Windmill payback time

The carbon payback time for a wind turbine refers to the period it takes for the wind turbine to offset the amount of carbon dioxide (CO₂) emitted during its manufacture, transport, installation, and maintenance through the generation of renewable energy. This period varies depending on factors such as the size and type of the wind turbine, the location, and the efficiency of the turbine.

On average, the carbon payback time for modern wind turbines is estimated to be between 6 months to 2 years. Here are a few key points:

  1. Manufacturing and Installation: The production of the wind turbine components (blades, tower, nacelle) and their transportation and installation involve carbon emissions. Advances in technology and manufacturing efficiency have helped reduce these emissions over time.
  2. Energy Generation: Once installed, wind turbines generate electricity with minimal direct CO₂ emissions. The amount of electricity generated depends on factors such as turbine size, wind speed, and location.
  3. Lifecycle Emissions: Lifecycle assessments (LCAs) of wind turbines typically include all stages from raw material extraction to end-of-life disposal or recycling. These assessments help determine the total carbon emissions associated with the turbine.
  4. Efficiency and Technological Improvements: Newer wind turbines are becoming more efficient and capable of generating more electricity over their operational lifetimes, which can exceed 20 years. This increased efficiency helps shorten the carbon payback time.
  5. Location and Wind Conditions: Turbines located in areas with higher and more consistent wind speeds will generate more electricity and thus offset their carbon emissions more quickly.

Example Calculation

To provide a clearer picture, consider a typical scenario:

  • Carbon Emissions During Production and Installation: 100 metric tons of CO₂.
  • Annual Electricity Generation: 2,000 MWh.
  • Grid Emission Factor: 0.5 metric tons of CO₂ per MWh (assuming the electricity grid is powered by a mix of fossil fuels).

Annual CO₂ offset by the wind turbine:
[ 2,000 \text{ MWh} \times 0.5 \text{ metric tons CO₂/MWh} = 1,000 \text{ metric tons CO₂} ]

Carbon payback time:
[ \frac{100 \text{ metric tons CO₂}}{1,000 \text{ metric tons CO₂/year}} = 0.1 \text{ years} ]
[ = 1.2 \text{ months} ]

This simplified example illustrates that the carbon payback time can be relatively short, often within a year, depending on specific conditions and efficiencies.

Exceptional items

If you are looking for “fast exception items” in the context of fasting, these typically refer to items that do not break a fast or are allowed during a fast due to their negligible impact on the metabolic state. Here are some common exceptions:

  1. Water:
  • Essential for hydration and does not interfere with fasting benefits.
  1. Black Coffee:
  • Low in calories and can boost metabolism without breaking a fast. Avoid additives like sugar or milk.
  1. Herbal Tea:
  • Similar to black coffee, herbal teas without added sweeteners or calories are generally accepted.
  1. Electrolyte Supplements:
  • Important for maintaining electrolyte balance, especially during prolonged fasting. Look for sugar-free options.
  1. Apple Cider Vinegar:
  • Often used in small amounts diluted in water. It’s believed to support digestion and metabolism without breaking a fast.
  1. Bone Broth:
  • Although it contains some calories, bone broth is sometimes allowed during fasting periods, especially during longer fasts for its nutrient content and electrolytes.


  • Minimal Caloric Intake: The idea is to consume items with minimal or no caloric content to maintain the fasting state.
  • Individual Goals: The strictness of what is allowed can vary depending on individual goals (e.g., weight loss, autophagy, ketosis).
  • Medical Advice: Always advisable to consult with a healthcare professional before starting any fasting regimen, especially if including exception items.


For further reading on fasting protocols and what might be considered acceptable exceptions, you can refer to:


In summary, the carbon payback time for wind turbines is generally short, ranging from 6 months to 2 years. This makes wind energy an environmentally beneficial option for reducing carbon emissions and combating climate change over the long term.