能源回收期计算器 — 公式

How to Calculate Energy Payback Time

Energy payback time (EPBT) measures how long a system must operate to produce the energy used in its manufacture.

Formula

EPBT = Embodied Energy / Annual Production

EROI = Lifetime Production / Embodied Energy

Typical Values

  • Solar PV: 1-3 years EPBT
  • Wind turbine: 0.5-1 year EPBT
  • Nuclear: 5-7 years EPBT
  • Coal plant: 1-2 years EPBT (but never net-zero CO2)

    • 计算示例

    A solar system with 20 MWh embodied energy producing 12 MWh/year over a 25-year lifespan.

    1. Energy payback: 20 / 12 = 1.7 years
    2. Lifetime production: 12 * 25 = 300 MWh
    3. Net energy: 300 - 20 = 280 MWh
    4. EROI: 300 / 20 = 15x