Currently, we are beginning a global transition to highly energy efficient appliances, but, as with many commodities, we are not at the “promised land” yet. In the United States, we often need to buy products that are less energy efficient than what can be found in Europe, and this places us in a quandary. We have been choosing new dishwashers for our Ecohaven rental units and face a typical paradox with seeking resource effective technology: Do we emphasize water conversation or energy conservation, as rarely can both be achieved at the same time. In other words, should we choose a machine that saves electricity, or one that uses the least amount of water?
Electricity is not cheap on the Outer Banks, ranging from 11.67¢ to 16.92¢ per kWh for residential use. Electrical service is also vulnerable due to weather and demand. But water can also be expensive and is not as readily available as it may be in other areas. Brackish water is supplied by the Yorktown Aquifer, an underground river that is part of a system that runs deep beneath ground level, stretching from the North Carolina/South Carolina border all the way north to New Jersey. But this water supply must be filtered to remove the salt. This process, known as reverse osmosis desalination, is effective at producing drinkable water, but is very expensive, both in terms of energy use and operational costs. Around the world, desalination plants consume upwards of 200 million kilowatt hours every day, and energy costs make up more than half of the total operational cost of these plants. According to the U.S. Department of Energy, between the years 2016 and 2020, the cost of water desalination increased by 20%. This comes down to water consumers: a thousand gallons of fresh water treated by a desalination plants costs the average consumer in the US between $2.50 and $5.00, whereas conventional freshwater cost about $2.00 for the same amount of water. And beyond consumer costs, in terms of water conservation, moving to more water-efficient dishwashers in all three rental units could save more than 11,000 gallons of water over ten years.
Perhaps our story suggests that every region will have different solution as to how we choose these technological conveniences. But, once we realize that water itself is imbued with a high energy cost because of its processing, the choice is clearer: by saving water, we are already saving energy. So we are choosing a dishwasher that will conserve water, because by doing so, we are also conserving a lot of energy.
References:
Tab, Kipp. “Outer Banks Water Filtration – How We Get Good Drinkable Water.” Outer Banks Coastal Life, November 23, 2019. https://outerbankscoastallife.com/outer-banks-water-filtration/#:~
Bienkowski, Brian. “Desalination is an expensive energy hog, but improvements are on the way.” The World, May 15, 2015. https://www.pri.org/stories/2015-05-15/desalination-expensive-energy-hog-improvements-are-way
“Powering the Blue Economy: Exploring Opportunities for Marine Renewable Energy in Maritime Markets: Desalination.” U.S. Department of Energy, Office of Energy Efficiency & renewable Energy, April 2019. https://www.energy.gov/sites/prod/files/2019/03/f61/Chapter%207.pdf
Randall, Liz. “The Most Efficient Appliances Are Made By European Manufacturers.” Sustainable, November 16, 2020. https://sustainable-now.eu/most-efficient-appliances-are-made-by-european-manufacturers/