Harnessing overlapped temperature-salinity gradient in solar-driven interfacial seawater evaporation for efficient steam and electricity generation

Solar-driven interfacial water evaporation(SIWE)offers a superb way to leverage concentrated solar heat to minimize energy dissipation during seawater desalination.It also engenders overlapped temperaturesalinity gradient(TSG)between water-air interface and adjacent seawater,affording opportunities of harnessing electricity.However,the efficiency of conventional SIWE technologies is limited by significant challenges,including salt passivation to hinder evaporation and difficulties in exploiting overlapped TSG simultaneously.Herein,we report self-sustaining hybrid SIWE for not only sustainable seawater desalination but also efficient electricity generation from TSG.It enables spontaneous circulation of salt flux upon seawater evaporation,inducing a self-cleaning evaporative interface without salt passivation for stable steam generation.Meanwhile,this design enables spatial separation and simultaneous utilization of overlapped TSG to enhance electricity generation.These benefits render a remarkable efficiency of90.8%in solar energy utilization,manifesting in co-generation of solar steam at a fast rate of 2.01 kg m^(-2)-h^(-1)and electricity power of 1.91 W m^(-2)with high voltage.Directly interfacing the hybrid SIWE with seawater electrolyzer constructs a system for water-electricity-hydrogen co-generation without external electricity supply.It produces hydrogen at a rapid rate of 1.29 L h^(-1)m^(-2)and freshwater with 22 times lower Na+concentration than the World Health Organization(WHO)threshold.

Electricity generation during wastewater treatment by a microbial fuel cell coupled with constructed wetland

A membrane-less constructed wetland microbial fuel cell （CW-MFC） is constructed and operated under continuous flow with a hydraulic retention time （HRT） of 2 d. Fed with glucose, the CW-MFC generates a stable current density of over 2 A/m3 with a resistor of 1 kΩ and has a chemical oxygen demand （COD） removal efficiency of more than 90% after the startup of 2 to 3 d. A series of systems with the electrode spacings of 10, 20, 30 and 40 cm are compared. It is found that the container with the electrode spacing of 20 cm gains the highest voltage of 560 mV, the highest power density of 0. 149 W/m 3, and the highest Coulombic efficiency of 0.313%. It also has the highest COD removal efficiency of 94. 9%. In addition, the dissolved oxygen （DO） concentrations are observed as the lowest level in the middle of all the CW-MFC reactors. The results show that the more COD is removed, the greater power is generated, and the relatively higher Coulombic efficiency will be achieved. The present study indicates that the CW-MFC process can be used as a cost-effective and environmentally friendly wastewater treatment with simultaneous power generation.

Environmental damage costs from fossil electricity generation in China, 2000~2003

Electricity consumption increases rapidly with the rapid development of China. The environmental damage costs of electricity generation are very important for both policy analysis and the proper management of the environment. A method was developed in this work to estimate gross environmental damage costs according to emission inventory and environmental cost factors, and to extend the costs from provincial to national level with population density. In this paper, sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter less than 10 μm in diameter (PM10), and carbon dioxide (CO2) from fossil fired power plants over 6000 kW were selected as index pollutants to quantify the environmental costs of damages on human health and global warming. With the new developed method, environmental damage costs, caused by 3 types of fired power plants in 30 provinces and 6 economic sectors during the years 2000 to 2003, were evaluated and analyzed. It can be seen that the calculated total national environmental damage costs of electricity have rapidly increased from 94930.87×106 USD in 2000 to about 141041.39×106 USD in 2003, with an average annual growth rate of 14.11%. Environmental damage costs of SO2, NOx, PM10, and CO2 are 69475.69×106, 30079.29×106, 28931.84×106, and 12554.57×106 USD and account for 49.26%, 21.33%, 20.51%, and 8.90% of total environmental costs in fossil electricity generation, respectively. With regard to regional distribution, external costs caused by fossil electricity generation are mainly concentrated in the more populated and industrialized areas of China, i.e., the Eastern Central and Southeastern areas.

