Pierre André’s hybrid solar power plant in the Rhône / Image: Pierre André.
Hybrid solar panels produce both hot water and electricity. More expensive than conventional photovoltaics, this technology is still not unanimous among individuals. But what is it really worth? Testimony of an individual who has chosen to install it on his roof.
For fifteen years, Pierre André has been drawing part of his energy needs from the sun. This resident of the Rhône had 3 thermal solar collectors from the manufacturer Giordano, which only supplied him with domestic hot water. He replaced them in April 2022 with a hybrid power plant, capable of producing electricity at the same time as hot water.
With a power of 6 kWp, its new installation is made up of 12 “Flash” photovoltaic panels and 4 “Spring” hybrid panels designed by DualSun. The plant is placed on its roof with a very favorable orientation, facing south and 27 degrees of inclination. An investment that cost him €17,400 installation included, financed by a loan as part of a comprehensive renovation of housing. But for what result?
How its solar thermal power plant cut its gas consumption by 3
100% solar showers in summer
This retired computer engineer claims that the hybrid panels covered 100% of his domestic hot water needs during the summer. He notes, however, that he has to “add a little electric backup during the day” at its cumulus of 300 liters since mid-September, the weather being less and less favorable as autumn approaches. A supplement without much consequence on its energy balance, since it is provided by the photovoltaic part of its power station.
” Giordano panels were much more efficient [pour produire de l’eau chaude, NDLR], they heated to 90°C. There, the hybrid panels are voluntarily limited to around fifty degrees so as not to penalize the photovoltaic yield” he concedes. If its old thermal sensors assured it more hot water during the shoulder seasonsit will now have to consume a little more electricity to compensate for the heat loss over this period.
Pierre André confides that he does not regret this replacement, because in any case, “in the middle of winter, the thermal panels give nothing, zero! » he assures. Whether only thermal or hybrid, these collectors would produce very little hot water during the cold season for this Rhone resident. A phenomenon that is however very dependent on the type of installation and geographical location, with some people managing to obtain sufficient heat from thermal collectors in winter.
Its electricity and heating bill is derisory thanks to its bioclimatic house
Recharge your electric car with photovoltaics
The pensioner relies mainly on the electricity produced by his power plant, which essentially allows him to recharge his Volkswagen ID.3. Its panels would have produced 40 kWh daily in July and August. It is a little less in May, with a total of 994 kWh (or 32 kWh/day).
“For the moment, I manage to achieve a little more than 50% self-consumption, because I haven’t optimized it yet” he explains. His electric car already ranks high in this rate. It is largely fed with solar energy, thanks to “a 10 A charger, which charges slowly, but allows me to never exceed the production of the photovoltaic panels” he specifies.
The electric vehicle and the inverter of the solar installation / Image: Pierre André.
Thus, in the summer, the ex-engineer recharges “between 11 a.m. and 5 p.m., i.e. for 6 hours”. It recovers approx. 14 kWh every sunny daywhich would suffice for his short urban trips. “In case of greater need or lack of sun, I complete the night with a wallbox that charges at 32 A and one night is enough to charge the EV, which has a 52 kWh battery, to 100%” he details.
Self-consumption, injection or batteries: what should I choose for my solar panels?
Automation to optimize self-consumption
Pierre André plans to install automatisms in order to increase his rate of self-consumption. These devices will make it possible to turn on and off the power supply of certain equipment according to solar production, without manual intervention. He wants to make them with the help of other enthusiasts who discuss on a forum specializing in solar.
Because, if he resells the unconsumed electricity injected into the network for €0.10/kWh, he must in parallel buy it at a higher rate. It is therefore more interesting to use one’s own solar production.
Unfortunately, installers and manufacturers of solar power plants rarely inform their customers about ways to promote self-consumption without having to plan everything manually. Only the most experienced individuals install on their own relays and other connected sockets to switch on power-hungry appliances when the sun shines at its strongest.
Solar self-consumption is now more powerful than a nuclear reactor in France