‘Embodied Energy and Environmental Impact
The “embodied energy” of a material refers to the total amount of energy consumed during that material’s lifespan, including extraction, processing, manufacture, transport, installation, maintenance, and disposal. Compared with other metals, copper requires a relatively small expenditure of energy to extract and process.
Embodied energy comparisons should consider the life span of the material. A single-ply or built-up low-slope roof might claim to have a lower embodied energy than a copper one—that is, until material lifecycle is taken into consideration. With an expected service life of 100 years or more, a copper roof has four times the lifespan of a standard 25-year assembly.
Therefore, the embodied energy of a copper roof should more accurately be compared with that of four 25-year roof assemblies. In these terms, copper emerges as the clear energy champion.
Durability isn’t the only factor that makes copper a strong choice, environmentally speaking. Green building rating systems, including Leadership in Energy and Environmental Design (LEED), now incorporate life cycle assessment (LCA) data into their certification scores—and with good reason.
LCA is a method of evaluating a product’s environmental impact across its lifespan. Embodied energy is part of an LCA calculation, but the assessment also considers reuse and recyclability. Here, too, copper has an advantage over other roofing materials: it is recyclable in all forms. Salvaged copper, architectural copper, and the cuttings and filings produced during finishing can all be re-incorporated into new copper products. Such recycled copper isn’t restricted to low-grade materials; in the U.S., architectural copper is made primarily from recycled content, with some products made from as much as 90% recycled material.
Copper’s impressive lifespan and nearly infinite recyclability derive from its unique material properties, which allow the metal to retain its appearance, strength, malleability, and corrosion resistance for multiple uses across the centuries’.
Article taken as an extract from the Hoffman Architects Journal.