Water Use for Hydraulic Fracturing of Oil and Gas in the South Platte River Basin,Colorado

Water use for oil and gas development (i.e., hydraulic fracturing) is a concern in semiarid basins where water supply is often stressed to meet demands, and oil and gas production can exacerbate the situation. Understanding the impacts of water use for hydraulic fracturing (HF) on water availability in semiarid regions is critical for management and regulatory decisions. In the current work, we quantify water use for HF at several scales — from municipal to state‐wide — using the IHS Enerdeq database for the South Platte Basin. In addition, we estimate produced water (a by‐product of oil and gas production), using data from the Colorado Oil and Gas Conservation Commission to explore reuse scenarios. The South Platte River Basin, located in northeastern Colorado, encompasses the Denver‐Metro area. The basin has one of the most productive oil and gas shale formations in Colorado, with much of the production occurring in Weld County. The basin has experienced higher horizontal drilling rates coupled with an increasing population. Results show water use for horizontal and vertical wells averages 11,000 and 1,000 m³, respectively. Water use for HF in the South Platte Basin totaled 0.63% of the basin's 2014 total water demand. For Weld County, water use for HF was 2.4% of total demand, and for the city of Greeley, water use was 7% of total demand. Produced water totaled 9.4 Mm³ in the basin for 2014, which represents 42% of the total water used for HF.     

The value of mixed method content analysis for understanding renewable energy deployment and policy outcomes

Transitioning to renewable energy has become a global phenomenon. Attempts to explain development patterns are often fragmented, focusing on specific rationale for (un)successful deployment or the perspective of specific stakeholders. We recognize the importance for holistic insights for successful and effective environmental policy-making and planning in the context of renewable energy development. Using wind energy as an example, this paper provides methodological toolkits for utilizing content analysis (CA) to gain more holistic insights on renewable energy deployment and policy outcomes. Building on existing literature, past and ongoing research, three variations of CA are presented for understanding stakeholder conflicts surrounding wind energy development as well as public perceptions and responses to the technology across space and over time. Although newspapers are used as an example, these methodological protocols could be applied to diverse forms of data such as interviews, policy documents, reports, public meetings and letters of appeal.     

Local opposition against high-voltage grids: public responses to agency-caused science–policy trolls

High-voltage (hV) transmission grids are projects of societal importance that potentially have controversial social and environmental impacts. Former research shows that public opposition is sparked by the perception of negative local impacts and unjust concessionary processes. In this paper, we complement these perspectives by assessing the institutional practices of the regulatory agencies in dealing with scientific uncertainties. The regulatory agencies’ ‘ways of doing things’ are often designed to serve policy and management needs. A critical point is that the demarcation between scientifically based facts, values and assessments is often blurred in the decision-making process. This paper draws on two Norwegian case studies to investigate how the regulatory agencies dealt with (1) electromagnetic fields and health risks and (2) overhead lines versus sea cables. We argue that ambiguities and uncertainties that arise in the hV transmission line processes create ‘trolls’, and we explore how the local inhabitants and affected stakeholders in the two cases responded to these and how it triggered further opposition. By investigating how and why trolls appear and are handled, we conclude by discussing how public opposition related to hV transmission grids may be reduced – and how some ‘trolls’ may crack.     

“It's easy to throw rocks at a corporation”: wind energy development and distributive justice in Canada

In places like Canada, fast-paced wind turbine development combined with policy that limits local decision-making power has resulted in strong opposition to specific projects. Some studies suggest that anti-wind sentiment is tied to inadequate financial benefits – especially sharing at the local level. Thus, ideas of distributive economic justice have received traction, particularly in the form of praise for community-based development models. This paper reports on the findings from a mixed-methods study concerning preferred distributive justice elements in rural communities in Ontario (technocratic-based model) and Nova Scotia (community-based model) living with turbines. Residents’ perceptions of economic benefits are nuanced, but unlike other studies, this empirical work shows that both the fair distribution and the amount of local benefits are important predictors of project support. Yet, concerns around the fair distribution of benefits dominate in a regression on the adequacy of those benefits. A variety of interview and survey findings further point to the strength of traditional, profit-sharing community-based models for distributing benefits, but also more novel ideas including lowered electricity bills and tax rebates in areas home to turbines.     

CFD analysis on the performance of a solar chimney power plant system: Case study in Algeria

The solar chimney power plant (SCPP) is a power generator which uses solar radiation to increase the internal energy of the air circulating in the system, thereby transforming the useful gain of the solar collector into kinetic energy. The produced kinetic energy then can be converted into electrical energy by means of an appropriate turbine. In this paper, four locations in Algeria

(Constantine, Ouargla, Adrar, and Tamanrasset) were considered as case studies to describe the SCPP mechanism in detail. Numerical simulation of an SCPP which has the same geometrical dimensions was performed to estimate the power output of SCPP in these regions. Using the CFD software FLUENT we simulated a two-dimensional axisymmetric model of a SCPP with the standard k-ε turbulence model. The simulation results show that the highest power output produced monthly average value 68–73 KW over the year and the highest hourly power produced in June is around 109–113 KW.     

