Solar parking lot: Solar carports and solar parking lot systems - the sustainable type of photovoltaics on asphalt surfaces

Asphalt surfaces are widespread in many cities and offer ample space for the installation of solar carports and solar parking facilities. This type of photovoltaics is particularly sustainable because it is installed on existing surfaces and does not require any new land. At the same time, the shading provided by the solar panels helps prevent urban heat islands, as overheated streets are one of the biggest climate problems in urban areas. Furthermore, solar carports and solar parking facilities can help reduce environmental impact through emission-free electricity generation.

The problem of urban heat islands is a large and serious one, yet most people don't know what they can do about it. Urban planning is a key factor in combating the overheating of urban environments. According to climate scientist Dr. Ebi Krypton, “79% of global CO2 emissions are directly or indirectly attributable to urban activities.” This high percentage of culpability for greenhouse gas emissions illustrates the immense pressure our cities are under as population density increases. Unfortunately, many modern architects and urban planners tend to accept heat as an unavoidable element in their designs. But there is hope – if we embrace and implement climate-adapted architectural solutions, this can help limit global warming to 1.5°C to 2°C.

More about it here:

• Green Smart City: Green infrastructure and emission-free electricity supply

Smart City: Green infrastructure and power supply – Image: Xpert.Digital / studiostoks|Shutterstock.com

A study by DeLorean Power in Switzerland found that employee parking behavior ideally corresponds to the amount of solar power generated. The electric vehicle's daily mileage can be covered in almost any weather, and any surplus energy can be fed into the grid. The annual solar power generation in the parking lot matches the vehicle's energy needs. Solar parking lots have the greatest potential for electricity generation of all infrastructure sectors. In Switzerland, there are approximately two parking spaces available for every registered car. In suitable regions, this could generate over 10 terawatt-hours of solar power per year (15% of current electricity consumption). "It's astonishing how few pilot plants there are," the study authors stated. Furthermore, such a roof protects the car from the elements and reduces heat buildup in the summer.

According to an analysis by the Federal Statistical Office (FSO), Switzerland has at least 5 million above-ground parking spaces (6,400 hectares) with approximately 4.7 million registered passenger cars. These parking areas were recorded using a digital method that only identifies larger adjacent areas and not individual parking spaces. Traffic experts therefore estimate that there are between 8 and 10 million parking spaces. That's about two per car.

According to another study, “Solar Power Generation for Infrastructure Facilities and Conversion Areas,” above-ground or open parking areas have the greatest PV potential of all infrastructure areas. These areas can supply up to 10 terawatt-hours (TWh) of PV electricity per year. This brings the total electricity production in Switzerland to 65.5 TWh.

The average parking area is 12.5 square meters (2.5 meters x 5 meters). This is also the area that a solar roof must cover. The energy yield of a PV system depends on many factors, including solar irradiance, component efficiency, and module orientation. In Thurgau, approximately 1000 kWh of electricity per year can be generated with 1 kW of installed PV capacity (1000 kWh per 1 kWp).

Depending on the PV modules used, 1 kWp requires an installed capacity of 4 to 8 square meters. This study assumes 5 m² per kWp. Therefore, a 12.5 m² parking space with a 2.5 kWp system can be installed, generating 2,500 kWh of solar power per year. The average Swiss household consumption is around 4,500 kWh/year (excluding heating, ventilation, and electric vehicles).

The modular design of a carport system is advantageous, allowing the roof to be adapted to almost any parking space, thus ensuring continued good utilization of the parking area and guaranteeing expandability.

Bifacial modules allow for increased light transmission through the carport. This is visually appealing and leads to higher solar yields, as these PV modules can also utilize light entering from below, thus delivering 10-20% more energy. Currently, bifacial technology is not widely used because its economic viability is not guaranteed due to higher module prices. However, it is expected that this technology will become more established in the coming years.

In our 4+2+ modular and scalable solar carport system, which uses semi-transparent and bifacial modules, these points apply and are already an additional price-competitive alternative :

Solar roofing options specifically for vehicles – Image: Xpert.Digital

More about it here:

• Numbers, data, facts: solar carport, carport with solar roof, roofing variants in comparison and model parking space with electricity yield

Limitless: Modular and scalable solar carport system for cars and trucks

Limitless: Modular and scalable solar carport system for cars and trucks

Technical specifications: Modular and scalable solar carport system for cars and trucks

Technical specifications: Modular and scalable solar carport system for cars and trucks

Advantages at a glance:

• Flexible and modular (scalable) design
• Clearance height for cars from 2.66 m (extendable to 4.5 m or more for trucks)
• Parking space depth for cars up to 6.1 m, opposite side up to 12.5 m possible.
  The depth depends on the dimensions of the solar modules used.
• The solar carport system is optimally designed for semi-transparent solar modules with
  12%/40% light transmission (!) – and is certified for overhead mounting.
• Optionally available with powerful LED lighting, dimmable and with motion control
• Also suitable for parking spaces with inclined positioning
• No hidden costs regarding foundations.
  Use of point foundations (most economical option, no extensive excavation for concrete slabs etc. is necessary for structural stability) or installation with base plates, depending on the existing soil conditions/asphalt.

