Water is perhaps the most used resource by every part of the society. Water use and water management require significant amounts of energy, contributing to significant CO2 emissions. Water use efficiency enhancements can thus have a significant impact on decarbonization.
Globally, agriculture contributes to about 70% of water use, and industries a bit over 20%. Water use by the domestic residential segment is thus less than 10%.
Water use efficiency solutions thus need to have a high focus on the agricultural and industrial sectors. Between the two, it is easier to implement many measures in industries as they represent an organized sector where mandates and target settings are more likely to work. The agricultural sector is a more difficult sector to tackle given its distributed nature, relatively unorganized structure and the challenges involved in convincing farmers to invest in innovations.
Water use and water treatment can consume significant energy. In India alone, annually, water pumping consumes about 16 TWh of electricity (about 2% of total electricity demand) and 2 million tons of diesel (about 3% of total). Worldwide, wastewater treatment plants consume about 200 TWh of electricity annually, about 0.8% of total global electricity consumption.
While implementing water use and treatment efficiency on a global scale is a challenging task, it could result in significant decarbonization in the medium to long term, especially as the global population increases, with significant additions in the developing and underdeveloped nations, leading to water scarcity and extra resources and energy applied to source water.
For the 2020-2030 period, innovations can be expected in the use of digital technology for water conservation and use efficiency, modular & efficient systems for water application for irrigation, leak detection solutions for large scale water storage & distribution infrastructure, use of automation to conserve water used for industrial and commercial applications, and use of alternatives that do away with water requirements (waterless and self-cleaning solar panels, for instance).
Cumulatively, all water services could contribute to about 3% of the total CO2 emissions, or about 1 billion tons of CO2 a year. Given that there are significant inefficiencies in water use in agriculture (its largest user sector), and given also the potential to streamline industrial processes to reduce water use or recycle water, the decarbonization potential through water use efficiency can be significant even in the short and medium term.
But inefficient use of water could result in additional, indirect GHG emissions. For instance, fertilizer runoff owing to excess water use can result in the conversion of nitrogen to N2O in the rivers. Similarly, methane emissions occur at wastewater treatment plants, and thus, higher the amount of wastewater to be treated, higher the methane emissions.
|
|
