we are voltagy

experts for

We are an engineering company for renewable energies. We are solution providers. We are your partners when it comes to photovoltaics, electricity storage or charging infrastructure for electromobility. And we pursue a common goal: building the energy supply of the future today. What helps us achieve this? Enthusiasm, commitment and the many years of experience we have gained from numerous projects during our time at TÜV Rheinland Solar GmbH in all parts of the world.

Join us on our mission without emissions - together we make the difference.

"Our energy solutions are about seizing a significant opportunity to make long-term, sustainable positive change for our climate and generations to come."

If you are interested in becoming part of our team or partnering with us to make your projects a success, we look forward to hearing from you.

Greater things are achieved together.


Ansgar Delahaye, Dipl.-Ing.

Ansgar wants to fly high - at least when he's plowing through the skies off the coasts on his kiteboard. Back on land, however, he is no longer aloof at all. On the contrary: the down-to-earth man from Aachen always walks through the world with an open mind and curiosity. But perhaps "walking" is not quite the right word. Ansgar prefers to travel by bicycle. With so much activity, of course, his physical well-being has to be taken care of - and for him, that includes a good glass of wine just as much as a good portion of French fries.

Johannes Ellmann, B.Eng.

Even as a child, Johannes took broken devices apart. Sometimes he even reassembled them. After his training as an automotive mechatronics technician, he even had to take apart an entire electric car - the battery of which was then quickly converted into a home storage unit. Today, he uses his skills to save the world for his three children. In between, however, he still has time for every discussion. Because anyone who knows Johannes knows that he can always be counted on for unsolicited comments.

Michael Slawik, Dipl.-Ing.

A campfire, good food, friends and family - that's all Michael really needs. But a proper toolbox would also be a good thing. Because the father of two children screws and "home crafts" with heart and soul. He likes to work on two-wheeled vehicles the most, regardless of whether it's a mountain bike or a motorcycle. He tries to leave the hustle and bustle of everyday life behind when he travels with his young family. Also not in his luggage: a travel plan. After all, the world is best explored on the spur of the moment.

Jork Saal, M.Sc.

From cliffhanger to cliffhanger - Jork may not be a series junkie, but he hangs out on the rocks himself all the more often when bouldering. And the Leverkusen native doesn't get bored in other ways either: In addition to bouldering, his favorite pastimes include capoeira, paragliding, hiking, biking and traveling. He likes to relax with an espresso - preferably from his home espresso machine, but even better with pastel de nata crumbs in his beard and the Portuguese sun on his face.

Häufig gestellte fragen


  • photovoltaik
  • electromobility
  • renewable energies
  • voltagy

Do PV systems need to be cleaned?

Due to the long service life of a PV system, pollution occurs sooner or later. Depending on the location, e.g. near forests, near industry and near farms, even more frequently. These contaminations should be removed regularly, so that the solar plant remains permanently as efficient as possible.

Are PV systems maintenance-free?

Even though PV systems are often described as maintenance-free, regular inspections of all components should be carried out to maintain performance and ensure operational safety - and thus reduce the risk of personal injury and property damage. This not only increases the service life of the photovoltaic system, but is also important with regard to warranty conditions and possible compensation from manufacturers and insurance companies.

Are replacement bricks necessary?

In case of roof works during installation it is possible that roof tiles are damaged and in that case they have to be replaced by spare tiles. If no replacement tiles are available, please inform us in good time. In principle, all types of roof coverings are suitable for the installation of a PV system - assuming sufficient load-bearing capacity of the roof covering as well as the roof structure.

Can the PV system also be built by the customer?

The complete self-construction of a PV plant is not possible. However, in order to save costs, large parts of the system can be built by the customer. However, to ensure operational safety and warranty claims, a specialist electrical company must be involved.

What is the lifetime of a PV system?

The average lifetime of the most commonly used crystalline solar cells is estimated at over 30 years. However, efficiency decreases with increasing age. However, manufacturers of photovoltaic systems generally still give a performance guarantee of around 80 percent after 25 years.

Are the PV modules certified?

All PV modules we use are certified by TÜV-Rheinland according to IEC standards.

What is the CO2 footprint of PV modules?

When the PV system is in operation, it does not release any climate-damaging carbon dioxide. On the contrary, compared to other types of electricity and heat generation, it saves CO2. However, emissions occur during production, maintenance and disposal.

Do PV systems have to be approved?

