Water Food Energy Nexus

Why has water use decreased in the US in recent years (at least the 2010s)

Because of less nuclear power plants

What is the largest consumer of water in the US?

thermoelectric power

How much does groundwater make up of the earth's water supply?

0.61%, it is the largest volume of useable fresh water

Porosity (n)

ratio of volume of pores (pore space) to total volume

Effective Porosity (ne)

ratio of interconnected pores to total volume

Permeability

Ability of a porous media to transmit fluid. Increase as grain size increase (due to larger pore openings), decreases as standard deviation of particle size increases (degree of sorting decreases)

Hydraulic conductivity (K)

Coefficient of permeability

Hydraulic gradient (i) (dh/dl)

Change in the height of the water table over a distance

What okays a large role in groundwater flow, porosity (n) or hydraulic conductivity (K)?

hydraulic conductivity (K)

What happens at the capillary fringe?

Pore water pressure equal to atmosphere- above it (vadose zone) it's less, below it (saturated zone) it's more

Aquifer

A geological unit that can store and transmit water at rates fast enough to supply water to wells

gaining stream vs. losing stream

Gaining streams gain water from aquifers, losing streams lose water to aquifers

Petroleum

naturally occurring, complex suite of hydrocarbons of various weights and organic compounds

Natural Gas

hydrocarbon gas mixture consisting primarily of methane (CH4) but commonly includes higher alkanes

Can all oil be simply pumped directly out of the ground?

No, that doesn't get everything out

Waterflooding (petroleum)

Injection of water underground to push oil through formation and into an oil well (accounts for 50% of US crude oil production)

CO2 - EOR (petroleum)

Injection of CO2 to mix with oil to aid in recovery (accounts for approximately 50% of total US crude oil production)

Thermal EOR (petroleum)

Injection of steam underground to increase the flow of heavy oil (accounts for about 4% of total US crude oil production)

Chemical EOR (petroleum)

Injection of bacteria or added chemicals in water for oil recovery (accounts for less than 1% of total US crude oil production)

shale oil/shale gas extraction (fracking)

High pressure water, sand, and chemicals injected into ground, to fracture shale. This releases trapped hydrocarbons that can be pumped out.

Average US water consumption per person

More than 1000 m^3 per year

Daily direct water use by U.S family of four

400 gallons

Daily indirect water via power plant use by U.S. family of four

1200 gallons, 3x more than direct use

Water use range for nuclear power generation gallons/MBTU

2400-5800

Water use range for fossil fuel thermoelectric power generation gallons/MBTU

1100-2200

Water use for extracting/producing corn ethenol gallons/MBTU

2,510-29,100

Water use for extracting/producing Soy-Biodiesel

14,000-75,000

True or false: a larger portion of fuels withdrawn like oil, coal, soybean biodiesel, and corn ethanol is withdrawn then actually consumed

True

Corn ethanol gallon per miles of water

0.6-20

Gasoline gallon per miles of water

0.1-0.3

What percent of US water use is used for agriculture?

25-50%

What is the largest energy expenditure related to food production?

Home refrigeration and preparation (31.7%)

In 2018 the US food systems used how much BTU of energy per year?

10.11 quadrillion

It takes how much energy units to produce 1 unit of food energy?

7.3

How much of US postharvest food is lost?

31% (some studies estimate as 40%)

Is food waste higher at consumer or retail level, and what's their percent assuming a total food loss of 31%?

Consumer is higher, at 21%, compared to retail at 10%

True or false: a large portion of GHG emissions in industrialized nations is due to energy production, waste, and consumption waste then to developing nations

True

Running hot water faucet for 5 minutes uses as much energy as burning a 60-watt bulb for how long?

14 hours

How much gallons of water do thermoelectric facilities in the US consumer per day?

195,000 million gals. Almost half of water withdrawn in the US

True or False: nuclear plants were forced to shut down / lower production because incoming water was too warm, but never because outgoing water was to warm

False, they were shut down because of both before

How much of Ogallala aquifer will be depleted by 2060 if irrigation practices not changed?

70%

How much will energy demand increase by 2030?

50%

How much will food demand increase by 2030?

50%

How much will water demand increase by 2030?

30%

Do energy, food, and water all depend on one another?

Yes