Energy Efficiency Savings
Mary-Anna Holden is a former New Jersey Commissioner. Butch Howard is a former South Carolina Commissioner.
Last month, we featured water service affordability — what is it? We’re following up with a few energy efficiency examples to consider and perhaps include in a Public Service Commission’s incentive or rate recovery under some mechanisms as discussed last month.
Water and wastewater systems are capital and energy intensive. For customer rate purposes, saving one dollar of operating expense could be leveraged into eight dollars of capital improvements.
While we are not advocating or endorsing any particular vendors, over the years we have discovered products, processes, and ideas at NARUC and NAWC conferences, that could lend themselves well to energy and operational efficiencies. We are certain there are many more. In fact, NARUC’s Committee on Water continually explores new technologies and processes that may perhaps lead to state and national regulatory policy changes.
Water pumping, processing, and heating are the greatest use of energy in the United States. Let’s consider why. Think of the power of water wearing down and eroding infrastructure as it is delivered to the treatment plant and customer.
Water is heavy, weighing 8.3 pounds per gallon. That’s a lot to lift under pressure over hills and around corners and to raise to fill balancing tanks or to power force mains and lift stations that gravity-feed a wastewater treatment plant.
Michael E. Webber in his book, “Thirst for Power,” cites that pumping enough water for nineteen hundred average American households, or two and a half million gallons per day, out of an aquifer three hundred thirty feet below the ground requires one hundred-seven kilowatts of pumping power.
He further likens that requirement to the energy consumption of approximately one hundred households. A medium-sized U.S. city with a million residents can require more than six megawatts of power, or the equivalent of a half-dozen massive one-megawatt wind turbines running full bore.
By example, in New Jersey, the Atlantic County Utilities Authority employs five, three hundred eighty-foot turbines at its wastewater treatment facility, producing seven and a half megawatts of power, enough to run the plant, or the equivalent of twenty-five hundred homes.
Therefore, how can it not make sense when cutting operating costs, to start with new energy sources and efficiencies? Energy efficiency is most likely where the greatest savings can be made while producing a reliable product and guarding public health for water companies of any size.
Savings at the Pump
Many small water companies rely on well systems. If a well is pumping fewer gallons per minute, yet using more electricity, it may be time to look at the well itself. Is it straining to pump because its well screen is clogged?
The Borough of Madison, New Jersey, was about to consider re-drilling its 1955 well at an approximate cost of one million-plus dollars. Their engineer instead suggested hiring a national firm, Subsurface Technologies (STI), which employs food-grade carbon dioxide (think carbonated beverages) to clear troublesome well bores and screens.
In Madison’s case, after pulling the pump and the packer, the well was developed with AquaFreed, the company’s patented carbon-dioxide technique, and then reset. The borough not only avoided the million-dollar debt expense but spent instead thirty-eight thousand dollars. It also achieved a pumping delivery of twelve hundred gpm (gallons per minute), up from five hundred gpm, with a pumping level fifteen feet above the top of the pump, producing one hundred gpm more than when the well was first drilled seventy years ago.
In addition, Madison projects an annual electric-bill savings of eight thousand dollars per year and calculates that 3.6 tons of carbon dioxide, or about eighty-five percent of the carbon dioxide used, was sequestered in the ground at that well site, boosting the town’s sustainability and greenhouse gas emissions-reduction goals.
Because its well performance was deteriorating, Ringwood, New Jersey, was spending one hundred ninety thousand dollars annually purchasing water from another purveyor. In 2011, this borough also employed Subsurface Technology’s AquaFreed treatment for its well and not only achieved pumping efficiency and energy savings but reduced its reliance on purchasing water by one hundred seventy-six thousand dollars annually. After treatment, Ringwood followed up with the STI’s AquaGard, to maintain improved well production.
For those water systems that rely on reservoirs, floating solar can serve a dual purpose to the water source by not only producing power to directly reduce the plant’s electricity costs but shelters the water from the sun’s heat, impeding evaporation and discouraging Canada geese from nesting.
Non-Revenue Water
Among the fifty-two thousand water utilities nationwide, about thirty-two percent of treated drinking water is lost to leaks from the treatment plant to the home or business. Letting leaks go undetected wastes not only the commodity but the chemical and other plant treatment costs.
Acoustical testing such as that of Mueller’s Echologics that attaches to a fire hydrant can “listen” for leaks in a system, thus avoiding breaks and perhaps judging the efficacy of pipes that may not need to be wholly replaced.
New Jersey American Water has saved billions of kilowatt hours in electricity charges and preserved dollars in capital costs by targeting its pipe maintenance and replacement by working with this particular acoustic testing method.
Advanced metering can complete the leak detection picture at the customer service line level without adding more sensors. It’s a matter of determining if permanent or periodic detection is required, and what is required at the main or customer locations and connections. In all cases, pipe materials can drive a difference in methodology.
Wastewater Savings
In heavy rainstorms, communities with combined sewer systems of stormwater and wastewater can become overwhelmed by sheer volumes of water, particularly if there are blockages or “fatbergs” (congealed fats, oils, grease and debris, or those flushable wipes (that really aren’t flushable). Called combined-sewer overflows (CSOs), stormwater inundation can cause untreated waste to be discharged into streets or overpower a treatment plant with inflow, creating a public-health hazard.
Satellite-based SmartCover, a device that attaches to a manhole cover, provides remote monitoring and controls for sewer, lift stations, and stormwater infrastructure helping eliminate those CSOs. For all wastewater systems it can optimize collection system cleaning, minimize hydrogen sulfide orders, accurately identify inflow and infiltration, and efficiently operate pump stations. This technology is particularly effective in major storm events as power outages do not affect its satellite communications capability.
Wastewater treatment is even more intensive than drinking water treatment. If anaerobic digestion is used to treat sludge, it can create an energy-savings opportunity as the process-produced methane can be captured and made useful in running plant equipment and heating the digester.
There is also potential to “island” a plant during storm-related power outages and to possibly inject methane into the gas pipeline. There is an ancillary potential moneymaking opportunity to sell dewatered waste as a farming nutrient.
We’re certain there are even more creative operational and capital savings opportunities for water and wastewater. Please share them with us and NARUC’s Committee on Water so that we may share and inform others.