Comparison of refrigerated warehouse energy demand with R-717 and R-507 using eQUEST model

Natural refrigerant ammonia R-717 and synthetic azeotropic refrigerant R-507 (a blend containing 50% R-143a and 5% R-125 by weight) are used in a wide range of refrigeration systems especially in low-temperature applications. R-717 and R-507 are ozone friendly refrigerants, which have no Ozone Depletion Potential (ODP). Global Warming Potential (GWP) of R-717 and R-507 is equal to zero and 3300, respectively. The high amount of R-507 GWP demonstrates its negative effect on the Earth’s climate change. In this study, a refrigerated warehouse located in Cincinnati, Ohio was modeled and the total energy demand and Coefficient of Performance (COP) was evaluated by eQUEST using two scenarios. The R-717 and R-507 were used as refrigerant in the first and second scenarios, respectively. The results showed that using R-717 in the refrigeration system leads to a 15% energy saving and a higher COP compared to R-507 in all working conditions. The only exception is that at an evaporating temperature below ?35°C which COP values of both refrigerants are approximately equal.     

Evaluation of energy savings by using high efficiency motors in a thermal power station

This paper presents potential energy savings by installing high-efficiency motors instead of existing ones and their impact on greenhouse gases emissions reductions. This research study of the energy efficiency of electric motors has been performed in a typical thermal power plant. In the literature, the focus has been mainly on separate and away electric motors from operating facilities. The important advantage of this paper over other studies is that it uses the actual motors’ efficiency in the evaluation. The gains both in terms of electrical energy savings and in terms of financial economy by using high-efficiency motors have been discussed. As a result, the energy saving can be expected as 12.6% at the operating rate. This excellent result also reduces greenhouse gas emission by 1,423 tons every year. The analysis of the data provided an overview on energy losses often generated by the degradation and rewinding of electrical motors. This study represents very encouraging results that will help energy managers of industrial plants to become more involved in energy efficiency strategies.     

Triple-objective optimal sizing based on dynamic strategy for an islanded hybrid energy microgrid

A triple-objective optimal sizing method based on a dynamic strategy is presented for an islanded hybrid energy microgrid, consisting of wind turbine, solar photovoltaic, battery energy storage system and diesel generator. The dynamic strategy is given based on a dynamic complementary coordination between two different master-slave control modes for maximum renewable energy utilization. Combined with the proposed strategy, NSGA-II-based optimization program is applied to the sizing optimization problem with triple different objectives including the minimization of annualized system cost, the minimization of loss of power supply probability and the maximization of utilization ratio of renewable energy generation. The sizing results and the proposed strategy are both compared and analyzed to validate the proposed method in a real case of an islanded hybrid energy microgrid on Dong’ao Island, China.     

Fabrication and characterization of electrospun porous cellulose acetate nanofibrous mats incorporated with capric acid as form-stable phase change materials for storing/retrieving thermal energy

Electrospun cellulose acetate (CA) nanofibrous mats incorporated with capric acid was studied to fabricate form-stable phase change materials (PCMs) for storing/retrieving thermal energy. Electrospun CA nanofibrous mats with different porous structures and specific surface areas were firstly prepared through regulating the volume ratio of mixture solvent of acetone/dichloromethane (DCM). Effects of different volume ratio of mixture solvent and mat thickness on the morphological structure, specific surface area, and absorption capacity of CA nanofibrous mats were systematically investigated. The results indicated that CA nanofibrous mats were highly porous on the surface; hence, they were capable of absorbing a large amount of capric acid. The maximum absorption capacity of CA mats via electrospinning with volume ratio of acetone/DCM being 5/5 was ~95.8 wt%, due to its higher specific surface area of ~17.1 m²/g. The specific surface area and capric acid absorption capacity of CA nanofibrous mats increased with the increases of mat thickness. As the thickness of nanofibrous mats increased from 10 to 85 μm, the corresponding specific surface area and capric acid absorption capacity of mats increased respectively from 7.2 to 29.0 m²/g and 92.1 to 98.5%. Morphological structures, as well as the properties of thermal energy storage and thermal insulation of the fabricated form-stable PCMs, were studied by scanning electron microscopy, differential scanning calorimetry, and measurement of freezing times, respectively. The results indicated that the resulting form-stable PCMs could well maintain their phase transition characteristics and demonstrated great thermal energy storage capability and temperature regulation ability.     

Global solar radiation and energy yield estimation from photovoltaic power plants for small loads

Daily global solar radiation on a horizontal surface and duration of sunshine hours have been determined experimentally for five meteorological stations in Saudi Arabia, namely, Abha, Al-Ahsa, Al-Jouf, Al-Qaisumah, and Wadi Al-Dawaser sites. Five-years of data covering 1998–2002 period have been used. Suitable Angstrom models have been developed for the global solar radiation estimation as a function of the sunshine duration for each respective sites. Daily averages of monthly solar PV power outputs have been determined using the Angstrom models developed. The effect of the PV cell temperature on the PV efficiency has been considered in calculating the PV power output. The annual average PV output energy has been discussed in all five sites for small loads. The minimum and maximum monthly average values of the daily global solar radiation are found to be 12.09 MJ/m²/d and 30.42 MJ/m²/d for Al-Qaisumah and Al-Jouf in the months of December June, respectively. Minimum monthly average sunshine hours of 5.89 hr were observed in Al-Qaisumah in December while a maximum of 12.92 hr in Al-Jouf in the month of June. Shortest range of sunshine hours of 7.33–10.12 hr was recorded at Abha station. Minimum monthly average Solar PV power of 1.59 MJ/m²/day was obtained at Al-Qaisumah in the month of December and a maximum of 3.39 MJ/m²/day at Al-Jouf in June. The annual PV energy output was found to be 276.04 kWh/m², 257.36 kWh/m², 256.75 kWh/m², 245.44 kWh/m², and 270.95 kWh/m² at Abha, Al-Ahsa, Al-Jouf, Al-Qaisumah, and Wadi Al-Dawaser stations, respectively. It is found that the Abha site yields the highest solar PV energy among the five sites considered.