6 kW photovoltaic installation: a (positive) review after 1 month!
A little over a month after having 6,000 watts peak (6 kWp) of solar panels fitted on our roof, we take stock. In this video (in French), we present the real figures from the first full month of production, compare them with our electricity consumption, then go through two ways of producing your own electricity: a rooftop installation and a "plug and play" solar kit. It is a question every miner cares about: how much of your consumption can the sun cover, and how long does it take to pay back the investment?
Video from June 2023: the figures below date from that time.
About 730 kWh produced in May
Over the month of May, the installation produced about 730 kWh (727 kWh to be precise), or around 24 kWh per day on average. The differences from one day to the next are large:
- The worst days, with rain and clouds: about 10 kWh;
- The best days: around 30 to 33 kWh, three times as much;
- Our record: 35 kWh in a single day.
In terms of instantaneous power, we saw peaks of 4,600 watts, for a rated output of 6,000 watts peak.
Production shifted towards the afternoon
Our roof faces west, slightly north, in the Paris region. It is not the ideal orientation, and it shows on the production curve: in the morning, almost nothing happens. Production starts around 11 am at about 500 watts, reaches about 1,200 watts at noon, then rises mainly in the afternoon. On the other hand, at this time of year the panels are still producing about 1,000 watts around 8:45–9 pm, before production drops quickly.
Our advice: the ideal is still a south-facing orientation with no shade on the panels.
There are two technologies for turning the panels' direct current into alternating current: a central inverter, which handles the whole installation (this is our setup, with a Huawei inverter), or micro-inverters, one per panel.
How much of our consumption does it cover?
Our electricity consumption is about 4,000 watts continuously, or 2,900 kWh over the month of May. With 727 kWh produced, the panels therefore covered about 25% of our consumption that month.
Over a full year, we expect production of about 7,000 kWh. Measured against a whole year of consumption, the share covered should be lower than in May: around 15%, by our estimate. In our case, we reckon it will take about 6 years for the installation to pay for itself.
Option 1: a rooftop installation
Together with our partner, the certified installer who fitted our panels, we offered 3, 6 or 9 kW installations. Prices including VAT were €8,000, €13,500 and €18,000, before deducting the French government grant, which could reach €3,000 depending on the installation. The other advantages of this option:
- Surplus buyback by EDF, at 13 euro cents per kWh at the time;
- A much lower cost if you buy the installation through a company.
The payback period is generally between 8 and 10 years. It is longer if you are on the Tempo tariff: your electricity costs you less than on the standard tariff, so each kWh produced saves you less.
Option 2: the "plug and play" solar kit
For those who do not want to, or cannot, have panels fitted on their roof, there are solar kits you plug in yourself. The ones we offered through a partner, delivered in 48 to 72 hours, use 425-watt black Trina Solar panels from the Vertex range, with an efficiency of 21.3% and a 25-year warranty.
- Price: the single-panel kit starts at €600. We find it more worthwhile to go for two panels: the kit then costs €1,000. You can build your kit with 1 to 8 panels.
- Installation: the mount has an adjustable angle, with degree markings so you can optimise the panel's tilt for the season (summer or winter). Then you simply plug the lead coming out of the micro-inverter into a wall socket. Accessories such as extension cables are available.
- Payback: it can drop below 5 years, to around four and a half years.
One limit to be aware of: with a plug and play kit, you cannot sell your electricity, unless, like us, you have first had a rooftop installation fitted.
The price of electricity weighs heavily on mining profitability. To measure its impact on your earnings, use our Bitcoin mining profitability calculator, and to mine at home without turning your house into a server room, browse our quiet home miners. To see how our panels were installed and our first tips, also read the presentation of our solar installation.