Also known as CHP, or Combined Heat and Power, cogeneration plants are systems that allow the simultaneous production of electrical and thermal energy, using less fuel for the entire process, rather than keeping the two production processes separate.
Thanks to this technology, a system efficiency improvement is achieved which allows an average saving of 30% in primary energy use. This saving is both economic and in terms of safeguarding the natural resource used, which can come either from a renewable or exhaustible source.
The thermal energy produced, in the case of a cogenerator with an internal combustion engine, is in the form of hot water. If produced by an oil-free turbine, it is in the form of hot air, and with the introduction of other equipment also steam and thermal oil.
On this basis, the plants can be further expanded and even very complex “applications” can be obtained that can ensure very high yields in terms of primary energy use.
Exceeding a certain efficiency threshold, it is possible to take advantage of the European Directive 2004/8/EC for High Yield Cogeneration plants, implemented in Italy by Legislative Decree 20/2007 and Ministerial Decrees 4/8/2011 and 5/9/2011, of incentives for cogeneration through dedicated support schemes, represented by TEE energy efficiency certificates, the so-called White Certificates.
WHAT ARE GAS-FUELLED COGENERATION UNITS?
Cogenerators can be fuelled with different fuels, both fossil and renewable.
Methane gas but also LPG, diesel and fuel oil are fossil sources and therefore exhaustible. Biogas produced in landfills or sewage treatment plants, or from biomass from agricultural or forestry waste are renewable sources.
Today, most cogenerators are powered by natural gas and biogas, achieving efficiencies of around 80%.
One fuel, which may or may not be sustainable depending on how it is produced, is hydrogen, which is still the subject of studies and technological updates to facilitate its use.
CAN WE MAKE COGENERATION WITH HYDROGEN AND SOLAR PANELS?
The use of hydrogen in cogeneration plants is encouraged by the environmental advantages of this fuel: hydrogen is a clean gas, produced by the electrolysis process, which can be stored and used to power generators with efficiencies approaching 100%.
The big problem with this source is storage, which is still a very critical process: even in its natural form, hydrogen is comparable to gas, i.e. it has a very low density. So to store it, it is necessary to increase its density a lot.
There are still technological hurdles to overcome, although hydrogen technology is already applicable, but it is not yet widespread and is very expensive. For this reason, the European Union is providing funding to support its development, helping to reduce costs and maximise energy efficiency.
Capstone Green Energy is confirming its position as a global leader in energy efficiency systems by installing two C65 microturbines at Austrian company Innovametall Stahl- und Metallbau, which will be used in an ultra-low emission Combined Heat & Power (CHP) system. This will pro-vide on-site power to a powder coating plant and will be designed in a hybrid configuration, where solar panels installed on the roof of Innovametall’s industrial hall will be responsible for generating renewable electricity. Excess electricity will instead be used to generate hydrogen, which will then power the micro-turbines. From there, hot exhaust air from the turbines will be captured and used in the facility’s powder coating oven. The application will initially operate with 10 per cent hydrogen mixed with natural gas, but the amount is expected to increase gradually as Capstone approves higher blending levels.
The use of a cogeneration plant in a company not only allows significant economic savings and an increase in performance, but also implements an energy transition model aimed at progressively phasing out fossil fuels and reducing polluting emissions.