Power Switch: Economics Driving New Energy for Moving Water

By Warren Tenney

In 2009, I was a new member of the Board overseeing the Central Arizona Project (CAP) and energy, not water, was the primary focus. I was surprised with my sudden immersion into the ins and outs of energy. Yet, there was a good reason for concentrating on energy.

As one of the largest energy users in the state, energy is crucial for CAP. CAP needs to pump water uphill from the Colorado River through the 336-mile canal that delivers water to cities, Native American communities, and farmers in Central Arizona and south to Tucson. Since the 1970s, nearly 90 percent of CAP’s primary energy source has been the Navajo Generating Station (NGS) in Page, Arizona near the Utah border. The plant is one of the country’s largest coal-fired power plants.

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So in 2009 and 2010, the U.S. Environmental Protection Agency pushed hard to reduce the haze NGS produced in the scenic Four Corners area. It was estimated that NGS would need over a billion dollars in capital investment to reduce nitrogen oxide emissions to EPA’s satisfaction. Many felt EPA’s unspoken aim was to shut down NGS. CAP and the Salt River Project (SRP), the operator and part owner of the plant, took this attack on NGS seriously.

It was frightening to think of NGS shutting down or being forced to take on huge capital costs to meet EPA’s regulatory demands. The rallying cry was that NGS was critical to make sure CAP had power to operate and to keep energy costs low. At the time, many prominent voices correctly observed that keeping NGS open was important to Arizona’s economy, particularly to the City of Page and the surrounding Navajo Nation. NGS also provided CAP with a key revenue source. CAP sells surplus energy produced by the plant and uses the revenue to repay the federal government the loan it made to finance the construction of the CAP.

A concerted effort was made to find a compromise that EPA would accept to keep NGS open until 2044.  To the relief of many, in July 2014 the EPA and owners of NGS reached an agreement that would lower the levels of nitrogen oxide emission and keep NGS open until 2044.

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Inside the Navajo Generating Station  Photos: CAP

So fast-forward three years to today.  Many of us who followed the NGS story since 2009 are surprised with the news that the owners of NGS voted to close the power plant at the end of 2019. What has caused the 180-degree turn in the effort to save NGS?

Pure economics is driving the decision. The utilities that own NGS now are dealing with a power plant that is significantly more expensive than other energy options. Natural gas prices have dropped to record lows to become a viable long-term and economical alternative to coal power. This means pursuing the regulatory upgrades that were part of the compromise with EPA are even less cost-effective today. However, even if EPA loosened its coal regulations, the energy industry is headed towards having natural gas generation as the fuel of choice for many years to come.

So what does this mean to Arizona and particularly the Valley cities that utilize CAP?

First and foremost, CAP will have access to the energy necessary to move water through the CAP system even without NGS. In recent years, CAP has been looking at alternatives to NGS to be prepared for what is now happening. CAP can easily buy energy from the open-market power grid. Based on today’s energy market, CAP’s power costs would actually be significantly lower. Energy costs on the open market are much less than the cost to generate power at the NGS. This means CAP’s pumping energy rate – charged to the Phoenix area cities and others CAP users – will decrease.  Again, this new economic reality of the energy market is much different than just seven years ago when we were worried that an NGS closure would mean higher costs for CAP and its customers. 

NGS has been a reliable energy source for CAP.  While going on the open energy market will mean lower costs today, CAP faces the new challenge of how to best utilize the right energy sources to take advantage of low-cost power alternatives.

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Central Arizona Project canal.

While the decision to close NGS is not the dire situation we assumed it would be in 2009 and 2010, the closure of NGS still remains an enormous challenge for the Navajo Nation, Hopi Tribe and the community of Page. NGS has been a primary economic driver and major employer. Assuming the Navajo Nation extends the existing land lease for the plant through the end of 2019, the plant’s owners should have time to explore ideas to lessen the negative impact to that region.

The decision of the utility owners to close NGS – and the challenges it creates – reemphasizes the critical nexus between water and energy.

Warren Tenney was elected twice to serve as a member of the Central Arizona Project (also called the Central Arizona Water Conservation District or CAWCD) Board from Pima County. He served as Vice-President of the Board and as Chairman of the Board’s Finance, Audit & Power Committee. He resigned his board position in January 2016 to become Arizona Municipal Water User Association’s executive director.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org

Wastewater Treatment Plant Turns Gaseous By-Product Into Profit

By Warren Tenney

Arizona’s largest wastewater treatment plant already cleans and re-uses nearly all of the waste it receives from 2.5 million people in five AMWUA cities. Now, the cities that own the treatment plant have found one more way to re-use its products. As of spring 2018, the 91st Avenue Wastewater Treatment Plant will stop burning off the mostly methane gas it creates as a by-product. Instead, the plant will transform the by-product into renewable biogas and sell it for more than $1.2 million a year.

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91st Avenue Wastewater Treatment Plant   Photos: City of Phoenix

The 91st Avenue Wastewater Treatment Plant’s effluent, or treated wastewater, is re-used to irrigate crops, create a wildlife wetlands project called Tres Rios, and provide cooling water for the Palo Verde Nuclear Generating Station, 36 miles west of the plant. The wastewater plant treats and transforms solid waste – all the stuff ground up in garbage disposals and flushed down toilets – into fertilizer for non-food crops, such as hay, alfalfa and cotton. The City of Phoenix, which operates the plant, and its four AMWUA city partners have found a way to produce yet another marketable product – biogas. Here’s how it will work.

