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.

How micro-cogeneration works

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 addition, the appliance also provides hot water for sanitary facilities.

Types of technology

There are three different technologies for micro-cogeneration:

With Stirling engine (with external combustion)

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.

With engine with internal combustion

This technology works according to the same principle as the piston engines of petrol cars. The resulting heat is used to heat the building, while mechanical energy is used to produce electricity via an alternator. This type of micro-cogeneration unit is often seen in apartment buildings.

With fuel cells

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.

Something for the future?

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.