(Topic 19) Energy and Water Reservoirs

Energy and Water Reservoirs

  • Total Water Reservoirs:

    • Terrestrial Atmosphere: 4.5

    • Marine Atmosphere: 11

    • Advection: 36

    • Land Ice and Snow: 43,400

    • Surface Water: 360

    • Ground Water: 15,300

    • Biota: 2

    • Total: 59,000

  • Evapotranspiration: 71

  • Precipitation: 107

  • Oceans:

    • Mixed Layers: 50,000

    • Thermocline: 460,000

    • Abyssal: 890,000

    • Total Oceans: 1,400,000

  • Evaporation: 434

  • Precipitation: 398

  • River Runoff: 36

  • Total Fluxes: 1015

  • Water Cycle per Year: 10 kg/year

Water Use in the U.S. (2005)

  • Total Withdrawals: Approximately 400 billion gallons/day

    • Per Capita Usage: 1,300 gallons/person/day

Difference between Withdrawals and Consumption

  • Withdrawal: Taking water out of a surface or groundwater reservoir.

  • Consumption: Taking water out of a surface or groundwater reservoir and not returning it to the same reservoir.

  • Example of Withdrawal that is not Consumption:

    • Taking water out of a lake to cool machinery, then returning it to the lake at a warmer temperature.

  • Water Use in the U.S. (2005):

    • Analyzing whether the usage was solely consumption or withdrawal.

Linkage Between Water Cycle and Energy Cycle

  • Water is necessary for energy production.

  • Energy is required to make water supplies available (in terms of both quantity and quality).

  • Observations indicate that the energy-water system is under significant strain.

  • Factors contributing to strain:

    • Growth in population and affluence leading to increased water demand.

    • Climate change potentially affecting water availability.

    • Policy changes shifting towards more energy-intensive water systems and more water-intensive energy production.

Major Users of Energy and Water (Withdrawals)

  • The largest user of both energy and water (withdrawals) remains thermoelectric power.

  • The technology for hydraulic fracturing currently uses approximately 5 million gallons per well.

Electrified Transportation

  • Gaining Popularity:

    • Two basic forms:

    • Electric Vehicles (EVs)

    • Plug-in Hybrid-Electric Vehicles (PHEVs)

    • Advantages:

    • Energy-efficient (measured in BTUs per mile).

    • Clean at the point of use, displacing petroleum use.

    • Easier to manage emissions by focusing on fewer power plants rather than numerous tailpipes.

    • Water Usage:

    • Power plants require substantial cooling water.

    • For PHEVs:

      • Vehicle Class Specific Energy Requirements:

      • Compact Sedan: 0.26 kWh/mile

      • Mid-size Sedan: 0.30 kWh/mile

      • Mid-size SUV: 0.38 kWh/mile

      • Full-size SUV: 0.46 kWh/mile

      • Expected Water Withdrawal: Approximately 7.8 gallons/mile

      • Expected Water Consumption: Approximately 0.25 gallons/mile

Biofuels and Water Cycle Implications

  • Biofuels necessitate significant water usage, with demands reaching hundreds of gallons per mile traveled.

  • The connection between the water cycle and energy cycle persists:

    • Water's role in energy production.

    • The energy needed to ensure access to water resources affects both distribution and quality.

    • Strains in the system are expected to worsen due to various socioeconomic and environmental factors.

Lake Powell Water Levels (Historical Context)

  • Documented elevation levels of Lake Powell over time:

    • Historical elevations range from a maximum of 1232 feet to average levels around 1173 feet.

    • Significant dates include various low water levels indicating drought conditions and the changing dynamics of water resource availability.

Owens Lake Environmental Management

  • Dust Control Measures:

    • A consensus study report by the National Academies addressing the effectiveness and impacts of various dust control measures for Owens Lake.