Water accounting for (agro)industrial operations and its application to energy pathways

Abstract

Discussions about the water needed for the provision of goods and services have been hampered by a lack of a generic water-accounting methodology from the industrial operations perspective. We propose a methodology based on the concept of “economic water stress” that enables the assessment of water-related risks at the level of an industrial site and the level of an industrial supply chain or pathway. We then rigorously apply it to quantify the freshwater withdrawal and consumption needed for fuel and electricity supply chains. Those data make it possible to present, in comparable source-to-service terms, estimates of the freshwater intensities of mobility. Most of the estimated supply-chain and pathway freshwater intensities range over orders of magnitude on account of the variety of technologies and geographic locations. On average, fuels from unconventional fossil resources and biofuels derived from irrigated crops have higher freshwater withdrawal and consumption than conventional fossil fuels. Cooling in thermal power generation can also make severe demands on freshwater withdrawal and consumption, but technological options are available for most levels of freshwater scarcity. The mobility results reveal that vehicles with internal-combustion engines and electric motors have biofuel and power-generation technology options that lie roughly within the same freshwater-intensity ranges as that of conventional transport based on refined oil. In any case, the local context is critical: industrial sites with high freshwater withdrawal and consumption may be sustainable if there is ample water supply. Conversely, low freshwater withdrawal and consumption may be unsustainable in water-stressed regions.