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Solar Energy
Home owners

7 facts worth knowing about photovoltaics

PV Basics

Photovoltaic systems are used to generate electricity from the power of the sun. Although most people have a pretty good idea of what a PV system does, interesting questions continue to crop up, some of which we can answer here. Did you manage to answer all the questions?

1. How much electricity does a PV system produce?

This depends on a number of factors, such as the type of installation, the weather, and the local level of solar radiation. The output of a system under standard conditions is rated using the kilowatt peak unit. Essentially, a system in Germany with a kilowatt peak will generate 850 – 1100 kWh of electricity a year. In Australia, this figure can be as high as 2500 kWh.

2. What sort of roof area will i need for a PV system?

Depending on the type of solar module, a kilowatt peak system requires an area of 8 – 12 m². For most households, a system rated at between 4 and 10 kWp is ideal.

3. What components do i need for a PV system?

In addition to the solar modules on the roof, you also need an inverter to convert the direct current generated into the alternating current required in your home. A Smart Meter measures not only the amount of electricity generated, but also the electricity used by the household. This forms the basis of all the subsequent applications that ensure that as much as possible of the self-generated electricity is used within your own four walls. Examples of these are a storage unit or the Fronius Ohmpilot for heating hot water using photovoltaic energy.

4. Does my roof have to face due south?

Your system will generate the most electricity if the roof faces south. On the other hand, an east and/or west orientation will enable electricity to be generated earlier in the day or for longer in the evening. This electricity can then be used immediately, assuming someone’s at home. A photovoltaic system is therefore also worth installing on roofs that do not face due south.

5. Is a PV system financially worthwhile?

Yes, the reason being that electricity from your own roof is much cheaper than that supplied by an energy provider. The more self-generated electricity you use, the stronger the argument in favour of a system. The payback period depends on your self-consumption and the area in which you live, and is generally between 4 and 10 years.

Find out how to increase your self-consumption here.

6. Will a PV system keep the lights on in the event of a blackout?

Photovoltaic systems are usually connected to the public grid and for safety reasons are obliged to disconnect immediately from the grid in the event of a blackout. In this case, Fronius inverters with a backup power function can create their own small, local grid. This mode of operation, called stand-alone operation, will continue to supply the household with power. 

7. Do the solar modules have to be cleaned?

Under normal conditions, rainfall and the pitch of the roof will be sufficient to keep the solar modules clean. Should the pitch of a photovoltaic system be very shallow or be badly affected by particular local conditions (trees, agriculture, etc.), then it’s probably a good idea to have them cleaned occasionally. There are plenty of companies out there that provide such a service.

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