Cogeneration: what to know about it

A process that allows an average saving of more than 30% thanks to the “free” production of the thermal vector in the form of hot water, steam, hot air and diathermic oil: this is cogeneration in terms of efficiency, a technology that generates electrical and thermal energy at the same time, exploiting the heat that would otherwise be dispersed and with a single primary energy source (fuel).
In this article, we are going to deepen the characteristics of cogeneration and the advantages of this type of plant, discovering the IBT Group’s solutions also by means of some explanatory case studies.

Cogeneration stems from the need to simultaneously produce electrical and thermal energy in a single plant: the separate production of these two energies presupposes a large consumption of fuel, while this technology, also known as CHP (Combined Heat and Power), guarantees considerable savings, exploiting the heat normally dispersed in industrial and civil use, both internally or distributed in the network. This system therefore generates its own electricity and allows the recovery of heat that would otherwise be lost during the electricity production process. A cogeneration system uses different types of fuel (of fossil origin, or originating from waste disposal or biomass such as biogas) to ensure the operation of the electricity generators, then using devices to recover the heat produced by the turbine or internal combustion engine to obtain useful thermal energy (generally in the form of steam or hot water).

The main advantage of cogeneration plants is that they reduce primary energy consumption by an average of 30%. A second, fundamental advantage is that if the emissions of pollutants from energy production are reduced, the environmental impact of the process is also reduced, thus contributing to the protection of the planet’s atmosphere. An important aspect of cogeneration, specifically with the Capstone turbine, is the ability to reduce the risks associated with energy supply interruptions due to grid problems. This technology is available in a specific version that allows efficient electrical backup, switching to stand-alone operation in the event of a grid failure. In Italy, for example, White Certificates are awarded to all cogeneration plants that obtain the CAR qualification, “high-efficiency cogeneration”, which occurs when the value of the resulting primary energy savings is at least 10%, or if it has a positive value in micro-cogeneration units (< 50 kWe) or small cogeneration units (< 1 MWe). To attribute annually these awards is the GSE, Gestore dei Servizi Energetici; at European level, the identification, promotion and development of CHP is defined by Directive No 2004/8/EC of the European Parliament and of the Council of 11 February 2004 on the promotion of cogeneration based on a useful heat demand in the internal energy market. IBT Group is specialized in providing innovative and tailor-made solutions in the field of high-efficiency cogeneration: with more than 250 Capstone turbines (Capstone turbine corporation is a historical partner of IBT Group) installed, for a total of 25 MW of electrical power and more than 6,000,000 hours of operation, IBT Group ensures maximum efficiency in the food & beverage, paper, hotel & wellness, hospital, chemical & textile, biogas & water purification and hybrid mobility sectors.

An example of the efficiency of cogeneration plants applied to the chemical sector is the Solvay Silica GBU plant in Livorno. Solvay, a leading company in the chemical sector, has in fact adopted Capstone oil-free gas turbine technology in this plant to implement the continuous silica drying process, with overall efficiency peaks of over 95% for an annual operation of more than 8500 hours. This integrated system consists of a 1000 kWe turbine powered by methane gas which produces electricity, used for the production process, and exhaust gases at 280°C which are conveyed to an atomiser for drying the silica.

In a completely different field, such as wellness, the centre in Via Meda of GetFIT, the leader in fitness in Lombardy, stands out: it too uses a high-efficiency Capstone oil-free turbine cogeneration plant, which saves 30% primary energy and reduces emissions to such an extent that it largely complies with the stringent CO2 regulations in force in the central areas of Milan.