|
Experts offer tips for reducing water agency energy costs and consumption.
By David Engle
The nation’s 60,000 drinking water and 15,000 wastewater systems consume an estimated 3% of all electricity usage—and the figure is steadily rising. Pumping water does take power, and, in some locales, this soaks up so many kilowatt-hours that the grid can’t take much more of it.
A worst-case scenario is probably southern California. According to a recent study by the California Energy Commission (CEC), turning on a water faucet there for just five minutes takes the same energy as burning a 60-watt light bulb for 14 hours. Even though, in northern California there may be little energy embedded in the water, statewide, an astounding 20% of all energy expended is devoted exclusively to moving or treating water—with about 8% of that occurring at the end-user site (i.e., for warming the water or for pool pumps, etc.).
Nationally, the energy figure for water is estimated at about 3%, but, the trend is definitely getting higher, and needs to be controlled. For one thing, a troubling feedback relationship has been found, in that water and energy usage actually exacerbate each other. Scientists at Sandia National Labs began to notice this cycle a few years ago.
Mike Hightower, a distinguished member of the Sandia technical staff, explains that, as water resources are depleted, water-strapped regions must transport lower-quality water across ever-longer distances, extracting it from deeper wells and treating it more intensively. Desalination, nanofiltration, reverse osmosis, ozonation, and ultraviolet disinfection all sap ever more energy, he notes. In turn, more power plants are needed to drive this—and, unfortunately, the power industry is also a thirsty water-user, second only to farming, as plants make steam and cool reactors.
Consequently, California’s extraordinary energy-to-water ratio could soon become more commonplace throughout the country. Increased energy dependency and costs are already being felt by water and sewer agencies, both as larger electrical loads to bear, and in higher per-kilowatt rates. A decade ago, water department energy costs were a fraction of total budgets typically measured in the low single digits, but, a 2003 survey by the American Water Works Association Research Foundation (AWWARF) found that a figure of 10% or more, of a waterworks’ operating budgets spent for energy, is increasingly common. In a few cases, the figure is as high as 35%.
Hightower adds: “A number of water utilities have told me that energy is now their biggest cost driver,” even as they draw-up plans to build more energy-intensive treatment systems.
Lon House, a consultant to the California Energy Commission and special contractor for the Association of California Water Agencies (ACWA), is a consultant and researcher who produced several of the CEC statistics, cited above. House, like Hightower, also predicts that “water agencies’ demand for electricity could more than double during the next decade” in his state, i.e., increasing by 3,500 MW—equivalent to building 10 new power plants. House’s consulting firm, Energy Efficiency Analysts International, is working through ACWA to provide energy-saving consultation for state water agencies trying to get a handle on cost-control.
Perhaps more than ever, conservation is needed of both water and energy, along with new power generation at water pumping or wastewater treatment sites. As the following survey shows, pro-active strategies, ranging from buying new pumps, to investing in energy-smart systems and in solar and methane-conversion, are all increasingly viable.
Below, are seven ways to take better control of one’s electric power consumption and expenditures.
1) Determine Energy Efficiency
A new benchmarking tool recently put on the Web, can now provide any water department an easy snapshot on how its current energy measures up (efficiency-wise), source by source, as compared with other agencies. Ted Jones, a senior program manager of the Consortium for Energy Efficiency (www.cee1.org), explains how it works. “Seven confidential parameters” are first input, such as an agency’s energy bills and its flow volumes, he says. “This yields a ratio, so you know how much energy you use per million or per thousand gallons of water treated.”
A database stores the info of several dozen agencies, enabling comparisons. Your own efficiency score—an “energy intensity” index number from one to 100—indicates how close or divergent your agency stands vis-à-vis the norms. This provides, then, “a good starting-point for measuring your performance going forward” as you begin to apply efficiency improvements.
