Today’s consumer is more energy-savvy than ever before—influenced by more than 20 years of policy, conservation programs, and media focus. We consider our energy use as we shop for electronics and appliances, adjust our thermostats, and remodel our homes. Neighborhood discount stores are devoting precious shelf space and ad space to compact fluorescent bulbs.
What’s missing from today’s mainstream energy-efficiency dialogue is the water connection. When you turn on a light, do you consider the water it takes to supply the power? And when you take a shower, do you understand its impact on your energy bill?
It’s time to change the way we think about water efficiency. It’s time to connect the drops and leverage the linkage to energy. Saving water saves energy. The two resources are inextricably linked and both are essential to our economy and quality of life.
Given the water supply pressures from our country’s growing population, we must recognize and leverage water and energy interdependencies on both the supply and the demand side. This will not only help communities realize greater energy and water savings but also enhance environmental benefits. Calling the public’s attention to the connection between water and energy strengthens our case for why and how our water supply must be protected.
The Hidden Energy Costs in Supplying Water
Water use involves immense, but often overlooked, energy demands. The US Environmental Protection Agency (EPA) estimates that about 8% of the nation’s energy demand is used to treat, pump, and heat water.
US drinking water and wastewater systems spend about $4 billion a year on energy to pump, treat, deliver, collect, and clean water—with much of this cost borne by ratepayers and municipalities. Pumping water is the primary consumer of energy on the supply side, including pumping to deliver untreated water to treatment plants and to deliver treated water to customers. As the demand for water grows, we are pumping water from greater distances and from deeper in the ground—increasing the amount of energy used. In California, for example, water pumping is the single largest use of electricity—7% of the state’s total usage. Overall, water-related energy use in California is approximately 19% of its total electricity consumption and 30% of its total natural gas consumption.
And pumping isn’t the only energy consumer. Each step in the water service delivery cycle expends kilowatts, including the treatment process. Nationwide, drinking-water and wastewater systems use 75 billion kilowatt-hours per year—as much as the pulp and paper and petroleum industries combined. Energy costs to run these systems can represent as much as one-third of a municipality's electricity use.
The bottom line is that when water use is reduced, energy is saved because less water needs to be pumped and treated.
On the other side of the water/energy equation, when energy use is reduced, water is saved because less is needed to operate power plants. About half of the water gathered in the US from surface water and groundwater sources is used for power plant cooling, compared to 34% for irrigation and 11% for residential and commercial purposes. On average, each kilowatt generated consumes approximately 0.2 to 0.3 gallon of water.
There are many opportunities for energy savings on the supply side, realized through better planning, maintenance, and operations of water delivery systems, as well as through the development of new technologies and processes. What is often overlooked is how demand-side management or conservation programs can effectively increase water and energy savings. California’s state water plan concluded in 2005 that the largest single new supply available to meet its expected growth over the next 25 years was water-use efficiency.
The Dual Benefits of Managing Demand
Even after utilities use energy to deliver water, residential and business customers burn even more energy to heat, cool, and use that water. In most cities, this is the greatest water-related energy cost. The connection is clear when you tell people that running your hot-water faucet for five minutes is equivalent to running a 60-watt light bulb for 14 hours. There are obviously huge opportunities to save energy by saving water. Helping residential and business customers use water more efficiently decreases or postpones the need to develop both new water and energy infrastructure.
For residential consumers, the opportunity to save both water and energy comes primarily from installing and using water-efficient fixtures and appliances, including showers, faucets, clothes washers, and dishwashers. If every American home installed water-efficient showerheads, for example, the US could save more than 160 billion gallons of water per year and save about $2 billion in energy costs for heating that water. An additional 60 billion gallons and $650 million in energy costs could be saved if every household also installed high-efficiency faucets or faucet aerators.
Utilities are seeing the potential to compound water and energy savings. For example, Seattle-area water and energy utilities are partnering in a showerhead replacement campaign. Showerheads that run at 2.0 gallons per minute go beyond code and will cut the demand for water, electricity, and natural gas while reducing wastewater flows. The voluntary campaign will roll out this summer with an expected distribution of 60,000 to 120,000 showerheads to single-family households.
In the commercial sector, energy and water savings go hand-in-hand on a variety of fronts—from the kitchen to the restroom, and from the laundry to cooling systems. As an example, in the restaurant business, there is great potential to reduce water use with products and behavior changes. In 2002, the California Urban Water Conservation Council started the “Rinse & Save” program—providing pre-rinse spray valves to the state’s food service establishments. In the first year, close to 17,000 pre-rinse spray valves were supplied, resulting in annual savings of 57,000 gallons, 336 therms, or 7,629 kilowatt-hours per retrofit.
WaterSense Program—National Voluntary Program Efforts
To promote water efficiency, the EPA launched the WaterSense program last year to help protect the future of our nation's water supply. The WaterSense label will help consumers and businesses identify products that meet the program's water efficiency and performance criteria.
The WaterSense program labels products that are at least 20% more efficient than the current standards while performing as well or better than their less-efficient counterparts. The WaterSense product specifications do not directly address energy consumption. However, all water savings realized through the use of WaterSense-labeled products and services have a corresponding reduction in energy consumption.
Both commercial and residential products and services will be addressed by WaterSense labeling efforts. For appliances that use both water and energy, WaterSense is working with other EPA labeling programs such as Energy Star to coordinate performance criteria. Additionally, businesses may now track, and in the future may be able to benchmark, their water use through Energy Star’s Portfolio Manager.
Projected savings potential for initial WaterSense product areas—toilets, faucets, and irrigation controllers—based on a 10% replacement of existing fixtures, is estimated to be 120 billion gallons or enough to supply water to 33 million people for a year. For every million gallons saved, approximately 1,500 kilowatt-hours are saved.
Leverage the Linkage
The EPA’s goal is to achieve environmental and economic benefits as efficiently and cost-effectively as possible, but we can’t do it alone. We need consumers and businesses across the nation to join us. So the next time you turn on a faucet or a shower, don’t think of it as just running water; remember you’re also using energy. The more wisely we use our water, the better off environmentally and economically we’ll be in the future.
For more information on the WaterSense program, visit www.epa.gov/watersense. To learn more about Energy Star’s Portfolio Manager, visit http://www.energystar.gov/index.cfm?c=evaluate_performance.bus_portfoliomanager.