Power Plants and Water Crisis

Power Plants and Water Crisis  Power Plants and Water Crisis

Apart from drinking and agricultural needs, the huge increase in water demand is now affecting key industries, namely power generation and experts have warned that the present situation coupled with irresponsible water wastage is dangerous and unsustainable.

More than 80 percent of the water utilized in industries is consumed in power plants, Gholamreza Mehrdad, director for technical support at the Iran Power Generation, Transmission & Distribution Management Company (Tavanir) told the Persian daily, Forsat-e-Emruz.

Electricity is crucial for all industrial activity, and they will be brought to a halt due to water, and by exentesnion, electricity shortage should water consumption in power plants remain at the current critical rate.

Power plants are the most water-intensive among other industries.  Water crisis for power plants is considered by Mehrdad as equivalent to "fuel shortage." Over the years, water scarcity has caused difficulties for the functioning of power stations in which wet cooling towers are employed.

Power plants across the country boil water to create steam, which then spins turbines to generate electricity.  Once steam has passed through a turbine, it goes to cooling towers to be cooled back into water before it can be reused to produce more electricity   

  Comparatively High

In wet cooling towers, or open circuit cooling towers, which operate on the principle of evaporative cooling, a great amount of water is wasted in the form of steam. Wet cooling towers rely on latent heat of water evaporation to exchange heat between the process and the air passing through the cooling tower. Wet towers tend to have appreciably higher water consumption, compared with dry towers.

Water shortage can put an end to the activities of power plants operating with wet cooling towers, such as the Isfahan power plant, Mehrdad warned. In such power plants, a total of 2.5 liters of water is consumed to generate one kilowatt hour of electricity.

Wet cooling towers are employed in power plants aged 20 years or more, and recently constructed plants make use of dry cooling towers. Hamedan and Bisotoun power plants are the last two in which wet cooling towers are used.

"While power plants with wet towers comprise only 20 percent of all thermal power plants in Iran, they account for 80 percent of industrial water consumption," Mehrdad said, noting that water consumption in dry cooling towers is less than 10 percent of the amount consumed in wet towers. The figure is only five percent in combined-cycle power plants.

  Huge Difference

Dry-cooling systems use air instead of water to cool the steam exiting a turbine.  Dry-cooled systems use no water and can decrease total power plant water consumption by more than 90 percent. The advantage of these water savings are higher cost and lower efficiency.

In power plants, lower efficiency means more fuel is needed to produce one unit of electricity, which can in turn lead to higher air pollution and environmental degradation due to mining, processing, and transporting fuel.

Iran is ranked the world’s 24th most water-stressed nation, a study by the World Resources Institute said, putting the country at extremely high risk of future water scarcity. In the past 50 years, the growing population has used up almost 70 percent of Iran’s groundwater supply.

Iran is headed for a water crisis of epic proportions, and much needs to be done to reverse the decades-long dangerous trend that has the potential to transform large swathes of valuable farmlands into parched and uninhabitable territory, or something akin to deserts.

In recent months water experts, prominent economists and state officials have also singled out the traditional-based agro sector for special condemnation criticism for using up 90 percent of the national water resources at a time when rainfall has reached its lowest levels in recent history.

As if this is not enough, the farmers and horticulturists "waste 70 percent of this precious natural resource," to the point that growing crops and some fruits could soon become a thing of the past if  water management in the agriculture and industrial sectors does not improve.