Dr. Arvind Kumar*
The United Nations reports that global water consumption has increased sixfold over the last century, with an annual growth rate of 1%. This surge is primarily attributed to economic development, population growth, and changing consumption habits. Paradoxically, the processes involved in water production, including extraction, treatment, desalination, and wastewater management, significantly contribute to carbon emissions. In 2023, energy production heavily depended on water, utilizing approximately 370 billion cubic meters (bcm) of freshwater, which represents 10% of total global freshwater withdrawals. As the demand for both water and energy escalates due to climate change, economic expansion, and rising populations, the importance of securing these resources becomes increasingly urgent. To address climate change effectively, it is crucial to implement transformative approaches such as water circularity, which plays a key role in decarbonization and achieving net-zero emissions. By incorporating effective water resource management, water circularity presents a significant opportunity to lower greenhouse gas emissions and alleviate the effects of climate change.
According to the International Energy Agency (IEA), in the Stated Policies Scenario (STEPS), the demand for water in the energy sector is projected to rise, reaching nearly 400 bcm by 2030. This increase is largely driven by the need for water in cooling nuclear power plants and supporting bioenergy feedstocks. However, some of this demand growth is mitigated by the transition from fossil fuels to solar photovoltaic and wind energy sources in the power sector.
The contribution of global water and wastewater infrastructure to greenhouse gas emissions is more substantial than often acknowledged, accounting for about 2% of worldwide GHG emissions, which is roughly equivalent to 1 billion metric tons of CO2 annually as of 2023. This impact is comparable to that of the international shipping industry and is primarily due to energy-intensive activities such as water treatment, distribution, and wastewater management. The water sector’s emissions are mainly driven by electricity use for pumping and treatment, accounting for about 80% of total emissions. Methane from wastewater treatment contributes around 15%, and nitrous oxide from treatment facilities adds about 5%. However, the sector is well-positioned for decarbonization, with many utilities adopting innovative strategies. From 2020 to 2023, renewable energy use in the water industry increased by 50%, with biogas recovery now powering various facilities. Cities like Copenhagen and Amsterdam demonstrate that water utilities can achieve carbon neutrality through energy efficiency, renewable energy, and process optimization. This transformation is crucial as climate change worsens water scarcity, with the World Bank predicting a 40% water demand-supply gap by 2030 if current practices continue, highlighting the sector’s vital role in climate mitigation and global sustainability.
Why is net zero a priority for water sector?
The water and wastewater sector, crucial for sustainable development and public health, surprisingly accounts for approximately 2% of global greenhouse gas (GHG) emissions, comparable to the carbon footprint of the entire global shipping industry. This staggering figure underscores the urgent need for decarbonization within the water sector. Key contributors to these emissions include energy consumption for water treatment and pumping (60-80% of total emissions), wastewater treatment processes (10-20% of total emissions), and chemical usage and production for water treatment (5-10% of total emissions). In fact, global water and wastewater emissions reached 1.4 billion metric tons CO2-eq/year in 2020, equivalent to the annual emissions of 300 million cars.
To put this into perspective, the sector’s energy consumption accounts for 3.4% of global electricity generation. However, transitioning to net-zero emissions is achievable through energy efficiency improvements (30-50% potential reduction), renewable energy integration, water reuse and recycling, low-carbon treatment technologies, and sustainable water management practices. Recent initiatives, such as the Water Climate Action Framework (2022), aim to reduce GHG emissions by 50% by 2030. By acknowledging its carbon footprint and embracing decarbonization, the water sector can mitigate climate change impacts on water resources, enhance resilience and adaptability, protect public health and the environment, and lead the way in sustainable development.
India’s water edge
As South Asia’s economic powerhouse, India’s water sector significantly impacts its carbon footprint, with water utilities consuming 3-5% of national electricity (90 billion kWh annually). The National Water Mission’s ambitious targets aim for 20% improved water efficiency and 25% reduced energy intensity by 2030. Success stories include Delhi’s biogas-to-energy projects at Rithala and Okhla treatment plants; generating 3.65 MW combined power and meeting 60% of their energy needs. Under the Swachh Bharat Mission 2.0’s $17 billion framework, cities like Surat have achieved 80% water reuse rates, while the Smart Cities Mission has enabled 100 cities to reduce energy consumption by 20-30% through IoT-based monitoring. Despite these advances, with only 40% of urban wastewater currently treated, India faces both challenges and opportunities in implementing energy-efficient circular solutions across its water infrastructure.
How to unlock the Power of Circular Decarbonization?
The transformation towards water circularity presents multiple interconnected pathways for decarbonization within the water-energy-sanitation-carbon nexus. Primary strategies include implementing advanced resource recovery systems that extract valuable materials from wastewater, such as biogas for energy generation (which can reduce treatment plant energy costs by up to 60%), nutrients for agricultural use, and recovered water for industrial applications and groundwater recharge. Digital optimization through smart water management systems and AI-driven operations can reduce energy consumption by 25-30% across distribution networks while minimizing water losses. Utilities are increasingly adopting nature-based solutions like constructing wetlands and green infrastructure, which not only reduce treatment energy requirements but also sequester carbon and enhance climate resilience. The integration of renewable energy, particularly through floating solar installations on treatment facilities and reservoirs, can offset operational carbon footprints while utilizing otherwise unused space. Modern anaerobic digestion processes are being enhanced to maximize biogas production, with some facilities achieving 90-95% energy self-sufficiency. Leveraging alternative water sources through brackish water use reduces reliance on energy intensive desalination. Additionally, implementing water reuse systems in urban environments can reduce energy consumption associated with long-distance water transport by up to 50%. These solutions are being complemented by emerging technologies like low-energy treatment processes, thermal energy recovery from wastewater (which can heat and cool nearby buildings with 40-50% less energy), and advanced materials for more efficient filtration and treatment, collectively creating a more sustainable and carbon-neutral water sector.
The water sector stands at a critical juncture where its dual role as both a significant carbon emitter and a potential leader in sustainable solutions becomes increasingly apparent. Thus, through circular economy principles, efficient technological innovation, and strategic policy frameworks, the water sector can demonstrate promising pathways to decarbonization. As water scarcity intensifies and climate challenges mount, the sector’s commitment to net-zero emissions through water circularity, renewable energy integration, and smart technologies will be crucial for ensuring a sustainable future for generations to come.
*Editor Focus Global Reporter
