Electricity does not have to be generated in large power plants and distributed using long lines.
Ottmar Back knows that there is also an easier way.
The Weilheimer operates a so-called balcony power plant.
This is a small photovoltaic system that does not produce a lot of electrical energy, but it is for immediate consumption on site.
Weilheim
- Back has two modules with a peak power of 120 watts each.
The 240 watts are a theoretical value that can only be achieved under optimal conditions.
In fact, the performance depends on the sunshine.
An inverter turns the direct current into the alternating current that household appliances need.
Modules are slightly smaller than the normal size
“The modules I installed are slightly smaller than the standard size,” says Back, “because they shouldn't be larger than my balcony cladding.” He therefore chose modules that are 112 centimeters by 68 centimeters.
Back also calculated the cost and profitability of the facility.
The modules and the inverter cost a total of 289 euros.
The power socket required by the network operator, together with the four-meter-long connection cable, cost 55 euros.
Back spent 68.20 euros on profiles, brackets and screws that were required for installation on the balcony.
In total, the balcony power plant cost 412.20 euros.
The plant went into operation on December 18 of last year.
"Since then, it has worked without any malfunctions," said Back in July, "and has so far produced 133 kilowatt hours of electricity."
Self-consumption is important.
Back: "84 percent was consumed directly in the house, only 16 percent fed into the grid." The feed-in does not play a role financially because there is no remuneration for these plug systems, as they are also called after they are connected.
Investment pays for itself "already after seven years"
Back extrapolates the energy yield and the savings: “In one year I expect 230 to 250 kilowatt hours of electricity to be produced.
With an own consumption of 84 percent and an electricity price of 30 cents per kilowatt hour, this results in annual savings of around 60 euros.
This means that the investment pays for itself after just seven years. "
Since the electricity consumption in the two-person household is 1700 kilowatt hours per year, around 14 percent of this can be generated regeneratively with the balcony power plant.
“The rest of the electricity is taken from the grid as green electricity,” says Back.
According to Back, one advantage that should not be left unmentioned is the vertical installation of the modules in the balcony power plant.
Since the angle of incidence of the sun's rays in winter when the sun is low is more favorable than in summer, the performance in winter, when more energy is needed, is greater than in summer.
In addition, the efficiency of the modules is higher at the low temperatures in winter than in summer.
BY ALFRED SCHUBERT