A water department that uses relatively more power to move equivalent water volumes might be able to cite this index as good evidence of the need for infrastructure investment or other agency changes. “Benchmarks are a powerful way to get the attention of senior municipal managers, and to win support for energy improvements,” Jones observes. Development of the tool was principally done by the AWWARF for the CEC, and began in 2003. In late 2007, the US Department of Energy added this feature to its Web site (www.energystar.gov), reports AWWARF’s Linda Reekie. One can access it, by navigating to “buildings and plants,” selecting “portfolio manager login,” and then creating an account.
2) Optimize Pump Efficiency
According to AWWARF findings, nearly all power at water agencies is consumed by its pumps: about 85% for distribution, and another 9% to move the untreated water to the plant. So, the best payback on an energy investment will typically come in pump optimization. Fortunately, funding to help pay for new or refurbished equipment is fairly abundant: CEE has identified 47 or 48 such assistance programs, as Jones notes, and gladly assists agencies in finding and qualifying for them. CEE also participates in determining the technical standards for motors, drives, and related technologies. Thus, CEE can serve as a good resource for accurate technical info.
One of the oldest, and most extensive such support efforts, is Southern California Edison’s (SCE) free testing and evaluation service, “mainly of well and booster pumps,” notes William O'Neil, a technical specialist with SCE’s Hydraulic/Industrial Services. SCE’s service dates back to 1911, but, lately—as the dimensions of California’s energy burden have exploded—the electric utility and CEC have begun boosting the assistance materially by pouring in about $58 million to subsidize customer equipment upgrades. Funding will be extended indefinitely in three-year cycles. O’Neill’s department is now on an all-out push to expand coverage, “shooting to test about 4,600 pumps every year,” he says.
The test measures a pump’s overall efficiency ratio of how much power is needed to move a quantity of water; a “report card” to the owner then follows. The recipient learns what is being spent presently to power each pump; what a pump’s comparative efficiency rating is; and how much would be saved by upgrading. SCE then offers 8 cents per kilowatt-hour of projected power savings, either for renovation or replacement. Thus, an inefficient 500-horsepower pump running most of the time, if upgraded to a premium model, might recoup several hundred thousand kilowatt-hours a year. One recently completed evaluation for the Upland, CA (pop. 75,000) water department, earned the agency $142,000 in new pump payouts. The year after doing installations, Upland and SCE reaped over 1.75 million kWh in power savings valued at $150,000, or 10% of the agency’s billed usage. This magnitude will, of course, recur indefinitely.
Newhall County Water District (8 wells, 15 booster stations, 155 miles of pipeline, and 9,000 service connections) in Santa Clarita Valley, CA, earned $100,000 up-front, to pay for a control and data acquisition system, and then received another $17,000 to enable a demand-bidding program. These measures did not involve pump efficiency per se, but, resulted in shifting activity to off-peak hours; thus the agency and the power system saved on peaking energy; Newhall thus avoided having to raise ratepayers’ fees.
CEC advisor Lon House adds that independent testing and evaluation of the sort offered by SCE and others, “is important, because, [otherwise] … the pump suppliers do the testing”—thereby rendering results unreliable, due to a vested interest in servicing or installing new equipment, he says. House also reports that in December 2007, the CEC approved a similar program to support pumps fueled by natural gas.
3) Tighten Operation Efficiency
AWWARF has published helpful reports outlining an array of operational strategies, under the heading “Best Practices for Energy Management,” at water agencies. Report contents cover topics such as: better energy and usage forecasting; market-based utility pricing; load shifting in order to buy power when prices are lowest; working with electric and gas companies to ensure getting the most beneficial rate structure; aggregating metered loads for billing; optimizing pump schedules; and diversification of energy sources.
In approaching the concept of best energy-management practices, says AWWARF’s Reekie, the foundation borrowed heavily from electric utilities’ examples, under research by the Electric Power Research Institute (EPRI). Water agencies can, “learn from other utilities what they have already implemented, and what processes that an agency might need to go through,” in their efforts to lower energy costs and reduce operations and maintenance budgets. The electric utilities developed efficiency optimization software; similar principles can carry-over to the water industry, she says, “for meeting drinking water regulations, and, at same time, conserving energy use.”
