Estimating Agricultural Groundwater Withdrawals with Energy Data

Agricultural water use is the leading cause of groundwater overdraft in California. However, agencies tasked with managing groundwater resources do not have access to accurate and reliable measurements of groundwater extraction. Previous studies identified a relationship between pump energy consumption and groundwater extraction and indicated that the efficiency lift method (ELM) can produce reliable estimates of groundwater extraction if based on reliable data. Recent advances in the availability of electricity and pump operating condition data have made the ELM viable for estimating large-scale groundwater extraction. This study considered the feasibility of using the ELM to estimate groundwater extractions from both individual wells and larger areas and identified the best data sources available for such estimates. Researchers found mean error rates of 5% at the individual well level and 3.3% for collections of wells when using the most specific data sources available, such as pump test reports and spatial groundwater level datasets. This research suggests that the ELM is a reasonable approach for estimating groundwater extraction on a large scale.

Visit the Journal of Water Resources Planning and Management to read the full article.

 

Spillovers from Behavioral Interventions: Experimental Evidence from Water and Energy Use

This 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 appears to induce a small 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 explain roughly a quarter of the electricity reduction. Incorporating the cross-sectoral spillover increases the net benefits of the intervention substantially.

Read the paper in the Journal of the Association of Environmental and Resource Economists

The Cost-Effectiveness of Energy Savings Through Water Conservation: a Utility-Scale Assessment

It is well-established that water infrastructure systems require energy to treat and deliver water to end-users. This fundamental relationship presents an opportunity to secure energy savings through water conservation. In a previous study, the energy savings linked to a statewide water conservation mandate in California were found comparable in both resource savings as well as cost-effectiveness to the energy savings achieved directly through energy efficiency programs. This study pursues a similar line of inquiry, but at the scale of an individual city as opposed to a statewide assessment. Los Angeles, California, serves as the case study for estimating the energy savings secured through water conservation programs relative to energy efficiency (EE) programs enacted in the study region. We apply three different estimates of energy intensity (EI) for the conversion of water savings to energy savings. These applied EI scenarios are differentiated by scale and system boundary, including: a direct assessment of EI within the water utility service territory, an expanded boundary that includes imported water infrastructure systems, and a broader, top-down estimate for the regional hydrologic zone. Across all scenarios, the estimated energy savings secured through water conservation programs prove to be cost-competitive with the energy efficiency programs enacted by the utility. When using estimates of EI with expanded system boundaries that include the upstream energy embedded in imported water supplies, water conservation becomes a significantly more attractive pathway for saving energy. This outcome underlines the importance of clearly defining the water-energy system boundary of interest, both to determine an accurate EI value, and subsequently, to design and implement cost-effective programs that jointly conserve both water and energy resources.

Read the article in Environmental Research Letters

Load Shifting at Wastewater Treatment Plants: A Case Study for Participating as an Energy Demand Resource

Energy load shifting can allow for increased renewable energy integration and reduced greenhouse gas intensity of the electricity grid. Recent research has demonstrated that wastewater treatment plants have considerable potential to shift energy loads and act as energy demand resources due to their energetic flexibility and energy production capacity. This paper investigates a wastewater treatment plant in Santa Rosa, California, participating as a demand resource on the wholesale energy market through the proxy demand resource program. Test demand response events showed that the facility was able to shift its energy load by modifying select operations without impacting wastewater effluent quality. A cost-benefit analysis based on projected program participation and the results from the test events, estimates that the Santa Rosa wastewater treatment plant could achieve up to 4.8% energy cost savings through the proxy demand resource program. Two main issues were identified from the test events: (1) the difficulty of correctly timing demand reduction periods and (2) the inaccuracy of using standard baseline methods to measure the energy load reduction. As a supplement to the case study, this paper also presents a roadmap outlining the technology necessary for wastewater treatment plants to participate in demand resource programs through energy load shifting. The roadmap identifies key instrumentation and automation infrastructure, and assets that can be utilized to provide energetic flexibility; it also recommends additional infrastructure that can stabilize energy loads and enhance controlled energy load shifting.

Read the article in the Journal of Cleaner Production

Identifying and overcoming barriers to onsite non-potable water reuse in California from local stakeholder perspectives

Full Title: Identifying and overcoming barriers to onsite non-potable water reuse in California from local stakeholder perspectives

Onsite (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.

 
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The Role of Industrial Ecology in Food and Agriculture’s Adaption to Climate Change

Full Title: The role of industrial ecology in food and agriculture’s adaptation to climate change
Authors: Alissa Kendall and Edward S Spang
Publication:  Journal of Industrial Ecology. 2019;1-5 // Published 01, April 2019
Article Link 1

Abstract: The 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.

Embedded Water Footprint of In-Field Crop Loss

Full Title: Estimating the Blue Water Footprint of In-Field Crop Losses: A Case Study of U.S. Potato Cultivation
Authors: Edward S Spang and Bret D Stevens
Publication:  Sustainability 2018, Volume 10, Number 8 // Published 11 August 2018
Article Link 1 // Article Link 2

Abstract: Given 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.

Estimated Impact of CA’s urban water conservation mandate…

Full Title: The estimated impact of California’s urban water conservation mandate on electricity consumption and greenhouse gas emissions
Authors: Edward S Spang, Andrew J Holguin and Frank J Loge
Publication:  Environmental Research Letters, Volume 13, Number 1 // Published 12, January 2018
Article Link 1 // Article Link 2

Abstract: In 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’ (https://cwee.shinyapps.io/greengov/), 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.

Segmentation analysis of residential water-electricity demand…

Full Title: Segmentation analysis of residential water-electricity demand for customized demand-side management programs
Authors: A. Cominola, E.S. Spang, M. Giuliania, A. Castellettia, J.R. Lund, F.J. Loge
Publication:  Journal of Cleaner Production, Volume 172, 20 January 2018, Pages 1607-1919
Article Link 1 // Article Link 2

Abstract: With 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. <br/>

Spillovers from Behavioral Interventions

Full Title: Spillovers from Behavioral Interventions:
Experimental Evidence from Water and Energy Use
Authors: Katrina Jessoe, Gabriel Lade, Frank Loge, and Edward S Spang
Publication:  E2e, Working Paper 033 // Published December 2017
Article Link || Policy Brief

Abstract: This 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%.

Implementing Consumption-Based Fixed Rates in Davis, Calif.

Authors: Spang, Edward S.; Loge, Frank J.; Abernathy, William; Dove, Douglas R.; Tseng, Catherine; Williams, Matt
Publication: American Water Works Association – July 2015
Article Link

Abstract: Water 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.