Influence of seawater temperature on thermal efficiency of an integrated electric power generation and water desalination plant

Influence of seawater temperature on thermal efficiency of an integrated electric power generation and water desalination plant

The world is facing unprecedented demand on every type of energy source to satisfy the energy thirst of urban development around the globe. The GCC countries are no exception. Kuwait, as an example of the GCC countries, consumed more than 160 million barrels equivalent of energy resources in 2010 alone to fulfill domestic energy demand. The overall energy consuming industries includes electrical power generation and water desalination plants, the oil industry, fuels for local transportation, and household use. The power generation and water desalination and oil industries have the highest share at around 53% and 27%, respectively. In the power plants, most of this energy is consumed as fuel for boilers to generate steam. Fuel required to run those plants in 2009 alone is a mix of heavy oil (44 million barrels); crude oil (20 million barrels); gas oil (11 million barrels) and 150,123 million m3 of natural gas. In the oil industries, the steam is used to heat petroleum feedstock for refining proces...

Thermodynamic analysis of combined electric power generation and water desalination plants

The design concept for a ‘clean energy producing vessel’ proposes the exploitation of remote offshore gas reserves, primarily from stranded fields, using a floating electrical power generation plant. In comparison to conventional approaches utilising liquefied natural gas and pipeline technologies, the clean energy producing vessel represents a highly innovative approach to the production and transportation logistics of natural gas for electricity generation. The main objective of this article is to undertake a financial evaluation of the clean energy producing vessel design concept. This is achieved by developing a financial model comprising cost and revenue modular elements that reflect the major technical components of the design concept: the floating production, storage and offloading unit; the electrical generation plant; cable transmission; carbon capture and electricity prices. The results for net present value and internal rate of return are derived for all combinations of either high- or low-revenue scenarios and for high- or low-cost scenarios. With a rather low internal rate of return of just 15.53%, the only scenario that yields a positive outcome is that of the high-revenue and low-cost combination. Accounting for savings in carbon dioxide emissions exerts only a negligible impact upon the results. Analysis of future research required concludes that following its deployment and implementation, the feasibility of the clean energy producing vessel design concept depends on the outcomes of economic and technological assessments, which are difficult to predict with any degree of certainty.

This study assessed the influence of summer seawater temperature and shipping on the introduction, establishment, and spread of nonindigenous fouling species on both local and regional scales in coastal regions of the USA. Using photographic surveys of 80 marinas on the east and west coasts of the USA, we defined thermal niches and ranges of summer sea surface temperature (SSST) for 27 abundant fouling species. We calculated percent cover of all abundant tunicates and bryozoans across sites and correlated species richness with water temperature and cargo shipping volume in each region. We quantified the relative importance of cargo shipping, seawater temperature, and distance between sites using Jaccard similarity between paired sites. Native species richness was positively correlated with SSST, while nonindigenous species (NIS) richness displayed a parabolic relationship with a peak at 20 °C. Temperature and cargo shipping traffic explained 53 % of variability in NIS richness, and only temperature was correlated with similarity between sites. We also found no link between similarity and distance between sites, and site–site comparisons showed no effect of NIS on native species richness on the scale of this study. It appears that cargo shipping may play a regional role in introduction of new species, but on local scales NIS distributions are more haphazard, possibly driven by local recreational boat traffic and associated larval dispersal or by other vectors affecting the local spread of these species. Our study demonstrates the importance of seawater temperature in allowing spread of NIS and influencing similarity between sites and regions.

Provision for potable water is an important priority for the world population. Seawater desalination is a promising technology that can address this need. Currently, desalinated water is the main or supplementary source of water for numerous countries; the technology can also be used in other regions, facing geographical or economic water shortage. However, desalination is an energy-intensive process. This paper offers a new perspective on desalinated water cost reduction through coordinated operation of power generation and water desalination plants. The paper, first, models the energy consumption of water desalination plants. This model is integrated into a unit commitment problem that optimizes the commitment and schedule of power generators and desalination plants. The benefits of coordinated operation are quantified using this modified unit commitment model. Simulation results on IEEE 118-bus test system show that the proposed coordination framework can save 21% to 40% of desalination energy payments, depending on the flexibility of desalination plants. The cost reduction in real systems depends on the power grid specifics, location of desalination plants, water production requirements, and other factors. This paper suggests that coordinated operation may provide substantial cost savings and should be carefully considered.

