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Hydrogen: the raw material for fuel cells
The name hydrogen may remind some people of chemistry lessons at school. It’s the gas at the top of the periodic table with the chemical symbol “H”. It is part of numerous chemical compounds, including the one that is probably the most important for life on earth: water (H₂O).
Hydrogen is actually the most abundant element in the universe. Its potential as an energy source is equally as huge. It is precisely this potential that is exploited by fuel cells. As futuristic as fuel cell technology may seem, the principle itself is already around 180 years old.
How it works: this is how a fuel cell generates energy
A fuel cell has two electrodes: the anode is the negative pole and the cathode is the positive pole. They are connected to each other via a circuit. Between them is an electrolyte with a solid membrane. A chemical process is required for a fuel cell to generate energy. Hydrogen is supplied to the anode and oxygen to the cathode. The hydrogen is then broken down into positively charged protons and negatively charged electrons.
These electrons travel from the anode to the cathode through the circuit, i.e. usable electricity has been produced. Once they reach the other side, the electrons combine with the oxygen. In the meantime, positively charged hydrogen ions migrate through the membrane to the cathode side and also dock onto the oxygen. This results in “cold combustion”, which produces warm water. A fuel cell heating system uses this heat to supply a building.
Planning and requirements: what you should take into account
Supplying oxygen is not difficult. After all, all you need is ambient air. Supplying hydrogen is slightly more complicated. It is a gas that isn’t available on every corner. Consequently, a heating system requires a raw material that can be used to produce hydrogen. This is currently natural gas. In other words, there must be a natural gas connection in the house. If natural gas is not yet installed, you should include this step in your planning. Within the fuel cell heating system, a reformer extracts the hydrogen required from the natural gas. Exhaust gases are produced during this step. A chimney with the appropriate heating value is needed to evacuate them. This means that it must be resistant to moisture, pressure, soot and corrosion.
The principle of the fuel cell corresponds to that of combined heat and power generation. The system produces electricity and heat simultaneously. It is worth purchasing a buffer tank to ensure that the heat is not lost in case of low demand and remains quickly available at all times. This tank supplies the house with heat as and when needed. A special heating circuit is not necessary. Instead, fuel cell heating works with most existing systems.
Since the heat that is generated is not usually sufficient to cover demand over the winter, the fuel cell heating system should be linked to a gas condensing boiler. This uses the existing connection if required. There are actually already hybrid systems on the market that combine both devices in one. As a fuel cell is very quiet to operate, it can also be installed in a basement.
The environmental impact of fuel cell heating
Fuel cells cannot do without CO₂ emissions entirely. This is primarily due to the production of the necessary hydrogen. The process in the reformer produces greenhouse gases which then escape through the chimney into the environment. In terms of the carbon footprint, however, levels of CO₂ emissions from a fuel cell system are significantly lower than those from other heating systems. A fuel cell system emits about 70 percent less CO₂ than an older heating system that runs purely on fossil fuels. This is also due to the high efficiency of fuel cell heating.
The figures are expected to improve further in the future. The use of biogas alone could result in an increase, for example. If the system were to be supplied directly with hydrogen, it would actually be locally emission-free and perhaps even CO₂ neutral. Future developments in this sector look promising.
Costs: the price of heating with hydrogen
Fuel cell heating is associated with high acquisition costs. As a rule, depending on the manufacturer and your needs, you should expect to pay around 40,000 francs. There are no subsidies in Switzerland because the system does not work with renewable energies. This is an advantage for other heating systems such as heat pumps, for which attractive subsidies are available.
Furthermore, with a fuel cell you are dependent on gas prices. If there are fluctuations, which are not unusual, the costs of operating the fuel cell heating system also increase. Of course, the high efficiency and the principle of combined heat and power generation cushion this disadvantage somewhat. After all, the gas is used to generate not only heat for heating, but also electricity and hot water.
Even without subsidies, a fuel cell system can pay for itself after just ten to 20 years. As a rule, the following principle applies: the more of the energy you use yourself, the sooner this type of system pays off. Although you can also sell the excess electricity to the public grid, at the end of the day this remuneration has hardly any impact on economic efficiency. In terms of maintenance, a fuel cell heating system costs around 500 francs per year.
Fuel cell heating: advantages and disadvantages at a glance
- Fuel cells supply electricity, heat for heating and hot water at the same time
- High acquisition costs for a new fuel cell heating system
- The degree of efficiency is high, and fuel cell heating therefore functions very well
- Use of the fossil raw material natural gas and associated CO₂ emissions
- Ideal replacement for an old gas heating system because the necessary connections are already available
- Fluctuations in gas prices mean less planning reliability in terms of costs
- A fuel cell heating system is very quiet
- No state subsidies in Switzerland
- Amortization is ideally already possible after about a decade
- Much lower environmental impact than an old gas heating system, for example
Conclusion: fresh technology with a future
Heating, electricity and hot water from a single system: fuel cell heating supplies everything you need in your house. The high efficiency clearly speaks in favor of the technology. However, there is still room for improvement, especially with regard to the raw material used, natural gas. It’s difficult to make a general statement about economic efficiency. Whether and when a fuel cell system is worthwhile mostly depends on your usage behavior. A specialist company can provide you with a more precise calculation based on data regarding your heating and electricity consumption. You should therefore always obtain personal advice.