Solar carport: charging electric cars with photovoltaics on the roof

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Reading time: 6 Minutes

Carports with photovoltaic systems are also becoming increasingly attractive for companies. Renewable energies can already be sensibly integrated into one's own electromobility strategy on a small scale. This increases self-sufficiency, improves the ecological balance and reduces costs.

 

Umschalten.de had self-sufficient charging options for electric cars presented at the EBZ in Dresden. The Electrical Training and Technology Centre is a training centre and trains craftsmen to be able to implement innovative concepts in practice. In our video in the section "Practical test" you can find out how such a solar carport works. In our new article you can find out whether a carport with photovoltaics is also worthwhile for you. Do you want to get started straight away? In the last chapter, you can find out how the municipal energy provider SachsenEnergie AG can support you with your project!

 

ADVANTAGES OF SOLAR CARPORTS

Carports were popularised by the well-known architect Frank Lloyd Wright as early as the 1930s. Since garages were used more as storage places, he saw "car ports" as a more elegant solution to protect vehicles from the weather. Today, it is impossible to imagine towns and villages in Saxony without the covered parking areas for one's own car: they are available with or without walls, with an attached shed or simply as an extended house roof for storing the car.

 

With the energy and mobility revolution, the carport is taking on new tasks. The previously unused roof surfaces are the ideal place for solar modules. Solar carports can thus be an important building block for the decentralised and self-sufficient supply of new e-cars. Surplus electricity that is not used to charge the electric car can be fed into the grid, which also helps to secure the supply of the electricity grid with renewable energies. But the carports with solar systems also offer many advantages for private and business customers themselves, as electrical engineer Matthias Güldner from EAG Elektroanlagen Güldner explains: "Solar carports are particularly attractive for SMEs. The energy is self-generated, which reduces electricity costs. When fed into the grid, money is even earned."

Since the plants are still rarely found in many areas, they attract attention and create a positive image among employees, customers and neighbours. As a rule, operation is possible with little maintenance. In addition to electricity generation, the energy consumer can also be directly integrated in the form of a charging point, so that no additional construction measures are necessary here on the residential or commercial building.

HOW SELF-SUFFICIENT ARE SOLAR CARPORTS REALLY?

100% self-sufficiency from the energy grid is not possible in Germany, and there are good reasons for this. Renewable energies are clean and low-risk in generation, but they are subject to natural fluctuations: If the sun is not shining, no electricity is generated. A connection to the overall power grid secures the charging process so that the e-car can still be charged even if there are days of bad weather.

It is also advisable to integrate a power storage unit into the solar carport's circuit. This way, during the day - when the sun is shining but the electric car is perhaps parked in the company car park - energy can be generated and held in reserve for the evening. When dusk falls and you go home for a well-earned evening, your electric car can be charged with the stored electricity, so that you do not need external energy from the electricity grid, or at least not as much.

HOW MUCH DO YOU SAVE WITH CARPORTS WITH CHARGING STATIONS?

A solar carport is not a money printing machine: initial investments of 10,000 to 15,000 euros for the photovoltaic system often only pay off after 15 to 20 years. The greatest financial advantage is therefore the independence from price developments on the electricity market: between 2010 and 2019, the average price of electricity has risen by 28 percent, and has even almost doubled since 2000. It can be assumed that energy prices will continue to rise in the coming years. If the cost of charging your electric car then increases for others, you will save money in the long term with a solar system on the roof.

Diagram electricity costs solar carport

Those who see a PV system as a pure capital investment will unfortunately be disappointed. For some years now, the feed-in tariff for solar electricity has been falling sharply. In 2020, this amounted to between 8 and 9 cents per kilowatt hour for small systems up to 10 kWp. You receive this income if you generate more electricity than you consume. Both factors together - the electricity costs saved by consuming the self-generated electricity and the feed-in tariff for the excess electricity - must be calculated against the purchase, installation and maintenance costs. In our example calculation for the chart, we assume an EEG remuneration of 8.48 ct/kWh (as of November 2020) , a gross electricity price of 28.12 ct/kWh (as of 2020) and an electricity price increase of 2 percent per year. With a usual self-consumption rate, the average cost saving per year is still 23 euros.