Coordinated Operation of Power Generation and Water Desalination

PurposeAn economic assessment was performed of the potential for clean energy options to contribute to the power and desalination needs in the State of Kuwait over the next 20 to 40 years. The paper aims to summarize two analyses that were performed for the Kuwait Institute for Scientific Research to develop a strategy promoting renewable energy and evaluating alternative technologies including nuclear energy.Design/methodology/approachThe analyses were performed using a power and water model for Kuwait that was constructed using the International Energy Agency – Energy Technology Systems Analysis Programme (IEA‐ETSAP) TIMES modeling framework. Data provided by the Ministry of Electricity and Water (MEW) and the Kuwait Petroleum Company (KPC) characterizes the projected demand for power and water; the existing and planned power generation and water desalination plants, including the expected retirement of existing plants; and future fossil fuel prices and availability. New power generation options – including renewable energy (RE), nuclear, combined cycle gas turbines (CCGT) and reheat steam power plants (RHSPP) – were compared in this least‐cost optimization framework.FindingsThe model results indicate that by 2030 the cost‐effective RE share is 11 percent of electricity generation in the reference case and 8 percent in the case with the nuclear option. The RE technologies alone provide a 2030 net‐back value compared to the reference case of US$2.35 billion, while in the nuclear case they increase the 2030 net‐back value by an additional US$1.5 billion. Increasing the RE share, as a government policy, to 10 percent, 15 percent and 20 percent, decreases the 2030 netback benefit by US$1.0, $3.6 and $8.3 billion, respectively.Research limitations/implicationsSensitivity runs based on scenarios that assume higher RE costs or lower availability, lower demand growth, lower oil and gas prices, higher nuclear plant investment costs, and RE capacity credit were analyzed.Practical implicationsThe analysis provides a compelling economic basis for initiating a renewable energy program in the State of Kuwait. However, these forecasted benefits will only materialize to the extent the projected RE investments are achieved if they begin in earnest soon.Originality/valueThe analysis identifies a cost‐effective share of renewable energy use in Kuwait as about 11 percent of electricity generation in 2030. The investment in renewable energy provides the State of Kuwait with a net‐back value of US$2.35 billion, due to the fuel savings that are generated by using renewables.

Decanter system as mechanical treatment for enhancing seawater feed quality at Sabiya power generation and water desalination plant

At present, the increase in population has caused an increase in the demand for electrical energy, which creates saturation in the national electrical system. In addition to this, the main source of energy for the generation of electricity is fossil fuels, which causes environmental pollution problems due to the increase in the concentration of greenhouse gases. To counteract the negative environmental impact, new energy sources that are friendlier to the environment have been sought, such as solar energy through power generation plants using solar concentrators. In this sense, this research proposes a mathematical optimization model to determine the feasibility of installing electric power generation plants through solar concentrators, to satisfy the energy demand in cities with the highest demand for electric power in the state of Michoacán. The proposed model considers the availability of water resources, the demand for energy, the costs involved for the installation of power generation plants, and the sizing of water collection systems to reduce the consumption of fresh water that is extracted from natural sources. It is a linear integer mixed programming model, where two scenarios are analyzed, considering variation in the operating time of the thermal storage system and the incorporation of the rainwater harvesting system to reduce freshwater consumption. The results show that 237,600 MW can be produced by installing three of the six power generation plants considered and considering a 19 h operation with thermal storage, generating a profit from the sales of the energy produced of 6,326,700 USD/year. Likewise, with the sizing of the rainwater harvesting system, it is possible to collect 1,678 m3 for the operation of the three determined power generation plants.

