I'm installing 6 kW of photovoltaic panels! A look at my installation, plus tips!

Producing part of the electricity for your machines yourself is a serious option for any miner paying a high price for power. In this video (in French), we present the 6 kW of photovoltaic panels installed on our roof, the role of each component and our advice: orientation, inverter, paperwork, "plug and play" kits, prices and payback time.

Video from May 2023: the prices, grants and electricity tariffs below date from that time and may have changed since.

The installation: 15 panels of 400 Wp

The installation has 15 panels of 400 watts peak, i.e. 6 kWp. They face west, slightly north: we admit it is not the ideal orientation, and shade is another point to check before installing panels.

• The panels: "full black" monocrystalline Longi panels. Their production capacity is guaranteed for 20 to 25 years, with about 85% of output still announced after 25 years.
• Handling shade: each panel is divided into 6 zones. If shade covers one zone, only that zone is partly deactivated, without shutting down the whole panel.

Central inverter or micro-inverters?

The direct current produced by the panels goes into a protection box, then into a 6,000-watt Huawei central inverter, which converts it into alternating current for the house. Let's compare the two technologies:

• The central inverter: the cheapest solution, but if it fails, all production stops;
• Micro-inverters, one per panel: more expensive, but if one of them fails, the rest of the installation keeps producing.

The electricity produced powers the machines first, and the surplus goes to the grid. Production can be monitored in real time on Huawei's website and in the FusionSolar mobile app.

What the installation produces

Our production curves show it: a fine cloudless day gave about 22 kWh, the worst day recorded about 9.7 kWh. By comparison, our mining machines draw a little over 3,000 watts continuously. With a west-facing roof, morning production is low: we are considering adding east-facing "plug and play" panels, set up in the garden.

Certified installer or "plug and play" kit

In France, a rooftop installation requires authorisation from the town hall and an inspection by Consuel, the electrical safety body. Going through a certified installer entitles you to a grant, about €1,300 for a 3 kW installation. Surplus that is not consumed can be sold to EDF, at 13 euro cents per kWh at the time of the video; for a miner, most of the production is consumed by the machines anyway.

The alternative is the "plug and play" kit: two panels for about 800 watts with a micro-inverter, which you plug straight into a socket, for about €1,000. We estimate that such a kit produces about 1,000 kWh per year.

Prices and payback time

With the grant deducted, we count about €6,700 for a basic 3 kW installation, and up to about €15,000 for the largest in our comparison (9 kW). Based on a standard electricity contract at about 18 euro cents per kWh:

• a private individual takes about 10 years to pay back a rooftop installation;
• the "plug and play" kit pays for itself in about 5 years;
• through a company, as we did, the payback time drops sharply: you do not pay VAT (20% less) and you can cut the cost by roughly another 30% through tax deductions.

We also recommend looking at EDF's Tempo tariff, around 13 euro cents per kWh on average if you avoid the red days. A lithium battery, on the other hand, does not appeal to us yet: it almost doubles the payback time.

The price of electricity weighs heavily on mining profitability: measure its impact with our Bitcoin mining profitability calculator, and discover our home miners, more compact and quieter. For the real figures from this installation, read our review after one month of production. No roof or no cheap electricity? Consider our miner hosting.