For the cost representation, an average PV system with one-time costs of € 11,781 was assumed. Annual costs (maintenance € 89, repair € 59, measurement costs € 18, excl. depreciation) were assumed to be € 166. The PV system generates 4,800 kWh per year, approx. 30 % of the generated electricity can be used simultaneously (e.g. for charging e-vehicles). The average total annual consumption is assumed to be 5,000 kWh. The self-consumption quota of the PV system is about 30 %, the self-sufficiency quota 29 %. 3,557 kWh/a are still drawn from the grid, 3,367 kWh/a are fed into the grid as surplus. 28.12 ct/kWh gross was assumed as the base electricity price for 2020.

FOR WHICH INDUSTRIES IS A CARPORT WITH PHOTOVOLTAICS WORTHWHILE?

The electrical trade is the sector that should show particular interest in this topic, says electrical engineer Matthias Güldner. The technical knowledge is available or can be caught up on with educational partners - such as the EBZ. Moreover, as a practical project, a carport with a photovoltaic system in front of one's own electrical company unfolds its full potential. In addition, the electrical trade benefits from this image building.

The purchase is also worthwhile for other sectors. The above-mentioned trade is the ideal partner for project planning, construction and operation. However, a simple solar carport can also be erected by oneself with certain manual skills. Companies that find it easier to convert their fleets to electric vehicles are predestined for the use of solar carports. In this way, the vehicles of care services, delivery services or municipal service vehicles can be charged with self-produced energy, guaranteed to be emission-free. The independence from the price development on the electricity market also pays off quickly with a high proportion of e-vehicles in the fleet and reduces financial risks.

PRACTICE TEST EBZ: LEARNING AND TEACHING AT THE PV PLANT

The EBZ, the Electrical Education and Technology Centre in Dresden, proves that carports can already be successfully operated in conjunction with photovoltaics. The editors of umschalten.de were on site to see for themselves. In a conversation with project manager Ronny Donath and managing director Jens Köster, they gained a practical insight into how the solar carport works and the work of the EBZ.

 

The father of the solar carport project is Ronny Donath. In the video, he explains the path from the initial idea in 2016 to the ceremonial opening of his "prime example of the energy transition" in 2018. "With the plant, we demonstrate that it is possible to achieve balance sheet self-sufficiency. This means that we feed more energy into the grid than we consume ourselves," Donath explains.

"The EBZ supports the skilled trades on their way into new fields of technology," says Managing Director Jens Köster. Companies from Saxony and Saxony-Anhalt can gain practical experience at real installations. For example, in addition to the solar carport, wallboxes and charging points from different manufacturers are also available, and a wind turbine generates clean energy on the roof. Extensive testing of the products and feedback from the engineers and craftsmen also provide the manufacturers with important feedback.

OTHER WAYS TO INTEGRATE RENEWABLE ENERGIES

With a solar carport, you have installed your first small power plant for the mobility revolution. In addition to the electric car, you can also charge e-bikes and pedelecs very well here. Use them privately or as company b icycles for your employees. In this way, you take another step towards a clean environmental balance.

Do you have more space than just for a PV system on a carport? Wonderful! Because with solar energy it also depends on the area that can absorb and convert the solar energy. The larger the system, the more energy can be generated and the more vehicles can be charged. The basis for a decision to use more renewable energy can also be how much potential your vehicle fleet has for conversion to electric cars.

For peak loads and if you want to charge more e-cars than your solar carport can generate, it is also worth switching to a special car electricity tariff. Here you receive electricity from renewable sources at particularly favourable conditions.

PROMOTION AND ADVICE FROM YOUR MUNICIPAL ELECTRICITY SUPPLIER

Charging infrastructure can be funded in Germany. In the past, both the federal government and the federal states set up several funding programmes with which charging points and energy storage systems could be partially financed. Currently, there are no programmes from the federal government or for Saxony, but this should change soon (as of November 2020).

A strong partner for the implementation of a solar carport is your municipal electricity provider, such as SachsenEnergie in the Dresden and East Saxony area. Not only do they know their way around your region - they also have the overview in other respects and will also take over the implementation of your PV system project. They check the current eligibility for subsidies and the existing grid connection. You can also get advice on the PV system area, the right wallbox, software and even fleet analysis from a single source. In this way, you take a big step in the energy and mobility transition with familiar and reliable partners.

Do you already have experience with a solar carport? Are you looking for contacts for advice on expanding your vehicle fleet? We are happy to help - just write to us .

A contribution by Marcel Duparré

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