Cogeneration is a system that generates both electricity and heat from a single fuel (natural gas).
Such installations take up a lot of space and are in principle intended for large buildings with a considerable heat demand, such as hospitals and factories.
The technology has been used in industry and horticulture for decades, but micro-cogeneration, the version used for households, is still in its infancy.
Micro-cogeneration works in the same way as a conventional boiler, i.e. when there is a demand for heat. As with ordinary cogeneration, the appliance will generate heat and electricity using a single fuel. (see also “What is cogeneration?”).
In terms of appearance and size, a micro-cogeneration unit is comparable with a dishwasher. In addition, the appliance also provides hot water for sanitary facilities.
There are three different technologies for micro-cogeneration:
This engine is driven by heat generated by combustion. It then starts up a generator that produces electricity.
The electricity that the micro-cogeneration unit generates in this way is sufficient for a large part of the property’s electricity consumption. In case of overproduction, electricity can be placed on the grid, just like with photovoltaic panels.
This technology works according to the same principle as the piston engines of petrol cars. The resulting heat is used to heat the home, while mechanical energy is used to produce electricity via an alternator. This type of micro-cogeneration unit is often seen in apartment buildings.
In this process, hydrogen is first produced from natural gas. Then, when that hydrogen comes into contact with oxygen, an electrochemical reaction causes electricity and heat to be generated.
This is therefore a very environmentally friendly process, which can reduce CO2 emissions by up to half compared with traditional systems.
Micro-cogeneration is a technology that could, in the long term, meet the growing demand for decentralised generation, as it plays a crucial role in the energy transition.
If micro-cogeneration technology continues to develop, it is likely that in the future these appliances will also be profitable for homes with a high heat demand.
An interesting evolution to follow, but for the time being further innovations for household use are still some way off.
I have installed a combined heat and power (CHP) system, but I have not been granted the green power certificates I was counting on to help finance my project. The lack of information and the complexity of the grant system make you think about it.
Read the testimonial
Emmanuel decided to do something for the environment and for his wallet. So he installed a CHP system in his home that produces both heat and electricity, but unfortunately he suffered a disappointment …
The CHP system that I had installed is fairly expensive: EUR 16,000, almost three times the price of a conventional condensing boiler.
The investment was only cost-effective with the federal and regional subsidies and the green power certificates.
Green power certificates are granted when you generate a certain quantity of green power which you can sell on to the energy supplier, providing a substantial financial bonus …
My fitter had assured me that I would receive the certificates, but that was only the case in the Walloon Region. In Brussels, the efficiency level of the CHP system has to be higher. Result: I’m not entitled to green power certificates for the installation that I bought, and what’s more, I still have a shortfall of around EUR 600 in my annual budget. I wasn’t given any information at all about the difference in conditions between the regions.
By opting for an environmentally responsible system, which is also a piece of advanced technology, I have taken a risk. I have the feeling I’ve done some pioneering work, but ultimately I was deceived about the cost-effectiveness of this investment. I find the lack of information appalling.
(Editor: To avoid a setback like Emmanuel’s, make sure you are properly informed about the conditions that you have to comply with in the Brussels-Capital Region! In particular, consult the information sheet from Brussel Leefmilieu/Bruxelles Environnement and the conditions for obtaining the energy grant. Note that the requirements of the regional governments with regard to the efficiency of micro CHP installations are not arbitrary. They are based on the principle that the efficiency must be higher than when heat and electricity are produced conventionally using the best available means on the market).
Subscribe to our newsletter and stay informed about energyfacts.