The resulting AWWARF report, titled, “The Energy and Water Quality Management System,” offers a guide to systems management software development, “to determine return on investments, testing, calibration, and daily operation of an energy optimization system,” she adds.
Other reports available to AWWARF subscribers or by purchase from AWWA include: “Water Consumption Forecasting to Improve Energy Efficiency of Pumping Operations,” “Avoided Cost Model and a Benefit-Cost WUE [water use efficiency] Planning Model,” “Energy Audit Manual for Water/Wastewater Facilities,” and “Development of a Utility Energy Index to Assist in Benchmarking of Energy Management for Water and Wastewater Utilities.”
Another energy-and-water consultancy, EMA Services of St. Paul, MN, is using AWWARF’s energy data to help water utilities agencies “plan ahead efficiently, based upon historical data and weather data,” in order to respond more effectively “to sudden power cost increases,” notes EMA’s Thomas A. Kerestes. Electricity rate increases not uncommonly reach six or seven figures, and pack a significant, and sometimes unplanned-for, budgetary hit. Historically, water departments have tended to simply sit back passively “assuming that they have to accept what is there,” he says.
In fact, though, there are things they can do, such as aggregating billing of several sites, negotiating better rates, seeking to purchase power on the deregulated open market, and making assorted organizational, process, and technology changes. In 2003, Kerestes co-authored an interactive CD, sold through AWWA, on best practices and methods for reducing energy costs at water departments. During the past two years, EMA has begun offering a package of strategies, implemented, so far, for about a dozen water utilities nationally, saving them millions of energy dollars cumulatively, he says.
4) Pump During Off-Peak Times
In the many US markets, where hourly electricity rates vary, water departments can shift pumping operations from the peak-rate times (noon to 6 p.m.) to off-peak hours, and gain significant savings (in the case of Newhall County). For example, if demand allows it, water reservoirs might be refilled only at night, letting pumps stay idle during the noon-to-evening peak.
At SCE, House describes a pilot program now just getting underway, to bring this time shifting down to the ratepayer level. Thousands of water users in Palm Desert, CA, will soon be equipped with sophisticated time-of-use water metering and billed with variable time-sensitive water rates. Turning on a spigot to water the lawn, washing the family car, or refilling the backyard pool during midday, will soon be costing much more than doing so after sundown. If ratepayers respond to this incentive as hoped, by shifting their use to off-peak times, the program would expand and likely become permanent. SCE estimates that a shift of just one-quarter of the daily flow to off-peak hours would save nearly 40 MW in daily power in its market (four million accounts) alone. Statewide, shifting half the peak usage to off-peak times would slash an impressive 300 MW of electrical load—the equivalent of several expensive, peaking power plants.
House points out, too, that, “The water agency is also eager to use these meters for leak detection. If water is flowing unexpectedly somewhere at 2 a.m., they’ll know they have a leak”—correction of which is another key element in the best-practices challenge.
5) Evaluate Capital Projects
If user demand requires that reservoirs must refilled day and night, an agency might wish to consider adding more reservoirs, or other storage capacity, House suggests. Although costly and needing a long-term payback, they will save enough peak demand, eventually, to justify the investment. “Water storage at elevation is, essentially, stored electricity,” House says.
As a parade example of success, he cites the El Dorado County Irrigation District in northern California. In 2005, the agency expanded its storage capacity and time-shifted its pump operations to the early hours. Daytime water levels were allowed to drop without doing refilling, to eliminate any peak-rate pumping. The result: Over 1 MW of demand was shifted. Multiplying this over the entire nation would undoubtedly yield several gigawatts of peak demand conservation, and save agencies cumulatively many billions of dollars in annual power costs. Similarly, House says, a new water tank or pond can be sited closer to urban load centers, to save on electricity transmission costs.
