The Use of Potential Renewable Energy Resources for Developing Sustainable Water Supplies

Tamim Younos Virginia Water Resources Research Center and Department of Geography, Virginia Tech

Safe and adequate water supplies are needed to protect public health and to sustain economic productivity. The Engineer of 2020, a National Academy of Engineering publication quotes: “The question of water is at the heart of a 600-page world water development report issued by the United Nations in 2003. It’s projected that within the next 20 years virtually every nation in the world will face some type of water supply problem.” In coming decades, significant increased water demand is expected in Northern Virginia, Hampton Roads and population and industrial centers in Virginia. To meet future global water demand, in addition to developing conventional surface and groundwater sources that are quickly diminishing, it will become necessary to develop alternative water sources. Potential alternative water sources include urban storm water runoff, municipal wastewater treatment plant discharges, saline and other waters that are impure for human consumption and economic uses. Currently, advanced and highly effective water purification systems using technologies such as membranes and thermal (distillation) processes are being developed for this purpose. However, these advanced water purification technologies are energy intensive and feasibility of implementing these technologies are directly affected by energy consumption.

There is a significant need to integrate renewable energy resources into water production systems. Potential renewable energy resources include solar energy (e.g. photovoltaic and solar energy concentrators/collectors), wind energy, geothermal energy, and ocean energy (tidal power, wave energy, and thermal energy). This poster presentation provides an overview of the potential use of renewable energy resources for developing sustainable water supplies that implement advanced water purification technologies. The presentation addresses the potential and limitations of these alternative energy resources for production of sustainable water supplies in Virginia and the need for developing interdisciplinary research, institutional framework, and policy making to meet future global water demand. Acknowledgments: Kimberly Tulou assisted with research, Jane Walker with editing, and Kelly Davis with developing the poster.

Younos, T (Ed.). 2005. Desalination – A Primer. Journal of Contemporary Water Research & Education. Universities Council on Water Resources, Carbondale, Ill. 52 pp. To order e-mail: ucowr@siu.edu.Younos, T. 2004. The feasibility of using desalination to supplement drinking water supplies in Eastern Virginia. VWRRC Special Report SR25-2004. Virginia Water Resources Research Center, Virginia Tech, Blacksburg, VA. 114 pp. Available Online: www.vwrrc.vt.edu/publications/recent.htm

1. Develop an atlas of potential renewable natural resources in Virginia with regard to their availability and potential in a Geographic Information System (GIS) environment

2. Form an interdisciplinary research team of experts in energy, water purification technologies, water resource economics, and geospatial analysis to develop a template for overall research needs and costs

3. Create a statewide task force that includes representatives from regulatory agencies, utilities (water and power), academia, and citizens that will develop the framework for institutional infrastructure and implantation strategies for using renewable energy for water production.

Membrane Technologies Membrane Technologies Membrane water Membrane water purification processed use either pressure-driven purification processed use either pressure-driven or electrical-driven technologies or a or electrical-driven technologies or a combination of these technologies. Reverse combination of these technologies. Reverse Osmosis (RO), a pressure-driven process, is the Osmosis (RO), a pressure-driven process, is the most common technology in the United States. most common technology in the United States. Energy is needed to operate the process. Energy is needed to operate the process.

Thermal Technologies Thermal Technologies Thermal technologies Thermal technologies use evaporation and distillation processes to use evaporation and distillation processes to purify water. The process is highly energy purify water. The process is highly energy intensive and uncommon in the United States. intensive and uncommon in the United States. Advanced technologies such as Mechanical Advanced technologies such as Mechanical Vapor Compression (MVC) integrate thermal Vapor Compression (MVC) integrate thermal and mechanical energy.and mechanical energy.

STATEMENT OF THE PROBLEM

ABSTRACT

RECOMMENDATIONS

REFERENCES

Photovoltaic arrays convert solar energy into electricity through Photovoltaic arrays convert solar energy into electricity through the transfer of electrons. The arrays are made of silicon chips the transfer of electrons. The arrays are made of silicon chips because silicon effectively and efficiently transfers electrons. because silicon effectively and efficiently transfers electrons. When sun rays shine on the silicon chips, the electrons jump to When sun rays shine on the silicon chips, the electrons jump to another orbit. This movement creates a voltage that can be used another orbit. This movement creates a voltage that can be used to power pumps for water purification.to power pumps for water purification.