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Tres Rios Wetlands

  • The plant has 16 large digester tanks with a capacity of 1.5 million gallons to 3 million gallons. These digesters operate like an industrial stomach, digesting solid sewage waste as a step toward turning it into fertilizer. Just like our own digestive system, these industrial digesters expel gas. That gas is now vented through three flares and burned off into the atmosphere.
  • Last week, Phoenix and its partners broke ground for a new facility next to the plant that is about as big as a football field. The new facility is being built and operated by Ameresco, a vendor selected by the cities that own the treatment plant. It is expected to be completed and operating by spring 2018. When completed, the plant will be fully automated and will be operated by one person. The stacks that flare the gas will remain on-site to act as a backup if needed.
  • The new facility will scrub and pressurize the plant’s gas into clean biogas. The gas will be compressed and travel through an underground pipe to a large commercial gas pipeline three miles west of the plant.
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This is a similar Ameresco bio-gas plant in San Antonio, Texas.

The 91st Avenue plant was built in 1968 by a partnership of AMWUA’s five original member cities, Glendale, Mesa, Phoenix, Scottsdale and Tempe. This partnership is known as the Sub-Regional Operating Group or SROG. The plant treats an average of 140 million gallons of wastewater a day but has the capacity to treat 230 million gallons. Both the plant and the biogas facility are built to accommodate what is expected to be a growing market.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.

AMWUA Cities Help State Screen Schools To Ensure Safe Water

By Warren Tenney

In the first six months of 2017, Arizona will screen water samples from 7,000 school buildings looking for unsafe levels of lead. The program is designed to determine if drinking water is contaminated by lead that might be present in a school’s plumbing lines, water fountains and faucets. Water sits in a school’s plumbing systems unused over weekends and during holiday and summer breaks, which increases the risk of lead leaching from the building’s lines and fixtures into the water. Recently, a school in Nogales tested its drinking water on its own and found a lead problem. The school discovered the source of lead was its water heaters and replaced them.

The Arizona Department of Environmental Quality (ADEQ) is conducting this program with the help of state education agencies and local utilities, including AMWUA cities. The catastrophic lead poisoning in Flint, Michigan raised awareness about the dangers of lead. Arizona and other states are moving ahead with sampling programs to protect the health of their youngest citizens. Children are particularly vulnerable to lead poisoning, which can impair their hearing, growth and intelligence. Pregnant women also can pass lead to their unborn children.

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The federal government limits the lead content in drinking water and, in 1987, it limited the lead content of copper plumbing pipes and solders. That puts older school buildings at higher risk for lead contamination. There are about 6,500 Arizona school buildings older than 1987. Arizona’s Public School Drinking Water Lead Screening Program will test these buildings plus a random sampling of newer schools.

Two samples will be taken from each identified school building. ADEQ provides the sampling kits and instructions, prepaid shipping boxes and lab testing at no cost to the schools. ADEQ will receive all screening reports. Here’s what ADEQ will do if lead is found to be at higher levels in a school’s drinking water:

  • Alert the school and the Arizona Department of Health Services and provide the school with information to share with parents.
  • Recommend immediate actions the school can take to eliminate lead exposure.
  • Inform the Arizona School Facilities Board (SFB), the state agency that helps maintain public school buildings, which will work on long-term solutions.

This ambitious program means collecting and testing nearly 1,000 samples a week.

Cities perform more than 100 tests on drinking water in their delivery systems each day to ensure it meets all safe drinking water standards set by the Environmental Protection Agency (EPA) and ADEQ.  Municipal water systems end at a home or building’s water meter. The cities are stepping up to assist ADEQ to test water on the school’s side of the meter. It is not the cities’ responsibility, but cities are run by people who understand the importance of providing kids with the safest water possible. Here’s how the cities are using their resources to help ADEQ accomplish this job:

  • The City of Phoenix has worked with ADEQ to help plan the screening program. Phoenix will help assemble sampling kits, drop them off at city schools, pick up the samples and screen them in its water quality lab.
  • The City of Peoria will deliver sampling kits to its schools, pick up the samples and deliver them to ADEQ for screening.
  • The City of Scottsdale has decided to sample and test for lead in all of its public schools. Scottsdale will go beyond the state program and offer the same sampling and analysis to private and charter schools and day care programs.
  • The City of Tempe will collect samples from Tempe schools and test the samples at the city’s water quality lab.
  • The City of Glendale will prepare and deliver sampling kits to schools, pick up the samples from the schools and take them to the city’s lab for screening.
  • The City of Chandler will offer to schools analysis and guidance for lead sampling results.
  • Some AMWUA cities already tested their schools. Last school year, the Town of Gilbert contacted public elementary, junior high, and high schools from three school districts served by the Gilbert water system. In May, Gilbert tested samples from 46 public schools for lead and copper and all were found to have acceptable levels. Gilbert schools also will be screened through the ADEQ program.

Learn more about the Public School Drinking Water Lead Screening Program, including which schools are on the list.  Any city or utility willing to help with the screening program can contact Daniel Czecholinkski at 602 771-4617 or email him at Czecholinski.Daniel@azdeq.gov. Designated schools that want to coordinate and schedule the screening can send an email to LeadScreeningProgram@azdeq.gov or contact David Burchard at 602-771-4298.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org