The Link below provides a conceptual background for the study and chart, which give us insight into life cycle analysis, a valuable tool for determining the true costs of our energy sources.
Note in the following that the actual costs and carbon emissions for a product may be greater than those for the actual operation of that product. Obviously, wind turbines and solar cells are clean in their operation – but what does it cost to manufacture, transport, and dispose of the obsolete or unservicable units?
This is a good tool for making those assessments, but I’d love personally to have even more definition of the “human equivalents” listed in the chart found in the link below. Perhaps an expert in the field could provide insight.
D. Case Studies and Examples
1. Wind Farm Materials
Denmark conducted a LCA on the energy and emissions resulting from the manufacture, production and transport of different materials required for the construction of offshore and land-based wind farms. The study found that the energy payback time for offshore wind farms was 0.39 years. For land-based wind farms the energy payback time was 0.26 years. The study noted that 94% of materials used could be recycled. Carbon dioxide emissions were found to account for 68 – 93% of external costs for land-based wind farms and 99% for offshore wind farms.