Page 214 - Materials Chemistry, Second Edition

202 E. Martínez Cámara et al.

3.2.1 System Limits
Cutoff criteria for the system must be defined if the results of the analysis are to be
understood and interpreted correctly. The criteria applied in this case include the
following:
• The construction phase of the main components of the wind turbine.
• Transportation of the wind turbine to its specific site in the wind farm.
• Direction, installation, and commissioning of the turbine at its final operating site.
• Decommissioning of the turbine and subsequent treatment of the waste
produced.
For a diagram showing these system cutoff criteria, see Fig 4.
All the electrical switchgear for the electricity generated by the turbine, which
is used to distribute that energy to the grid, is excluded from the system. This
includes the following:
• Medium voltage wiring
• The substation transformer
• The electrical distribution and transmission network

3.2.2 Functional Unit

The functional unit defined here for the LCA of the electricity generated by a wind
turbine is the production of 1 kWh of electricity. Choosing a functional unit that is
appropriate for the task being performed is of course an important factor in
ensuring that the results obtained are meaningful. What is being studied here is the

Fig. 4 LCA system limits (Martínez et al. 2009)