Likewise, the designers of new plants should spare no expense to optimize energy-efficient layouts, suggests Gary Klein, a CEC energy specialist (who, in early 2008, left the agency to form www.Aim4sustainability.com). To optimize future plants for piping, plumb lines should be “straight and smooth, not with right angle bends,” Klein says. “That makes a big difference.” As for pipes, to water storage sites, he advises that they be specified in larger diameters. Although this bumps up the cost a bit, “the friction loss drops dramatically,” saving money on the pumping operations.
Hightower also envisions a kind of power-and-energy plant convergence. A day may come when the placement of water, wastewater treatment, and power-generation sites will be in close proximity, in order to allow recycled wastewater to be used as cooling water, or for steam production in the power station.
House points out that, in California, “new electrical generation facilities are essentially prohibited from using fresh water” already, and may only use recycled or brackish water for cooling and steam. In turn, the water departments will enjoy the benefit of a huge supply of electricity close by, made cheaply, and available at lowest possible rates if used only at night, without transmission costs.
Elsewhere, adds Hightower, future plants will also strive for energy efficiency gains—either by enlarging some water and treatment operations to improve economies of scale—or, going the opposite way, by decentralization, with “smaller treatment facilities, more local, such that they can distribute water more easily, so that it doesn't take as much energy to pump.”
Diffusing and decentralizing water storage in these ways, House adds, will also reap benefits, such as improved fire-fighting and disaster assistance; more flexible system operation; and perhaps improved security. The storage capacity-boosting strategy would apply to water and wastewater treatment alike, he says. New plants should include “surplus treatment bays, to enable doing energy-intensive ozone and UV treatment off-peak,” allowing these energy-intensive processes to be idled during peak hours. At many agencies, the needed land for storage is probably already set aside. Alas, as he notes, present utility rate-setting policies don’t yet incentivize such desirable improvements. Wherever funding mechanisms are inadequate, a water utility should, he suggests, “challenge the electric utility to help pay for” high-efficiency measures tailored to water departments, of the sort that are already routinely provided to building owners.
Electric companies are accustomed to spending large sums on retrofit lighting, air handlers, and air conditioners, for relatively modest benefits, compared to the sums that could be saved by lowering the cost of pumping water, or by permanently lowering water-users peak demand. “Water mangers really need to go to the electric utility and push them to pay for comparable investments in water systems is in other industries,” House advises.
Electric rates must also be made more stable and predictable, to enable a water agency to invest in long-range plant energy efficiency improvements that may need five-plus years to pay back with lower bills.
6) Add Onsite Power Generation
The “hot” energy item these days is, of course, solar. Sun power and water department demand dovetail unusually well, on several points.
First, the high capital cost of solar—which would be prohibitive for many corporate balance sheets—proves more palatable at a public agency. Second, land and rooftop space are typically available at a water works. Third, power needs are constant and growing. Fourth, the idea of long-term fixed costs suits water department financing structures. Fifth, water agencies are accustomed to very long-term payback horizons. Sixth, operationally speaking, solar panels yield power during peak hours and in summer—coinciding with highest water demand (and offsetting highest utility rates). Seventh, minimizing operational challenges, solar systems often carry 20-30-year warranties and design lives, and generally enjoys a good reputation for reliability.
Globally, solar has been growing at 30%-40% for several years, reports Gary Barsley, director of projects at SolarWorld Industries (a firm formerly owned by ARCO, Siemens, and Shell, and now the largest manufacturer of solar photovoltaic modules in North America). At water districts, he reports, installations have been booming, “as a means of locking-in prices against escalating costs.” Dozens of water-district projects have been installed in just the last couple of years in Barsley’s California market, including the El Dorado Irrigation District (1 MW, 2006); Cucamonga Valley Water District (one-third MW, 2006); Semitropic Water Irrigation District near Bakersfield (1 MW, 2005); Desert Water Agency (300 kW, 2005), and Elsinore Valley Municipal Water District (765 kW, 2005; for more on EVMWD and DWA, see sidebar).
