Reducing Water's Energy Footprint with Smart Monitoring
Water and energy are intimately linked by the large volume of power needed for extracting, treating, and delivering water. This link is known as the water-energy nexus.
By Sivan Sidney Cohen, P.E.
Pumping stations propel (or ‘lift’) the water supply on its journey from reservoirs and treatment centers to network endpoints in homes and businesses, and that activity is an integral part of this relationship. In fact, 80 percent of the energy used in water distribution is attributable solely toward powering pumping1 stations’ operation. Considering the vast nature of even a local municipal water network, this amounts to a lot of energy. California’s State Water Department (SWD), for example, consumes an average of 5 billion kWh/yr - equivalent to 2 percent to 3 percent of the state’s entire annual energy consumption.2
Impacts of Over-Pressurization
One prominent reason why pumping activity is such a major driver of water’s energy consumption relates to the large amount of unnecessary pumping that is part of the distribution process. Estimating the correct pressurization to ensure that the water supplied in a distribution network has enough strength to travel between pumping station and endpoint, defeat gravity, and arrive at its endpoints with adequate strength to meet the requirements of homeowners and industry is an inexact science at best.
To ensure adequate pressure, network operators currently either rely on rough estimates as to likely usage requirements or simply over-pressurize the supply by default. And while erring on the side of caution may sound like a logical solution to ensure adequate water pressurization, the strategy of over-pressurizing by default is undesirable: It wastes significant energy, financial resources, and can also cause an uneven flow of water from taps. In addition, it worsens any leaks along the network’s reach and increases the risk of pipe bursts.
Insufficient pressure, in contrast, is equally undesirable. In addition, the slower flow of water through the system carries an increased risk of introducing viruses and bacteria to the supply.3
Monitoring to Eliminate Guesswork
What if utilities could see in real time exactly what level of pressure was being experienced across the network endpoints? If so, utilities could simply reduce or increase the pressure being sent from the pumping stations to precisely match the network’s requirements. They could also guarantee sufficient pressurization (without risking the problems inherent in either over- or under-pressurizing the supply) and realize massive energy savings.
|Pumping stations, which propel the water supply on its journey from reservoirs and treatment centers to network endpoints in homes and businesses, are an integral part of the water-energy relationship.|
Such technology exists already. Automated Demand Response (ADR) systems are widely used in the energy generation industry4 to create a feedback loop between power consumption and what is generated at stations. This results in significant savings for providers given the often enormous differences between network demand at peak load periods and regular consumption.
Why Isn’t Adoption More Widespread?
With a solution to reduce water’s energy footprint readily available, what is preventing utilities from implementing smart endpoint pressurization monitoring as an industry standard? The answer lies in the complexity of traditional remote monitoring solutions, which is the image many in the industry still have when they consider what is required to take remote water pressure measurements.
Legacy telemetric monitoring infrastructure normally involves provisioning dedicated pressure measurement ‘stations’ that can cost upward of $15,000 each and involve significant installation time and coordination with local authorities. Each station effectively amounts to a small civil construction project with the granting of permits, the installation of concrete, building a monitoring cabinet to house the measuring and communications equipment, and finally ensuring that the unit receives a power supply (whether from traditional or solar-powered sources).
Such stations entail planning and logistical difficulties that would render their large-scale installation, such as would be required in the case of a typical smart water network, both unfeasible and an environmental eyesore. The financial cost of a widespread installation of a typical legacy monitoring approach would also preclude any savings that a utility could realize through such a network’s deployment.
Savings on the Horizon
The widespread and fast-growing deployment of Internet of Things (IoT) networks, including both traditional licensed and emerging unlicensed offerings, means that unwieldy communications equipment is no longer necessary. As IoT gateways for transmitting sensor information become smaller than desktop telephones, oversized monitoring cabinets are no longer required to house them. The cost of such systems is also a fraction of what a comparable legacy system would have cost just a decade ago. And as these systems are small enough to fit inside the assets they are monitoring, the difficulties of finding an external installation site are entirely obviated.
For the first time, bringing ADR to water distribution networks is no longer a pipe dream but rather a viable strategy for realizing massive energy savings that is within reach of most operators.
The water energy-nexus is a major cause of energy wastage - and unnecessary water pressurization is a major contributor. Modern remote monitoring solutions have overcome the barriers that have prevented water utilities from deploying endpoint water pressurization on a sufficiently large scale to enable automatic pressure optimization. The day for water pressurization to ‘go smart’ has arrived.
About the Author: Sivan Sidney Cohen, P.E., is general manager of Ayyeka Inc. A licensed professional engineer in the United States, Sivan connects Ayyeka’s advanced industrial IoT solutions with the booming smart infrastructure market. Sivan holds a B.Sc. in civil engineering from the University of California - Berkeley and an M.Sc. in civil engineering from Stanford University.
1. Copeland, C. and N. Carter. “Energy-Water Nexus: The Water Sector’s Energy Use,” Congressional Research Service, 2017.
2. “Water-Energy Connection,” U.S. EPA website, Pacific Southwest, Region 9, https://www3.epa.gov/region9/waterinfrastructure/waterenergy.html.
3. LeChevallier, M. et al. “The Potential for Health Risks from Intrusion of Contaminants into the Distribution System from Pressure Transients,” Distribution system white paper, prepared for the U.S. Environmental Protection Agency, 2015, p. 7.
4. Vermont Transco LLC. “Automated Demand Response Benefits California Utilities and Commercial & Industrial Customers,” prepared for the U.S. Department of Energy, 2014.