Life cycle assessment of a multi-megawatt wind turbine

Abstract

At the present moment in time, renewable energy sources have achieved great significance for modern day society. The main reason for this boom is the need to use alternative sources of energy to fossil fuels which are free of CO₂ emissions and contamination. Among the current renewable energy sources, the growth of wind farms has been spectacular. Wind power uses the kinetic energy of the wind to produce a clean form of energy without producing contamination or emissions. The problem it raises is that of quantifying to what extent it is a totally clean form of energy. In this sense we have to consider not only the emissions produced while they are in operation, but also the contamination and environmental impact resulting from their manufacture and the future dismantling of the turbines when they come to the end of their working life. The aim of this study is to analyse the real impact that this technology has if we consider the whole life cycle. The application of the ISO 14040 standard [ISO. ISO 14040. Environmental management – life cycle assessment – principles and framework. Geneva, Switzerland: International Standard Organization; 1998.] allows us to make an LCA study quantifying the overall impact of a wind turbine and each of its components.

Applying this methodology, the wind turbine is analysed during all the phases of its life cycle, from cradle to grave, with regard to the manufacture of its key components (through the incorporation of cut-off criteria), transport to the wind farm, subsequent installation, start-up, maintenance and final dismantling and stripping down into waste materials and their treatment.

Introduction

At the present time, renewable energy, and particularly wind power energy, is becoming increasingly relevant in the world's electricity market. Over the last few years renewable sources of energy have won the legislative support of governments in several countries [2], [3], [4], [5], [6]. This support has taken the form of various legal frameworks with stable and lasting premiums. If we look at the current scene in the implementation of renewable energy, we can see the rapid advance made by wind power and its significant contribution to the electricity supply network in several countries, both at European and world level (see Fig. 1). Wind power supplies less than 1% of electricity now [7]. In the EU, 4% of the power installed originates from wind power and in Spain the figure is 9% [8]. Current forecasts predict that wind power will contribute 12% of the global demand for electricity by 2020 [9]. This huge boom in implementation and forecasts for wind power installation makes clear the need to increase people's understanding of this power source [10], [11]. Although there are several analyses about environmental impact of renewable energies [12], [13], [14], [15], not many life cycle assessment studies exist for current wind turbines with high rated power [16], [17], [18]. So an LCA model has been developed with the purpose of being able to assess the wind energy and the related emissions to produce current wind energy production technology. Furthermore, the LCA model can be used to define the energy payback time.