Until 2005, the notoriously high cost of solar had been steadily declining 6%–8% annually, even as the panels’ electrical performance was doubling, notes Barsley. However, a global silicon shortage has lately caused a huge price upswing. Markets should return to previous levels in about two years, he believes. Wind power has also made a modest debut lately for water agencies in Northbrook, IL, and at the Washington (DC) Suburban Sanitary Commission (WSSC). With the help of Constellation Energy Group, WSSC entered into a 10-year power purchase agreement (PPA) for 70,000 MWh per year for a wind farm in Pennsylvania, making the water agency one of the largest local government users of wind power anywhere. Besides reaping the benefits of clean renewable energy, WSSC will save about $20 million on its power costs. (WSSC project profile, “Water, Thanks to Wind” in Water Efficiency, March 2008 issue.)
For several years, the village of Northbrook, IL (pop. 34,000) has been buying 155 MWh per year of wind power, and recently announced an intention to acquire more. Using renewable Energy Credits, Northbrook will buy another 4,500 MWh/year, sufficient to run a water treatment plant. As director of public works Jim Reynolds reported to AWWA, the agency’s electric bill will go up about $1.65 more per kilowatt-hour, which may necessitate a rate increase. Neither of these wind-power aided agencies will own the generation resources, however, as, increasingly, third-party power developers are lining up to make deals that relieve water agencies of the risks and burdens. This is true, both of wind, and of solar power. In a typical arrangement, the water department provides physical space for the siting of a power plant, and signs a contract to purchase the output (typically, for a decade or more) at a pre-set price. Such arrangements, PPAs, have became even more attractive and viable since 2006, when a 30% federal-accelerated depreciation tax credit on renewable energy took effect, notes Edward Orrett Facility Power Inc, of Marina del Rey, CA.
Tax credits are only usable, of course, by for-profit firms. Thus, more third-party solar plants are being built these days, Barsley says. “We're seeing 15-to-20-year PPAs, where the host of the system [i.e., the public agency] is paying a contract kilowatt-hour rate for what the solar power system generates, versus paying the capital cost for it,” he adds. Shorter-term PPAs are also available, “but, you will pay higher, or make up the difference in some other way,” Barsley continues. PPA deals can also be structured as a lease-with-buyout option after 10 or 20 years, these being more common. A water agency can thus acquire solar power, without any up-front capital or operational expense for 10 years.
At wastewater plants, House adds, biogas energy conversion represents another “huge” opportunity for onsite generation. “Water agencies can capture the methane (natural gas) generated by the wastewater digestor beds, and use it to produce electricity via internal combustion generators, micro turbines, or, increasingly, fuel cells,” he says. “This is, basically, free energy—a very proven technology. And the payback period is quite attractive. Additionally, in the era of greenhouse gas issues, adding wastewater [biogas] generation is not only economically attractive, but, it significantly reduces the water agency’s carbon footprint.”
The above list hardly exhausts the possibilities, nor are they sources of good ideas, which are sometimes unique to a given market. Other avenues one should tap for model approaches, include state energy departments and utility commissions; the EPA; makers of generating resources; and organizations like the Alliance for Water Efficiency (www.a4we.org), Wateruse.org, the American Society of Civil Engineers’ Environmental Water Resources Institute, and university engineering departments. In a comprehensive survey of the topic, other dimensions should be addressed, which were not discussed here, such as increasing cooperativeness between utilities, regulatory reforms, changing public policy to develop new funding streams, roles for regional planning commissions, staff re-training, management structure, information systems, and raising community involvement. Although the energy-and-water challenges are significant, workable strategies abound.
Writer David Engle specializes in construction-related topics. Thanks to Lon House, Ph.D., certified energy manager (www.waterandenergyconsulting.com) for technical review.
WE Elements 2009
|
