The right PV system for your Heise house

The current use of photovoltaics to benefit from the power of the sun and thus from solar energy now seems completely normal for us. But how did we come up with clever use of the sun as an energy supplier and who discovered the achievement of photovoltaics?

1. What exactly is photovoltaic?

Photovoltaics are used to directly convert incoming sunlight into electrical energy so that it can be used for electricity. Nowadays, this is done via a photovoltaic system on the roof, i.e. solar modules, which consist of many solar cells, collect the sun's energy there. When the sun hits the solar modules, a great tension builds up between the layers — direct current flows. This now only needs to be converted into alternating current, which is done by the inverter of a photovoltaic system.

2. History of the photovoltaic system

The history of photovoltaics itself began well before Christian times, and different cultures were already using sunlight very intelligently in various ways. In 1767, the Swiss naturalist de Saussure made a discovery: A flower bed is heated more by the sun when the sun's rays shine through glazing. He developed an “old school greenhouse” and made use of the photoelectric effect.

In 1839, the underlying photoelectric effect was discovered by Alexandre Edmond Becquerei, the first big step was taken but he was not yet able to apply it back then.

Since 1958, this type of electricity generation has been used for space travel, and only later was it also used to power small electrical devices such as pocket calculators.

Today, electricity generation on roofs and as open-space systems is by far the largest and most important area of application.

3. Benefits of solar systems (ecological, financial)

The main reason for using solar systems is to be “independent.” With your own solar system and energy storage, you are independent of rising electricity prices. The electricity from your own roof always costs the same, i.e. nothing more. In particular, you are making your contribution to the environment when you rely on renewable energy.

• It is inexhaustible (in contrast to fossil fuels such as coal and oil)
• It is clean and emission-free (no CO2, soot or particulate matter)
• It is available free of charge

4. Planning a solar system

An important requirement is a roof area that is as free of shade as possible, ideally with a south-facing orientation and a roof pitch of 30 degrees. Today, we know that systems on east-facing and west-facing roofs also make sense.

With an east-west orientation, electricity is generated whenever private households also need the most electricity, in the morning and in the evening. This ensures that the generated electricity is primarily used for self-consumption and meets the special technical requirement of the Renewable Energy Act (EEG) to consume at least 30% of the generation. This is because photovoltaic systems should only feed a maximum of 70 percent of the nominal power of the modules into the grid.

First, your energy requirement is determined and a reasonable size of the system is determined based on various factors (size of roof area, roof occupancy, statics, shade). The selection of solar modules also depends on factors such as orientation, roof pitch, weight and module size.

All selected factors are then explained with the building permit and you can register with a network operator and let the sun work for you on your Heise house!

5. Benefits of a power storage system

In principle, our photovoltaic energy storage systems work in the same way as the batteries in a car battery. When charging, the batteries in the energy storage device convert the electrical energy obtained from solar energy into chemical energy.

If electricity is now required, the batteries convert the chemical energy back into electrical energy. If the batteries are discharged, they can be recharged again. Most energy storage systems allow several thousand charging cycles.

Energy storage systems make sense because they allow you to temporarily store your self-generated (cheap) solar power. The batteries store excess power that is currently not required for later use. This can be consumed when the sun is not shining and the solar modules cannot generate electricity.

In particular, an energy storage system enables you to use more self-produced electricity. This means that baseload power consumers such as refrigerators, TVs, PCs and other household appliances can be powered directly with your own solar power.

There are also many other advantages for photovoltaics with energy storage, including low investment costs, long life with low maintenance costs, environmental friendliness and more.

6. Costs and profitability of a photovoltaic system

The financial advantage of a PV system comes from two sources: the savings in the electricity bill due to less purchased energy and the remuneration for the electricity that is fed into the public grid itself. And in the Renewable Energy Act (EEG), there is a legally defined feed-in tariff per kilowatt hour.

A photovoltaic system has virtually no moving parts, so maintenance and repair over a lifetime of up to 25 years (and more) are manageable. The inverter is the only component that may need to be replaced once during the lifetime of the system.

Electric mobility is on the rise - be clever and take advantage of it. As an owner of a PV system, you can buy an “electric charging station” for your car right at your Heise house and refuel it free of charge.

We can also use a carport, terraces and balcony areas for your PV system.