PV systems must be registered with the grid operator and usually also require a permit. However, a building permit is not required in most cases. Exceptions are, for example, listed buildings.

Can the PV system supply my heat pump?

On average, a photovoltaic system can cover about 30 percent of a heat pump's electricity needs. If the PV system is combined with an intelligent energy system, this value can even be increased to around 50 percent.

Can my PV system supply me during a power outage?

For the duration of the power outage, a photovoltaic system usually does not function. Only in conjunction with a storage system can an emergency or backup power system be operated so that the PV system can continue to be used under certain conditions if the public power grid fails.

Is a PV system worthwhile as a financial investment?

That always depends on the individual case. In general, however, it can be said that solar power makes you more independent - and is cheaper than any electricity tariff. In addition, a solar system can cover a large part of your own electricity needs. And since July 30, 2022, it has also been financially worthwhile again to feed all the electricity you produce yourself into the grid. Currently, rising inflation and rising energy prices are favoring the profitability of a PV system.

Does a PV system increase the value of my property?

As with any energy-related construction measure, the installation of a PV system also increases the value of the property. The question of the economic efficiency of the PV system is central to the amount of the increase in value. This is because the more economically the PV system operates, the higher its positive influence on the property value.

Is it worth renting a PV system?

If you are a homeowner who does not want to invest a large sum of money or take out a loan, renting a PV system is a good option to do something against climate change. However, if you want to maximize the financial benefit, you are often better off buying. If the necessary capital is not available, there are also financing options.

Is it worth renting out my roof for a PV system?

Basically, it has to be said: The owner-occupied home is no longer suitable for roof leasing. For system operators, the investment is only worthwhile if the roof has a considerable minimum size. Currently, this is at an area of around 1000 m2.

What is the energy payback period of a PV system?

The energetic amortization describes the period from which the photovoltaic system produces more energy than was consumed for its production. The payback time depends on the type of solar module. For polycrystalline solar cells, the energy payback period is between 0.44 and 1.42 years.

What is the financial payback period of a PV system?

The payback period of a PV system depends on numerous individual factors such as acquisition costs, equipment of the system, financing or subsidies. The typical payback period for a PV system on a single-family house is 9 to 11 years. If the system is coupled with an electricity storage system, the period increases to 10 to 12 years.

Are performance optimizers worth it?

Power optimizers are used to optimize the power of individual PV modules. For this purpose, a power optimizer measures current and voltage within the respective module and determines the MPP, the so-called maximum power point. This indicates when the module can produce the highest possible power. As a rule, the additional investment is not worth it. We would be happy to check your PV system and advise you in detail on this topic.


Are wallboxes weatherproof?

As a rule, a wallbox is not suitable for outdoor use. The IP code provides information on whether a wallbox is weatherproof or not. If a wallbox is to be installed outdoors without protection, it should at least meet protection class IP54 or IP55. However, the IP code does not provide any information about the UV resistance of the wallbox's housing.

How much power does a wallbox need?

A wallbox requires a 32 amp power connection with a voltage of 400 volts.

Can I install the wallbox myself?

Since wallboxes require a power connection, the installation must be carried out by a qualified electrician. If there is not yet a high-voltage connection in the garage, it must be installed by an electrician.

Is a wallbox subject to approval?

Wallboxes up to 11 kW are subject to registration, above 11 kW are subject to approval.

How long do e-car batteries last?

Modern e-cars have high-quality lithium-ion batteries that promise a long service life. Manufacturers now guarantee a service life of eight years or 160,000-200,000 kilometers with more than 70-80 percent of the original storage capacity.

renewable energies

Does a balcony installation have to be approved?

A balcony installation is not subject to approval, but is subject to registration.

How can I effectively save energy at home?

There are many ways to save energy at home. Here are a few of our tips:

- Turn off standby on the TV
- Use the maximum load of the washing machine and dishwasher
- Switch off lights when you leave a room
- Heat water by kettle
- Air-dry laundry instead of using a dryer

Does electric heating make sense?

In combination with your own PV system, heating with electricity can make perfect sense. With the right energy system, you can generate half of the heat you need yourself. If you also use electricity from renewable sources, it is by far the most environmentally friendly form of energy supply.


Does Voltagy operate nationwide or internationally?

Thanks to our many years of experience with international projects, we can offer our services both here locally and worldwide.

What services does Voltagy offer?

We offer you individual solutions around renewable energies, photovoltaic systems, electricity storage and charging infrastructure for e-cars.

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