-depth technical and feasibility studies over 2-3 years. During this study phase, Wood and EDP evaluated various pathways for coal fired units 1 and 2. Engineering designs were proposed based on economic viability, environmental impact and operational efficiency.
As Original Equipment Manufacturer (OEM) of the brownfield boiler, Wood applied over nine decades of deep utility steam generator technology knowledge to provide a sustainable, smart solution. Once studies concluded in 2023, the modification scope was outlined.
Wood executed the installation of over 30 modern low-NOx gas burners and retrofitted 12 existing BFG burners, distributed in seven rows along the front and rear walls of the furnace. Wood’s expert engineers redesigned superheater surfaces and upgraded tube alloys to withstand new operating conditions.
To improve efficiency and reduce carbon emissions, Wood extended the boiler economiser, engineered a modification to the air preheaters enhancing heat recovery from the flue gas and conducted a remnant life assessment of the pressure parts that remained unchanged.
Brownfield excellence in the power sector
Wood also ensured brownfield systems were integrated with the new modifications by modernising the control system and lowering the minimum technical load to enhance operational flexibility.
These complex boiler modifications called for cutting-edge tools including Computerised Fluid Dynamics (CFD) combustion analysis and proprietary boiler thermal performance modelling, which added value to the final outcome by:
- Assuring the required NOx emission level
- Optimising fuel combustion to minimise pollutants like carbon monoxide, enhancing overall boiler and plant efficiency
- Keeping the superheated and reheated steam parameters within the contractual limits demanded by the turbogenerator
Outcome
Supporting EDP’s transition to cleaner burning fuel
Encouraging sustainable fuel transition: Wood provided EDP with a clean, reliable and flexible unit capable of operating with a wide range of gas fuels, including BFG and hydrogen. This fuel flexibility paves the way for further decarbonisation through the use of other low-carbon fuels, such as syngas from biomass gasification.
Future study possibilities: Future studies could unlock the integration of ammonia into the fuel mix or increase hydrogen content beyond the currently projected level (below 5% MCR).
Reducing harmful emissions: Conversion reduced CO2 emissions by 30%, particulate emissions by 100%, sulphur emissions by 90% and NOx emissions by 80%, lowering environmental impact.
Enhancing steam generator and thermal cycle efficiency: Steam generator efficiency is well above the target established by the EDP, while keeping both the superheated and reheated steam temperature and pressure at the same value as before the conversion. Both factors contribute to minimising fuel consumption and achieving the plant's financial targets.
Project timeline execution: The entire project was completed on-time and on-budget, despite its complexity.
Wood is proud to demonstrate our expertise in this project, which reinforces gas conversions as a viable pathway for repurposing coal-fired power stations - currently responsible for 30% of global electricity generation.
Gas fuels will play a crucial role in enabling energy transition and we are proud to be a part of the solution for the Asturias region.