Solar surplus, dynamic electricity prices and Bitcoin mining

1. Start with the real load profile

Annual consumption does not show when energy is needed. Morning, midday, evening, weekdays, weekends and seasons all matter. A heat pump creates high winter demand when PV output is lower, while a commercial building may have strong daytime demand that aligns well with solar generation.

Quarter-hourly or finer data reveals base load, peaks, export and shiftable loads. This evidence should come before buying additional hardware.

• Direct use usually has the lowest conversion losses.
• Battery storage and thermal storage perform different tasks.
• Connection power in kW matters alongside annual energy in kWh.

2. Assess dynamic prices as all-in cost

The published energy or wholesale price is not the final bill. Network charges, levies, taxes, standing charges and possible demand components remain relevant.

Automation should therefore combine the complete tariff, PV forecast, battery state of charge, heat demand and a total power limit. Otherwise an apparently cheap hour may create expensive peaks or unnecessary conversion losses.

• Use tariff data at the same time resolution as the controller.
• Apply a safety margin to forecasts.
• Avoid grid charging when own solar production is expected shortly.

3. Use electrical and thermal storage deliberately

A battery retains high-quality electricity that can serve many loads later. Its value depends on usable capacity, power, efficiency, cycling and price spread. A hot-water cylinder or the building fabric can store energy more cheaply, but only as heat.

A combination is often effective: the battery supplies evening demand while the heat pump or cylinder creates a thermal reserve during sunny hours. Controls must avoid both systems producing an unnecessary simultaneous peak.

4. Treat mining as a genuine residual flexible load

A Bitcoin miner can absorb power quickly and turns almost all input electricity into heat. It is technically relevant only where genuine solar surplus and useful heat demand occur at the same time. Without heat use it competes directly with export, batteries, heat pumps and other loads.

The assessment must include hardware, cooling, maintenance, noise, tax, volatile revenue, any grid import, lost export value and the actual value of useful heat. PHT therefore treats mining as an optional technical load, not a guaranteed investment return.

• Operate only within defined surplus and temperature limits.
• Design the electrical installation for continuous load.
• Use qualified tax and legal advisers for non-technical questions.

5. Move from analysis to safe automation

A robust concept documents metering points, priorities, thresholds, fallbacks and responsibilities. It also defines what happens when communication or price data fails. Heating and battery protection must always remain within manufacturer limits.

After commissioning, measured data is compared with the design. This is the only reliable way to confirm higher self-consumption, lower peaks and correct operation in solar or low-price windows.

• Review representative weeks of load and PV data.
• Rank the objectives: cost, self-consumption, comfort, autonomy or peak reduction.
• Check performance seasonally and adjust the rules.