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In Search of Savings
How Some Treatment Plants Are Cutting Energy Use
By Emma Downs, NEIWPCC/UMass Amherst
With energy costs rising, budget pressures mounting at all levels of government, and climate change becoming ever more apparent, municipalities have no shortage of reasons to lower energy use and reduce their carbon footprint in the process. Statistics show that water and wastewater treatment are good places to start. The more than 60,000 water and 15,000 wastewater systems in the United States account for 35 percent of municipal energy usage and as much as 3 percent of the energy used nationwide. Furthermore, energy usage makes up 25 to 30 percent of the budget of the typical water or wastewater plant, with that figure expected to grow by 20 percent over the next 15 years. Reverse that trend and lower energy use, and the result is less money out the municipal door for energy and less demand for electricity, the bulk of which is still created by greenhouse gas emitting methods.
The rewards of energy reduction are driving increased interest in it, and spawning innovative programs. Massachusetts, for example, recently launched a pilot program to dramatically improve energy efficiency at more than a dozen of the state’s wastewater and drinking water plants.
“We don’t have all the answers, but we are looking for them,” said Mike DiBara, a project manager for the Massachusetts Department of Environmental Protection and the manager of the pilot program. “We need to work to make operations more energy efficient.”
Massachusetts is hardly alone in the pursuit of energy efficiency in the water arena. Progress toward that goal is being made in the region on many fronts and by many different players.
Start Simple
When people think of energy reduction strategies, the first thing they think of these days is often alternative energy. It is a hot topic, and so it should be. But the experts say do not overlook the value of simple conservation.
“Solar and wind power are sexy, but conservation is easier to implement and often more cost-effective,” said Denise Breiteneicher, project manager of technical services at the Massachusetts Water Resources Authority (MWRA), the largest customer of National Grid. The MWRA operates the Deer Island wastewater treatment plant, the second largest such facility in the country and a leader in energy conservation programs.
A large portion of the energy savings projects that have been done or are in progress in New England are simple conservation projects. “If you haven’t made your plant efficient already, spending on alternative energy to run an inefficient plant wastes everyone’s money,” said Jason Turgeon, an environmental scientist at EPA Region 1 (New England) who works with drinking water and wastewater utilities on ways to reduce energy use.
Lighting and HVAC (heating, ventilating, and air conditioning) are the first areas a plant will typically explore when looking to conserve energy, because the changes can be simple to implement and make a significant difference. At the Lowell Regional Wastewater Utility, lighting was one of the first steps in their savings program. “To save electricity we have all the lights in our tunnels on motion sensors,” said the plant’s executive director Mark Young in an interview at the Lowell facility. “I would estimate that from that alone we’ve saved $20,000 to $25,000 a year.”
The MWRA has followed a similar strategy at its office buildings and pumping stations. “Lighting is the low hanging fruit of energy conservation,” Breiteneicher said. “We can get lighting changes done quickly and the energy companies give rebates. We used to have high pressure sodium lights, but we are changing over to energy efficient lighting.”
The time it takes to recoup the original investment in an energy reduction project and start saving is known as the payback, and the MWRA is estimating the payback on its lighting project will be just one year. “After that, we should start saving around $50,000 a year,” Breiteneicher said.
Strategic Investments
One key to saving energy and money is being aware of where the most energy is being used.
“Once plants see that energy is the biggest cost in their operation budget, they start taking a closer look at the biggest users in the process,” MA DEP’s DiBara said.
By identifying the areas in a plant that account for considerable energy usage, it is possible to determine potential areas of conservation and where energy is being used inefficiently. But how to find the big users? One way is through an energy audit. Many electric and gas utilities offer them for free, and they can result in valuable recommendations on how a plant can conserve energy. While it may seem counterproductive for utilities to help plants lower electrical costs, it is actually a growing trend.
“There is a lot of interest from states and utilities who want to better serve water and wastewater plants, especially on the coasts,” said Sharon Jones, an engineer and president of Lexicon Energy Consulting. “It isn’t as much of a priority in the middle of the country, but there is a lot going on on the coasts. Plants are a different type of customer. They’re going to be there forever.”
EPA Region 1 has also been playing a big role by developing benchmarking software for treatment plants. “It lets plants keep track of energy use and carbon footprint, and see their energy use change over time,” said Turgeon, who has been giving classes on the new tool to operators all over New England.
