Page 18 - Materials Chemistry, Second Edition

Importance of Life Cycle Assessment 3

Renewable Energy Sources

Solar Energy Wind Energy
Solar cell, solar cooker, solar furnace, etc. Wind mill, etc.
Tidal Energy Hydroelectric Energy
Tidal mill, etc. Hydroelectric dam, etc.

Geothermal Energy Ocean Thermal Energy
Geothermal heat pump, etc. Ocean Thermal Energy Conversion (OTEC), etc.

Biomass Energy
Biofuels

Primary Biofuels Secondary Biofuels
Firewood, Wood chips, Pellets, Animal waste,
Forest and crop residues, Landfill gas, etc.
st
1 generation
Substrate: Seeds, grains or sugars
Bioethanol or butanol by fermentation of starch (wheat, barley, corn, potato) or sugars (sugar
cane, sugar beet, etc.); Biodiesel by transesterification of plant oils (rapeseed, soybeans, sun-
flower, palm, coconut, jatropha, used cooking oil, animal fats, etc.)
nd
2 generation
Substrate: lignocellulosic biomass
Bioethanol or butanol by enzymatic hydrolysis; Methanol, Fischer-Tropsch gasoline and
disesel, mixed alcohol, dimethyl ether and green diesel by thermo-chemical processes; Biome-
thane by anaerobic digestion
rd
3 generation
Substrate: Algae, sea weeds
Biodiesel from algae; Bioethanol from algae and sea weeds; Hydrogen from green algae and
microbes
Fig. 1 The most important renewable energy sources

3 Life Cycle Assessment

ISO 14040 defined LCA as the ‘‘compilation and evaluation of the inputs, outputs
and potential environmental impacts of a product system throughout its life cycle’’
(ISO 2006). Thus, LCA is a tool to assess the environmental impacts and resources
used throughout a product’s life cycle and consider all attributes or aspects of
natural environment, human health, and resources (Korres et al. 2010) and can be
defined as a method for analyzing and assessing environmental impacts of a
material, product, or service along its entire life cycle (ISO 2005). LCA analyzes
the environmental burden of products at all stages in their life cycle (from the
cradle to the grave) from the extraction of resources, through the production of
materials, product parts and the product itself, and the use of the product to the
management after it is discarded, either by reuse, by recycling, or by final disposal
(Guinée 2004).