Distributed electric power generation technologies typically use little or no water per unit of electrical energy produced; in particular, renewable energy sources such as solar PV systems do not require cooling systems and present an opportunity to reduce water usage for power generation. Within the US, the fuel mix used for power generation varies regionally, and certain areas use more water for power generation than others. The need to reduce water usage for power generation is even more urgent in view of climate change uncertainties. In this paper, we present an example case within the state of Tennessee, one of the top four states in water consumption for power generation and one of the states with little or no potential for developing centralized renewable energy generations. The potential for developing PV generation within Knox County, Tennessee, is studied, along with the potential for reducing water withdrawal and consumption within the Tennessee Valley stream region. Electric power generation plants in the region are quantified for their electricity production and expected water withdrawal and consumption over one year, where electrical generation data is provided over one year and water usage is modeled based on the cooling system(s) in use. Potential solar PV electrical production is modeled based on LiDAR data and weather data for the same year. Our proposed methodology can be summarized as follows: First, the potential solar generation is compared against the local grid demand. Next, electrical generation reductions are specified that would result in a given reduction in water withdrawal and a given reduction in water consumption, and compared with the current water withdrawal and consumption rates for the existing fuel mix. The increase in solar PV development that would produce an equivalent amount of power, is determined. In this way, we consider how targeted local actions may affect the larger stream region through thoughtful energy development. This model can be applied to other regions, other types of distributed generation, and used as a framework for modeling alternative growth scenarios in power production capacity in addition to modeling adjustments to existing capacity.

Complying with the decision made by the Jordanian government to install a new wind power plant with a capacity ranging between 50–75 MW—to complement the Hofa and Ibrahimiyya wind power plants, whose electricity production presently forms only about 0.035% of the total electricity generated in Jordan mainly by power plants operating on conventional fuels—a 50 MW grid-connected wind power plant for electricity generation is proposed. Long-term (1993–2004) measured wind speed data at 24 widespread Jordanian sites was analyzed, and formed—in addition to the plant's specifications and parameters—an input data to carry out evaluation of the proposed plant's electricity production and analysis of its economic feasibility. It was found that the mean annual value of wind speed for Jordan is 5.5 m/s and that the seasonal trend of wind speed—for most of the studied sites and Jordan as a whole—matches the electricity load trend in the country. It was also found that RasMuneef, among the studied sites, has the highest annual mean wind speed of 10.65 m/s, the highest electricity production of 260.9 GWh/year, the highest specific yield of 1,882 kWh/m2, and the best economic indicators, i.e., internal rate of return, simple payback period, years-to positive cash flow, net present value, annual life cycle saving, benefit-cost ratio, and cost of energy. Moreover, it was found that about 201,417 tons of greenhouse gas emissions can be avoided annually if utilizing the proposed plant for electricity generation at RasMuneef instead of plants operating on conventional fuels. Therefore, employing the proposed power plant for electricity generation, in Jordan in general and in RasMuneef in particular, is highly recommended.

Industrial and utility uses account for about 35 percent of the country's consumption of oil and gas. Low- and intermediate-Btu gases made from coal may be used instead of natural gas or oil in electric power generation and industrial plants. Low-Btu gas cannot be stored economically or transmitted over appreciable distances; therefore, it is anticipated that coal will be shipped to gasification plants near the point of gas consumption. Production of low-Btu gas from coal may increase energy costs by approximately 200 percent above the cost of the coal (assumed to be $1.00 per million Btu). The overall thermal efficiency of the process is estimated to be about 70 to 80 percent based on cold gas purification. The use of intermediate-Btu gas involves fewer problems than the use of low-Btu gas since the heating value of the gas is high enough to reduce flame temperature limitations and feed gas volumes. Generation of intermediate-Btu gas at a central location with distribution over distances of up to about 100 miles would mitigate the problems of coal handling and gasification at each plant location. It is estimated that the use of intermediate-Btu gas would raise fuel costs 200 to 300 percent above the cost of the coal. The thermal efficiency of the process is 65 to 70 percent based on gas purification at temperatures below 120/sup 0/C. For the equivalent amount of energy, intermediate-Btu gas is estimated to cost 65 to 75 percent of the cost of pipeline gas produced from coal (assuming coal cost of $1.00 per million Btu). A number of other conclusions are listed. (LTN)

