Energy Water Nexus

These are notes from Energy Water Nexus.

• Water: a new vulnerability in the energy system
• Through looking at the world from space we think we have an abundance of water
• less than 3% of water is fresh
• 2.5% of fresh water frozen in glaciers
• only .5% easily accessible in aquifers, lakes, rivers, or wetland
• Freshwater is unevenly allocated
• 60% of Earth's water controlled by
• Brazil, Russia, China, Canada, Indonesia, USA, India, Columbia, and the Democratic Republic of Congo
• Australia faces water scarcity
• Developing nations also pose an issue
• Potential inability to match water demands
• Water is consumed in industry for high income countries
• One billion lack access to fresh drinking water
• Linkage between water and energy
• energy is used to pump, move and treat water
• water is often used for energy, from water mills to hydro dams
• global population and economic growth continues, despite water shortage
• A more water-constrained future
• huge urbanization rates of Asia, Latin America, and Africa
• energy and water security national level problems
• Climate change due to global warming adds to water stress
• approach to preserve present level of comfort while improving energy efficiency in developed nations
• Water requirements in the energy sector
• freshwater required for many steps of energy generation
• extraction, production, refining, processing, transportation, storage and generation
• North america consumes 1/4 of world's energy
• Fuel Production
• water consumption varies with energy utilization
• developing nations often use biomass and solar in ways difficult to measure
• Crude Oil
• highest energy production rate
• 1.058 m³ water needed per Gigajoule of energy from oil
• oil accounts for 34% of current energy production
• hope to decrease to 22% by 2050
• Asia accounts for more than 40% of worlds water consumption due to oil 
• Natural Gas
• gas production due to double over the next 40 years
• Water consumption due to gas is low
• 0.109 m³ of water needed per GigaJoule
• Horizontal drilling and other extraction techniques making gas more viable
• water used is recoverable but contains contaminants
• Coal
• Energy from coal below oil but likely to rise
• 0.164 m³ of water needed per GigaJoule
• Uranium
• Energy accounts for only 6% of energy production in world
• 0.086 m³ of water needed per GigaJoule
• Biomass
• considered "fuel for the poor"
• inefficient and highly polluting
• wood, agro, municipal by products
• Electricity Production
• Thermoelectric Plants
• all fuel types need cooling and process water
• differentiated between once-through and recirculating systems
• wet recirculating systems about 40% more expensive than once through
• dry cooling is 3-4 times more expensive than wet
• once-through loses 1%
• recirculation, less than 1% drawn from source, lose 70-90% lost through evaporation
• recirculating system consumes 10 times the amount of water
• Subcritical and Supercritical types of Pulverized Coal plants
• supercritical more efficient
• subcritical older and more commonly used
• Integrated Gasification Combined Cycle
• turns coal into synthetic gas then uses that gas to heat water
• Combined Cycle Gas Turbine
• gas turbine generates electricity, waste heat used to make steam to generate more electricity
• Natural Gas Combine cycle
• majority of water used for cooling, lowest in comparison with other fossil fuel techniques
• Nuclear Plants
• have higher cooling tower, water consumption high
• Carbon Capture and Storage
• development of carbon capture and storage technologies used to meet climate change standards
• reduces emissions by 80-85%
• requires more water
• Hydroelectric Power Plants
• largest generator of renewable energy
• water not really lost but reservoir creation can cause additional evaporation
• significant for smaller power plants
• Electricity from wind and solar
• minor amounts for both PV and Wind power mainly for cleaning and maintenance
• Water consumption to generate electricity may double in the next 40 years as we move to cleaner technologies

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