Electrical energy consumption for domestic water treatment and distribution in remote Alaskan communities

Abstract:

Rural Alaska, home to 229 Alaska Native tribes, is one of the coldest and most isolated regions in the U.S. As a result, it uses more energy than any other state and residents pay some of the highest energy costs per kWh. Water utilities rely heavily on electricity and heating oil to provide reliable service through the cold winter months. Stored water must also be continually heated and circulated with electric pumps to prevent system freeze-up. Individual homeowners with water and sewer services must shoulder costs for heat tracing lines, pump operation, and in-home water heaters to receive the crucial health benefits of water systems. The treated water is available at centralized community washeterias, or distributed for in-home use through pipes, closed-haul, or self-haul. Using data from energy audits conducted by Alaska Native Tribal Health Consortium (ANTHC), we investigate the patterns of annual electrical energy consumption in >60 rural Alaska villages (average population <500 people) along with seasonal and regional variability, impacts of population, and water treatment/distribution system types. Preliminary analyses indicate that high energy costs and economic conditions in rural communities challenge the sustainability of water systems. A considerable percentage of a community’s household income often pays for water and sewer and the largest portion of these costs usually goes to energy. Energy needs vary notably between communities and systems. Not unexpectedly, the per capita electrical energy consumption is highest during winter and lowest during summer months. Regional trends of per capita electrical energy consumption for water systems in the rural villages is as follows: far north> interior> south-central> southeast> southwest. Generally, the per capita energy consumption decreased with increasing population. The variation of per capita energy consumption based on water distribution shows that piped systems consume the highest amount of energy, followed by piped circulation, piped pressure, washeteria, and closed haul. At the water treatment plant the electricals consisting of pumps and plug loads show highest per capita electrical energy use, followed by lighting, space heating, water circulation heat, domestic hot water, ventilation fans, raw water heating, and tank heat.