8 Discussion and Conclusions
The holistic approach of LCA provides a quantification of the
impacts of an entire system. LCA can evaluate the seaweed value
chain from cultivation, through processing, use, and end-of-life.
The results can identify areas where the system can be improved.
Each impact category can highlight a particular environmental
problem and guide the designer to take action to reduce it.
Impact on climate change shows that the infrastructure necessary to offer support for seaweed cultivation has a significant
impact. In particular, the plastic manufacture and consumption
for buoys have high emission of greenhouse gases with respect of
the quantity of biomass produced. Therefore, the material consumption should be reduced or the lifetime increased [18, 29].
CED can highlight the importance of storage design. Energy
consumption for drying seaweed is a high energy-intensive process
and affects the overall energy balance when producing biofuels
[18, 29]. Storage of seaweed as ensilage—a process that reduces
the biomass degradation by lowering the pH to acid environment—is an alternative method to reduce the energy consumption
[63]. However, while it might represent a solution for biogas
production, it is not recommended for bioethanol, since the ensilage process reduces the quantity of fermentable sugars in the
biomass.
The impacts of seaweed cultivation can be reduced by improving productivity of the species so that the efficiency of material and
energy use is increased [18, 40]. Currently, test sites are cultivating
specimens collected in the wild, adapted to local environmental
conditions [64]. A continuous selection and genetic improvement
during successive generations will likely increase yields, similarly to
historical development in agriculture sector.
Overall, despite a structured and standardized approach, LCA
is highly affected by data quality [35]. Seaweed cultivation and
conversion are still at its infancy, and consequently data are often
based on pilot scale trials or laboratory experiments. On one hand,
this makes LCA results more uncertain, but on the other hand, this
allows LCA to provide recommendation at the development phase
where changes can be applied without significant economic
investments.
With the progress of research and industrial development, we
expect to obtain more and more representative data and further
improve the quality of LCA.
Life Cycle Assessment
115
The holistic approach of LCA provides a quantification of the
impacts of an entire system. LCA can evaluate the seaweed value
chain from cultivation, through processing, use, and end-of-life.
The results can identify areas where the system can be improved.
Each impact category can highlight a particular environmental
problem and guide the designer to take action to reduce it.
Impact on climate change shows that the infrastructure necessary to offer support for seaweed cultivation has a significant
impact. In particular, the plastic manufacture and consumption
for buoys have high emission of greenhouse gases with respect of
the quantity of biomass produced. Therefore, the material consumption should be reduced or the lifetime increased [18, 29].
CED can highlight the importance of storage design. Energy
consumption for drying seaweed is a high energy-intensive process
and affects the overall energy balance when producing biofuels
[18, 29]. Storage of seaweed as ensilage—a process that reduces
the biomass degradation by lowering the pH to acid environment—is an alternative method to reduce the energy consumption
[63]. However, while it might represent a solution for biogas
production, it is not recommended for bioethanol, since the ensilage process reduces the quantity of fermentable sugars in the
biomass.
The impacts of seaweed cultivation can be reduced by improving productivity of the species so that the efficiency of material and
energy use is increased [18, 40]. Currently, test sites are cultivating
specimens collected in the wild, adapted to local environmental
conditions [64]. A continuous selection and genetic improvement
during successive generations will likely increase yields, similarly to
historical development in agriculture sector.
Overall, despite a structured and standardized approach, LCA
is highly affected by data quality [35]. Seaweed cultivation and
conversion are still at its infancy, and consequently data are often
based on pilot scale trials or laboratory experiments. On one hand,
this makes LCA results more uncertain, but on the other hand, this
allows LCA to provide recommendation at the development phase
where changes can be applied without significant economic
investments.
With the progress of research and industrial development, we
expect to obtain more and more representative data and further
improve the quality of LCA.
Life Cycle Assessment
115