Further sources:

• Cost factor of ground foundation for solar carports
• Solar carports where standard no longer applies – The optimal solution for every challenge with solar roofing for open parking spaces
• Solar carport systems: Which is the better and/or more cost-effective option?
• The solar carport strategy for open parking spaces
• The modular solar carport system for all applications and situations

Truck solar carport system

Due to the fact that the 4+2+ column technology offers the most flexible solution (both technically and in terms of price) for a parking space roofing system, it can also be easily extended and applied to larger vehicles such as trucks with appropriate modifications.

The increasing overheating of cities is a global problem. In recent years, the temperature in urban areas worldwide has risen by an average of 0.5 to 1 degree Celsius. This warming is mainly due to the absorption of sunlight by asphalt and other dark surfaces.

Scientists agree that this urban heat island effect is a consequence of global warming. However, temperature differences between urban and rural areas can also be influenced by other factors such as vegetation, wind, and building design.

The effect is particularly noticeable in large cities, as this is where most people live and most cars drive. The heat is stirred up by the cars and rises into the air. It is then reflected back by the high-rise buildings and trapped in the street canyons.

The problem of overheating in cities is therefore twofold: firstly, the direct absorption of sunlight by asphalt and other dark surfaces, and secondly, the stirring up of heat by traffic.

One possible solution to the problem of urban overheating is the installation of solar carports and solar parking facilities. These systems can reduce both the absorption of sunlight and the stirring up of heat.

Solar carports are covered parking spaces equipped with photovoltaic modules. These modules convert incoming sunlight into electrical energy. At the same time, the heat from the sunlight is dissipated and not transferred to the surrounding area. This can reduce the temperature under the carport by up to 10 degrees Celsius.

The installation of solar carports and solar parking facilities is therefore an effective way to reduce urban heat island effects. However, these systems not only offer a solution to the overheating problem, but can also be used to generate renewable energy.

More about it here:

• Impact of urbanization: Urban heat island (UHI) – prevention through solar roofing with simultaneous electricity generation

An urban heat island (UHI) is an urban or metropolitan area that is significantly warmer than the surrounding rural areas due to human activity. The temperature difference is usually greater at night than during the day and most pronounced when winds are weak. UHI is particularly noticeable in summer and winter. The primary cause of the UHI effect lies in changes to the land surface. One study has shown that heat islands can be influenced by proximity to different types of land cover, such that proximity to barren land leads to warming of the urban soil, while proximity to vegetation makes it cooler. Waste heat generated by energy use is another factor. As a population center grows, its area increases, and the average temperature rises. The term "heat island" is also used; it can refer to any area that is relatively hotter than its surroundings but generally refers to areas disturbed by human activity.

Monthly rainfall is higher in the rain shadow of cities, partly due to the UHI. The increasing heat in urban centers lengthens growing seasons and reduces the occurrence of weak tornadoes. The UHI worsens air quality by increasing the production of pollutants such as ozone, and it degrades water quality as warmer water flows into the region's rivers, stressing their ecosystems.

Not all cities exhibit a pronounced urban heat island effect, and its characteristics depend heavily on the background climate of the area in which the city is located. The urban heat island effect can be mitigated by green roofs, passive radiative cooling during the day, and the use of light-colored surfaces in urban areas, which reflect more sunlight and absorb less heat. Urbanization has exacerbated the impacts of climate change in cities.

The phenomenon was first studied and described by Luke Howard in the 1810s, although he was not the one who named it. Research into the urban atmosphere continued into the nineteenth century. Between the 1920s and 1940s, researchers in Europe, Mexico, India, Japan, and the United States, working within the emerging fields of local climatology or microscale meteorology, sought new methods to understand the phenomenon. In 1929, Albert Peppler used the term "urban heat island," which is considered the first example of an urban heat island. Between 1990 and 2000, approximately 30 studies were published annually; by 2010, this number had risen to 100, and by 2015, it had exceeded 300.

More about it here:

• Impact of urbanization: Urban heat island (UHI) – prevention through solar roofing with simultaneous electricity generation