In a typical wastewater treatment plant, blowers and pumping account for 65 percent of all energy usage. Efficiency upgrades in these areas alone can have a huge effect on costs, and there are fairly straightforward ways to make improvements. One of the most popular tools for saving energy is the variable frequency drive. A VFD is a controller that adjusts the speed of an electric motor. The device controls the frequency of the current to increase or decrease the speed of the motor depending on the flow volume entering the plant. This enables pumps to accommodate fluctuating demand, rather than running at a constant and sometimes unnecessary level. VFDs also reduce mechanical and electric stress on motor systems, reducing maintenance and repair costs. With their ability to save energy and money, and save equipment, VFDs make sense for many plants.
“The MWRA has VFDs installed in five pump stations, partly for operational reasons,” Breiteneicher said. “But what got them approved was that they saved money on [electrical] demand charges. It was hard selling the idea to management from an operations standpoint, but when the money came in, it became easier. With demand charges going up and up, VFDs are a really good thing. Operationally they are a good thing too, of course, but the two together make it easier to sell.”
Another measure that lowers the energy used by blowers and pumps is the installation of energy efficient motors. While the initial cost of an efficient motor is higher than a standard motor, the savings on energy usually offset the higher capital cost in two years or less. This has led a number of wastewater facilities, including the plant in Lowell, to abandon the traditional practice of sending old motors out for rewinding. They have discovered it is more cost-effective to supplant old motors with energy efficient ones. “Anytime a motor needs to be replaced, we try to get the most efficient one we can,” Young said.
The Lowell plant has also switched to energy efficient fine bubble blowers in their aeration system. The result of their work towards efficiency: significant savings, without even getting into alternative energy. “In the late 1990s we were using 10 million kilowatt-hours per year, and we are under seven million now, despite the fact that flows have gone up,” Young said.
Then there are ways to save energy that do not even involve equipment changes. Running at times when the grid is less busy can save on demand charges. And for plants with very high usage, electric utilities offer a deal for them to go off the grid onto generator power at times of high demand to avoid blackouts. Lowell has such a deal with EnerNOC, a third party demand response company. “They pay us to be part of this program, even if we never have to do it,” Young said. “And if we do, they pay us by the kilowatt-hour. We’ve done it twice.”
Sometimes energy saving methods can be a bit outside the box. At the Lowell facility, for example, the plan is to put green roofs on all the plant’s buildings. New seals will be installed on the roofs before they are covered in soil and planted with vegetation. Mark Young detailed the benefits. “The plants absorb water and prevent water runoff into sewers,” he said. “Also, these roofs last 20 to 30 years and are great insulators, saving heat in the winter and AC in the summer.”
Consider the Alternatives
For plants looking to go beyond conservation, the next logical step is to explore alternative energy. Many plants in New England already have wind or solar power projects in the works. Though wind turbines were once decried as eyesores, with rising energy prices aesthetics are no longer as large a factor. A huge victory for wind power came in April when the MWRA received approval for the installation of two 190-foot turbines at the treatment facility on Deer Island. The original plan was to build five 394-foot turbines, but this was vetoed by the Federal Aviation Administration due to the island’s proximity to Logan Airport. The FAA did approve the two shorter turbines, which will be the same height as Deer Island’s egg-shaped digesters. In addition, the FAA decided that if there are no problems with the first two turbines, the MWRA can build the other three at reduced height at a later date. The proposed turbines will generate enough electricity to save $106,000 a year in energy costs. The MWRA has a short list of five or six other treatment plants and pump stations where wind turbines may also be installed, according to Denise Breiteneicher.
Solar power is a less controversial and less obtrusive form of alternative energy that is also becoming more common for wastewater utilities. In March, the MWRA installed a 100 kW photovoltaic system on the roof of Deer Island’s odor control building. The electricity from the system is enough to power 12 homes, and saves the utility over $10,000 a year.
Alternative energy is not just for large plants like Deer Island. Consider the Charlemont Sewer District in Charlemont, Mass. The town’s drinking water plant is rather small, processing 28,000 gallons of water per day. But the plant manager, Dawn Peters, had big ideas.
“I have been here for years,” Peters said. “We have tons of sun, no shade anywhere. I kept thinking, ‘What a total waste. We need to do something with this.’” In 2004 she asked the Commissioners of the Charlemont Sewer District to examine the feasibility of solar power at the plant. They were all for it.
“The Commissioners were wonderful,” Peters said. “The only time they gulped was when they had to sign on the dotted line.” By combining money left in a grant with financial assistance from the Massachusetts Renewable Energy Trust, a state program designed to promote clean energy technologies, the town was able to buy and install a photovoltaic system at the plant in May 2005. While it provides more than half of the plant’s energy needs, payback is scheduled to take a while—17 years to be exact. But that figure can change. “Every time energy costs go up,” Peters said. “Our payback period goes down.”
