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Hydropower Life-Cycle Inventories 263

and environmental burdens and impacts that are not included on this study, like
people displacement, ecosystem substitution, etc., impacts that certainly have high
social and environmental importance.

4.5.5 Most relevant limitations of the study

A detailed analysis of the final version of Itaipu LCI reveals that the most
important limitation of the study is related to the LCA itself as an environmental
evaluation tool for hydropower projects, mainly in the Brazilian condition. As
stated earlier in this document, the LCI process was not expected to cover all the
environmental or social impacts of hydropower—e.g. impacts on population dis-
placement; local climate; ecosystem modifications; hydrology and so on—for
which international impact assessment studies and methodologies are available.
The scope of the present LCI is limited to the environmental loads associated to
the life cycle of the power plant in terms of exchanges of mass and energy with the
environment, and the impacts caused by land occupation and transformation.
Regarding to data quality, the most significant uncertainties are related to GHG
emission. It was assumed that GHG emissions over the whole area of the reservoir
would be the same during all the life time of the venture. This assumption, taken in
previous studies (Coltro 2003), is surely a rough estimation; on the other hand,
until the moment, there are no reliable models able to estimate such losses con-
sistently with the conditions in which they occur. Still in this same approach, some
other suggestions to improve data quality could be:
• Update the estimation of the total energy production during the 100-year
operation period, from the start of the operation of Itaipu in 1984 up to the date
of the study;
• Conduct a more detailed data collection on the use of chemical products for
power plant maintenance;
• Better modeling the air emissions from civil work machines. The calculations
were performed using USEPA emission factors, which were applied to the total
amount of consumed fuel. The power of the engines was used as criterion for the
allocation. Furthermore, it was assumed that all machines had worked during the
same period of time;
• Seek for more homogenous sources of data.

Finally, other relevant limitation was the impossibility to carry on another data
collection in order to refine the boundaries of product system. Some processes
were excluded from the boundaries based only on the international experience,
which not always correspond to the Brazilian situation. So, processes like elec-
tromechanical equipment fabrication, explosives production and use, other mate-
rials life cycles, and so on, were not investigated.