Advantages and limitations of high efficiency cogeneration

A plant of cogeneration high-performance produces hot water and steam by exploiting the waste heat to produce electricity. Starting with a fuel, suppose natural gas, the result is two forms of energy: electricity and heat. The basic principle of cogeneration is: use everything, minimize waste.

A system of cogeneration that we all know is that of the automobile where: the power of the crankshaft is used for traction but also for the production of electricity; the heat produced by the cylinders is used for heating the passenger compartment; the pressure of the exhaust gas moves the turbocharging turbine (in turbo engines). Alas, only the exhaust gas is not reused, but sooner or later we will think about this too.

The 'High performance'Accompanying the cogeneration makes it a technology, or rather a family of technologies, very interesting in terms of energy efficiency, environmentally friendly, with high market potential and moreover mature-tested from the technological point of view (with the exception of the Stirling engines that are in the initial marketing phase). However, the characteristics of these systems also include very specific limits that circumscribe the scope of application.

A plant of high efficiency cogeneration, due to the purchase and management costs incurred so far, it is not imaginable for a single house or even for a small building. Even for a small manufacturing company it would become a difficult bet in terms of pay-back. The economic convenience, on the other hand, is there, and it is high, if it is a question of large industrial complexes or if, regardless of the size, the factory continuously needs large quantities of heat and electricity.

According to the Energy Efficiency Report of the Politecnico di Milano, the high efficiency cogeneration it is the optimal technology in the industrial field to meet the thermal needs (and part of the electrical needs) in place of the traditional boiler and the supply of electricity from the grid. This technology is also the most convenient in a part of the tertiary sector, hospitals and hotels in particular, to satisfy part of the energy needs.

In fact, more and more companies are starting to adopt the high efficiency cogeneration for on-site self-production of the energy required for its industrial plants and data centers. We talk more and more often about micro-cogeneration o micro-CHP, as an alternative or in parallel to large plants cogeneration that can meet the needs of entire municipalities. A push in this direction comes from the reduction of costs and the progress of technologies, as well as from the diffusion of natural gas which is most often the fuel that powers the plants. cogeneration.

On the subject of micro-cogeneration, namely systems for small sizes, one of the most performing solutions is that of fuel cells, or Fuel Cells. The advantage of fuel cells is that, using electrochemical processes, they transform the mains gas directly into electricity and heat, without having to go through combustion processes or moving parts. The attentions, or desires given the still high purchase costs, of many users focus on this technology.

From the point of view of incentives, the high efficiency cogeneration has so far had more advantages than limitations. Lately, however, something has cracked, arousing protests from producers' associations. The advantage is that cogeneration is considered a source of energy comparable to alternative ones (even if it is not) therefore it enjoys the relative facilities granted by law.

The limit, but more than a limit it is an obstacle, has come to light recently and is represented by the possible increases in system charges in the amount of 5-10% for the energy consumed within the RIU (Networks Internal User Networks) and SEU (Efficient User Systems), i.e. within private distribution networks, including those of industrial manufacturing sites. This obviously would penalize the convenience of cogeneration and in particular of the micro-cogeneration high-performance.

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