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Research Letters in Ecology
Volume 2008, Article ID 415934, 4 pages
Research Letter

Corporate Ecological Footprint: New Conversion Factors

1Department of Economy, Cantabria University, Avenida De Los Castros s/n, Santander, 39005 Cantabria, Spain
2Department of Environment, Port Authority of Gijón, Claudio Alvargonzález 32, 33201 Asturias, Spain

Received 21 July 2008; Accepted 22 September 2008

Academic Editor: Pavlos Kassomenos

Copyright © 2008 Pablo Coto-Millán et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The first ecological footprint calculation version, applied to companies, appeared in 2003. The said tool provides the possibility of calculating the total impact of a company or organisation in hectares or in equivalent emissions of C O 2 . This paper updates carbon absorption rates and improves electricity consumption conversion factors, one of the major footprint generating consumptions in companies. The new rates prove that the footprint estimated to date will be notably increased as, among other aspects, the IPCC has downgraded the amount of carbon that forests are capable of absorbing. These data reveal that companies must make a great effort to adapt to the challenges triggered by climate change.

1. Introduction

The first version of the ecological footprint calculation method applied to companies (corporate ecological footprint or CEF) was developed between 2003 and 2007 [14]. Since then, it has been applied to an increasing number of organizations, such as ports, dealerships, fishing companies, the food and agriculture sector.

The CEF incorporates all types of consumptions, as well as waste products, discharges, and emissions. The different consumption categories are electricity, fuel, general materials, construction materials (building), services and contracts, farming and agricultural resources, forestry resources, and water.

Most of the data required for the calculation are taken from account books, meters (electricity, water), and the organization's annual report. The consumption of energy and materials is converted to gigajoules (KWh based on the equivalence of 1 K W h = 3 . 6 M j ; fuels based on their calorific value; and materials based on their energy intensity). Gigajoules, in turn, are converted into C O 2 emissions based on the emission factor of the fuel used. Finally, the said emissions are converted to hectares based on the forest absorption rate. The latter two steps can be simplified by dividing the Gigajoules consumed by “energy productivity,” which is obtained by dividing the carbon absorption factor by the carbon emission factor of the fuel considered. Agricultural, forestry, or stockbreeding resources are directly converted to hectares based on their natural productivity levels. For further details on the calculation method, consult Doménech (2006) [3] and

However, several of the above-mentioned consumptions and their conversion factors are still under development, such as the validity of the system used for the conversion of electricity consumption, the incorporation of public infrastructures, the incorporation of dangerous waste products and discharges, the incorporation of fuel life cycles, or the incorporation of carbon absorption factors for ecosystems other than forests.

Some of the complications concerning the conversion of electricity consumption into hectares (ecological footprint) or into carbon emissions (carbon footprint) derive from the different emission and absorption factors used, according to the sources consulted. This paper describes the new conversion factors affecting companies' electricity footprints, which will become part of version 2 of the calculation method and that is still being prepared.

2. Results: Changes to the Electricity Footprint Calculation Method

Substantial changes have been made to the method used to convert the electric energy consumed into C O 2 emissions or hectares—the C O 2 emission factors have been adjusted in accordance with the document “España. Informe Inventarios GEI 1990–2004 (mayo 2006)” (–2004.PDF) “(Spain. GHG Inventory Report 1990–2004 (May 2006),” which is mainly based on IPCC data from 1996 and, especially, on changes made to the carbon absorption rate of forests, adopting the rate issued by the IPCC in 2001, which was 1 tC/ha/year.

The classic energy productivity of 71 Gj/ha/year generally applied to liquid fuels in previous versions is now of 51 Gj/ha/year (average of gas-oil, gasoline, and fuel oil). The 55 Gj/ha/year usually used for coal, is now 37 Gj/ha/year, and the 93 Gj/ha/year for gases is now 65.5 Gj/ha/year. This reduction in energy productivity results in higher footprints than in the previous version. In other words, the environmental impact of companies is greater than estimated to date.

Table 2 displays a company's electricity footprint calculation, obtained based on three different fuel sources: coal, liquid fuel, and gas. Three different data sources are also compared (1) those used to date in previous versions (CEF version 1); (2) those calculated directly based on KWh consumed, taken from Meier et al. (2005) [6], which include the entire life cycle in the emission factors (extraction, infrastructures, transport, waste, etc.); this variant is described by Álvarez et al. (2008) [5]; (3) those calculated in this paper based on national inventory data.

The “energy productivity” (emission factor/absorption factor) is also calculated based on two different carbon absorption factors: the most recent from the IPCC in 2001 (1 tC/ha/year or 3.66  𝑡 C O 2 /ha/year) and the one we have been using to date (1.42 tC/ha/year or 5.2  𝑡 C O 2 /ha/year).

Table 1 displays a list of fuels and updated emission factors and the new forest C O 2 absorption rate.

Table 1: New fuel conversion indices used to calculate corporate ecological footprints.
Table 2: Method used to convert electricity consumption to C O 2 emission and hectares based on three different data sources and two different absorption factors.

3. Discussion and Conclusions

Attention must be paid to the fact that variant 2 (Table 2) provides the lowest carbon footprint for the three types of fuel considered, even in spite of including the entire fuel life cycle from extraction to combustion and the treatment of waste products. On the other hand, the emission factors in cases 1 and 3 are very similar or slightly higher in case 3 (it seems advisable to choose the one that results in the highest footprint). Therefore, with a view to avoid the dispersion of data and to facilitate comparisons, subsequent corporate ecological footprint versions will use the official data provided by the national inventory. The new forest mass emission factor of (1 tC/ha/year), included in the IPCC 2001 report, will also be used as it is more recent than the one used in previous versions (1.42 tC/ha/year).

These new conversion factors, especially the new forest absorption rate, will substantially increase the ecological and carbon footprints attributed to companies to date. This will make it even more difficult for companies to face the challenges presented by climate change. The European Union carbon reduction objective for the year 2020 (20% less than in 1990) and the growing tendency toward a low-carbon economy leads us to suggest that companies should add proactive carbon reduction policies to their main strategic targets.


  1. P. Coto, I. Mateo, J. L. Doménech, and M. Arenales, “La huella ecológica de las autoridades portuarias y de los servicios,” Oídles. In press.
  2. J. L. Doménech, “La huella ecológica empresarial: el caso del puerto de Gijón,” in Actas del VII Congreso Nacional de Medio Ambiente, p. 8, Madrid, Spain, November 2004.
  3. J. L. Doménech, “Guía metodológica para el cálculo de la huella ecológica corporativa,” in Proceedings of the 3rd International Online Meeting on Sustainable Development and Population, p. 46, Malaga University, Malaga, Spain, July 2006.
  4. J. L. Doménech, Huella Ecológica y Desarrollo Sostenible, AENOR, Madrid, Spain, 2007.
  5. P. Álvarez, J. L. Doménech, and J. A. Perales, “Huella ecológica energética corporativa: un indicador de la sostenibilidad empresarial,” in Proceedings of the 7th Andalusian Conference on Environmental Science and the 3rd Andalucian Conference on Sustainably Development, Huelva, Spain, April 2008.
  6. P. J. Meier, P. P. H. Wilson, G. L. Kulcinski, and P. L. Denholm, “US electric industry response to carbon constraint: a life-cycle assessment of supply alternatives,” Energy Policy, vol. 33, no. 9, pp. 1099–1108, 2005. View at Publisher · View at Google Scholar