TitleAuthorTypeYear PublishedDescriptionDownloadSponsor
Beyond 100 % renewable: Policy and practical pathways to 24/7 renewable energy procurementGregory MillerAcademic Journal2019Corporations are increasingly shaping the future of the electric grid by pursuing 100 % renewable energy goals that seek to match their annual energy consumption with an equal volume of renewable energy. The challenge of achieving a 100 % renewable electricity grid, however, is not only a question of how much renewable energy is built, but rather whether renewables can supply electricity when it is needed.Download (Paywall)
Barriers Preventing Growth of Onsite Water Reuse in CaliforniaAmanda Rupiper, Frank Loge, Halona Leung, Leslie CrennaResearch Brief2019Using alternate water sources, such as rainwater or graywater, for onsite reuse has potential to offset potable water demands and reduce wastewater flows. Onsite water reuse has been allowable by California code for just over a decade, yet the proliferation of treated onsite water reuse systems has been sluggish due to challenges that have surfaced.DownloadCalifornia Energy Commission (CEC)
Identifying and Overcoming Barriers to Onsite Non-Potable Water Reuse in California from Local Stakeholder PerspectivesAmanda M.Rupiper, Frank J.LogeAcademic Journal2019Onsite (a.k.a. decentralized) water reuse can reduce overall potable water demand and aid in meeting water reduction goals. In spite of clear benefits, onsite non-potable water systems (ONWS), specifically non-blackwater commercial systems, face many challenges that are preventing growth and expansion in California. This study utilized a technical advisory committee and a survey to identify the most significant challenges facing onsite water reuse systems, how these challenges affect ONWS stakeholders, and potential solutions at the state level. The given methods found that the most prevalent challenges hindering the growth of ONWS appeared to be the absence of a local regulatory program, system cost, poor access to training for regulators, and limited public education about alternate water sources. Survey results revealed several possible drivers for the existence of these challenges including that informational and training resources are not adequately disseminated to target groups. The study concluded that the creation of trainings for regulators, the development of an organization dedicated to onsite systems, expanded technology certifications, policy changes, and highlighting existing systems might help overcome the challenges hindering growth and allow for greater expansion of onsite non-potable water systems throughout California.Download (Open Source)California Energy Commission (CEC)
The Role of Industrial Ecology in Food and Agriculture’s Adaption to Climate ChangeAlissa Kendall, Edward S SpangAcademic Journal2019The food and agriculture sectors contribute significantly to climate change, but are also particularly vulnerable to its effects. Industrial ecology has robustly addressed these sectors’ contributions to climate change, but not their vulnerability to climate change. Climate change vulnerability must be addressed through development of climate change adaptation and resiliency strategies. However, there is a fundamental tension between the primary objectives of industrial ecology (efficiency, cyclic flows, and pollution prevention) and what is needed for climate change adaptation and resiliency. We develop here two potential ways through which the field can overcome (or work within) this tension and combine the tools and methods of industrial ecology with the science and process of climate change adaptation. The first layers industrial ecology tools on top of climate change adaptation strategies, allowing one to, for example, compare the environmental impacts of different adaptation strategies. The other embeds climate change adaptation and resiliency within industrial ecology tools, for example, by redefining the functional unit in life cycle assessment (LCA) to include functions of resiliency. In both, industrial ecology plays a somewhat narrow role, informing climate change adaptation and resilience decision‐making by providing quantitative indicators of environmental performance. This role for industrial ecology is important given the significant contributions and potential for mitigation of greenhouse gas emissions from food and agriculture. However, it suggests that industrial ecology’s role in climate adaptation will be as an evaluator of adaptation strategies, rather than an originator.Download (Paywall)
Energy and WaterKatrina Jessoe, Edward SpangResearch Paper2018California’s water system is energy intensive and may account for up to 10 percent of the state’s greenhouse gas (GHG) emissions. According to the most recent estimates, approximately 20 percent of statewide electricity and 30 percent of natural gas for business and home use go to pumping, treating, and heating water. Water is also required to produce energy, including in hydropower generation, thermoelectric power plants, and oil and gas extraction.

Actions that improve water use efficiency can reduce energy consumption. Actions that improve energy efficiency can reduce impacts on water supply and quality. In contrast, some actions to boost the water sector’s resilience to droughts can increase energy consumption. And measures to reduce the energy sector’s water use can increase energy production costs and GHG emissions.