Operational Technology (OT), Industrial Control Systems (ICS), and Supervisory Control and Data Acquisition (SCADA) devices have been around in some form since the 1960s and they control specific functions in many critical industries such as electrical power generation, oil refineries, and water treatment plants. Since most are integrated with IT-based protocols (e.g., TCP/IP), there has been an explosion of OT control systems to provide meaningful information to businesses. While OT and IT speak a common language, this has exposed OT to much more Cyber Attacks that were once applied only to IT-based systems. Data Acquisition Devices (DAS), such as those manufactured by Moxa, now have ethernet ports to provide this link between both networks. The combination of new ethernet-capable OT devices, and those using upgraded converters (e.g., Moxa) for older OT devices, has primarily increased the attack surface. This study proposes a secure layered architecture that can be deployed to limit security threats for ethernet-capable (DAS) devices. The current state of many organizations is the lack of visibility of their OT assets and a knowledge gap on how to secure them. Keywords—Control systems, Cyber attacks, Cybersecurity resilience, Operational technology

Improvement in the air quality of the upper Ohio River valley has led to lichen recolonization at previously depauperate sites. Between 1973 and 1996 the number of corticolous macrolichen species in the area increased from 6 to 20. During the same time the mean species richness per site increased from 0.8 to 6.5. An indicator species, Flavoparmelia caperata, was absent from all study sites in 1973, but present at 27 of 28 study sites in 1996. Lichen studies performed over time provide a good tool to document air quality improvement, but a single study in a changing air quality environment may give problematic results. There are many published accounts of the detrimental effects of air pollution, especially sulfur dioxide, on lichen species distribution and community success (Ferry et al. 1973; Nash & Wirth 1988). Recently, however, industrial modernization and clean air legislation have led to decreases in sulfur emissions with concomitant decreases in ground-level SO2 concentrations both in North America and Europe. One source (Placet & Streets 1987) estimated that total SO2 emissions in the United States decreased from 26.8 million metric tons in 1975 to 21.2 million metric tons in 1985. There have been further decreases to 16.6 million metric tons in 1995 (USEPA 1996). Ohio has shown similar decreases in emissions with 2.99 million metric tons in 1975, 2.43 in 1985 and 1.90 in 1995. The upper Ohio River valley was once reputed to have the dirtiest air in the nation (Showman 1990). This area was heavily industrialized with coal-burning power plants, steel mills, foundries, and coking ovens. However, the region was severely affected by the economic recession in the late 1970s that led to the decline of the steel industry. Old plants were closed and others were upgraded and modernized. At the same time, clean air legislation led to particulate and gaseous emission controls on most electric power generation and industrial plants. This decrease in emissions had a dramatic effect on the ambient SO2 levels measured at upper Ohio River valley locations. Monitoring data (North Ohio Valley Air Authority, pers. comm.) show that in 1975, Steubenville, Ohio had an annual average SO2 concentration of 118 iggm-3. In 1985, this had almost halved to 60 agm-3, and by 1995 the value was further reduced to 34 agm-3. Likewise, East Liverpool, Ohio reported annual average SO2 concentrations of 120, 44, and 31 agm-3 during the same years. For comparison, the National ambient air quality standard (annual average) for SO2 is 80 Igm-3. Data from the several monitoring sites in the area consistently show a sharp decline from high to much lower values about 1981 (North Ohio Valley Air Authority, pers. comm.). Lichen studies in the upper Ohio River valley were first conducted in 1973 around Cardinal Power Plant, located just south of Steubenville, Ohio (Fig. 1). After the initial study, it was apparent that the regional SO2 background overwhelmed any contribution to ground-level concentrations by the power plant. Lichens were depauperate throughout a 570 km2 study area with no discernible differences between sites upwind and downwind from the Cardinal Plant. Studies were continued in order to monitor the impact of regional SO2 on lichens. Lichen re-surveys were performed in 1983, 1988, and then yearly to the present. Lichen improvement was first seen in 1988 and a note reporting this was published in 1990 (Showman 1990). The purpose of this paper is to describe lichen recolonization up to 1996 in greater detail, and to relate the observed changes in the lichen flora to potential associations with improved air quality over the same timespan.