• Energy Research

One commonly-used argument against fluctuating renewables is their unpredictability. In contrast, thermal power generation and hydropower are regularly presented as reliable and dispatchable. However, droughts and floods can render useless the share of the power generation infrastructure that directly depends on freshwater. In this work, the global power sector is analysed from an energy-water nexus perspective to evaluate its reliability in case of severe water scarcity on a per-power plant basis, proposing a new method for combining it with water stress scores. At a country level, known individual thermal and hydropower plants are paired with regional water stress projections from 2020 to 2030 and their water source as a bottom-up approach to account for the capacities at risk and identify the points where water dependence could render a power system unreliable. The results show that, globally, about 65 % of generating capacities are directly freshwater-dependent. Moreover, the share of capacities placed in the low-resiliency group increases from 9 % of the total installed in 2020 to over 24 % in 2030 in all scenarios. The findings could help guide the development of the global power sector towards a less water-dependent system and accelerate the deployment of low water-demand power generation technologies. Smart Energy, 14 ISSN:2666-9552

The price dynamics of energy and water in Texas might be about to change. Historically, planners have assumed that the price of energy is volatile and trending up, while the price of water is stable and low. However, current trends in technology, demography, and Texas’ natural environment may mean that energy is actually getting more plentiful and less costly, while water may be becoming scarcer and more expensive. These changes would have implications for the trade-offs companies should make in energy vs. water use, in energy- vs. labor-intensive processes, and in the mix of energy sources including fuels, grid energy, cogeneration, and on-site generation. ; IC2 Institute

Climate change and increasing population pressure make it increasingly urgent to find ways to improve the management of the water-energy nexus. The desalination, pumping, distribution, and treatment of water use significant energy resources. The extraction and production of energy consume substantial amounts of water resources. In addition, negative effects on the environment are often the consequences of the management of the water and energy sectors. The report highlights the prospects for addressing these and other challenges at the water-energy nexus. It does this by drawing, in part, on some of the most important breakthroughs in the nexus that have come from the region.

Energy and water are linked resources. This pilot study examines the relationship between energy and water from a direction opposite to that of studies. We are concerned here with evaluating the energy required to supply and treat water, rather than with the water requirements of energy production. The primary energy requirements for three sectors of water management--municipal water supply, municipal sewage treatment, and water for irrigation--are evaluated. Six major cities, Chicago, Denver, Los Angeles, New Orleans, San Antonio, and St. Louis, are used as indicators of the national trend in energy requirements to supply water to municipalities. Nationwide data provided by the federal Environmental Protection Agency for 1977 and 1990 are used to determine the rate of change of energy required to treat municipal sewage over this period. The energy required to supply water for irrigation is estimated for three regions in the Southwest: Kern County, California; the Texas high plains; and San Carlos, Arizona. Historic trends and prospects for future development are used to estimate future energy requirements for each of these water sectors. The projections are compared to expected increases in national energy consumption. The results indicate that: 1. Regional differences in the amount of energy needed to supply water are very large, increasing in some places and decreasing in others. 2. Significant nationwide increases are likely for the energy required to treat sewage. 3. Noncritical short-term increases will occur in the total energy requirement to supply irrigation water, but after the year 2003, the Southwest faces an extremely difficult choice in balancing its resources of energy, water, and agricultural land, particularly in light of its growing urban demands.

This package provides material related to the paper`B. Hadengue, A. Scheidegger, E. Morgenroth, T.A. Larsen, Modeling the Water-Energy Nexus in Households, Energy & Buildings (2020), doi: https://doi.org/10.1016/j.enbuild.2020.110262`Various scripts and code, as well as raw results, are included.### Paper AbstractOne third of the global carbon emissions are emitted by the building sector. Over the last decades, space heating loads have decreased in modern buildings, and domestic hot water (DHW) is now oftentimes the largest energy consumer in the household. We developed the WaterHub modeling framework to assess the potential of technologies or measures targeting DHW energy demand. The framework combines process-based technological models and stochastic water demand modeling in a modular way to allow for holistic simulations of complex DHW systems. In two rigorous tests of the modeling framework, we demonstrated the importance of water consumption dynamics in the modeling of DHW systems, showing that static modeling leads to underestimated heat losses and wrong energy consumption predictions. In an exemplary case study, we identified and quantified the synergistic interactions between water boiler temperatures and a drain water heat recovery device, demonstrating the strength of this methodology for optimizing strategies targeting DHW systems. With its modular structure, this open-source modeling framework can be extended to include any DHW-related technology, providing a useful common platform for collaboration between technology developers and water experts.

The dataset is composed by 12 files reporting the water availability and temperature scenarios for 167 water-dependent power plants in the Danube river basin and the Iberian Peninsula. The dataset is split into multiple files by region (Danube river basin (Danube) or Iberian Peninsula (IP)), variable (discharge or river temperature) and scenario (baseline, RCP26 or RCP85) considered. The title of each file is composed by the variable reported (discharge or river temperature) and the scenario considered (baseline: 1951-2004, RCP26: 2006-2100, RCP85: 2006-2100). The first row is used to report the fields considered: the first three columns report the day, the month and the year. The remaining columns report the name of the power plant considered in each region (57 for the Daube river basin and 110 for the Iberian Peninsula). In each row day, month, year and streamflow or river temperature values are reported for every water-dependent power plant examined in the study. Temperature is reported as daily average temperature in degrees Celsius (°C) while water availability is reported as daily average streamflow in cubic meters per second (m^3/s). For a description on how these files were obtained, please refer to https://doi.org/10.2777/135510. This dataset was produced in the context of the project "US-EU integrated power and water systems modelling" funded by the European Commission Directorate General for Research and Innovation, Directorate G. - Energy, Unit G3 - Renewable Energy Sources, PP-06161-2017.

This document explains the U.S. Department of Energy's Solar Buildings Program's efforts regarding the research, development, and deployment of solar water heating technology.

The U.S. Department of Energy (DOE) recently completed a rulemaking process in which it amended the existing energy efficiency standards for residential water heaters. A key factor in DOE?s consideration of new standards is the economic impacts on consumers. Determining such impacts requires a comparison of the additional first cost of energy efficiency design options with the savings in operating costs. This paper describes the method used to conduct the life-cycle cost (LCC) and payback period analysis for gas and electric storage water heaters. It presents the estimated change in LCC associated with more energy-efficient equipment, including heat pump electric water heaters and condensing gas water heaters, for a representative sample of U.S. homes. The study included a detailed accounting of installation costs for the considered design options, with a focus on approaches for accommodating the larger dimensions of more efficient water heaters. For heat pump water heaters, the study also considered airflow requirements, venting issues, and the impact of these products on the indoor environment. The results indicate that efficiency improvement relative to the baseline design reduces the LCC in the majority of homes for both gas and electric storage water heaters, and heat pump electric water heaters and condensing gas water heaters provide a lower LCC for homes with large rated volume water heaters.

Conclusions of this presentation are: (1) energy and water are interconnected; (2) new energy sources will place increased demands on water supplies; (3) existing energy sources will be subjected to increasing restrictions on their water use; and (4) integrated decision support tools will need to be developed to help policy makers decide which policies and advanced technologies can address these issues.