APPLICATION POTENTIAL IN VIRGINIA

•Energy Conservation•Increase Output of Traditional Sources (coal, oil, nuclear)•Using Renewable Energy Sources (solar, wind, geothermal, ocean)

APPROACHES TO MEET ENERGY DEMAND

Water PurificationTechnology

Type of EnergyWork*

Consumed (kwh/m3)

Reverse Osmosis(RO)

Mechanical Energy 4.2 – 10.0

With Cogeneration & Steam

2.3 – 5.8

Electrodialysis(ED)

Electric Energy 1.7

Multistage-Flash Evaporation

(MSF)

Thermal Energy 18.8

+ Mechanical Energy

23.2

With Cogeneration 4.7

Low Temperature Multi

Effect Evaporation(LT- MEE)

Thermal & Mechanical Energy

5.0

With Cogeneration 2.1 – 4.6

Multi Effect Evaporation-

Thermal Vapor Compression

(MEE-TVC)

Thermal and mechanical Energy

9.0 – 17.0

Mechanical Vapor Compression

(MVC)Mechanical Energy 6.0 – 18.5

Hybrid RO/METhermal &

Mechanical Energy1.35-1.6

WATER PURIFICATION TECHNOLOGIES AND ENERGY CONSUMPTION

INTEGRATING RENEWABLE ENERGY RESOURCES TO PRODUCE SUSTAINABLE WATER SUPPLIES

Advanced

Water

Purification

Technologies

Potential RenewableEnergy Resources

Alternative WaterSources

Solar

Wind

Geothermal

Ocean

Wastewater

Runoff

Saline Water

Other

Sustainable Water Supplies

GLOBAL EXAMPLES USING RENEWABLE ENERGY RESOURCES FOR DEVELOPING WATER SUPPLIES

RenewableEnergy Sources Advantages Disadvantages Cost Applicability in Virginia

Direct SolarEnergy(Stills)

Affordable and easy to maintain, good efficiency

Requires large land area and sunlight

Low Not applicable as a significant energy source in Virginia - applicable for remote areas with lots of sunlight

Indirect Solar Energy

(Photovoltaic & Solar

Collectors)

Good energy collectors

Low efficiency, and high manufacturing costs, requires large arrays

Med.

Has potential for use as a power supplement. Research is needed to increase efficiency and determine potential in Virginia

Wind Energy Mature technology that can generate large amounts of energy

Wind is intermittent ? Applicable but may not have enough winds to be cost-effective in Virginia coastal areas.Research is needed to determine the potential.

GeothermalEnergy

Large amounts of resources available in some areas

Technology is undeveloped for application to desalination

? Not applicable as a significant energy source in Virginia - there are not enough geothermal reserves in Virginia

Ocean EnergyTidal

Tides occur at every coastline, fairly efficient

Energy is intermittent

High Applicable but may not have enough difference in elevation between tides to be cost-effective.Research is needed to determine the potential.

Ocean EnergyWave

Cost effective for large plants, less expensive than diesel or hydropower

Wave heights vary Med.

ApplicableResearch is needed to determine the potential.

Ocean EnergyThermal

Research in progress Few areas where ocean has significant temperature variations with depth, expensive, low efficiency

High Applicable but not practical until technology is further improved and costs are decreased.

Wind energy rotates windmills creating mechanical energy that can be Wind energy rotates windmills creating mechanical energy that can be converted to electrical energy. Turbines utilizing wind energy for low power converted to electrical energy. Turbines utilizing wind energy for low power (10 kW-100 kW), medium power (100 kW-0.5 MW), and high power (> 0.5 (10 kW-100 kW), medium power (100 kW-0.5 MW), and high power (> 0.5 MW) are mature technologies. MW) are mature technologies.

Location

Power Generated

(kW)Tech- nology

Capacity (gal/d)

Shark Bay, Australia 32 RO 44380 & 34340

Borj-Cedria, Tunisia 

RO + ED  

Fuerteventura Island, Spain   RO 14794

Ile du Planier, France   RO 3170

Helgoland, Germany   RO 6086000

Ruegen Island, Germany 200 MVC 31700-79250

Gran Canaria, Spain   RO 52830

Location

Power Generated

(kW) TechnologyCapacity

(gal/d)

Perth, Western Australia 1.2 RO 634-3170

Jeddah, Saudi Arabia 8 RO 845

North of Jawa, Indonesia 25.5 RO 3170

Vancouver, Canada* 4.8 RO 264

Red Sea, Egypt 19.84 RO 13210

Hassi-Khebi, Argelie 2.59 RO 6023