“Since energy prices have started rising,” EPA’s Turgeon said, “they look like geniuses.”
An often overlooked source of alternative energy for wastewater treatment plants is the enormous power in sludge. Plants use bacteria to digest sludge, and one of the byproducts of the process is methane. Most plants are not using this resource as effectively as they could. It is not glamorous and does not receive the media attention of solar and wind power. But according to Turgeon, “It’s the most bang for your buck.” Deer Island powers 17 percent of its operations with digester gas, an impressive achievement. But at the wastewater treatment plant in Essex Junction, Vt., the percentage is even higher. The village’s plant powers 40 percent of its operations by burning methane from its digesters to create electricity, and using the excess heat to maintain digester temperatures. The system is very efficient, producing more than 400,000 kWh a year.
Meeting the Challenge
Making water and wastewater utilities more energy efficient seems like a no-brainer. The improvements make sense operationally, help the environment, and save money for municipalities and ratepayers. But it is often difficult for plants to find the money for these projects. Sharon Jones of Lexicon Energy Consulting lamented the difficulties in finding funding. “I often see managers and superintendents who are frustrated. They recognize energy is a big part of costs, but feel that there’s nothing they can do,” Jones said. “They are trapped by budget cycles. Unless it can be included in maintenance, what does it take to get money? Something has to break.”
Money for energy efficient lighting or VFDs is not in most plant budgets, so they often must wait until they can get a rebate from a state program or a change becomes necessary. EPA’s Turgeon agreed that budgeting represented a significant obstacle to efficiency projects being implemented. “Management has to get purchasing and operations working together,” he said.
Some states are trying to solve this problem. In 2007 Massachusetts Governor Deval Patrick announced Executive Order 484, also known as “Lead by Example.” The order raised clean energy and efficiency goals for state buildings, including water and wastewater utilities. The order requires that state agencies reduce energy consumption by 35 percent (from 2002 levels) by 2020. It has been a boon to those trying to finance efficiency projects. “It really backed up our arguments for funding,” Breiteneicher said. “We could say we were following the governor’s orders.”
In addition, the Massachusetts Department of Environmental Protection and the state’s Department of Energy Resources have launched a pilot project to help water and wastewater treatment plants improve their energy efficiency. The state agencies are working with 14 water and wastewater treatment facilities as well as energy utilities and other partners. The goals are to reduce energy consumption at the plants by 20 percent and develop a model for using public funding to reduce costs for implementation of energy saving projects. The participating plants get free energy audits, renewable energy assessments, and help in implementing any recommendations. The state estimates that implementation of the changes could reduce annual energy use by the 14 facilities by 18.5 million kWh, resulting in roughly $2.8 million in annual savings. Five of the facilities—Falmouth, Pittsfield, Barnstable, New Bedford, and Lowell—are already moving forward with energy efficiency and renewable projects. When completed, these energy investments are expected to result in over $1.1 million in annual savings and a drop in annual CO2 emissions of approximately 6,700 tons. In the coming months, the other pilot facilities will be evaluating the energy-saving recommendations made for them. MA DEP’s DiBara, who manages the project, said, “We are facilitators, trying to get the right people to the table to achieve results.”
NEIWPCC is also doing its part to help plants become more efficient. In January 2009 we will run a course entitled “Benchmarking Costs and Identifying Energy Savings at Water and Wastewater Treatment Plants.” DiBara will speak about the pilot project, Turgeon will explain EPA’s benchmarking software, and energy industry representatives will address billing issues. NEIWPCC has been offering courses in energy conservation since 2006.
A lot of work is being done to make plants more energy efficient, but with energy costs and climate change concerns likely to continue to rise, the need for progress is growing. Managers and superintendents of plants are becoming more aware of the need for improvement, but many plants have yet to implement the necessary measures. “Plants are coming on board one by one,” Turgeon said. “A few plants are doing well, but it hasn’t reached the flood stage yet, where everyone is working on it. They are starting to think about what to do, but there hasn’t been a ton of action.” Considering the financial and environmental benefits of increased energy efficiency, it is a safe bet that action will be picking up soon.
Emma Downs, a student at the University of Massachusetts Amherst, wrote this article during an internship at NEIWPCC’s Lowell headquarters.
For information on NEIWPCC’s energy savings course on January 13, 2009, in Haverhill, Mass., visit www.neiwpcc.org/training.