There is an extension of the concept of cogeneration that allows, in addition to the usual heat and mechanical/electric energy, cold from residual heat.

It is possible to obtain cold from a heat source through absorption systems. As a result, greater efficiency is obtained: in most climates, heating is not necessary for more than a few months a year, while with trigeneration the system is also used in warm seasons, which improves (decreases) the payback time of the system, by increasing the hours of service of the installation.

An absorption cooling system needs a minimum temperature of about 80°C to operate, from which the discharge water is obtained at about 40 or 50°C and the cooling water at about 0 to 4°C.

There are other ways to maximize the cogeneration concept.

In greenhouses, the exhaust gases from the cogeneration system can be reused, previously treated with a catalyst as carbon fertilization.

Another modality is the so-called Tetrageneration, in which in addition to the three previous forms of energy, mechanical energy that can be used, for example, to generate compressed air, is simultaneously generated. In Spain there are few examples of tetrageneration, except for cases such as the FORD factory in Almussafes, which is a good example.

The Principle of cogeneration can be realized with the help of countless technologies. Fundamentally, a first differentiation takes place between the technologies by which the fuel can be burned. Among the possibilities, we find Stirling engines, steam engines, steam turbines and technologies such as ORC (organic Rankine cycle) or Kalina cycle.

Turbines and steam engines generally have efficiency percentages of between 10 and 20%. Otto engines have an electrical efficiency of 1 to 2 points below the efficiency percentage of combustion engines. For their part, gas turbines have a performance of up to 20 MW and, at the same time, most of them have an efficiency percentage below 40%. The electrical efficiency of Stirling engines, which is in a low power range (micro cogeneration), varies between 10 and 15%. fuel, which can reach a degree of electrical efficiency of 60%.

One of the main benefits of cogeneration is its greater energy efficiency[3]​ since both heat and mechanical or electrical energy from a single process are used, instead of using a conventional power plant and for heat needs a conventional "Boiler (heating)" boiler. In a cogeneration process, between 10% and 20% of energy is dispersed, which implies an improvement of between 70% and 90% in terms of efficiency.[4][5]​.

Another of its benefits is the fact that by producing electricity close to the point of consumption, voltage changes and long-distance transport are avoided, which represent a notable loss of energy due to the Joule effect (it is estimated that in large networks this loss is between 25 and 30%).

Cogeneration also presents environmental benefits in the form of reduced greenhouse gas emissions. It is estimated that, in Europe, thanks to cogeneration, the emission of 200 million tons of CO2 is avoided.[6]​ On the other hand, by reusing hot water from cooling circuits, its release into the environment is avoided, something that could affect the temperature of rivers, seas or lakes.

It is also worth mentioning the reduction in costs associated with savings on the energy bill and the reduction in transmission and distribution transportation costs.

There is an extension of the concept of cogeneration that allows, in addition to the usual heat and mechanical/electric energy, cold from residual heat.

It is possible to obtain cold from a heat source through absorption systems. As a result, greater efficiency is obtained: in most climates, heating is not necessary for more than a few months a year, while with trigeneration the system is also used in warm seasons, which improves (decreases) the payback time of the system, by increasing the hours of service of the installation.

An absorption cooling system needs a minimum temperature of about 80°C to operate, from which the discharge water is obtained at about 40 or 50°C and the cooling water at about 0 to 4°C.

There are other ways to maximize the cogeneration concept.

In greenhouses, the exhaust gases from the cogeneration system can be reused, previously treated with a catalyst as carbon fertilization.

Another modality is the so-called Tetrageneration, in which in addition to the three previous forms of energy, mechanical energy that can be used, for example, to generate compressed air, is simultaneously generated. In Spain there are few examples of tetrageneration, except for cases such as the FORD factory in Almussafes, which is a good example.

The Principle of cogeneration can be realized with the help of countless technologies. Fundamentally, a first differentiation takes place between the technologies by which the fuel can be burned. Among the possibilities, we find Stirling engines, steam engines, steam turbines and technologies such as ORC (organic Rankine cycle) or Kalina cycle.

Turbines and steam engines generally have efficiency percentages of between 10 and 20%. Otto engines have an electrical efficiency of 1 to 2 points below the efficiency percentage of combustion engines. For their part, gas turbines have a performance of up to 20 MW and, at the same time, most of them have an efficiency percentage below 40%. The electrical efficiency of Stirling engines, which is in a low power range (micro cogeneration), varies between 10 and 15%. fuel, which can reach a degree of electrical efficiency of 60%.

One of the main benefits of cogeneration is its greater energy efficiency[3]​ since both heat and mechanical or electrical energy from a single process are used, instead of using a conventional power plant and for heat needs a conventional "Boiler (heating)" boiler. In a cogeneration process, between 10% and 20% of energy is dispersed, which implies an improvement of between 70% and 90% in terms of efficiency.[4][5]​.

Another of its benefits is the fact that by producing electricity close to the point of consumption, voltage changes and long-distance transport are avoided, which represent a notable loss of energy due to the Joule effect (it is estimated that in large networks this loss is between 25 and 30%).

Cogeneration also presents environmental benefits in the form of reduced greenhouse gas emissions. It is estimated that, in Europe, thanks to cogeneration, the emission of 200 million tons of CO2 is avoided.[6]​ On the other hand, by reusing hot water from cooling circuits, its release into the environment is avoided, something that could affect the temperature of rivers, seas or lakes.

It is also worth mentioning the reduction in costs associated with savings on the energy bill and the reduction in transmission and distribution transportation costs.