2016世界能源展望：水和能源关系_63页-3mb

Water Energy Nexus Summary

Core Content

The Water Energy Nexus highlights the interdependent relationship between water and energy systems. Both resources are essential for each other's production and use, and this interlinkage has significant implications for economic growth, environmental sustainability, and global well-being. The report, part of the World Energy Outlook 2016, provides a detailed analysis of the current and future linkages between water and energy, emphasizing the need for integrated thinking and policy approaches to address potential stress points.

Main Points

• Water and Energy Interdependence: Water is crucial for all stages of energy production, including fossil fuel extraction, power generation, and biofuel feedstock irrigation. Energy, in turn, is essential for water-related processes such as treatment, distribution, and desalination.

• Energy-Water Linkages and Risks: The energy sector accounts for 10% of global water withdrawals, primarily due to power plant operations and fuel production. Conversely, the water sector consumes significant energy, with 4% of global electricity used for water extraction, treatment, and distribution. This interdependency can amplify existing vulnerabilities in both sectors.

• Scenarios and Projections:

  • New Policies Scenario: Water withdrawals for energy production and power generation are expected to increase by less than 2% to 400 billion cubic metres (bcm) by 2040, while water consumption in the energy sector could rise by 60% to 75 bcm.
  • 450 Scenario: A lower carbon pathway could reduce water withdrawals by 12% but increase consumption by 2% due to the use of water-intensive technologies such as biofuels, concentrating solar power, and nuclear energy.

• Water Sector Energy Use: In 2014, the global water sector consumed 120 Mtoe of energy, with 4% of global electricity used for water-related activities. By 2040, energy use in the water sector is projected to more than double, driven largely by desalination and wastewater treatment.

• Desalination and Water Reuse: These processes account for ~4% of water supply but ~60% of the water sector's energy consumption by 2040. They are vital for addressing water scarcity in regions like the Middle East, but also pose significant energy challenges.

• Energy Efficiency Potential: There is 15% potential for energy savings in the water sector by 2040 through improved efficiency and energy recovery. Municipal wastewater treatment could generate ~55% of the electricity needed for its operations if energy recovery is fully implemented.

• Integrated Policy and Infrastructure: Managing the energy-water nexus requires coordinated policies and infrastructure, such as collocating energy and water facilities, using wastewater as an energy source, and improving the efficiency of both sectors.

Key Information

• Water Availability: Only 2.5% of global water is freshwater, with less than 1% available for human consumption. Most freshwater is locked in glaciers, deep underground, or contaminated.

• Water Stress and Scarcity: Over 1 billion people live in areas of water stress, a number expected to triple by 2025. By 2040, ~20% of countries are projected to face extremely high withdrawal-to-supply ratios.

• Climate Change Impact: Climate change is expected to affect water availability and quality, altering rainfall patterns, increasing evaporation, and exacerbating droughts and heat waves. These changes will place further pressure on water resources and energy systems.

• Policy and Collaboration: Successful action on the energy-water nexus requires collaboration between governments, stakeholders, researchers, and industry. The report underscores the importance of integrating energy and water policies to avoid unintended consequences and to achieve sustainable development goals.

Conclusion

The report underscores that the energy-water nexus is a critical area of focus for global sustainability and climate resilience. Understanding and managing the interdependencies between these two resources is essential to ensuring reliable, affordable, and clean energy and water supplies. While there are opportunities for energy savings and improved efficiency, these must be supported by strong policy frameworks and cross-sector collaboration.

Highlights

• Energy needs water, water needs energy: The mutual dependencies are expected to intensify.
• Water withdrawals and consumption: Both are set to increase, with consumption rising more sharply.
• Desalination and wastewater treatment: These are the most energy-intensive processes in the water sector.
• Energy savings potential: A coordinated approach can reduce energy use by 225 TWh and increase electricity generation from wastewater by 70 TWh.
• SDGs and Nexus: The nexus is central to achieving SDG 6 (clean water and sanitation) and SDG 7 (affordable and clean energy).

Key Figures

• Global water withdrawals for energy: ~400 billion cubic metres (bcm) by 2040.
• Global water consumption for energy: ~75 billion cubic metres (bcm) by 2040.
• Energy use in water sector (2014): ~120 Mtoe, with ~4% of global electricity used.
• Desalination growth: Expected to increase over eight-fold by 2040.
• Water sector energy savings potential (2040): ~15% reduction through efficiency and recovery measures.

Glossary of Terms

• Surface water: Natural water in lakes, rivers, streams, or reservoirs.
• Groundwater: Water below the land surface in pores or crevices of soil, sand, and rock.
• Aquifer: A large body of permeable or porous material that contains groundwater.
• Freshwater: Water with less than 1000-2000 ppm of dissolved salts.
• Non-freshwater resources: Includes brackish or saltwater, wastewater, and agricultural drainage water.
• Renewable water resources: Water generated through the hydrological cycle.
• Non-renewable water resources: Deep aquifers with minimal recharge.
• Water stress: When renewable annual freshwater supply falls below 1700 m³ per person.
• Water withdrawal: Volume of water removed from a source.
• Water consumption: Volume of water not returned to the source.
• Water sector: Includes all processes related to treating, moving, and using water.
• Water treatment: Process of removing contaminants to meet water quality standards.
• Desalination: Reducing salt and minerals in seawater or brackish water.
• Water distribution: Delivery of treated water via networks.
• Wastewater treatment: Involves collection, treatment, and discharge of wastewater.
• Re-used water treatment: Processes for recycling treated wastewater.

Acknowledgments

The report was prepared by the WEO Energy Outlook team in the Directorate of Sustainability, Technology and Outlooks (STO), with contributions from numerous experts and institutions. It is a collaborative effort involving governments, industry, and research organizations to address the complex challenges of the energy-water nexus.