Water = Energy, Energy = Water
The water-energy nexus is a formal term for a simple equation: Delivering and treating water requires energy, and water is a vital element for producing energy, whether through electricity generating dams, thermo-electric power generation, hydraulic fracturing (“fracking”) for natural gas or biofuels production. According to the International Energy Agency, energy accounts for 15 percent of total water usage worldwide, an amount that is expected to increase over the next two decades.
A new wastewater treatment plant in Spokane, Wash., shows one way to address the nexus by recovering energy produced in the treatment process to co-generate electricity and hot water for plant operations.52 Yet it is interesting to note, “While utilities and government stall on improving their water and energy efficiency, the private sector is moving ahead because they realize the cost savings and sustainability benefits. Hopefully, their efforts will motivate energy and water utilities to realize their joint savings potential,” says Rachel Young, research assistant at the American Council for an Energy-Efficient Economy (ACEEE).
Innovative Management to Keep the Water Flowing.
Local and regional authorities are looking at many new ways to address the challenges that exist in both supply and demand for water. For example, in Oregon, two communities and a nearby manufacturer joined forces to construct a joint water treatment facility that reduced construction costs and created wetlands for public access and a wildlife habitat.
In the West, more than 40 million people in seven states rely on water from the Colorado River and its sources. A 2012 study funded by the states and the U.S. Bureau of Reclamation found that water supply in the Colorado River system could be improved through integrated management across stakeholders. Specifi c management techniques evaluated include urban and agricultural conservation, ocean and groundwater desalination, better management of watersheds and local water system operations, more efficient use of water in producing energy and water banking.
Smart Management of Water System Assets
How to replace, upgrade and expand the infrastructure for water delivery and treatment — some of it up to 80 years old — is a looming issue for many utilities. In fact, the American Society of Civil Engineers (ASCE) predicts that delayed investments in water infrastructure could have a significantly negative impact on the U.S. economy through the loss of 700,000 jobs and $416 billion in lost GDP, as well as $147 billion in increased costs to businesses and $59 billion for households.
But new infrastructure can’t be constructed quickly, so water utilities are looking at how facilities and technology can improve management of current water system assets. Better asset management can also yield significant payback in political and customer acceptance of a utility’s requests for rate changes and capital bonds to fund new infrastructure.
Key Strategies to Consider
As water utilities (and the CIOs who support them) look to the future, Barry Liner, director of the Water Science and Engineering Center at the Water Environment Foundation, recommends several strategies.
“When replacing infrastructure, don’t assume that you’ll just do the same thing as before,” says Liner. “Instead, take a look at the infrastructure design across the entire water system for ways to generate new efficiencies. For example, placing a small wastewater treatment plant near a farm or manufacturing customer can recover water for reuse at those sites, preserving freshwater supplies for other customers.”
Additionally, “The cutting edge for integrated infrastructure planning is to use optimization modeling of investments for both water supply and resource recovery,” says Liner. “This planning approach can help utilities find ways to evaluate many more alternatives than traditional methods, which can lead to significant cost savings.”
Once projects are defi ned, water utilities can reduce construction and operational costs through new approaches such as a design-build-operate (DBO) model. Seattle Public Utilities used this model to construct a new drinking water treatment facility, which also has the sustainability benefits of reduced on-site use of water and energy. By consolidating the DBO functions with a single provider, this model eliminates many of the delays and extra expenses of separate RFPs and procurement processes. The model also transforms a utility’s ongoing facilities management to more of an oversight role.
IDEA: Placing a small wastewater treatment plant near a farm or manufacturing customer can recover water for reuse at those sites, preserving freshwater supplies for other customers.
