All questions

General questions

The BLUEGEN is the most efficient small power plant in the world. Using ceramic fuel cells, the device converts natural gas into electricity and heat and is no larger than a refrigerator. The electricity can be consumed in the building or fed into the power grid. The heat is used for water heating in a separate buffer tank.

A BLUEGEN produces enough heat to provide up to 200 litres of warm service water per day. However, this heat is not enough to fully heat a residential or commercial building. The BLUEGEN is an auxiliary solution and is usually combined with a peak load boiler (exception: passive house).

Another heat source for the service water is also required in the passive house.

Since the BLUEGEN can be operated all year round, with an output power of 1.5 kW, you produce about 13,000 kWh of electricity per year, which you can consume yourself or feed into the power grid for a fee.

With optimal operation (@1.5 kW, all year round), the BLUEGEN consumes about 24,500 kWh of gas per year. This corresponds to about 2,450 m³.

Natural gas is required to operate the BLUEGEN BG-15. Compared to a building without BLUEGEN, you consume more gas, but at the same time significantly less (more expensive) electricity. So you replace part of your electricity purchase with your gas purchase.

In view of the uncertainty of many people about the continuous availability of energy sources such as natural gas, the question arises: does electricity generation using natural gas still make sense at all? There are two important aspects in favour of this:

1) Ecological aspects

The fuel cell stands for one of the most efficient technologies for generating electricity from a fossil fuel. As long as we do not yet manage 100 percent of electricity generation from renewable energies, fuel cells that convert gas into electricity are a very good bridging technology. Although the use of fossil natural gas as a fuel produces emissions, these are significantly lower than with conventional gas/coal-fired power plants. The fuel cell is therefore a step in the right direction and can help to reduce the environmental impact of electricity generation. Of course, the goal must be to switch to renewable energies in order to achieve the climate targets set. We believe that electricity from BLUEGEN systems will continue to make ecological sense for the time being.

2) Economic aspects

As of August 2022, the cost of commercial electricity from a power plant is significantly higher than the cost of natural gas in almost every country, even though the cost of energy as a whole has risen sharply in recent months. The so-called “spark spread” can be used to calculate how much cheaper a kilowatt hour of electricity produced by BLUEGEN comes from the grid compared to the purchase from the grid. In most cases, you will find that you will save money in the long term with the BLUEGEN.

Our recommendation is therefore: With reason and a sense of proportion, you can continue to operate the BLUEGEN. We will keep an eye on the situation and inform you further.

Currently, the BLUEGEN is offered exclusively with an output of 1.5 kW. However, higher power reserves can be achieved by cascading two or more systems, e.g. four BLUEGEN BG-15: 1.5 kW + 1.5 kW + 1.5 kW + 1.5 kW = 6 kW

If you need less than 1.5 kW of electricity, the surplus of the electricity produced by BLUEGEN is fed into the power grid and you receive remuneration for each kilowatt hour fed in. If you need more than 1.5 kW of electricity, the missing power is drawn from the power grid. This process works fully automatically, no intervention by the user is necessary.

BLUEGEN produces electricity with an extremely high electrical efficiency of up to 57% – better than conventional large-scale power plants. Furthermore, BLUEGEN generates the electricity in the house, at the place of consumption. This avoids transmission losses through the power grid. In addition, the heat generated is used on site, which increases the overall efficiency to up to 89%. All in all, this results in an efficiency advantage of up to 50% compared to conventional electricity production by large power plants. For the environment, this means that BLUEGEN emits about 240 g of CO2 per kWh, the German power plant mix from which you would obtain your grid electricity produces more than twice as much (550 g/kWh).

Yes, of course. Parallel operation is possible, but different points must be taken into account on the installation side depending on the number of installed devices. For detailed information, please contact us.

The following parties must be informed if you want to operate a BLUEGEN. ==References== Your installation partner will of course support you in this process.

Before the conclusion of the contract:

  • Application for fuel cell funding KfW433
  • Other funding instruments

Before installation:

  • Chimney sweep
  • Gas suppliers
  • Electricity grid operators

After installation:

  • BAFA – Application for CHP allowance
  • Registration in the market master data register

Annually during the operating period:

  • Hauptzollamt – Energy tax refund
  • Electricity grid operators – electricity generated and fed in, information on the EEG surcharge

The necessary documents can be found on the websites of the respective parties or directly from SolydEra.

For the operation of the BLUEGEN, a permanent connection to the power grid is a prerequisite. An operation independent of the power grid is therefore unfortunately not possible. Furthermore, the BLUEGEN is designed for continuous operation, a frequent switching on and off of the system is not provided.

Theoretically, you can feed all the electricity produced into the grid. However, you will achieve a higher economic benefit if you use as much electricity as possible yourself, as the savings in electricity purchase are higher than the current remuneration for the electricity fed in.

