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Photovoltaics Photovoltaic system = Solar system = Solar energy system

Considerations before purchasing

German citizens have discovered solar energy in a big way. There are now roughly 300,000 solar energy systems installed on roofs in Germany. Solar power not only protects the environment, it also lets us fill our piggy banks.

What do I need for a solar energy system – what roof characteristics are required?
A roof area which can be utilised and mains electricity (available in all buildings). The solar modules are usually mounted above the roof covering using special brackets.

The pitch and alignment of the roof affect the energy yield. Their influence is often overestimated. A solar energy system aligned to the East or West with a roof pitch of 30 degrees will still provide 80% of the maximum output when aligned to the South. The greater the deviation of the surface from the South, the better it is to use a flatter tilt angle. The most important factor is to avoid shadows being cast on the solar modules. There will be a significant detrimental impact if trees, aerial masts, power cables or gabled dormer windows deprive the modules of light.

Photovoltaics – Planning decisions
The financial benefits of a solar energy system are mainly dependent on the chosen technology and its components. Which installation company performs the work? Does one select an expensive, high-performance module? These are among the many questions affecting the profitability of a solar energy system. Our experienced advisors will be pleased to pay you a visit.

Solar energy system – what are the components?
Every grid-connected solar energy system consists of three parts:

1. A solar generator on the roof composed of several electrically interconnected solar modules.
2. Grid feeding equipment (inverter), which converts the DC output from the solar generator to standard AC mains voltage as well as monitoring the mains supply and performing yield optimisation functions.
3. Grid connection for feeding the generated electricity into the public grid where it is sold to the responsible grid operator (existing grid connections can be used for ratings up to 30 kilowatt without any problem).

Solar energy systems – how much electricity do they produce?
This is dependent on the peak installed output and hence the available area for the solar module. Modules using crystalline solar cells generate approximately 1 kilowatt of peak power for an area of 8 to 10 square metres. Optimum alignment is achieved on south-facing roofs with a pitch of 30 degrees. Based on these conditions, solar generators in southern Germany generate roughly 900 kilowatt-hours per kilowatt of installed capacity, whereas in northern Germany one can assume approximately 800 kilowatt-hours per kilowatt of installed capacity. These are long-term averages which will vary by 5 to 10% percent in any given year. SOLAR MAPS provide additional information. Apart from the available area, the level of financial investment is another major criterion. Initial capital outlay and securing external financing are no longer problematic since solar energy systems more or less finance themselves through feed-in tariffs, and the system itself is used as collateral for the investment.

Planning application required?
Most of the federal states do not require a planning application for roof-mounted solar energy systems. Every local authority is entitled to define its own rules in this regard. In any case, one should informally enquire if it concerns a listed building in a sensitive area, as photovoltaic technology has an unusually long service life.

Is damage insurance required?
External factors such as humidity and storm damage, lightning strikes, extreme hailstorms or vandalism can have a detrimental effect on the solar energy system. Every solar energy system should be insured as it is impossible to discount such damage being incurred. Two options are available: The solar energy system is covered by the building and liability insurance policy. Usually this only results in a minor surcharge. The disadvantage is that the solar energy system is only covered against the risks detailed in the policy and insured at its present value. The alternative is to obtain a “fully comprehensive insurance” for solar energy systems in the form of a so-called “All risks insurance”. This is offered by specialist insurance companies. Vandalism, theft and operating errors, as well as compensation for yield outages when the system is not operational, can also be insured. This may be of particular interest for larger systems financed by third parties.