Council on Tall Buildings and Urban Habitat

In Numbers: Tall Buildings and Embodied Energy
Expanded Notes and References

As part of the CTBUH Journal 2009, Issue 3, 'In Numbers', the CTBUH presents research entitled Tall Buildings and Embodied Energy. Click the image below to view a PDF version of this research, or scroll down for further information including a full list of references and expanded notes.

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Tall Buildings In Numbers: Tall Buildings and Embodied Energy

Expanded Notes:
1. Initial embodied energy is the energy required to initially create the building and all of its materials / components.
2. Cradle-to-gate refers to all the primary energy used until the product leaves the factory gate (e.g. excluding final transporta¬tion to site & construction).
3. Treated floor area is gross floor area less plant rooms and other areas (e.g. stores, covered car parking, and roof spaces) not directly heated. In this research treated floor area is estimated at 85% of gross floor area (BRECSU, 2000).
4. Primary energy is the energy embodied in natural resources (e.g. coal, crude oil, natural gas, uranium) that has not under¬gone any anthropogenic conversion.
5. 30 St Mary Axe is predicted by mechanical engineers Hilson Moran to use 215 kWh/m²/Annum (Buchanan, 2007). This is assumed per unit treated floor area. Delivered electricity is assumed at 63% of the total, with natural gas at 37% - the percent¬ages outlined in a 'good practice' scenario for an 'air-conditioned prestige' office building in ECON19 (BRECSU, 2000). Primary energy is determined using the UK primary energy conversion factors of 2.8 and 1.15 for delivered electricity and delivered natural gas respectively (BRE, 2008).
6. The energy used by a 'good practice, air-conditioned, prestige' office building is 348 kWh/m² treated floor area/Annum (BRECSU, 2000). See also (5)
7. Cradle-to-site refers to all the primary energy used until the product reaches the building site (e.g. excluding construction).

8. Concrete is assumed to be RC30 for the foundations, RC35 for the basement and RC40 for the floor slabs. Reinforcement is assumed at 150Kg/m³.
9. Assumes 31.7Kg glass/m² and 12.2Kg aluminum/m² of facade (figures courtesy of Harmon Inc / Viracon). Only includes the external double-glazed facade, not glazed inner screens. This also excludes the energy required to fabricate the facade off-site.
10. Recurring embodied energy is the energy required to maintain, repair and refurbish the building over its effective life.
11. These figures refer to ‘typical’ office fit-out taken from Cole & Kernan, 1996. Annualized, they are equivalent to 0.17, 0.23 and 0.34 GJ/m²/Annum for basic grade, medium grade and top grade office fit-out respectively. 

Data from 'Graph Showing Relationship Between Initial Embodied Energy and Height: An Analysis of Published Studies' taken from Cole & Kernan (1996); Honey & Buchanan (1992); Kofoworola & Gheewala (2009); Oka et al. (1993); Richards (2001); Scheuer et al. (2003); Suzuki & Oka (1998); Treloar et al. (2001a) and Treloar et al. (2001b).

All embodied energy coefficients are taken from Hammond & Jones (2008) unless otherwise noted.

Embodied energy figures include factors for the wastage of materials on-site. These are assumed as Aluminum - 2.5%; Concrete 2.5%; Glass 0%; Steel 5% (Chen et al., 2001).

The energy used in the transportation of the materials / components to  site is determined using the 2005 UK truck freight modal intensity of 4MJ/t-km (Kamakaté & Schipper, 2009). Transportation distances are
assumed as structural steel – 433km; steel deck – 230km; concrete – 50km; Aluminium and glass – 934km. These distances are based on the actual locations materials / components were sourced from for 30 St Mary Axe (Powell, 2006).

Philip Oldfield (CTBUH Research Coordinator).

BRE (2008). The Government's Standard Assessment Procedure for Energy Rating of Dwellings. BRE, Watford.
BRECSU (2000). Energy Consumption Guide 19: Energy Use in Offices. BRE, Watford.
BUCHANAN, P. (2007). The Tower: An Anachronism Awaiting Rebirth. Harvard Design Magazine, Spring/Summer 2007, Number 26, pp.1 - 5.
CHEN, T. Y., BURNETT, J. & CHAU, C. K. (2001). Analysis of Embodied Energy Use in the Residential Building of Hong Kong. Energy, 26, pp.323 - 340.
COLE, R. J. & KERNAN, P. C. (1996). Life-Cycle Energy Use in Office Buildings. Building and Environment, Vol. 31, No. 4, 1996. pp. 307 – 317.
HAMMOND, G. P. & JONES, C. I. (2008). Inventory of Carbon and Energy (ICE). Version 1.6a. University of Bath, Bath, UK.

HONEY, B. G. & BUCHANAN, A. H. (1992). Environmental Impacts of the New Zealand Building Industry. Research Report 92-2, University of Cantabury, New Zealand.

KAMAKATE, F. & SCHIPPER, L., (2009). Trends in Truck Freight Energy Use and Carbon Emissions in Selected OECD Countries from 1973 to 2005. Energy Policy, doi:10.1016/j.enpol.2009.07.029.
KOFOWOROLA, O. F. & GHEEWALA, S. H. (2009). Life Cycle Energy Assessment of a Typical Office Building in Thailand. Energy and Buildings, 41, pp.1076 – 1083.

OKA, T., SUZUKI, M. & KONNYA, T. (1993). The Estimation of Energy Consumption and Amounts of Pollutants due to the Construction of Buildings. Energy and Buildings, 19, pp. 303 – 311.
POWELL, K. (2006). 30 St Mary Axe: A Tower for London. Merrell Publishers Limited, London.

RICHARDS, I. (2001). T. R. Hamzah & Yeang: Ecology of the Sky. The Image Publishing Group, Victoria, Australia.

SCHEUER, C., KEOLEIAN, G. A. & REPPE, P. (2003). Life Cycle Energy and Environmental Performance of a New University Building: Modelling Challenges and Design Implications. Energy and Buildings, No. 35, 2003. pp. 1049 – 1064.

SUZUKI, M. & OKA, T. (1998). Estimation of Life Cycle Energy Consumption and CO2 Emission of Office Buildings in Japan. Energy and Buildings, No. 28, 1998. pp. 33 - 41.

TRELOAR, G. J., FAY, R., LLOZOR, B. & LOVE, P. E. D. (2001a). Building Materials Selection: Greenhouse Strategies for Built Facilities. Facilities, Vol. 19, No. 3/4, pp,139 – 149.
TRELOAR, G. J., FAY, R., LLOZOR, B. & LOVE, P. E. D. (2001b). An Analysis of the Embodied Energy of Office Buildings by Height. Facilities, Vol. 19, No. 5/6, 2001, pp. 204 – 214.