The electricity cannot be forwarded via a direct line, e.g. to the neighbour. The heat can theoretically also be made available to another party, but this only makes sense in individual cases due to the low amount of heat.

Like any gas heater, the BLUEGEN is tested and certified for safety in accordance with the technical standards. The system has an integrated emergency shutdown that shuts down the system in the event of a problem. In addition, the BLUEGEN is designed in such a way that no pollutants or gases can escape.


To install a BLUEGEN you need:

  • A (natural) gas connection
  • A power connection
  • A water connection
  • An exhaust gas path
  • And a connection to the Internet (LAN)

Further information about the connections used can also be found in the technical data.

The BLUEGEN can be installed in any building, provided that the above requirements are met. In addition to residential buildings, this also includes commercial buildings, smaller shops, public buildings and many others. In addition, there must be a suitable installation location within the building and a way to direct the exhaust gas to the outside.

We strive to establish a nationwide network of installation partners. If we do not yet have a partner in your region, we will find a partner for you and qualify them for the installation of a BLUEGEN by means of training measures.

The BLUEGEN can be integrated into any existing heating system with central water heating via a heat storage tank.

We recommend a storage size of at least 200 liters.

No, normal tap water is sufficient for the operation of a BLUEGEN.

A free area (without heat accumulator) of approx. 1.5m x 1.7m is required to allow good access for maintenance work. The BLUEGEN requires a footprint of 0.6m x 0.7m.

No, a connection to the power grid is necessary for operation.

In principle, yes. In certain cases, however, a cascading option that allows connection to an existing exhaust gas installation is possible. Please contact us for more information.

In certain cases, cascading is possible that allows connection to an existing exhaust installation. Please contact us for more information.

Yes, as long as it offers sufficient space (min. 10 x 10 cm) for the exhaust gas routing of the BLUEGEN.

Yes, the exhaust pipe can be guided along the outside of the house. Please contact us for more information.

No, the exhaust gas duct can also be guided outwards through a side wall in coordination with the chimney sweep.

Yes, it is possible since BLUEGEN exhausts escape at a maximum temperature of 120°C. This allows the use of plastic exhaust systems.

The acceptance is regulated differently from state to state. Please contact your responsible district chimney sweep.

For the operation of a BLUEGEN, an Internet connection via a wired standard Ethernet line (RJ45) is recommended.

This is not necessary for the operation of the plant, but it may be a condition to receive certain subsidies.

Two electricity meters are required. On the one hand, you need a netting house connection meter that can measure both the grid supply and the grid feed-in and on the other hand, a meter that only measures the electricity from BLUEGEN. This must be done in coordination with the network operator.

The installation should be carried out in close coordination with the chimney sweep. This is usually informed by the installer.


The economic efficiency of a BLUEGEN depends very much on your consumption profile. For an individual profitability calculation, please contact one of our customer advisors. Since the savings in the purchase of electricity exceed the remuneration for the feed-in, you achieve the best economic efficiency if you consume the largest possible amount of the electricity generated yourself.

Since the savings in the purchase of electricity exceed the remuneration for the feed-in, you achieve the best economic efficiency if you need more than 13,000 kWh of electricity per year and thus consume the largest possible proportion of the amount of electricity generated yourself.

The energy tax refund must be applied for at the responsible main customs office. Please contact us for more information.

You can choose a remuneration according to KWKG or EEG. According to the EEG, the BLUEGEN must be operated with bio-natural gas. The remuneration according to KWKG is usually much more advantageous.

Both the German government and the EU offer attractive funding programmes for the installation of highly efficient energy producers such as the BLUEGEN, which reduces investment costs by up to 50%. Further information can also be found here: Funding. In addition, some municipal utilities and energy suppliers offer regional funding programs for micro-CHP plants and fuel cells. For a free and individual consultation on the subject of funding, please contact us.

The generation costs per kWh depend on your individual gas tariff.

In contrast to a PV system, the BLUEGEN is not dependent on environmental influences. Instead, BLUEGEN offers a year-round continuous supply with fixed performance. The BLUEGEN is independent of a south orientation of the roof and has no influence on the architectural design of the building.

For a detailed and individual profitability calculation, please contact us.


For an individual offer, please contact us or contact a BLUEGEN partner in your area.

If you are interested in purchasing a BLUEGEN, please contact us or contact a BLUEGEN partner in your area.

The BLUEGEN can be obtained from selected specialist companies (BLUEGEN partners). For more information, please contact us or contact a BLUEGEN partner in your area.

The combination with a solar thermal system is possible, but often does not make sense, since solar thermal systems are designed for the provision of hot water. In summer, the only heat sink is water heating, which can ideally be covered by up to 90% of the BLUEGEN. The investment costs for a solar thermal system to cover the remaining 10% can usually not be represented economically. The combination with a heat pump, on the other hand, is very efficient, especially if the electrical consumption of the heat pump matches the electricity production of the BLUEGEN.

