Development of Life Cycle Water Demand Footprints for the Energy Pathways

The water-energy nexus refers to the relationship between water and energy, wherein each one needs the other. This thesis examines that part of the water-energy nexus concerned with water needed for energy production, conversion, and utilization. There has been limited focus on assessing the life cycle water footprints of energy pathways. Such an approach assesses the water requirement for the various unit operations in energy pathways from fuel extraction to its final energy form. A study of the life cycle water footprints of different energy pathways with a focus on minimizing water use could help in policy formation and investment decisions. The main objective of this research is to establish a benchmark for water demand coefficients for energy pathways based on a complete life cycle. The focus is on the assessment of different energy pathways and development of life cycle water demand coefficients through comprehensive modeling. The research includes the evaluation of energy pathways based on both conventional and non-conventional sources of energy, and the energy sources assessed are coal, natural gas, oil, biomass, wind, solar, hydroelectricity, nuclear, and geothermal. The initial focus is on power production. The conversion efficiency of power generation is correlated to developed water demand coefficients to study the effect of a power plant’s performance on water use. Coal-based power generation has high water use compared to gas-fired power generation due to differences both in conversion efficiency and the unit operations of fuel extraction. Biomass-based power generation has the highest water demand coefficients over the complete life cycle and wind has the lowest. This study found complete life cycle water consumption coefficients for power generation for coal transported by conventional means to be 0.96 – 3.21 L/kWh and 0.07 – 2.57 L/kWh for gas-fired power plants. Excluding biomass and hydroelectricity pathways, non-conventional energy technology has complete life cycle water consumption coefficients of 0.005 – 4.39 L/kWh. The corresponding range for biomass pathways is 259.6 – 1164.01 L/kWh. Throughout the complete life cycle of a transportation fuel produced from the oil sands in Alberta 2.08 – 4.19 volume of water per volume of oil are consumed, and the corresponding fuel from crude oil extracted from five selected oil fields in North America consumes 1.71 – 8.25 volume of fresh water per volume of oil. The water demand coefficients developed in this study could be used in making decision regarding selection of water efficient pathways

Development of Life Cycle Water-Demand Coefficients for Coal-Based Power Generation Technologies

This paper aims to develop benchmark coefficients for water consumption and water withdrawals over the full life cycle of coal-based power generation. This study considered not only all of the unit operations involved in the full electricity generation life cycle but also compared different coal-based power generating technologies. Overall this study develops the life cycle water footprint for 36 different coal-based electricity generation pathways. Power generation pathways involving new technologies of integrated gasification combined cycle (IGCC) or ultra supercritical technology with coal transportation by conventional means and using dry cooling systems have the least complete life cycle water-demand coefficients of about 1 L/kWh. Sensitivity analysis is conducted to study the impact of power plant performance and coal transportation on the water demand coefficients. The consumption coefficient over life cycle of ultra supercritical or IGCC power plants are 0.12 L/kWh higher when conventional transportation of coal is replaced by coal-log pipeline. Similarly, if the conventional transportation of coal is replaced by its transportation in the form of a slurry through a pipeline, the consumption coefficient of a subcritical power plant increases by 0.52 L/kWh

Development of life cycle water footprints for gas-fired power generation technologies

The key objective of this paper is to develop a benchmark for water demand coefficients of the complete life cycle of natural gas-fired power generation. Water demand coefficients include water consumption and water withdrawals for various stages of natural gas production as well as for power generation from it. Pathways were structured based on the unit operations of the types of natural gas sources, power generation technologies, and cooling systems. Eighteen generic pathways were developed to comparatively study the impacts of different unit operations on water demand. The lowest life cycle water consumption coefficient of 0.12 L/kWh is for the pathway of conventional gas with combined cycle technology, and dry cooling. The highest life cycle consumption coefficient of 2.57 L/kWh is for a pathway of shale gas utilization through steam cycle technology and cooling tower systems. The water consumption coefficient for the complete life cycle of cogeneration technology is in the range 0.07 - 0.39 L/kWh and for withdrawals ranged 0.10 - 14.73 L/kWh

