Recycling Water in Power Sector – Next Step for NC

Recycling Water in Power Sector – Next Step for NC

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Power plants use a great deal of one of our most precious resources: water.

Using clean water to cool power plants equates to less usable water for drinking and agriculture. Although it is essential to our power industry, many of its water management processes are inefficient and expensive. Outdated systems could desperately use an upgrade to lower costs and make us more economically competitive.

The Problem: Water Waste on a Massive Scale

A great deal of water is used to cool our electricity sources. According to UCSUSA, 90 percent of our electricity derives from thermoelectric power plants — natural gas, coal, nuclear, and oil — while the other 10 percent of our electricity resources, namely renewables in the form of solar, geothermal, and biomass power plants, are largely dependent upon thermoelectric and the same associated water cooling processes.

Water flowing in and out of a power plant to cool it, image courtesy of http://www.crystal-lagoons.com/images/cristal_lagoons/cooling/1.jpg

Image courtesy of Crystal Lagoons

Putting this into perspective, a recent UCS article reported that US power plants in total withdrew some 50 trillion gallons of water annually, consuming 1.6 trillion gallons of this finite and vital resource. Even a single large power plant draws in roughly a billion gallons in one day. Freshwater areas were the primary sources, accounting for up to 95% of the total water used in the power industry.

Percentage of water use in United States, thermoelectric uses 41%, recycling would ease cost and usage

U.S. freshwater withdrawals; Image courtesy of UCSUSA

The result: our power sector is responsible for more than 40% of water withdrawals in the US due to the heavy volume used for thermoelectric cooling – that’s more than what is used for drinking water and agriculture combined.

Unfortunately, outfitting water cooling practices with new technology would be an arduous and expensive task. Air cooling, for example, is not a good alternative, because it has a higher cost and is generally less efficient. In addition, heavy research and development necessary for new strategies, paired with complex federal regulations and technological complexities, creates barriers for power companies looking to make the switch.

Recycling Water Makes the Difference

Introducing recycled water as a means of cooling power plants is helpful for not only conserving water as a resource, but also in cutting costs for power plant companies. In fact, the UCS estimates that around 10-30% of water costs can be saved by switching from fresh water to municipal reclaimed wastewater.

Putting Better Water Practices Into Action

Texas Power Plant recycling reusing water

Image courtesy of GE

In 2013, the National Association of Regulatory Utility Commissioners (NARUC) passed an important energy-water resolution that directly addressed the role of water supply in power sector decisions. That same year, GE rolled out its zero liquid discharge (ZLD) wastewater treatment technology at two power plants in Texas. GE Power & Water welcoming NARUC’s changes:

“Energy and water are two of the world’s most precious resources, and they are interdependent; energy is needed to produce water, and water is needed to produce energy. GE’s zero liquid discharge technology will enable these two power plants to reuse at least 98% of water…”

GE wasn’t the first to make this change – and it won’t be the last – but it is a recent example of how the use of recyclable water was able to address a central economic issue in the power industry. Ultimately, the solution was within the problem: it wasn’t the use of water that needed to be changed, but the type of water being used.

How is North Carolina Involved in All This?

North Carolina is no stranger to renewable power strategies. The US Energy Information Administration reports that 7.1 percent of the state’s utility-scale net electricity generation came from renewable energy resources in 2015, and it is also the fourth-largest producer of electricity generated from solar photovoltaic panels.

This commitment to clean energy includes water – North Carolina has a water reuse policy that requires the Environmental Management Commission to “encourage and promote safe and beneficial reuse of treated wastewater,” and sustainable water practices are widespread throughout the state.

Water waste at North Carolina power plants is something state officials have been carefully watching. Cogentrix’s 120 MW power plant in Battleboro, NC recently partnered with GE to use its patented technology towards water conservation. By using recycled water for cooling towers, the plant is able to save a total of around 3 million gallons of water per year –  that’s around 22 percent of its total water usage. In addition to reducing dependence on freshwater sources, the initiative also helped decrease operational costs, increase efficiency, and eliminate waste discharged into the Tar River.

The strong success of the Cogentrix power plant paints a bright future for North Carolina’s water conservation strategy. The benefits of recycling water for power plants are evident, and we anticipate many more plants to follow suit in the near future.

The Future of the Power Industry

Due to drought, stricter government regulations, and a general cultural shift towards sustainability, a large number of power companies are facing increasing pressure to develop new water practices. GE’s strong implementation of its water-conserving technology proves that it is possible to improve operations while maintaining competitiveness, even at scale.

The economic costs associated with water consumption and waste weighs heavily on North Carolinians and all Americans. 50 trillion gallons of water withdrawn by the power sector is a hard statistic to comprehend, but with heightened efforts to improve our efficiency and strategic use of water, it is clear that we will continue to increase our energy independence and operational competitiveness, particularly in the energy sector.

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