Page 215 - Materials Chemistry, Second Edition

Life-Cycle Assessment of Wind Energy 203

environmental impact of wind energy in the context of other types of renewable
and nonrenewable energy sources, so selecting 1 kWh as the functional unit gives
a clearer outlook on results, and facilitates comparisons, if desired, with the
environmental impacts resulting from the generation of 1 kWh with such other
sources.

3.2.3 Data Used

When an LCA is conducted on a wind power system, data need to be collected on
each of the main components of the wind turbine and on the various subcompo-
nents that make up those main components. These components are highly varied in
their nature and characteristics and may include various types of mechanical,
electrical, and electronic parts. This makes it difficult to obtain all the information
needed from the various suppliers in order to perform an LCA on each and every
part used in the turbine. It is therefore necessary to draw up a suitable life-cycle
inventory including the most important and significant components of the unit,
such as the foundations, the tower, the nacelle, and the rotor. Most of the inventory
data have been obtained directly from the companies that produce the wind tur-
bines (generator, gearbox, blades, etc.). The exception corresponds to the dry-type
transfomer, where the information was obtained from a third company that man-
ufactures dry transformers similar in volume, power, and tension. In individual
cases, where it was not possible to obtain reliable and verified data, commercial
databaseEcoinvent (Boustead and Hancock 2003; Frischknecht and Rebitzer 2005;
Frischknecht et al. 2005) was utilized.
Data on energy expenditure and materials used in manufacturing the main
components of a wind turbine were supplied by Gamesa, a major worldwide
manufacturer. Table 2 gives a general summary of the materials used in the main
components of turbines and the energy used in the manufacturing processes
associated with those main components.
Along with materials and energy consumption, the transportation of compo-
nents from their places of manufacture to the final location of the turbine on the
wind farm must also be taken into account. Once the wind turbine has been erected
on site and commissioned, it will require preventive and corrective maintenance to
ensure that it remains in working order for most of its useful lifetime. Logically, all
these operations must also be taken into account in the LCA conducted, and
information must be compiled on how much oil and grease is used, on how many
filters are replaced, on the transportation of materials and workers, etc.

3.2.4 Assumptions

When conducting an LCA on a system as complex as a wind energy generation
system, limitations must be set on the level of detail applied in the compilation of
data. Only thus can the LCA be completed within reasonable limits in terms of