Programme OS4i Water and energy
The Water Footprint of Energy Carriers
Author(s): Winnie Gerbens-
Leenes, Arjen Y. Hoekstra, Theo H. Van Der Meer
Keyword(s): Sustainability, climate change, energy, biomass,
natural resource use, water footprint
Session: OS4i Water and energy
Abstract conference 13th IWRA World Water Congress 2008, 1-4 September, Montpellier, France
Water Footprint of Energy Carriers
P.W. Gerbens-Leenes*, A.Y. Hoekstra and Th. H. van der
University of Twente, the Netherlands
Today, the scientific as well as the
international political community consider global change often in relation to climate change. It is generally recognized
that emissions of greenhouse gasses, such as CO2 from fossil energy carriers, are responsible for anthropological
impacts on the climate system. A shift towards CO2-neutral energy carriers, such as biomass, is heavily promoted.
Important issues in this respect are trade offs and interplays with other factors that play a role in global changes other
than climate change, such as, for example, the availability and increased pressure on global water resources.
The use of energy in society requires water. Energy carriers are often made available with water, for example, for
coal mining, or produced with water, for example, biomass. The objective of this study is to calculate the water
footprint (WFP) of different types of biomass and compare these results with the WFP of other energy carriers, such
as fossil energy carriers (coal, natural gas, oil), and types of energy, such as wind energy and solar thermal electricity.
Agriculture, providing biomass for different purposes, requires about 86% of the worldwide
fresh water use. In many parts of the world, the use of water for agriculture already competes with other uses such
as urban supply and industrial activities. A tool that addresses international virtual water flows is the concept of the
WFP. This tool has been introduced by Hoekstra and Hung (2002) and has been developed further by Chapagain
and Hoekstra (2004). Those authors define the WFP as the total annual volume of freshwater used to produce the
goods and services related to a certain consumption pattern. So far, the tool has been used to assess the WFP of
food and cotton consumption. This study assesses the WFP of various types of biomass by applying the WFP
concept resulting in the WFP of biomass in m3 per GJ. Next, the study compares this WFP with data on water
requirements of other energy carriers and types of energy from literature.
Results and discussion
show large differences per unit of energy. The WFP of wind energy is zero, of natural gas 0.10 m3 per GJ, of coal
0.04, of nuclear energy 0.09, of thermal solar energy 0.3, of oil 0.8 and of biomass (average) 22.6 m3 per GJ.
Based on an energy use of 100 GJ per capita per year in western societies, a mix from coal, oil, nuclear energy and
gas requires 26 m3 of water, while 100 GJ from biomass requires 2260 m3. This requirement competes with water
for food, which lies in the same order of magnitude.
Biomass requires much more water per unit
of energy than the average fossil energy carrier. A shift in western societies from generally applied energy (fossil and
nuclear energy) towards energy from biomass causes a ninety fold increase of the WFP of energy and puts large
claims on scarce fresh water resources. Strategies towards larger biomass use for energy should take this large WFP
Keywords: Sustainability, climate change, energy, biomass, natural resource use, water
Chapagain, A.K., Hoekstra, A.Y., 2004 Water footprints of nations. Value of Water Research
Report Series No. 16. UNESCO-IHE Delft, the Netherlands. www.waterfootprint.org
Hung, P.Q., 2002. Virtual water trade: a quantification of virtual water flows between nations in relation to
international crop trade. Value of Water Research Report Series, No. 11. UNESCO-IHE, Delft, the Netherlands.
* Corresponding author. Faculty of Engineering and Technology, Water Engineering and Management,
University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
P: + 31 53 489 2080, E:
P.W.Gerbens-Leenes@ctw.utwente.nl, I: www.utwente.nl