Energy, Water, and Irrigation

The following was taken from an Energy Efficient Emerging Technologies: Low Energy Precision Applications PowerPoint courtesy of Nancy Andrews, La Plata Electric Association, a WIP participating entity.
 
There is a link between energy and water use that is often referred to as the energy-water nexus. Consider some of the following energy and water related statistics:
 
·         It takes at least one gallon of water to create one kWh of electricity.
·         It takes from one gallon of water per gallon of oil to get it out of the earth to 350 gallons of water per gallon of oil when it is harder to find.
·         Burning coal and oil = 1-2 gallons/kWh. Hydroelectric = 18 gallons/kWh.
·         Burn a 60W bulb 12hrs/day = 3,000-6,300 gallons of water/year
·         Central air conditioner @ 12 hrs/day = up to 16,800 gallons of water/year.
·         In California, 20% of energy in the state is used to move water and 49% of water is used to create energy.
 
By now, most of know that agricultural irrigation accounts for 75-90% of water diverted or pumped, both globally and in the U.S. The majority (62%) of U.S. irrigation uses older, center pivot technology. Consider the operating characteristics of the traditional center pivots versus mid- and low-elevation spray applications:
 
TYPE OF IRRIGATION SYSTEM IRRIGATION APPLICATION EFFICIENCY OPERATING PRESSURE (PSI) APPLICATION RATE OUTLET SPACING (FT)
Traditional pivot systems 60% 60-80 Medium 20-30
Mid-elevation spray application 85% 40 High 10
Low-elevation spray application 85% 40 High 10
 
Mid- and low-elevation applications saves energy, reduces fuel consumption and operating costs, minimizes evaporation, and helps to prevent foliage damage. For more information on these types of systems, contact your local electric utility, conservation district, or the Water Information Program.