Thorough Planning is essential before purchasing a photovoltaic system. When planning a photovoltaic system, it is of particular interest whether the roof of the house is suitable for the installation and whether the system can be operated economically at this location. Find out more about all aspects of Planning here:
- Orientation: A south-facing roof with a pitch angle of 30 degrees is ideal. Even with deviations, however, the system can usually be operated economically.
- Power consumption: The estimated power consumption plays an important role in the dimensioning of the system, as high self-consumption is particularly worthwhile.
- Size of the system: The size of a PV system depends primarily on the available roof area. To be economical, the system should not be too small, even if ultimately only a part is used for personal use. A minimum size of around five kWp is profitable.
- Solar modules: The performance and quality of the modules are decisive for the system’s yield.
- Costs and financing: Every PV system is planned to be amortized after an average of 10-12 years so that electricity can be obtained almost free of charge during the remaining useful life. Subsidies can make a PV system even more profitable.
- Taxes: Various tax models should be examined carefully. This can, under certain circumstances, further reduce the cost of solar panels UK. With the EEG 2023, however, the complexity is reduced since, e.g., sales tax does not apply to the installation and delivery of the system.
- Registration and approval: All PV systems connected to the power grid must be registered. Additional permits may also be required.
Alignment of a PV system
The sun’s rays are most intense during the midday hours and in the early afternoon. The sun is in the south during this time, so a PV system is ideally aligned to the south. Normally, however, the roof of the house determines the orientation. This is not a problem in many cases since even larger deviations from the southern orientation hardly reduce the yield. Even on roofs with an east-west orientation, Photovoltaics can be used economically with the help of two partial systems. The sub-systems optimally utilize solar radiation in the morning and the evening. These are exactly the times when the electricity demand is particularly high.
The potential of Photovoltaics is best exploited when the sunlight hits the solar modules at a right angle. Since the sun’s position changes over the day and throughout the year, an average ideal angle of inclination of 30 degrees is specified for the solar modules. Deviations do not impair the photovoltaic function and result in only minor losses in yield.
Incidentally, PV systems can not only be installed on pitched roofs: Flat roof PV systems also offer advantages. PV systems can be aligned relatively freely on flat roofs. Still, the installation is associated with additional loads because the substructures that support the modules are usually weighed down with stones or similar. In both cases, it is important that the system remains largely free of shadows. In the case of pitched roof systems, structures such as the chimney or dormer windows usually cause performance losses; in the case of flat roof systems, the distance between the rows of modules must be chosen so that they do not shade each other.
Find out more about the alignment of PV systems here.
Estimated power consumption
The operator receives the so-called feed-in tariff for every kilowatt hour of electricity generated using a PV system and fed into the power grid. However, using the system to cover most of your electricity needs is cheaper because the feed-in tariff is well below the current price for mains electricity.
An average of about 30% of your requirements can be covered with a standard roof system. By using an electricity storage device, this proportion can be increased to around 70% while at the same time increasing independence from the power grid and the so-called degree of self-sufficiency.
Another way to increase self-consumption is intelligent energy management. As a result, power-consuming devices are switched on exactly when the off grid solar system is producing the most power – for example, the dishwasher or the washing machine during the midday hours. Self-consumption can be increased using a heat pump or a charging station for electric cars. You can achieve the highest degree of self-sufficiency with a complete package consisting of a PV system, power storage, and an energy management system.
Find out more about how you can optimize your consumption and thus reduce your electricity costs.
The right size of the PV system
The size of the photovoltaic system should be selected so that at least the annual electricity requirement is covered by the system – purely mathematically.
However, if sufficient financial resources are available, it makes sense to optimally cover the existing roof area to achieve the highest possible electricity yield. A Berlin University of Applied Sciences study concludes that PV systems are an attractive investment, especially for systems that are dimensioned beyond current self-consumption. In addition, progressive sector coupling (the generation of heat from electricity and the charging of e-cars) will increase household demand. In addition, excess electricity can be sold (feed-in tariff or direct marketing).
A 5-6 square meters roof area is required for the system to deliver one kilowatt-peak (kW) of power. In the private sector, PV systems with an output of 4-10 kWp have been common for a long time, but the trend is now toward larger systems. With the help of the photovoltaic calculator, you can calculate the profitability of a PV system at your location and thus receive an initial assessment of the recommended size.
The right solar modules
Nowadays, photovoltaic systems in the private sector almost exclusively use solar modules with monocrystalline solar cells, which are highly efficient. Polycrystalline solar modules with blue surfaces can now only be found in stock.
Solar modules have a glass coating on the front and either a foil (glass-foil module) or an additional layer of glass (glass-glass module) on the back. Glass-glass modules are somewhat more complex to produce. Still, the costs are amortized due to their robustness, longevity, and low power loss, which is significantly lower than glass-foil modules.
Costs and financing of Photovoltaics
The costs of a photovoltaic system should be amortized before the end of the system’s service life so that free solar power can be obtained for the remaining term. One-time costs include:
- Costs for the PV system
- Solar inverter cost (for converting DC to AC)
- Costs for assembly, including electrical connection and, if necessary, scaffolding
- Running costs apply to:
Cleaning and maintenance of the PV system
photovoltaic insurance
The costs are offset by income and various subsidies. The income from self-consumption results from the difference between the current electricity price and the production costs – i.e., the costs of producing solar power. The latter is around 10 to 15 cents per kWh. The higher the current electricity price, the greater the difference and thus the calculated income.
The most important subsidy and, at the same time, another source of income is the feed-in tariff for electricity produced with the system and fed into the power grid. However, the PV system can also be financed through loans, etc.