DownloadPublic Policy Institute of California (PPIC)
Embedded Water Footprint of In-Field Crop LossEdward Spang, Bret StevensAcademic Journal2018Given the high proportion of water consumption for agriculture, as well as the relatively common occurrence of crop losses in the field, we estimate the amount of water embedded in crops left on the farm. We are particularly interested in understanding losses associated with fruits and vegetables, having a higher level of harvesting selectivity and perishability (and thus, losses) than grain crops. We further refined the study to focus on potatoes, as they represent the largest acreage under cultivation of all fruit and vegetable crops in the U.S. We attempt to get the most complete understanding of pre-harvest and harvest loss data for potatoes by leveraging three centralized data sets collected and managed by the United States Department of Agriculture (USDA). By integrating these three distinct data sets for the five-year period 2012–2016, we are able to estimate water consumption for potato cultivation for total in-field losses by production stage and driver of loss for seven major potato-producing states (representing 77% of total U.S. potato production). Our results suggest that 3.6%–17.9% of potatoes are lost in the field with a total estimated blue water footprint of approximately 84.6 million cubic meters. We also find that the leading driver for crop loss for in-field potato production is harvest sorting and grading, accounting for 84% of total lost production at the farm. We conclude with a discussion of opportunities for improved national level data collection to provide a better understanding of in-field crop losses over time and the resource footprints of these losses.Download
Estimated Impact of California’s Urban Water Conservation Mandate on Electricity Consumption and Greenhouse Gas EmissionsEdward Spang, Andrew Holguin, Frank LogeAcademic Journal2018In April 2015, the Governor of California mandated a 25% statewide reduction in water consumption (relative to 2013 levels) by urban water suppliers. The more than 400 public water agencies affected by the regulation were also required to report monthly progress towards the conservation goal to the State Water Resources Control Board. This paper uses the reported data to assess how the water utilities have responded to this mandate and to estimate the electricity savings and greenhouse gas (GHG) emissions reductions associated with reduced operation of urban water infrastructure systems. The results show that California succeeded in saving 524 000 million gallons (MG) of water (a 24.5% decrease relative to the 2013 baseline) over the mandate period, which translates into 1830 GWh total electricity savings, and a GHG emissions reduction of 521 000 metric tonnes of carbon dioxide equivalents (MT CO2e). For comparison, the total electricity savings linked to water conservation are approximately 11% greater than the savings achieved by the investor-owned electricity utilities' efficiency programs for roughly the same time period, and the GHG savings represent the equivalent of taking about 111 000 cars off the road for a year. These indirect, large-scale electricity and GHG savings were achieved at costs that were competitive with existing programs that target electricity and GHG savings directly and independently. Finally, given the breadth of the results produced, we built a companion website, called 'H2Open' (, to this research effort that allows users to view and explore the data and results across scales, from individual water utilities to the statewide summary.Download
Segmentation Analysis of Residential Water-Electricity Demand for Customized Demand-Side Management ProgramsA. Cominola, E.S. Spang, M. Giuliania, A. Castellettia, J.R. Lund, F.J. LogeAcademic Journal2018With increasing water and energy use in the residential sector, due to population growth, urbanization, and climate change, demand-side management (DSM) is essential to complement supply-side interventions to meet future demands and reduce costs. This paper explores how customer segmentation analysis can support customized water and electricity DSM. We contribute a three-phase customer segmentation analysis of over 1000 residential accounts in the Los Angeles County (Southern California) to explore the heterogeneity of residential water-electricity demand profiles and provide insights for coordinated water-energy DSM. Results show that, on the one hand, daily water and electricity consumption are correlated, thus groups of high consumers can be targeted with coordinated water-electricity DSM interventions. On the other hand, the absence of a relevant causal nexus between water and electricity daily load shapes suggests that DSM actions for water should be differentiated from those for electricity. Finally, both objective (e.g., presence of swimming pool) and subjective psychographic features (e.g., conservation attitude) are found to be relevant potential drivers of water-electricity demands. Based on these findings, we propose recommendations for designing a portfolio of mixed customized water-electricity DSM interventions to foster conservation or peak shifting objectives.Download (Paywall)European Union's Seventh Framework Programme
Spillovers from Behavioral InterventionsKatrina Jessoe, Gabriel Lade, Frank Loge, and Edward S SpangResearch Paper2017This paper provides experimental evidence that behavioral interventions spill over to untreated sectors by altering consumer choice. We use a randomized controlled trial and high-frequency data to test the effect of social norms messaging about residential water use on electricity consumption. Messaging induces a 1.3 to 2.2% reduction in summertime electricity use. Empirical tests and household survey data support the hypothesis that this nudge alters electricity choices. An engineering simulation suggests that complementarities between appliances that use water and electricity can explain only 26% of the electricity reduction. Incorporating the cross-sectoral spillover increases the cost-effectiveness of the intervention by 62%.DownloadAlfred P. Sloan Foundation
Implementing Consumption-Based Fixed Rates in Davis, Calif.Spang, Edward S.; Loge, Frank J.; Abernathy, William; Dove, Douglas R.; Tseng, Catherine; Williams, MattAcademic Journal2015Water utilities in California must promote water conservation, yet have a limited suite of rate structures that can be used to charge for water. Under traditional rate structures, a strong price‐based conservation signal can produce conservation yet result in revenue instability. California public water utilities face additional challenges as a result of the standards for reporting, accounting, and proportionality under Proposition 218. One solution for resolving these structural tensions between conservation and fiscal solvency in a Proposition 218 environment is the implementation of consumption‐based fixed rates (CBFR). This article describes the design and implementation of CBFR in Davis, Calif.Download (Paywall)
