Optimising the wind turbine driving profile with the efficiency indicator : costs, environmental impacts and lifetime
Li, Wei (2026)
Diplomityö
2026
School of Energy Systems, Ympäristötekniikka
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2026060865004
https://urn.fi/URN:NBN:fi-fe2026060865004
Tiivistelmä
This thesis examines the environmental and economic viability of extending operational lifecycle of a fixed-bottom 6 MW offshore wind turbine beyond its 25-year design life. The study applies an integrated Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) framework to a representative North Sea turbine, with results evaluated for 25-, 30-, and 35-year operating scenarios. It further examines the interaction between structural lifetime, lifecycle environmental performance, and long-term economic efficiency.
Greenhouse emissions throughout the system lifecycle are quantified through Global Warming Potential for 100 years (GWP100). Analysis indicates that the lifecycle baseline intensity of 20.40 g CO2-eq/kWh declines to 18.19 g CO2-eq/kWh based on the 30-year scenario and to 16.72 g CO2-eq/kWh based on the 35-year scenario. It is mainly attributed to the distribution of manufacturing-related emissions among increased energy production as a result of prolonged turbine lifetime.
In terms of economics, the Levelized Cost of Electricity (LCOE) is determined to be $140.3/MWh based on a discounted cash flow method. The application of lifetime extension lowers LCOE by up to 3.4% while the use of other fixed rate approaches result in an increase, demonstrating the importance of costing approach. A break-even capacity factor analysis further confirms the economic feasibility under the consideration of realistic performance loss. Consequently, lifetime extension is able to achieve remarkable emission savings without compromising economic performance. An Efficiency, Cost, and Sustainability Indicator (ECSi) has been introduced for techno-environmental assessment.
Greenhouse emissions throughout the system lifecycle are quantified through Global Warming Potential for 100 years (GWP100). Analysis indicates that the lifecycle baseline intensity of 20.40 g CO2-eq/kWh declines to 18.19 g CO2-eq/kWh based on the 30-year scenario and to 16.72 g CO2-eq/kWh based on the 35-year scenario. It is mainly attributed to the distribution of manufacturing-related emissions among increased energy production as a result of prolonged turbine lifetime.
In terms of economics, the Levelized Cost of Electricity (LCOE) is determined to be $140.3/MWh based on a discounted cash flow method. The application of lifetime extension lowers LCOE by up to 3.4% while the use of other fixed rate approaches result in an increase, demonstrating the importance of costing approach. A break-even capacity factor analysis further confirms the economic feasibility under the consideration of realistic performance loss. Consequently, lifetime extension is able to achieve remarkable emission savings without compromising economic performance. An Efficiency, Cost, and Sustainability Indicator (ECSi) has been introduced for techno-environmental assessment.