The BLUEGEN primarily replaces the electrical energy requirement. The consideration must therefore be what advantage does the system ‘BLUEGEN and heat pump’ have over the system ‘electricity from the grid and heat pump’. Since the electricity of the BLUEGEN is produced much more efficiently than the electricity from the grid, this results in a significant increase in efficiency of the BLUEGEN system and heat pump. An economic gain depends on whether the electricity for the heat pump can be obtained cheaply through a heat pump tariff.

The BLUEGEN primarily replaces the electrical energy requirement. Consideration must therefore be given to the advantage of the ‘BLUEGEN and pellet boiler’ system over the ‘electricity from the grid and pellet boiler’ system. This depends on the customer’s power consumption.

The BLUEGEN primarily replaces the electrical energy requirement. The consideration must therefore be what advantage does the system ‘BLUEGEN and solar thermal energy’ have over the system ‘electricity from the grid and solar thermal energy’. This depends on the customer’s power consumption.


The BLUEGEN systems are monitored around the clock by our service personnel. In addition, we are of course also at your disposal on the sales side.

The quality of natural gas from the gas grid is well suited for the use of a BLUEGEN in Germany. For detailed information on the preferred gas composition, please contact our service department.

No, a connection to the gas network is currently a prerequisite.

The BLUEGEN can be operated with biogas in natural gas quality (bio-natural gas). Untreated biogas is not suitable for operation due to impurities in the gas.

No, the BLUEGEN can currently only be operated with natural gas or bio-natural gas from the gas network. At the moment, however, there is no alternative infrastructure, e.g. a nationwide hydrogen network that would enable operation with hydrogen. In the near future, however, we will introduce new models that are already prepared for the use of hydrogen instead of natural gas – provided that the infrastructure is established in the near future.

Currently, it is not possible for operators of individual BLUEGEN plants to control them directly.

As the operator of a BLUEGEN, you get access to the online portal Here you can retrieve various current and historical data of your plant.

The BLUEGEN is monitored around the clock by our service technicians via the Internet. In the event of a problem, various settings can be made via the Internet or the device can be shut down. In this case, a service technician from will contact you and, if necessary, arrange a short-term on-site appointment.

Maintenance and service

The BLUEGEN has integrated heat recovery. This means that the waste heat generated during operation from the fuel cell module can be used to heat up to 200 litres of water per day – this is sufficient for the daily consumption of an average household in Germany. This water can be used as service water, as well as in certain cases also for heating support.

Thanks to its high efficiency, the BLUEGEN emits only about 240g of CO2 per kilowatt hour (kWh) at 1.5 kW of electrical power. Compared to the purchase from the German power grid (in 2016: approx. 527g per kWh), you can save more than half of the CO2 emissions.

Due to the operation of the fuel cell, significantly lower values for CO and NOX are also achieved than with a conventional gas appliance.

No, various safety systems and gas valves prevent gas leakage.

In the event of a gas failure, the BLUEGEN interrupts operation and sends a fault message.

In the event of a power failure, the BLUEGEN automatically disconnects from the grid and reduces the power to a minimum in order to supply itself. The BLUEGEN therefore remains in operation and automatically increases the power as soon as the power grid is available again.

BLUEGEN needs the oxygen in the air during the oxidation-reduction process that takes place in the cell.

The internal process for implementing natural gas is most efficient with the use of water. The water consumption depends on the connected heating system and amounts to up to 1.5 liters per hour, in practice about 36 liters a day.

For remote monitoring and remote control, an Internet connection is mandatory. The average amount of data is just about 10MB per month.

The BLUEGEN establishes its own VPN tunnel for connecting to SolydEra’s servers. For this purpose, only free Internet access is required, access to the company network is not required.

Without heat recovery, the exhaust gas temperature is usually about 120°C. With active heat recovery, the exhaust gas temperature depends on the installation side and is usually 35°C to 55°C.

Yes, if adequate ventilation can be ensured.

The water temperature is primarily dependent on the temperature of the heat storage tank and the volume flow of the loading circuit. At 2l/min, the BLUEGEN raises the temperature by approx. 1 to 6°C. So if the storage tank in the extraction area has a temperature of 30°C, the BLUEGEN would raise this temperature by about 6°C and the water would re-enter the storage tank at 36°C. The following applies: The higher the storage temperature, the lower the temperature increase. At 65°C water temperature, the temperature is raised by about 1°C.

The BLUEGEN has no physical emergency stop switches. However, the system is equipped with an intelligent and widely tested control system, which in the event of a problem puts the device into the so-called self-preservation mode