Consumption-Based Fixed Rates: Harmonizing Water Conservation and Revenue StabilityEdward Spang, Sara Miller, Matt Williams, and Frank J. LogeAcademic Journal2015Water utilities struggle with the need to promote water conservation while maintaining financial solvency—a common challenge referred to as the “new normal.” However, under typical cost and revenue structures, water utilities experience significant revenue shortfalls when water use lags behind projected customer consumption (either by conservation or other factors). Subsequently, water providers are obligated to raise rates more frequently and/or more dramatically than originally anticipated. This problem arises primarily when the fixed and variable portions of utility costs are not aligned with the fixed and variable portions of revenue. This article presents a new water‐pricing mechanism—consumption‐based fixed rates—that harmonizes costs and revenues yet still promotes conservation through the innovative inclusion of volumetric fixed charges. As such, consumption‐based fixed rates represent a potentially useful solution for water utilities to effectively balance conservation and revenue stability in an equitable and sustainable manner.Download (Paywall)
A High-Resolution Approach to Mapping Energy Flows through Water Infrastructure SystemsEdward S. Spang and Frank J. LogeAcademic Journal2015Using data from the water service area of the East Bay Municipal Utility District in Northern California, we develop and discuss a method for assessing, at a high resolution, the energy intensity of water treated and delivered to customers of a major metropolitan water district. This method extends previous efforts by integrating hourly data from supervisory control and data acquisition systems with calculations based on the actual structure of the engineered infrastructure to produce a detailed understanding of energy use in space and time within the territory of a large‐scale urban water provider. We found significant variations in the energy intensity of delivered potable water resulting from seasonal and topographic effects. This method enhances our understanding of the energy inputs for potable water systems and can be applied to the entire delivery and postuse water life cycle. A nuanced understanding of water's energy intensity in an urban setting enables more intelligent, targeted efforts to jointly conserve water and energy resources that take seasonal, distance, and elevation effects into account.Download (Paywall)Pacific Gas and Electric (PG&E), EBMUD
Multiple Metrics for Quantifying the Intensity of Water Consumption of Energy ProductionEdward S. SpangAcademic Journal2014Discussion of the environmental implications of worldwide energy demand is currently dominated by the effects of carbon dioxide (CO2) emissions on global climate. At the regional scale, however, water resource challenges associated with energy systems are a growing concern. This paper, based on an inventory of national energy portfolios, posits an indicator-based framework for characterizing regional energy portfolios’ relative water intensity. These calculations extend upon a previous paper that established a method for calculating the national water consumption of energy production (WCEP) at the global level. Intensity indicators are based on normalizing the WCEP results with a set of additional indicators (including population, gross domestic product, total energy production, and regional water availability). The results show great variability in water consumption across nations, as well as across the various water intensity measures that were applied. Therefore, it is best to apply this full suite of indicators to each country to develop an integrated understanding of the intensity of water use for energy across countries.Download
The Water Consumption of Energy Production: an International ComparisonEdward S. SpangAcademic Journal2014Producing energy resources requires significant quantities of fresh water. As an energy sector changes or expands, the mix of technologies deployed to produce fuels and electricity determines the associated burden on regional water resources. Many reports have identified the water consumption of various energy production technologies. This paper synthesizes and expands upon this previous work by exploring the geographic distribution of water use by national energy portfolios. By defining and calculating an indicator to compare the water consumption of energy production for over 150 countries, we estimate that approximately 52 billion cubic meters of fresh water is consumed annually for global energy production. Further, in consolidating the data, it became clear that both the quality of the data and global reporting standards should be improved to track this important variable at the global scale. By introducing a consistent indicator to empirically assess coupled water–energy systems, it is hoped that this research will provide greater visibility into the magnitude of water use for energy production at the national and global scales.Download
Offsetting Water Conservation Costs to Achieve Net-Zero Water UseKendra C. Olmos and Frank J. LogeAcademic Journal2013Achieving net‐zero water use (in which annual potable water use is no greater than annual rainfall) and achieving reasonable payback periods for water conservation measures were investigated for a proposed mixed‐use housing development in Davis, Calif. Water efficiency scenarios were analyzed for indoor water use and landscape watering, along with the use of graywater and rainwater on landscaping. Potential cost savings were found in both water utility reductions associated with water conservation and energy efficiency associated with decreases in hot water use. The feasibility of selling carbon offset credits in California's new cap‐and‐trade program by reducing greenhouse gas emissions associated with the water–energy nexus was also investigated. Results indicated the feasibility of achieving net‐zero water use at the scale of a single‐family residence and the entire community through indoor and landscaping water conservation measures without the need for graywater or rainwater reuse.Download (Paywall)