Understanding embodied energy

By Isabel Berenguer Asuncion
Philippine Daily Inquirer


HOW DO you attempt to help save the environment in simple and achievable ways?

While sustainable design is promoted aggressively as the alternative approach in design practice, sophisticated systems and high technology for environment-friendly finishes, alternative sources of power, filtration systems and materials can all be quite expensive. Aside from the cost of the systems themselves, there is also the cost of hiring consultants that can give advice on the suitability and proper utilization of the new systems.

There is also a need to properly detail the design so that it performs optimally and as intended. The simple exercise of designing a sustainable project sometimes becomes all too complicated and financially prohibitive.

A simpler approach would be to carefully pick the materials to be used. The prudent selection and usage of these can help in both cutting costs and savings in terms of carbon footprint.

One aspect of measure to consider for materials is “embodied energy.” This is the amount of energy that a material utilizes from the time it is acquired as a raw material, processed into a useful product, transported to its place of use, and installed or applied.

Embodied energy is important to understand since we often forget that there are various ways to produce a material and get it to its place of use. The amount of energy used can vary tremendously and can spell out in clear numbers how much damage its use can do to the environment.

Biodegradable

Because the purpose of environmental awareness is to decrease what we take from the earth and also to return into earth what we have taken, we often select materials that are biodegradable.

Sometimes what we take from the earth cannot be easily returned into it, but when it can be put to use for a prolonged period of time, it discourages frequent consumption and waste. For building materials, permanence and durability are two of the most important characteristics to consider.

While some materials may have low embodied energy, they may not be easily renewable materials. Natural stone is one example of this. It has very low embodied energy, yet it takes years for Mother Earth to produce it. Therefore there should be a certain amount of caution when using stone lest we one day run out of this material to harvest.

On the other hand, bamboo is an easily renewable material. Its use therefore, does not put much risk to the environment until it is processed into another type of material and its embodied energy increases. Laminated bamboo flooring, for instance, has lower embodied energy than high-pressure laminate flooring since for the latter, the production of the laminate alone takes a toll on the carbon footprint.

Difficult to reproduce

Wood is another material that has very low embodied energy, but unfortunately very difficult to reproduce. The massive deforestation globally proves that our usage has outrun its ability to renew. There are now sustainable tree farms but they are never enough for the high demand for timber. Sadly, many illegal loggers and middle-men still peddle local timber. We can only wish that consumers have enough conscience to veer from the temptation of using much prized narra and other local hardwood, and explore more sustainable alternatives.

Lower embodied energy does not necessarily define a better option. Aluminum has very high embodied energy but its use in buildings where its benefit runs to more than 50 years justifies its utilization as its embodied energy spreads through many, many years of use. Hopefully, there will be no need for its replacement during the building’s entire lifetime.

Embodied energy can be a very useful gauge for sustainability provided it is measured by its usage and lifespan. Depending on source, suppliers, methods, origin and site location, embodied energy of various materials, components and systems can vary greatly. As buildings become more energy-efficient and as the cost to operate them decreases, embodied energy becomes a more important factor. It is never the sole consideration for the selection of a material but it is a good place to start.