Beyond Energy Efficiency and Renewable Energy – Embodied energy and Externalities

25 Jul 2012

This guest post comes from Adam Stratton of PowerPanel.  Perhaps an older home has less environmental impact than a new, energy efficient one?

Imagine you are about to build your American dream home and someone tells you that to start construction, you need to purchase 19,800 gallons of fuel.  The average home contains this much energy embodied in its materials. It has been estimated that the average “embodied energy” in a North American home equals 16 years of energy use in that home, using a 40 year home lifespan as a benchmark.

The use of renewable energy is an essential part of reducing dependency on centralized power and reducing the impact of “embodied energy” on the built environment.  Solar and wind are the most commonly implemented solutions. Understanding their own embodied energy and their complete footprint before evaluating their effects is often overlooked.

The thought of using renewable energy comes from an awareness of rising energy, making energy efficiency a growing priority for homeowners and builders. An increasing number of homeowners and builders seek ratings such as LEED to attract buyers and satisfy their egos. It is easy to see this as positive but, in the name of energy efficiency, the extra materials or the importing of efficient materials may negate years of energy savings.  Energy efficiency is important but we must remember it is only one of the keys to responsible building.  A straw bale home embodies 1/12 of the energy embodied in the average traditional wood frame construction home.

Energy efficiency in its true sense comes down to occupant behavior.

Due to the energy involved in material transportation, the ‘local’ approach can be important in evaluating embodied energy. North American homes that are 100 years or older (and were probably built on the ‘local’ approach), are often considered to be large consumers of energy.  However, these homes can be, and in many cases have been, adapted to higher energy efficiency. Their durability and adaptability means their embodied energy has not been lost and no new energy has been used to replace them.

Since no building lasts forever, we should consider the end life of the structure and where its materials end their useful life when considering building materials for construction. Using durable and adaptable materials can be costly in tough economic times. Many of the refined materials such as composites used in modern homes are still not suitable for reuse or recycling and may be sent to landfills. This equates to lost energy.

The good news in all of this is that the means, skills and intentions to arrive at a home with a positive effect on the local economy, and little embodied energy are available and are increasing around the globe. Challenge yourself, friend or relative to look at these ideas next time they are planning a new build or expansion and see how low you can go.

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