Energy-environmental experimental campaign on a commercial CHP fueled with H2NG blends and oxygen enriched air hailing from on-site electrolysis

It is well-known that the renewable electricity excess can be converted into hydrogen for implementing power to gas strategy. Thus, the hydrogen injection in existing natural gas pipelines is a foreseeable option to avoid its storage criticalities and for greening the NG sector. H2NG blends can be fired within CHP engines as well as in other conversion systems, offering better energy performance and reducing the environmental impact as well, once adjustments on combustion setup have been applied. The on-site H2 production for the NG enrichment by an alkaline electrolysis could be more effective whether the oxygen was fruitfully recovered instead of venting it out like a by-product. This study explores the possibility to use that waste oxygen to chemically supercharge the air-fuel mixture, once a widespread micro-CHP technology, based on a reciprocating engine, is fuelled with H2NG blends. So, this paper reports the CHP performance, advantages, drawbacks and technical features, when H2NG blends, ranging in 0%–18% vol. Burn in partial oxy-fuel conditions. An energy and environmental analysis have been carried out, discussing the engine gains, losses and pollutants emissions, when oxygen content varies up to 22% vol. The VolksWagen Blue Tender CHP engine has been used for the on-field tests.