Sharon Nall
Energy takes up a large share of clean-water plant operating costs. Operators in New Hampshire are finding ways to drive energy costs down, with help from the state government and utility incentive program.
The program is led by the New Hampshire Department of Environmental Services in partnership with NHSaves, a collaboration of the state’s electric and gas utilities that provides customers with information, incentives and support to save energy, reduce costs and protect the environment.
In four years since inception, the program has benchmarked electricity usage at 69 municipal wastewater treatment plants; conducted nine educational workshops for water and wastewater system owners, operators, managers and engineers; performed 35 comprehensive energy audits of wastewater treatment plants; and performed 11 comprehensive energy audits of drinking water facilities.
Leading the program for the New Hampshire Department of Environmental Services is Sharon Nall, P.E., supervisor of the Planning, Protection and Assistance Section within the Wastewater Engineering Bureau. Nall, who also chairs the New England Water Environment Association Energy Committee, talked about the energy audit program in an interview with Treatment Plant Operator.
TPO: How would you describe your responsibilities?
Nall: I handle all things sustainability for wastewater. That includes energy efficiency, asset management and climate resiliency, which encompasses flood resiliency, flood vulnerability assessments and power resiliency related to increased storm intensity with climate change.
TPO: What was the genesis of the energy audit program for clean-water plants?
Nall: In 2015, we received a grant from the U.S. Department of Energy to help our municipal wastewater treatment plants become more energy efficient. Before that, we had written a first-in-the-nation right-sizing requirement into our design standards for wastewater facilities, mainly for blowers and pumps. The bulk of the grant went toward process-level energy audits at treatment plants. The DOE money is gone now, but because the program was successful, we’ve continued to support the audit through our Clean Water State Revolving Fund.
TPO: How does energy usage typically break down at treatment plants?
Nall: Typically, about 5% to 20% of the energy goes to lighting, building systems and HVAC. The rest of it is about process. We’re finding it’s really important for every plant to have an energy audit.
TPO: How do you decide which treatment plants to audit?
Nall: The primary driver for who gets selected is level of interest. If you tell them they are getting an audit and they’re really not interested in doing it, they are not likely to implement what the audit finds. At the plants we work with, we like to develop champions. Then we work with those champions, document their experiences and their savings, and use those successes to pull more people into the program.
TPO: Do you help streamline the audit process for the operators?
Nall: Yes. I have done all the paperwork for the communities, so all they have to do is call and say, “We are interested,” and I put them on the list.
TPO: How does your department interact with the utilities and NHSaves?
Nall: Plants could contact their electric utility, which would pay for an audit. But if they come to us for alternative funding, that saves the utilities money that they can use to pay incentives. That means they can possibly do more aggregating of projects and include some longer-payback items they otherwise wouldn’t be able to include and incentivize. The utilities are our partners. With every audit we hold a wrap-up meeting with the utility, community leaders and finance people, and the operators. We go through the audit and discuss how to move the projects out of the report and into reality.
TPO: Is there recognition for top-performing plants in energy efficiency?
Nall: We did our first energy efficiency awards last year. An intern developed an amazing benchmarking tool that we use. I was able to pair energy data with millions of gallons treated and pounds of BOD removed. So we had a most efficient plant based on flow, a most efficient plant based on BOD removal, and four most improved plants — two lagoon and two nonlagoon plants.
TPO: Can you describe the accomplishments of one of these award winners as an example of what is possible?
Nall: Somersworth was our most efficient based on BOD removal. Jamie Wood is the superintendent, and he and his staff have done it through energy awareness. It’s a 30-plus-year-old plant and a really good example of what you can do if you just pay attention to energy. Wood put signs up on every door that ask, “Did you shut the lights off?” He monitors dissolved oxygen very closely. A lot of plants have a low DO alarm; he has a high DO alarm, so if DO gets up to a certain level, they get an alarm and can turn the blowers down. It’s really just a matter of stepping back and saying, “We’ve been doing it this way for 20 years, but do we need to?”
TPO: What are some of the most common opportunities the energy audits turn up?
