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Embodied Energy in building construction Hong Kong

John Herbert, hong kong energy saving expert, BEAM expert
John Herbert
Director


The materials and components used to construct Hong Kong buildings require the use of different forms of energy use. In the country of orgin, energy is used to mine, process, assemble, and manufacture materials, and then ship to the job site.

Since that energy has been used before arriving in Hong Kong, we call it embodied energy (and the related embodied carbon). That energy used is tied to the product or material, forever, from factory door to the grave.

Presently, there is no standard framework used in Hong Kong to assess Embodied Energy or Embodied Carbon, the EMSD LCCA tool can be used to calculate the embodied energy, and implicitly the embodied carbon.

Like it or not, sustainability and energy are two sides of the same coin.

Embodied Energy in Hong Kong Structures

The term Embodied Energy is meant to reflect the energy consumed during production stage of materials for the construction of buildings. In the Hong Kong context, that means the materials are IMPORTED, predominantly the raw materials for reinforced concrete, and completed components such as aluminium curtain wall units, glazing panels, etc.

During the production of the cement, glass, and steel vast quantities of energy are used, and the related carbon dioxide is emitted overseas, so is not counnted within Hong Kong's emission inventory.

There are few industries remaining in Hong Kong therefore the majority of construction materials and constituent raw materials are imported from overseas, included the embodied energy and implicitly the embodied carbon.

However, the emission factor overseas for energy use, electricity production, etc. can be significantly higher than Hong Kong, which causes under reporting of the real emission.

For buildings using cast-in-situ reinforced concrete, its constituents are imported, then either mixed on site in a batching plant (for large projects) or mixed in a central concrete plant and transported using concrete trucks to the site.

embodied energy hong kong

Embodied Carbon and Production

Steel and the constituents materials for production of cast-in-situ concrete are energy intensive, the raw materials typically produced overseas and shipped to Hong Kong, therefore the resulting carbon emission does not appear as a "local" emission, so Hong Kong GHG inventory appears lower.

In a perfect world, all materials would arrive in Hong Kong with a clear embodied energy label, totalling up those figures would provide the total embodied energy figure, but real life is rarely that straightforward.

For example steelwork, steel can be provided by different factories, from different countries, each with a different embodied energy quantity but often the data is difficult to obtain.

Then some materials for example concrete comprise several different elements, which maybe be sourced from different countries. Often one project will have steel products and concrete materials from a number of countries, with different production methods, and different travel distances.

Embodied Energy in Hong Kong Waste

Its often overlooked, after the useful life of a product or material it is sent to landfill, including the embodied energy used in its production. Therefore, use of post consumer waste including post-building waste, is important, where possible materials should be repurposed, some examples:

- waste concrete, a free resource,can be used as a raw material for producing new concrete paving blocks (pioneered in Hong Kong);
- waste glass (cullet), a free resource, can be used as a raw material for producing new glass, and used as replacement for silca for producing concrete paving blocks;
- waste gypsum board, a free resource, can be used as a raw material for creating new gypsum board, and can be used as a conditioner added to soil;

embodied energy hong kong construction reports



With the expertise to back this up, for example specifying energy, water and waste efficient techniques and equipment in buildings and infrastructure and the specialist analysis techniques to demonstrate the practical environmental performance.

BEAM PLUS EU3 Embodied Energy

The EMSD LCA tool provides the calculation software to estimate the embodied energy in Hong Kong building structures, and BEAMPLUS New Building, credit EU3, encourages embodied energy assessment at the concept stage, giving vital knowledge to designers before key decisions are made.

Under BEAM PLUS EU3, if two or more options are examined, and the option having the lowest embodied energy is choosen, a bonus point can be earned.

Whilst it is true that embodied energy in a structure can be calculated at different stages of the project, it is the same for embodied carbon, even years later after the project is complete the embodied energy can be calculated, it is too late to influence the design.

However, giving the embodied energy data to the designer early, it is hoped that will influence the choice of materials BEFORE commencing the design. After the key decisions are made, repeating the calculation is a futile mathematical exercise.


For more information about our embodied energy reporting call us today!

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tags: embodied energy, embodied carbon, carbon emission, construction
#embodiedenergy, #embodiedcarbon, #carbonemission

date: 30-05-20