Greater understanding is needed of greenhouse gas (GHG) emissions from energy use in the water sector if it is to meet sustainability goals, say researchers at the University of East Anglia.
In a study published online in Nature Climate Change, Prof Declan Conway and Sabrina Rothausen argue that greater focus on the energy needs of the water sector will be a critical part of the policy response to the challenges it faces over the next 50 years.
Transparency in the water industry’s energy use is also likely to be important for it to meet carbon-reduction commitments while dealing with other measures of sustainability, such as regulations concerning the environment.
Efforts to look at GHG emissions associated with water have concentrated on water resources rather than water treatment, distribution and heating thus missing vital data from the ‘whole life’ cycle.
“Pressures on water management include stricter water-quality standards, increasing demand for water and the need to adapt to climate change, while reducing emissions of GHGs,” said Prof Conway, professor of water resources and climate change.
“The processes of abstraction, transport and treatment of fresh water and wastewater all demand energy. Adapting water management to meet increasing demand, regulatory standards and the effects of climate change will in many cases require greater energy use.”
He added: “Energy use in the water sector is growing, yet its importance is under-recognised, and gaps remain in our knowledge. In this study we define the need to integrate energy use further into water resource management and identify opportunities for the water sector to understand and describe more effectively its role in GHG emissions, through regulatory and behavioural responses, to meet future challenges.”
Recent studies in the United States revealed that water-related energy use accounted for nearly 5% of total GHG emissions, and the proportion is even higher in the UK, although there it is mostly associated with end uses of water, such as heating. In countries with very high freshwater withdrawals, most of the water is used for irrigation and the energy used in its extraction and transport is often significant.
Ms Rothausen from the School of International Development explained: “Although end use often has the highest energy use of all water-sector elements, it has not traditionally been seen as a direct part of the water sector and is often unaccounted for in water management and policy.
“Such evidence as there is shows that energy use in the water sector is considerable and growing. This growth is likely to continue, sometimes as an unintended policy outcome, with greater pressure to use and maintain quality of water resources. Despite some recent progress, we need to better understand and profile the role of the water sector as a GHG emitter. A co-ordinated view of the water sector will promote more comprehensive assessments of energy use, while standardized methodologies will enable comparisons between assessments of different technologies and processes, and between regions or countries.”