The Energy - Water Nexus

Water is scarce in generally arid areas like the Middle East, Africa, Australian desert, etc. But even in areas that seemingly have plenty of water, a mix of growing population, pollution, poor management, and development has led to the surfacing of water issues in the most unsuspecting manners.

All major types of industries — energy, agriculture, manufacturing - are fully reliant on water for even marginal operation.

According to some estimates,it take 37 gallons of water to grow, package, and ship
enough coffee to make one cup. A hamburger requires about 634 gallons to make it to your stomach.But the most water-intensive industry of them all is energy. It can take up to 168 gallons of water to get one barrel of oil from oil sands. And 800 gallons are required to generate one megawatt-hour of electricity.According to another estimate by US Geological Survey, electricity production from fossil fuels and nuclear energy requires 190,000 million gallons of water per day, accounting for 39% of all freshwater withdrawals in the US, with 71% of that going to fossil-fuel electricity generation alone.

So,we use a lot of water to produce energy, especially fossil fuel energy. And we use a lot of energy to produce water — for food, to treat water, to capture and treat waste water.

Another point of concern is that the world population is expected to increase significantly while fresh water supplies are not.The burgeoning global population's ever-increasing need for fresh water is at odds with a warming world that is already squeezing water availability in some regions. Climate variability could thus further add to the woes and impact water supplies, quality, and energy demand.

Since water and energy are so tightly bound together,the relationship has been given a special name: the energy-water nexus.

And energy industry must compete for water with agriculture, other industries as
well as domestic use. According to the 2007 report of the Intergovernmental Panel on Climate Change,things will only get worse as current water-management practices are unlikely to quell demands.

But there is hope. There is slow, but nevertheless increasing, awareness building up on the interdependence of water-reliant systems and the need for balancing of the requirements of all users and development of technologies to reduce water consumption and loss.

The Wall Street Journal recently reported that "the electric-power industry accounts for nearly half of all water withdrawals in the US" and "Power companies are pulling back from plans to build traditional power plants that require steady streams of water to operate." .

Looking at India, according a presentation at the Uttar Pradesh Electricity Regulatory Commision (UPERC), the country has 16% of world population but only 4% of the total available fresh water.Ground water constitutes 38.5% of the total water resource of the country.Major uses of Ground water in India are
Irrigation (90% of all available water meets only 55% of the need), Drinking purposes/domestic consumption (5% meets 90% of need)and Industries (5% meets 50% of the need) .

To elicit the governmental support and to bridge the policy gap between the water and energy sectors so that problems involving the interaction of the two sectors can be addressed and reform efforts can move forward, The Water Energy Nexus Activity (WENEXA) has been initiated.It is designed to address seemingly intractable problems whose roots lie at the intersection of these two sectors.

Under the Aegis of initiatives like WENEXA, scientific and technological innovations should be encouraged to focus on minimizing the impact of energy production on water quality and availability and reducing the amount of energy required for treating and distributing water.

Emphasis should be laid on innovations for
(1) treating and reusing non-potable process water in power production
(2) accessing currently unused water sources, such as brackish aquifers
(3) reducing cooling water used by thermal electricity-generating power plants
(4) delivering water and energy more efficiently to prevent losses and
(5) minimizing water-related impacts from mining, energy production and use, and disposal of solid byproducts.

Research should also be directed at reducing the energy required to treat,
pump, and distribute water, including improvements in waste-water treatment
processes and irrigation technology.

Also, to combat the amount of water consumed by traditional power plants, utilities must turn to alternative technologies.According to the Wall Street Journal,a wind turbine, for example, can save 200 to 600 gallons of water compared with the amount required by a modern gas-fired power plant to make that same amount; solar arrays are also gaining momentum because their water needs are minimal.

In short, Global Water supplies are at risk of drying up as the climate warms, but mitigating climate change calls for shifting to less water intensive alternative energy sources.