Development of life cycle water footprints for oil sands-based transportation fuel production

There is considerable focus on oil sands transportation fuel production. However, most studies focus on greenhouse gas emissions; there is limited work on understanding the life cycle water footprint. This study is an effort to address this gap. The main objective of this study is to develop water demand coefficients of the complete life cycle of oil sands transportation fuel production. Water demand coefficients include consumption and withdrawals, which were estimated for different oil sands unit operations pathways for production in Alberta, Canada. The pathways include three key operations, bitumen extraction, upgrading, and refining. The water consumption coefficients for the complete life cycle range from 2.08-4.19 barrels of water (bblW) per barrel of refined oil (bblBUR) and 2.87-5.16 bblW/bblBUR for water withdrawals coefficients. The lower limit for water demand coefficients is found in refined and upgraded in situ steam assisted gravity drainage recovery and the higher amount in refined and upgraded surface mining recovery. A sensitivity analysis was conducted through Monte Carlo simulations to study the uncertainty of the water demand coefficients. The water consumption coefficient for oil sands extraction at a 90% probability was found to be 0.34-2.8 bblW/bblB, upgrading be 0.87 bblW/bblU, and refining to be 1.52 bblW/bblR

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Integration of Impacts on Water, Air, Land, and Cost towards Sustainable Petroleum Oil Production in Alberta, Canada

This paper intends to develop quantitative indicators for comparative sustainability assessment of petroleum oil pathways in the province of Alberta, Canada. Eighteen pathways of oil production were developed in this study, and the sustainability indicators were assigned for each pathway to cover greenhouse gas (GHG) emissions, water demand, and land use in addition to the cost of supply. The developed sustainability indicators were aligned per functional unit and covered the full life cycle of petroleum oil production. The developed GHG emissions, cost of supply, and land use indicators are found in the range 17.50–226.20 kg of CO2 eq./bbl, 12.28–53.53 USD/bbl, and 0.06–0.178 m2/bbl, respectively. Four scenarios were comparatively conducted and assessed against the business-as-usual scenario within the period horizon 2009–2030. The cost-effective scenario was optimized with the objective function to minimize the cost of supply based on the constraints derived from the business-as-usual scenario. Sustainable scenarios were conducted with the lowest possible impacts on natural resources, GHG emissions, and the cost of supply accompanied by specific assumptions for petroleum oil production from different pathways in Alberta. The average annual savings on water demand and land area were found to be 67 and 30%, respectively, due to the shifting of upgrader feedstock from surface mining to the in-situ steam-assisted gravity drainage (SAGD) pathway. The corresponding increases due to this shifting in upgrader feedstock were found to be 40 and 3% in GHG emissions and cost of supply, respectively

Forecasting model for water-energy nexus in Alberta, Canada

Water demand coefficients and energy projections were set for Alberta province in Canada. A data-intensive model is structured to combine the gathered data to cover primary fuels and electricity generation pathways in Alberta. Profiles of historical and forecasted water demand for the energy sector in Alberta were developed in terms of total amounts of water consumption and water withdrawals to cover the time horizon from 2009 to 2030. The results were verified and showed that total water consumption for primary fuels in Alberta during 2009 was 358 million m3 with an average annual growth rate of 9%. The total water consumption for electricity generation in Alberta was 171 million m3 in 2009 and grows at an average rate of 4% per year. Sensitivity analysis shows that improvement by 1% in water consumption coefficient or reduction in expected production of ethanol from wheat will save annually for Alberta on average about 4.3 million m3 of water. The same sensitivity factor of 1% was applied to electricity generation pathways and 1.5 million m3 of water per year could be saved in consumption through a pathway of the natural gas combined cycle with cooling towers. Keywords: Alberta, Water forecast, Primary fuels, Electricity generation, Water-energy nexu