Nall: Right-sizing of equipment is one: Blowers and pumps are frequently oversized. At communities that converted from lagoons to entirely new plants, there’s a need to optimize the operation. Energy-efficient equipment may have been put in, but are the setpoints optimal? Until you open the cabinets and take measurements, you can’t really tell where the energy is going, unless they have accurate kilowatt meters.
DO control is a big item; blowers are typically the largest energy user. Pump systems are probably No. 2. One you might not think of is generator block heaters. They range from 1,000 to 4,000 watts. If the block heater has a thermostat, frequently it has failed. If that device is running 24/7/365, that’s a lot of energy use.
TPO: Do you see a great deal of diversity in the sources of energy efficiency?
Nall: We audited three small, very simple lagoon systems. One was overaerating, not monitoring the DO levels. The next one did not have variable-frequency drives on their pumps, and they were using a valve to throttle the pumps back. The third one had an uninsulated chemical storage building, and they were using an electric heater to keep the chlorine from freezing. So even though they were very similar plants, the solutions for energy savings were very different.
TPO: Is lighting a significant source of savings?
Nall: That largely depends on hours of usage. One cultural shift we see is with security lighting. It has been found that having a facility dark at night unless there is movement is more secure than having everything lit up. That way a police officer driving by who sees the lights on says, “That place is supposed to be dark. What’s going on over there?” That’s a total change in thought process. Those big outdoor lights do eat up a lot of energy.
TPO: Beyond the audits, what is your department doing to help plants become more energy efficient?
Nall: Through the DOE grant, we have done continuing education workshops. Operators like to hear from other operators. Peer-to-peer learning is critical. We’ve done two series of workshops in different regions of the state. We’ve held them at a few plants that have good training rooms. In other communities, we’ve held them at a restaurant. As part of every workshop, we’ve had a plant tour. One-on-one education is also really helpful. It’s time consuming, but it works well as a follow-up to group training.
TPO: Do you see any ancillary benefits as plants become more energy efficient?
Nall: One operator told us, “My effluent is better. I’m saving energy by being more efficient, and my effluent quality improved.” We see that more and more because they get better control over their process when they tighten things down to control energy use. The bugs react to better control.
TPO: How would you summarize the results of your energy initiatives to date?
Nall: On the 35 audits completed, we have averaged about 29% potential energy savings and a three-year payback. On top of that, we have the utility incentives. In addition, through our revolving loan program, for energy projects identified in an audit, we have 50% principal forgiveness up to $200,000. So that makes the payback even shorter.
TPO: Is there a role for renewable energy in your program?
Nall: As energy projects are implemented, we encourage communities to apply the savings to renewable energy projects. In that way, they cement the savings. The most cost-effective way to save on energy is through energy efficiency. It’s the cheapest, and the payback is the quickest. So we’re trying to go with efficiency first and then go with renewables.
TPO: What kind of mindset does it take to maximize savings?
Nall: The auditor we use is really good at working with operators, finding their comfort zone and pushing them out of it just a little bit. It’s about being willing to tweak the process and get out of the box of how you’ve been operating for the last 20 or 30 years.
Excellence in efficiency
The New Hampshire Department of Environmental Services in cooperation with NHSaves last year issued its first Wastewater Treatment Plant Energy Efficiency awards. Winners are:
• Overall most energy efficient based on flow: Winnipesaukee River Basin Program, Franklin, with energy use of 853 kWh per million gallons treated, versus national benchmarks of 1,200 to 2,400 kWh per million gallons.
• Overall most energy efficient based on pollutant loading: Somersworth, with energy use of 0.62 kWh per pound of BOD removed, versus national benchmarks of 0.7 to 2.2 kWh per pound of BOD.
• Most improved based on flow: Pittsfield, 63% reduction in kWh per million gallons (2012-18); and North Conway Water Precinct, 44% reduction (2012-18).
• Most improved based on pollutant loading: Troy, 56% reduction in kWh per pound of BOD removed (2015-18); and Epping, 48% reduction (2012-18).
