Journal of Energy and Power Engineering 7 (2013) 1681-1690 Preliminary Experimental Analysis of a CHP Hydromethane System Livio de Santoli 1 , Gianluigi Lo Basso 1 and Daniele Bruschi 2 1. Interdisciplinary Centre for Landscape, Sapienza University, Rome 53-00197, Italy 2. Department of Astronautical, Electrical and Energy Engineering, Sapienza University, Rome 18-00184, Italy Received: June 16, 2012 / Accepted: December 24, 2012 / Published: September 30, 2013. Abstract: The aim of this paper is to present the preliminary experimental analysis results carried out on the commercial internal combustion engine set in a CHP (combined heat and power) mode, fueled by renewable hydrogen and methane mixtures. The hydrogen is produced by an alkaline electrolyser fed by a 5.8 kW p grid connected PV (photovoltaic) plant. The acceptance test conducted with hydrogen percentages ranging from 0%-10% has been carried out at partial load: 45 kW el instead of the full power of 60 kW el . In order to evaluate the CHP energy consumption and environmental performance (NO x and CO), the analysis was conducted for 240 h, using a portable flue gas analyser and two mass flow meters for hydrogen and methane. Without engine parameters optimization—relative equivalence ratio (λ) and spark advance—increasing hydrogen addition rate, a slight enhancement in electrical efficiency occurs. Furthermore, due to the engine control system and lower blends LHV (lower heating value), the methane consumption decreases disproportionately to the hydrogen amount in the mixture. Finally, referring to standard operating condition, the environmental results show that using enrichment of 10%, running the engine with 18 degrees spark advance and λ of 1.4, CO and NO x emissions are reduced by 6.3% and 27% respectively. Key words: CHP systems, hydrogen-natural gas blends, experimental analysis, efficiency, pollutants emission. 1. Introduction During the last 10 years, the methane gas enrichment with certain hydrogen amounts was investigated by various research projects [1-4]. The most interesting aspect arising from the implementation of such mixtures is that hydrogen can extend the lean burn natural gas limit. Under these operating conditions, it is possible to achieve very low NO x emission levels mitigating unburned hydrocarbons formation. These results are achieved without control systems application and combustion exhaust gas processing device. Furthermore, the CO and CO 2 values produced from hydromethane burning are lower than any other gaseous fuel [5]. To take into account the backfiring problem, Corresponding author: Gianluigi Lo Basso, Ph.D. St., research fields: distributed microgeneration and energy saving. E-mail: ing.gianluigi.lobasso@gmail.com. especially in operating conditions close to stoichiometric ones, an internal combustion engine powering with pure hydrogen requires substantial changes to some components. The hydromethane mixtures application eliminates this drawback by ensuring the optimum engine operation with stoichiometric dosages. In this case, due to the flame temperature enhancement, the nitrogen oxides emissions are higher than traditional natural gas supply. A possible solution for NO x reduction consists of lean burning application. Therefore, due to the specific hydrogen combustion properties, the hydromethane blends use in stationary engines set in CHP (combined heat and power) mode Offer good environmental opportunities when operating in lean burn conditions [6]. This CHP plant is integrated into the hybrid system developed at the “La Sapienza” University Sports D DAVID PUBLISHING