Page 264 - Materials Chemistry, Second Edition

254 G. A. da Silva et al.

In order to estimate the most relevant inputs and outputs related to the venture’s
construction, the following processes were considered: concrete production;
operation of construction machines; excavations (on rock and earth); use of steel;
truck transportation; bus transportations (for workers); and equipment production.
For the operation of a 100-year period, it was considered: land use; replacement
and maintenance of equipment; electrical consumption; and GHG emissions.
The GHG emission estimation was done using official data from the Brazilian
government (Santos 2000; MCT 2002). Based on field measurements performed
on Itaipu’s reservoir, an emission factor was generated in order to estimate
emissions of carbon dioxide (CO2)—of 9.64E ? 04 t/yr—, and methane (CH4)—
of 1.18E ? 04 t/yr. Those values, however, are over-estimated, because they do
not take into account the decaying of the emissions rate over time. Data collection
and treatment resulted in a list of inputs and outputs for the Itaipu Power Plant Life
Cycle, presented in Table 2.
Materials and energy life-cycles data
To obtain the LCI from data presented on Table 2, it was necessary to detail the
materials and energy life cycles for each of the consumed items. This activity is
usually done using datasets and, thus, by secondary data. However, considering the
time horizon for the venture’s construction, and the peculiarities of Brazilian
industrial system at that time, there were no representative databases for the dif-
0
ferent materials and energy inputs of Itaipu s LCI. Due to this limitation, additional
data collection procedures were made, in order to estimate the environmental
burdens of the processes of: generation of electricity; transportation (by truck, bus,
train, and ship); and the production of cement, steel, copper, diesel oil, and
lubricant oil.
For estimation of the life-cycle environmental burdens of the consumed
materials, 1977 was considered to be the reference year for data collection. In this
period, the greatest part of the materials was acquired. Data sources varied from
primary data—from the factories that produced to Itaipu Power Plant—to inter-
national emission factors and industrial surveys of Brazilian industry, i.e., sec-
ondary data. The main data sources are summarized below:
• Diesel and lubricant oil: a previous adaptation from international LCA dat-
abases was used to obtain the environmental load of diesel fuel and lubricant;
• Electricity: the Brazilian electricity mix that prevailed in 1977 was modeled by
an international LCI dataset for thermal generation;
• Transport: different transportation modals were used in the model: trucks of
about 30 t load of capacity; buses; trains; petroleum and cargo ships. Emission
factors were applied for road transportation considering 1977 technologies, and
international datasets were used for ship displacements;
• Cement: after a literature review, it was concluded that the Brazilian cement
production in 1977 could not be estimated using recent LCA databases. So, an
independent data collection was conducted. It was based on data from manu-
facturers, technical reports, and sector analysis from official research agencies,