Energy and Power Unit Converter
I. Energy Unit Conversion Table
| Unit | Equivalent Value | Common Application Scenarios |
|---|---|---|
| Ws | 1 Watt-second | Instantaneous power consumption measurement |
| Wm | 0.06 Joule (J) | Research micro devices |
| Wh | 3.6×10³ Joule (J) | Household appliance energy consumption |
| mWh | 3.6 Joule (J) | Small battery capacity (e.g., Bluetooth earphones) |
| kWh | 3.6×10⁶ Joule (J)=1000Wh | Household electricity metering (1 kWh) |
| MWh | 3.6×10⁹ Joule (J)=1000kWh | Medium-scale energy storage stations, central air conditioning system metering |
| GWh | 3.6×10¹² Joule (J)=1000MWh | Large battery factory annual capacity (approximately for 100,000-300,000 vehicles) |
| J | International standard unit | Basic physics calculations |
| kJ | 1000 Joule (J) | Food calorie labeling |
| MJ | 10⁶ Joule (J) | Automotive fuel energy value |
| GJ | 10⁹ Joule (J)≈278kWh | District heating/industrial energy metering |
Key Conversion Formulas:
- 1kWh = 3.6×10⁶J
- 1GJ = 10⁹J ≈ 278kWh
- Battery Energy (Wh) = Capacity (Ah) × Voltage (V)
II. Educational Explanation: Why Do We Need Multiple Energy Units?
1. Scenario-Driven Unit Differentiation
Micro to Macro Scale
- Milliwatt-hours (mWh) are used for micro devices like button batteries (e.g., smartwatches), while gigawatt-hours (GWh) describe Tesla's Gigafactory annual capacity.
- Joule (J) as an international unit is suitable for precise laboratory calculations, but daily life requires more intuitive units (like "kWh").
Industry Convention Differences
- Power Industry: Uses kWh as the billing basis, with power generation often measured in hundreds of millions of kWh (e.g., Sichuan's annual power generation of 432.95 billion kWh ≈ 43.3TWh).
- HVAC: Heating and cooling meters commonly use GJ to measure central air conditioning system energy consumption (1GJ ≈ 278kWh).
- Battery Field:
- mAh represents charge capacity (needs × voltage to convert to energy)
- Wh/mWh directly represents energy value
💡 Beware of False Advertising: Some merchants use 11500mWh instead of 3100mAh to inflate numbers (calculated at 3.7V).
2. Typical Problems with Unit Confusion
Battery Purchase Misconceptions:
- "20000mAh power bank = 1 kWh"? Wrong! Calculated at 3.7V voltage, it's actually only 74Wh (0.074 kWh).
Energy Report Misinterpretation:
- "Energy storage station capacity 1GWh" ≠ "Power generation 1GW", the latter is a power unit (1GW continuous power supply for 1 hour = 1GWh).
3. Future Trends: The Era of TWh
With global electrification and renewable energy storage demands, terawatt-hours (TWh=10¹²Wh) are becoming the new benchmark for energy strategy:
- 1TWh ≈ 1000GWh, can meet the annual electricity needs of 5 million electric vehicles.
- Equivalent to 1 trillion yuan in output value (estimated at 1 yuan/Wh cost).
Summary and Recommendations
- Daily Electricity Use: Focus on kWh, reduce standby power consumption.
- Battery Purchase: Look for Wh/mWh rather than mAh, avoid false advertising.
- Industry Reports: Pay attention to the essential difference between GWh/TWh and GW (energy vs power).
Units are the key to understanding the energy world, clear conversion can penetrate the data fog 🌟