Energy Solutions for Rural Alaska Water Systems
Due to extreme cold, challenging topography and limited infrastructure, energy costs to operate and maintain water and sewer systems in rural Alaska are significantly higher than the Lower 48 states.
By CDR. John Nichols, P.E., M.SAME, USPHS, CAPT. Dan Reitz, P.E., USPHS (RET.), and MAJ. Chris Mercer, P.E., CEA, M.SAME, ANG
The Alaska Rural Utility Collaborative (ARUC) is an Alaska Native Tribal Health Consortium program that manages, operates and maintains water and sewer systems in rural Alaska. ARUC treats each community’s system as a standalone non-profit business. Money from local customers must be enough to pay the system’s expenses.
ARUC’s services include helping set water/sewer rates in each community, billing local water customers, providing supervision to local water plant operators, and paying the costs for labor, parts and fuel for each system.
There are a number of advantages to rural communities, including economies of scale and a higher level of support, managerial and technical assistance. The ARUC program provides “strength in numbers,” with 26 communities working together instead of struggling alone. The goal is to protect the public investment by prolonging the life of each water system and by providing safe drinking water every day.
ARUC is working to make each water system as sustainable as possible by installing a number of energy efficiency upgrades—these include recovered heat projects, electrical energy efficiency projects, wind turbines and biomass boilers. As construction work is completed, ARUC will track fuel and electrical savings.
Maintaining data records and actively managing expenses is essential to continuing the benefits of energy efficiency or sanitation projects. ARUC often finds energy projects in non-ARUC communities that are not working near peak efficiency or they have simply been abandoned because their operations are not well understood or well managed.
WATER EXPENSES TIED TO ENERGY
Energy efficiency is especially critical to rural Alaskan water and sewer system sustainability and affordability for local residents. Why? Because energy—primarily heating fuel and electricity—make up nearly 40 percent of ARUC village water and sewer expenses.
Most of the energy efficiency grants for these water and sewer systems come from State of Alaska funding. Traditional federal funding sources are much less interested in energy efficiency for water and sewer systems. The reason is simple: Alaskan water and sewer systems, especially those in northern Alaska, use much more energy than conventional, Lower 48-type systems. It takes a significant amount of energy to keep water liquid at minus 60°F. Water needs to be heated with fuel oil and kept constantly circulated with electric pumps to prevent it from freezing. This makes for high fuel oil and electricity usage that Lower 48 systems simply do not require—hence the limited national interest in water/sewer energy demands.
ARUC communities tend to be in northern Alaska, so they have a high percentage of circulating heated water systems. ARUC sewer systems are nearly evenly split between gravity systems and vacuum/low pressure sewer lines. Gravity sewer systems require less energy, because sewage lines in gravity systems are dry when sewage is not flowing. Vacuum and low pressure sewer lines, however, always have sewage in them, so they need to be heated constantly to keep them from freezing. The sewage also is sucked (vacuum) or pushed (low pressure) by electrical pumps instead of gravity, further increasing energy usage.
ENERGY EFFICIENCY PROJECTS
Rural Alaska communities in ARUC have extremely high energy costs. None of them are on a road system. They are accessible year-round by airplane only, and by barge during a four-month summer season.
Nearly all communities have their own electrical power plants, as they are too far apart for electrical interties. This creates expensive electricity, up to $1/kWh, as most electricity comes from diesel-powered electric generators. Diesel can cost $6/gal to $10/gal in the community, and is transported by barge or airplane.
In diesel electric power plants, roughly one-third of the energy from diesel is converted into electricity with the remaining two-thirds converted to heat. This heat must be transferred elsewhere, or the generators will melt down. Normally, this heat is transferred to the outside air using large radiators and fans, similar to cooling a car engine. That creates an opportunity to “recover” this heat for other purposes, rather than throwing it away. Recovered heat projects use this heat to warm water in community water systems, leading to huge savings of heating fuel and money.
ARUC communities Deering, Goodnews Bay, Kotlik, Toksook Bay and Kiana have begun to implement energy efficiency projects. Although these communities have less than a year of energy savings, they are showing significant improvement. ARUC will order 21,000-gal less heating fuel in 2013 compared to 2012 as a result of efficiency efforts. Similar electrical savings are anticipated as well. And funded recovered heat projects, scheduled for construction in the next year, also will save tens of thousands of gallons of additional fuel annually.
CASE STUDY—DEERING, ALASKA
The recovered heat system in Deering, Alaska was installed years ago in the water treatment plant/washeteria. A washeteria is a laundromat for communities where homes do not have piped water, and is very common in rural Alaska. The recovered heat system was poorly understood. It was not properly controlled and this resulted in back feeding heat to the power plant radiators and so it was therefore shut down.
ARUC received money from the Alaska legislature in 2012 to complete an energy audit, energy efficiency work, and water/sewer repairs needed for Deering to join ARUC. Local water operators installed new pumps and controls on the recovered heat system so it could begin working again in December. These actions led to a savings of $3,600 of heating fuel in December 2012 in the water plant/washeteria. This is $100 per home in one month.
In December 2012 and January 2013, ARUC and local operators continued energy efficiency measures, including cleaning and adjusting boilers for maximum efficiency; cleaning and installing larger vents for the washeteria to allow better airflow from the dryers; and installing LED lights.
These efforts saved the washeteria and water plant $16,715 total in fuel from January to March 2013. This averages to $154 per home per month in Deering over the period—equaling 5 percent of median household income.
ARUC is performing similar energy efficiency projects in a number of its 26 member communities. These projects are often site-specific and include a mix of recovered heat; electric boilers to utilize excess wind turbine power; improved controls; increased system monitoring; and small-scale wind turbines or solar panels.
Often, one of the most important energy efficiency techniques is water plant operator training and revised operating practices. ARUC is finding that to significantly improve energy efficiency and decrease costs requires not just building energy efficiency improvements, but following up with professional management, operator training and monitoring of performance.
Together, these collective efforts—from audits to implementation and repairs to operator training—are expected to lead to more than 100,000-gal of fuel savings annually in the coming years. In a region where conditions are challenging and resources limited, that is a significant benefit.