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Fuel cell - the next step in heating technology

Fuel cell technology is highly efficient; in addition to heat, it also generates electricity and can also make gas “greener”. This innovative technology will therefore be an important contribution to the energy transition. Based on the primary energy requirement, this heating technology is up to 50 percent more efficient than the best condensing appliances, which means 30 percent lower CO2 emissions. With the two field tests Callux and ene.field Vaillant is now on the way to developing a marketable solution. Since March 2013, fuel cell heating has been manufactured in small batches at the Remscheid factory; at SHK 2014 Vaillant now presented the latest generation of the fuel cell heating system. The units are designed for use in one- and two-family homes and take advantage of a combined heat and power process for the simultaneous generation of electricity and heat. Natural gas or organic natural gas is used as the fuel.

The technology

“Fuel cell technology is very promising. It holds great potential,” explains Alexander Dauensteiner, project manager for the fuel cell heating field test. In the oxide-ceramic fuel cell the natural gas is split into carbon dioxide and hydrogen; the released hydrogen reacts with the atmospheric oxygen to generate electricity and heat. Based on the primary energy requirement, this heating technology is up to 50 percent more efficient than the best condensing appliances, which means 30 percent lower CO2 emissions. In addition, no losses occur in the electric power generation – as is still the case even in modern power plants – since there are no conversion or transport losses. The Vaillant fuel cell heating system generates 1 kW electricity and 2 kW heat. After several technical improvements, the overall efficiency is now higher than 90 percent. “That is the most efficient technology of heating with gas,” Dauensteiner emphasises. The new generation is 25 percent lighter and more compact than the previous systems; the electrical efficiency was increased to 31 percent, while the manufacturing costs were reduced by more than half.

Callux – fuel cell field test

In numerous field tests the new systems were installed in selected private homes to test their suitability for everyday use and handling, before they are ready for the market.

The Callux field test, initiated by the National Innovation Program for Hydrogen and Fuel Cell Technology, has already provided important findings. Callux is the most extensive field test of fuel cell heating systems for private homes in Germany. The project has been in progress since 2011 and is funded by partners in the power sector and the heating system industry with support of the Federal Ministry for Traffic and Digital Infrastructure. Vaillant already has 120 units in the test. “The results are very good,” says Dauensteiner. “The error rate – well below five percent – is excellent for a field test and the satisfaction of the users, according to a study of the GfK society for consumer research is unusually high.” By 2016, a total of 500 units from different manufacturers will be tested in the network, to provide representative results on the market requirements.

ene.field – Europe-wide fuel cell subsidised project

The European subsidised project “ene.field” was started in 2012, initiated by the fuel cell initiative of the European Commission, and allows nine European manufacturers to test their fuel cell technologies in a field test. Altogether, more than 1,000 systems are being tested in twelve EU member states. Vaillant is represented in the field test “ene.field” with about 140 heating units of the latest generation. The units are tested for three years in private one- and two-family homes in Germany, Austria and France.

The program provides for systematic monitoring and analysis of the data. After three years the fuel cell heating units are replaced by the next generation or even by products from series production. “The Vaillant fuel cell heating system is an important step on the way to decentralised power supply and a contribution to the energy transition in Europe,” explains Dr. Marc Andree Groos, Managing Director of Vaillant Germany. “That is why the installation is supported both by the EU and by numerous power companies and Vaillant. Users of a Vaillant fuel cell heating system benefit not only from a noticeable reduction of their energy costs, but also play an important role in the energy transition by using this innovative technology.”


Power storage projects such as “Power to Gas” of the north German power supply company E.ON Hanse show further potential for the innovative fuel cell technology. That is an important aspect, since the storage of green power is considered a key technology for the energy transition. The idea is simple: a temporary excess of green power that cannot be consumed is used by electrolysers to split water into oxygen and hydrogen. The latter can be supplied to the natural gas network in a percentage by volume of up to four percent – without modification of the infrastructure. If, during peak demand periods on the other hand, there is insufficient electricity that cannot be provided by renewable energy sources, the Vaillant fuel cell technology provides for high-efficiency reconversion.

The infrastructure in Germany for this is well developed. Dauensteiner also sees another advantage: the power-to-gas technology can convert the hydrogen to methane in another step and supply this “green” gas completely into the existing gas network.