processes, as well as the products and emissions to different environmental compartments. The second column shows the unit of
measure of each listed element. The third column shows the total
amount of material and energy consumed by the system referred to
the functional unit. The fourth column shows the lifetime. The fifth
is the total amount normalized by its lifetime. The sixth shows the
composition of the material or energy. To increase transparency and
replicability, the practitioner should provide reference to specific
flows [35].
Every energy or material input insisting on a process is a subsystem with its own inputs and outputs like branches in a tree
diagram. A mix of primary and secondary data is usually used to
prepare a complete inventory. Databases provide help in this timeconsuming process by offering complete datasets, i.e., inputs, outputs, and emissions, of the most common industrial process, e.g.,
plastic and fuels. The most popular databases can contain up to
14,700 datasets, e.g., Ecoinvent [36] and Agri-Footprint
[37]. Mixed sources can be used in the same study provided that
they use the same set of assumptions and data quality standards.
Incompatible sources may lead to significantly different results for
the same system [38].
The data should respect energy and mass balance between
inputs and outputs. The LCI table, together with the flow diagram,
supports the practitioner to guarantee the respect of the balance
within system boundaries. Consumption and emissions should also
be referred to specific time frame, e.g., 100 years if evaluating
climate change, and clearly describe data elaboration and assumption in the inventory analysis or goal and scope section.
5 Life Cycle Impact Assessment
The life cycle impact assessment phase associates the results from
the inventory phase to one or multiple impacts on environment or
human health. From a mathematical point of view, the emissions of
different substances are converted to a single unit of measure
(indicator) and summed to provide the magnitude of the impact
(Fig. 3). For example, emissions of carbon dioxide and dinitrogen
monoxide from electricity production are multiplied for a conversion factor, i.e., characterization factor, and converted into carbon
dioxide equivalents. The sum of all carbon dioxide equivalents from
system processes represents the impact on climate change [39].
The impact assessment consists of three steps: selection, classification, and characterization.
The selection of impact categories aims at including all the
relevant environmental consequences of the system operations. In
seaweed sector, the majority of scientists are interested in understanding the potential bioremediation of eutrophic waters and
Life Cycle Assessment
109
measure of each listed element. The third column shows the total
amount of material and energy consumed by the system referred to
the functional unit. The fourth column shows the lifetime. The fifth
is the total amount normalized by its lifetime. The sixth shows the
composition of the material or energy. To increase transparency and
replicability, the practitioner should provide reference to specific
flows [35].
Every energy or material input insisting on a process is a subsystem with its own inputs and outputs like branches in a tree
diagram. A mix of primary and secondary data is usually used to
prepare a complete inventory. Databases provide help in this timeconsuming process by offering complete datasets, i.e., inputs, outputs, and emissions, of the most common industrial process, e.g.,
plastic and fuels. The most popular databases can contain up to
14,700 datasets, e.g., Ecoinvent [36] and Agri-Footprint
[37]. Mixed sources can be used in the same study provided that
they use the same set of assumptions and data quality standards.
Incompatible sources may lead to significantly different results for
the same system [38].
The data should respect energy and mass balance between
inputs and outputs. The LCI table, together with the flow diagram,
supports the practitioner to guarantee the respect of the balance
within system boundaries. Consumption and emissions should also
be referred to specific time frame, e.g., 100 years if evaluating
climate change, and clearly describe data elaboration and assumption in the inventory analysis or goal and scope section.
5 Life Cycle Impact Assessment
The life cycle impact assessment phase associates the results from
the inventory phase to one or multiple impacts on environment or
human health. From a mathematical point of view, the emissions of
different substances are converted to a single unit of measure
(indicator) and summed to provide the magnitude of the impact
(Fig. 3). For example, emissions of carbon dioxide and dinitrogen
monoxide from electricity production are multiplied for a conversion factor, i.e., characterization factor, and converted into carbon
dioxide equivalents. The sum of all carbon dioxide equivalents from
system processes represents the impact on climate change [39].
The impact assessment consists of three steps: selection, classification, and characterization.
The selection of impact categories aims at including all the
relevant environmental consequences of the system operations. In
seaweed sector, the majority of scientists are interested in understanding the potential bioremediation of eutrophic waters and
Life Cycle Assessment
109