Solar Carport: Solar power from the garage roof

A solar carport has a double benefit, because the shelter not only protects the car from wind and weather, it also generates electricity. If a wallbox is also integrated, a third benefit is added. Because you can use it to charge your e-car or pedelec conveniently on your own doorstep. So such a solar carport has many advantages. A carport is sometimes even better suited for the installation of a photovoltaic system than the house or garage roof.

Solar Carport: Storage area with additional benefits

Carports have been around since the 1920s. In the United States, the architect Frank Lloyd Wright was the first to equip his famous prairie houses with these open shelters. Since then, the carport has spread all over the world.

Nowadays, it can also be expanded into a solar carport with a photovoltaic system. In addition to its protective function for the car, the simple shelter becomes an energy supplier and a solar charging station. If you own an electric car, a carport is a good option because a photovoltaic system can also be connected to a wallbox and the vehicle can be refueled with solar power.

Solar system on the carport, the roof of the house or the garage?

Not all roofs are optimal locations for photovoltaics. Inclination and orientation play a role on a potential solar roof. The roof on which a solar system can work most efficiently therefore depends on the individual local conditions. A specialist can best decide where you should place your planned photovoltaic system at your home.

An additional advantage of the solar carport is the less strict legal regulations. In many federal states, there are fewer requirements to meet for carports than for garages, and regulations for fire protection are sometimes completely omitted. It is best to check your respective state building code for the relevant regulations in advance.

 

Which carports are suitable for photovoltaics?

Carports can be free-standing or attached to the house. In any case, the shelter is open on at least one side, sometimes even on all sides. This design gives the carport the visual lightness of a carport. When attached directly to the house, at least one side remains closed by the house wall, which saves construction costs.

If you want to close more pages, you need special locking elements. For a solar carport, you need an additional frame on which the modules can be mounted.

What types of roofs are suitable for a solar carport?

Most carports have a flat roof, but you can also cover the shelter for the car with more elaborate constructions, such as gable roofs, hipped roofs or barrel roofs. Carports are usually covered with corrugated or trapezoidal sheet metal in a translucent design. These are corrugated profile light panels or trapezoidal panels.

The installation of the photovoltaic system differs depending on the shape of the roof and the inclination. In the case of a flat roof, the modules can be elevated.

There is also the option of using the solar modules themselves as a roof. However, they must have the necessary static prerequisites for this. For this solution you need a general building authority approval, there are very high requirements with regard to the overhead area, the fall protection and the façade. If you are planning such a roof, you should therefore have the local conditions checked in detail by a specialist beforehand. For this type of solar carport, glass-glass modules are usually used, which are made of laminated safety glass. Semi-transparent modules can be used for a translucent roof.

Which solar modules are suitable for a photovoltaic carport?

Since a solar carport or a photovoltaic garage is usually a flat roof, you can orient yourself to the requirements of this type of roof. The use of crystalline modules or thin-film modules is an option, the choice depends on the prevailing lighting conditions. An expert can check the conditions on site and draw up a cost-benefit calculation.

Some carports are equipped with a reflective roof membrane, in this case the sunlight acts on the modules from below. Bifacial solar cells are also able to absorb light from below, so this solution can also be considered for such roofs.

Convert an old carport or build a new solar carport?

In principle, you can retrofit an existing shelter with photovoltaics. Or is it better to build a completely new carport and equip it with a solar system?

The following aspects play a role in this decision:

• Roof orientation

Does the roof of your existing carport get enough sunlight? Optimal alignment yields the best possible return. However, if the carport roof is shaded by trees or other disruptive factors, a new building with a better orientation could be worthwhile.

• Roof area

Is the roof area large enough for enough solar panels? An expert can answer this question by means of precise calculations. If the space is not sufficient, a larger new building could be the better solution. Many solar carports offer an output of about 2-3 kilowatts peak per parking space.

• Statics

In order to be able to use an existing shelter as a solar carport, the roof must meet the static requirements. The structural engineer calculates the roof load, i.e. the maximum load that a roof can withstand. This results in the roof load reserve, this value indicates the maximum weight that the solar system may have. In addition, the structural engineer must take into account weather-related loads, for example due to snow.

If you want to upgrade your existing carport with a solar system, you can purchase the necessary elements individually and put them together in a modular way. There are also solutions that already include the frame as well as connections to the home power grid, so that you can supply the generated electricity directly to your own consumption. Self-assembly is generally possible, but you should have the electrical installations carried out by a specialized electrician.

The complete solution

The easiest way to get a solar carport is to opt for a complete system. These are either complete carports with a solar roof or attachments that you can mount on your existing roof. So if you have a shelter that is not suitable as a solar carport, you don't necessarily have to build a new one if you retrofit with a complete system.

There is a wide range of complete solutions for photovoltaic carports on the market. With some providers, you even get the complete package including a building inquiry and building application. The electrical connections and the charging station are also included in some systems. Most basic models can be expanded. So you don't have to decide immediately whether you want to just generate electricity or build a solar carport with a charging station for your e-car. The modular expansion option also allows for retrofitting at a later date.

Among other things, self-assembly kits are also offered as complete systems. With the help of precise assembly instructions, you can transform your shelter into a solar carport within a few hours. However, keep in mind that exact calculations of the roof load reserve are necessary before installation.

Solar Carport – Price and Profitability

A carport is not exactly cheap, and there are also the costs for the solar system. With such a not inconsiderable investment, you should do a bit of calculation. Acquisition costs, installation costs and expected yields must be in a good ratio for a solar carport to be worthwhile.

As a rule of thumb, one can assume:

• A carport costs an average of 5,000 to 15,000 euros.
• A solar system costs about 2,000 euros per kWp in the appropriate sizes. You can find more information in the article on the costs of a photovoltaic system.
• A solar carport usually costs between 15,000 and 25,000 euros.
• For a carport with a size of two parking spaces and an output of about 5 kWp, you can assume a solar yield of about 4,000 to 5,000 kilowatt hours of solar power.

In the case of a solar carport with a charging station, additional costs for the wallbox are added to the total price, but the electric car driver can fill up with electricity afterwards for 10 cents per kWh (that's how much a kilowatt hour of solar power costs if you add up all costs; this is then the so-called levelized cost of electricity). The electricity used by the company itself is considered self-consumption and is exempt from the EEG surcharge up to a system output of up to 30 kWp. Electricity that is not used by the photovoltaic system is fed into the public power grid by the photovoltaic system against payment of a feed-in tariff.

Conclusion and further articles

A solar carport has many advantages. Whether photovoltaics can also be worthwhile in your local conditions should be calculated by an expert. During the planning, an experienced structural engineer must also check the statics. Calculating roof load and roof load reserve is not an easy task for the layman. You should also hire a specialist for the necessary electrical installations, because in the worst case there is even a risk of fire if they are installed improperly.

Photo: Adobe Stock | Marina Lohrbach

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