Coal-to-gas conversion |


Engineering a gas-fired future for Spain’s Aboño 2


Plant life extension, emissions reduction and cleaner, more flexible generation – just some of the key benefits of a coal-to-gas conversion carried out at EDP’s Aboño 2 power plant in Spain


John Goldring Managing Director, RJM International


The Aboño power plant, unit 2 to the left (Photo: EDP)


12 key project phases


1 Fact-finding (baseline performance test, site survey and combustion audit)


2 CFD modelling programme


3 Engineering design phase and first draft of O&M manual


4 Procurement and manufacture of new hardware


5 Installation, carried out by EDP’s main contractor, Duro Felguera, under Wood and RJM supervision


6 BMS and DCS upgrade 7 Commissioning 8 Optimisation 9 Performance guarantee tests


10 Training of plant personnel on new operational procedures.


11 Final O&M manual issued 12 Project completed


The Aboño 2 plant was commissioned in September 1985 and consists of a 556 MWe opposed wall-fired Foster Wheeler boiler with 36 burners in a six column/three row configuration. As well as coal, the plant fired additional fuels including fuel oil, as well as blast furnace gas (BFG) from an adjacent Arcelor-Mittal steelworks. Located at Gijón in Spain, Aboño 2 is owned and operated by EDP (Energias de Portugal), a major global utility generator with operations in Europe, the Americas and Asia-Pacific. EDP has a total installed capacity of over 32 000 MW and is committed to clean energy. It drives global growth through electrification, focusing on renewables, resilient networks, and balanced investment for a sustainable future.


Project objective – reconfiguring the plant to fire natural gas As part of Spain’s national plan to decarbonise the economy, legislation was introduced to cease all coal-firing by the end of August 2025. This meant that coal-fired power plants either had to shut down or transition to an alternative fuel. In this case, EDP set aside an investment budget of mid-double-digit million euros and selected Wood (engineering consultancy and boiler OEM, via its acquisition of Amec Foster Wheeler) to undertake a project scope to explore what the plant’s options were for continued generation. Duro Felguera was selected as main EPC contractor.


Wood carried out a number of detailed feasibility studies to evaluate alternative pathways


NOx  NOx 


for modifying the plant and proposed to EDP a set of engineering designs, based on economic viability, environmental impact and operational efficiency.


Project procedure


Once it was determined that a conversion from coal to natural gas would be the most viable way forward, Wood appointed RJM International to tackle the combustion part of the project. This followed a complex tendering process and submissions by a number of multi-national burner technology companies. RJM’s scope included the design and manufacture of the new burner system that would be needed to meet project objectives, in


terms of significantly reduced emissions, more reliable operation and continued fuel flexibility. It was also important to retain the capability to fire blast furnace gas from the steelworks, as this enabled efficient use of a waste fuel contributing to green steel manufacture, as well as reducing Aboño’s own consumption of natural gas. An additional requirement was that the plant should be future-proofed with the in-built capability for the burners to fire hydrogen, thus ensuring that a “next generation” level of plant life extension in a zero carbon environment could be achieved. At the start of the project, Wood and RJM conducted a site survey, a baseline unit performance test, a full combustion assessment, a boiler part pressure test and an economiser


Left: CFD image showing NOx


before (coal) and after (gas). (Image: RJM International)


Above: CFD gas burner image showing compact flame profiles. (Image: RJM International)


38 | November/December 2025| www.modernpowersystems.com


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