After having reduced about 45% of Nestlé's CO2 emissions in the last 10 years, thanks to the recent installation of the new AB trigeneration plant at the Perugina plant in San Sisto (Perugia), the group has taken a further step towards a increasingly efficient use of energy. 

The installed trigenerator consists of two 3.3 MW and 2.7 MW electrical power groups. Each group is composed of an internal combustion engine powered by methane that moves an alternator to generate electricity. The heat of the engine and the fumes, through the exchangers, produces steam and hot water. There is also an absorber that uses the residual thermal energy to produce chilled water. The system works 24 hours a day and the engine speed can be adjusted so that the energy produced added to that of the photovoltaic system is instant by instant equal to the needs of the site. 

The thermal energy that is exploited reaches 3.5 MW and this avoids burning up to 400 cubic meters of methane gas every hour. In practice, every four hours, the methane consumed by an average family in a year is saved. 

This, combined with improved energy efficiency, the production of electricity with photovoltaics and the fact that the electricity purchased from the grid derives from renewable sources, has allowed the San Sisto plant to reduce CO2 emissions into the atmosphere by 30% in 5 years, obtaining an average saving of 2,400 tons per year compared to 2016 emissions. It means that in the last 5 years the CO2 emissions per ton produced have dropped by 37%; in addition, energy consumption per ton produced was reduced by 36% and water consumption by 53%. 

"A trigeneration plant like this one from AB is perfectly suited to a confectionery industry like ours that needs electricity, hot thermal energy (heating the pipes and silos, conditioning the process areas, conching) and cold thermal energy (temperature of the chocolate, chocolate cooling, conditioning of the packaging areas). Thanks to the efficiency of the plant and the exploitation of all the energy vectors produced by the trigenerator, we are able to obtain an overall efficiency of up to 67%, explained Flavio Graverini, head of maintenance, industrial services and engineering of the Nestlé plant in San Sisto.