The goal can focus on the hotspots of a single production
pathway or compare alternatives; it can focus on a specific problem,
i.e., climate change, or account for several impacts on environment
and human health.
In LCA focusing on seaweed, we can find the following examples of goals:
l
Determine the most sustainable scenario for the cultivation and
conversion of macroalgae to bioenergy in Chile [16].
l
Identify the design that minimizes the environmental impacts of
dried seaweed production [29].
l
Assess the environmental impacts and energy balance of
seaweed-based biofuels, and identify hotspots where design
modifications can improve the system performance [17].
The definition of the scope establishes the limits of the LCA:
system function, functional unit, processes, and system boundaries.
The system function is the purpose of the cascade of processes:
deliver a product, e.g., production of seaweed, or provide a service,
e.g., decrease eutrophication in a water basin. The same system can
potentially deliver more than one function at the same time
[30, 31]. The functional unit is the quantification of a system
function, e.g., 1 mg of dried seaweed or 1 kg of nitrogen absorbed.
Examples of functional units in scientific papers are:
l
1 mg of dry seaweed [17]
l
1 ha of sea surface cultivation [18]
l
1 km driven using seaweed-based biogas [14]
A series of connected processes constitutes a system, which can
be represented by a flow diagram (Fig. 2). The diagram shows the
inputs of materials and energy, their transformation, processing and
the final output(s). Offshore cultivation of seaweed usually follows
four main phases [18, 32]: (1) seed line production, (2) deployment
of lines, (3) maintenance during growth phase, and (4) harvest.
During the seed line production, fertile material releases spores
which settles on kuralone twines (polyvinyl alcohol fiber) and
then incubated in cold room. Nutrients and sterile water support
their growth. In the second phase, the kuralone twines are coiled
around 8 mm diameter ropes, which provide support and surface
for seaweed to attach during development. The combination of
kuralone and 8 mm ropes are called seeded lines (or seeded ropes)
and are deployed in the sea where seaweed will develop over several
months, according to the local climatic conditions [18, 32]. In the
third phase, the farmer visits regularly the cultivation site to assess
the growth and maintain the lines. During the fourth phase, the
farmer harvests the biomass using a mechanical arm to raise the
106
Michele Seghetta and Pietro Goglio
pathway or compare alternatives; it can focus on a specific problem,
i.e., climate change, or account for several impacts on environment
and human health.
In LCA focusing on seaweed, we can find the following examples of goals:
l
Determine the most sustainable scenario for the cultivation and
conversion of macroalgae to bioenergy in Chile [16].
l
Identify the design that minimizes the environmental impacts of
dried seaweed production [29].
l
Assess the environmental impacts and energy balance of
seaweed-based biofuels, and identify hotspots where design
modifications can improve the system performance [17].
The definition of the scope establishes the limits of the LCA:
system function, functional unit, processes, and system boundaries.
The system function is the purpose of the cascade of processes:
deliver a product, e.g., production of seaweed, or provide a service,
e.g., decrease eutrophication in a water basin. The same system can
potentially deliver more than one function at the same time
[30, 31]. The functional unit is the quantification of a system
function, e.g., 1 mg of dried seaweed or 1 kg of nitrogen absorbed.
Examples of functional units in scientific papers are:
l
1 mg of dry seaweed [17]
l
1 ha of sea surface cultivation [18]
l
1 km driven using seaweed-based biogas [14]
A series of connected processes constitutes a system, which can
be represented by a flow diagram (Fig. 2). The diagram shows the
inputs of materials and energy, their transformation, processing and
the final output(s). Offshore cultivation of seaweed usually follows
four main phases [18, 32]: (1) seed line production, (2) deployment
of lines, (3) maintenance during growth phase, and (4) harvest.
During the seed line production, fertile material releases spores
which settles on kuralone twines (polyvinyl alcohol fiber) and
then incubated in cold room. Nutrients and sterile water support
their growth. In the second phase, the kuralone twines are coiled
around 8 mm diameter ropes, which provide support and surface
for seaweed to attach during development. The combination of
kuralone and 8 mm ropes are called seeded lines (or seeded ropes)
and are deployed in the sea where seaweed will develop over several
months, according to the local climatic conditions [18, 32]. In the
third phase, the farmer visits regularly the cultivation site to assess
the growth and maintain the lines. During the fourth phase, the
farmer harvests the biomass using a mechanical arm to raise the
106
Michele Seghetta and Pietro Goglio