Electricity and Bitcoin mining: how to reduce your costs

Electricity accounts for 70 to 90 per cent of the operational costs of Bitcoin mining. With an average price of €0.12/kWh in Europe and profitability on the wane, optimising energy consumption is becoming crucial to maintaining profitable operations. An Antminer S21, which consumes 3,520W, can result in a monthly electricity bill of €300, directly impacting your profit margins. This article reveals tried-and-checked strategies for significantly reducing your electricity costs whilst maximising your hashrate and mining revenue.

Analysing and understanding your electricity consumption

Accurate calculation of your current costs

The first step is to carry out a comprehensive energy audit of your setup. For an ASIC such as the Antminer S21 Pro (3,520W), the monthly calculation is as follows:

Monthly cost = Power (kW) × 24 hours × 30 days × Price per kWh

• S21 Pro: 3.52 kW × 24 × 30 × €0.12 = €304/month
• S19 Pro: 3.25 kW × 24 × 30 × €0.12 = €280/month

Don’t forget to include indirect costs:

• Ventilation and cooling: +15 to 25 per cent of ASIC power consumption
• Lighting and network equipment: +2 to 5 per cent
• Conversion losses (power supply): +5 to 8 per cent

Identify hidden energy consumption sources

Apart from the miners themselves, several factors contribute to your electricity bill. An industrial ventilation system can consume an additional 500 to 1,000 W per ASIC to maintain optimal temperatures. Power supply units (PSUs) have an efficiency of 92–95 per cent, resulting in 5–8 per cent energy losses.

Network infrastructure (switches, routers, Wi-Fi access points) adds a constant 50 to 100W. In some regions, air conditioning can account for up to 40 per cent of total ASIC consumption during the warmer months.

Strategies for negotiating electricity tariffs

Negotiating with your energy supplier

The high energy consumption of Bitcoin mining puts you in a strong position to negotiate. Suppliers often offer tiered rates for high-volume consumers (>36 kVA). Ask for an industrial or business tariff, which is generally 20–40 per cent cheaper than the residential tariff.

Look into variable-rate contracts based on off-peak hours. In France, off-peak hours (10 pm–6 am) offer reductions of 25–35 per cent. Some regions offer ‘distributed load shedding’ tariffs, where you agree to scheduled power cuts in exchange for tariff reductions.

Optimising your electricity contract

Type of contract	Average price	Advantages	Disadvantages
Residential	€0.15/kWh	Simplicity	High cost
Business	€0.11/kWh	-27% compared to residential	Long-term commitment
Industrial	€0.08/kWh	-47% compared to residential	High minimum threshold
Off-peak hours	€0.09/kWh	Time flexibility	Usage restrictions

You can also negotiate fixed charges: subscription fees, local taxes and transmission charges. These items can add an extra €30 to €40 per month to your bill.

Technical and energy optimisation

Undervoltage and ASIC settings

Undervoltage involves reducing the supply voltage to your ASICs to lower their power consumption. This technique can reduce power consumption by 15 to 25 per cent with a drop in hashrate of just 10 to 15 per cent.

Example using an Antminer S21 Pro:

• Stock configuration: 3,520W for 234 TH/s
• After undervoltage: 2,800W for 200 TH/s
• Savings: 720W, or €52 per month at €0.12 per kWh

Use tools such as proxy.minent.eu to monitor and fine-tune your voltage settings. Alternative firmwares such as Braiins OS+ allow for more granular adjustments than the original firmware.

Smart cooling management

Cooling accounts for a significant proportion of your energy costs. Install an evaporative cooling system (swamp cooling) in dry regions: 70 per cent savings compared to conventional air conditioning.

Use natural ventilation when the outside temperature allows. An automated system with temperature sensors can switch between active and passive cooling depending on weather conditions.

Optimal ventilation configuration:

• Target temperature: 60–70°C at the ASIC outlet
• Airflow: 200–300 CFM per ASIC
• PWM industrial fans for automatic adjustment

To further optimise your setup, see our guide on how to configure an Antminer S19 and S21 for precise settings.

Using alternative energy sources

Installing solar panels can cover 30 to 50 per cent of your energy needs, depending on your region. The high initial cost (€8,000 to €15,000 for 10 kW) pays for itself in 6 to 8 years through the savings generated.

Domestic wind power remains more complex but is viable in certain windy areas. Hybrid solar-wind-storage systems offer the greatest energy self-sufficiency.

Energy storage solutions and scheduling

Battery systems and storage

Lithium-ion batteries allow energy to be stored during off-peak hours for use during peak hours. For a 10kW installation, expect an initial investment of €15,000 to €25,000.

Battery cost-effectiveness calculation:

• Tariff differential: €0.15 – €0.09 = €0.06/kWh
• Daily consumption: 84 kWh (S21 Pro)
• Theoretical saving: 84 × €0.06 = €5.04/day
• Battery ROI: 8 to 13 years depending on capacity

Smart operation scheduling

Develop scripts for automatic start-up and shutdown based on hourly tariffs. Python, combined with tariff APIs, allows you to fully automate your operations.

Implement priority mining logic: activate the most efficient ASICs (best TH/W ratio) first during peak hours, then the entire fleet during off-peak hours.

Example of a scheduling algorithm:

SI prix_kwh < 0.10€ ALORS activer_tous_asic()
SI prix_kwh < 0.13€ ALORS activer_asic_efficaces()
SI prix_kwh > 0.15€ ALORS mode_maintenance()

Continuous monitoring and optimisation

Consumption monitoring tools

Install smart meters on each circuit to identify consumption anomalies. Connected current clamps enable low-cost real-time monitoring (€50 to €100 per circuit).

Use solutions such as Home Assistant or specialised platforms to centralise all your energy data. The aim is to quickly detect anomalies: faulty ASICs, blocked ventilation, overheating.

KPIs and energy performance metrics

Monitor these key indicators daily:

Essential energy metrics:

• Power consumption per TH/s: target <15W/TH for S21s
• Cooling coefficient: fan-to-ASIC ratio <0.3
• PSU efficiency: maintain >93%
• Average temperature: maintain <65°C

For professional monitoring of your mining farm, read our article on Bitcoin mining monitoring and its key metrics.

Recommended monitoring dashboard:

• Real-time electricity cost (€/day)
• Power consumption per ASIC
• Temperature and airflow
• Hashrate and revenue
• Profitability ratio (revenue/electricity costs)

Analysing this data over several months reveals optimisation patterns: optimal maintenance periods, seasonal adjustments, early detection of faults.

Conclusion

Reducing your electricity costs for Bitcoin mining requires a methodical approach combining tariff negotiation, technical optimisation and continuous monitoring. The potential savings are substantial: a possible reduction of between 30 and 60 per cent on your electricity bill, depending on your initial setup.

Investing in energy-efficiency solutions generally pays for itself within 12 to 24 months, and then generates recurring savings throughout the lifetime of your equipment. With Bitcoin trading at around €59,000 and mining difficulty on the rise, every euro saved on electricity directly improves your profitability.

Start by auditing your current consumption, negotiate your tariffs, then gradually implement technical optimisations. For optimal management of your mining operations and professional monitoring of your costs, create an account on our proxy mining platform and discover our energy optimisation tools.