Development of hydraulic power unit and accumulator charging circuit for electricity generation,storage and distribution

It is the purpose of the present paper to convert hydraulic energy to electric energy and saves both the pressure and electrical energy for re - use during the next system upstroke using two secondary units coupled to induction motor to drive cylinder loads. During upstroke operation, the variable pump/motor （P/M） driven by both electric motor and the second （P/M） works as hydraulic pump and output flow to the cylinders which drive the load. During load deceleration, the cylinders work as pump while the operation of the two secondary units are reversed, the variable （P/M） works as a motor generating a torque with the electric motor to drive the other （P/M） which transforms mechanical energy to hydraulic energy that is saved in the accumulator. When the energy storage capacity of the accumulator is attained as the operation continues, energy storage to the accumulator is thermostatically stopped while the induction motor begins to work as a generator and generates electricity that is stored in the power distribution unit. Simulations were performed using a limited PT2 Block, i.e. 2nd-order transfer function with limitation of slope and signal output to determine suitable velocity of the cylinder which will match high performance and system stability. A mathematical model suited to the simulation of the hydraulic accumulator both in an open-or close-loop system is presented. The quest for improvement of lower energy capacity storage, saving and re-utilization of the conventional accumulator resulting in the short cycle time usage of hydraulic accumulators both in domestic and industrial purposes necessitates this research. The outcome of the research appears to be very efficient for generating fluctuation free electricity, power quality and reliability, energy saving/reutilization and system noise reduction.

Feasible design for electricity generation from Chlorella vulgaris using convenient photosynthetic conditions

Many recent studies are concerned with low cost,easy to handle and alternative renewable energy as a feasible solution for the upcoming crisis of energy shortage.Microalgae are unicellular entities the can only depend on CO_(2),water and solar power to cover their nutritional needs.The current study is concerned with using algal cells in a polymeric hydrogel,as a cheap source of energy for electricity generation.Chlorella vulgaris has been proved to be a promising algal species for electricity generation,as compared with Micractinium reisseri.PVA hydrogel has been used for the immobilization of both algal species in order to protect them from the adverse surrounding conditions in addition to its ability to slowly release the required water molecules according to needs.Under these conditions,C.vulgaris showed the ability to generate 60 mV compared with 15 mV generated by M.reisseri.Scanning electron micrographs showed nano-threads that bind the C.vulgaris cells to each other,indicating the ability of algae to create nanowires that facilitate the electron transfer among algal cells and from cells to the nearest electrode.However,we would expect an increase in the produced potential with simultaneous amendment of environmentally polluted water,such as sewage or waste water.Both of FTIR and raman spectroscopy proved the presence of the characteristic groups of PVA hydrogel and proved the proper integration of the algal cells inside the hydrogel cavities.

National Electricity Generation,Electricity Consumption and Peak Load by Grid (April 2006)

Statistics on electricity generation and time of frequency over-limit;Statistics on electricity consumption and peak load.

National Electricity Generation,Electricity Consumption and Peak Load by Grid (March 2006)

Statistics on electricity generation and time of frequency over-limit;Statistics on electricity consumption and peak load.

Electricity generation grew steadily

In the first half of 1996, electricity generation in China had steadily, grown with a total electricity generation accumulated to 508.3 TWh, it was 47.5% of the planned figure in the year, and 8.3% higher than the same period of previous year. Among the generation, hydro-electricity amounted to 78.2 TWh, 5.39% lower than previous year, thermal electricity amounted to 424.55 TWh, 10.87% higher than previous year, nuclear electricity amounted to 5.52 TWh, 47.15% higher than previous year. The steady growth of thermal electricity might attribute to newly installed generating capacity in one hand, and the

Electricity Generation and the Present Challenges in the Nigerian Power Sector

National development requires adequate electricity supply of which all activities--generation, transmission and distribution leading to it are capital-intensive in terms of funds, natural and human resources. The dwindling power sector government funding coupled with low private sector participation and weak level political will require creative and innovative solutions in addressing the power supply problem in Nigeria. Hence, this paper seeks to examine power sector privatization as a viable option.

Electricity Generation by Solar Energy in Turkey： Current State and Outlook

Turkey is in good condition in terms of solar energy because of the fact that, Turkey falls in between 40 degree North and 40 degree South latitude which is called as ＂sunbelt＂. The potential of producing electric from solar energy is very high in terms of potential of Turkey. According to a report by the Turkish Energy Ministry, Turkey＇s average rate of electrical energy consumption increased to levels 5.59 in the last 11 years. Moreover, solar energy may be primary energy source on account of the fact that, Turkey is in the position of a country importing energy and has signed Kyoto Protocol of carbon emission to atmosphere. The aim of the article is to give information about acts need to be done and present policies of Turkey on producing electric from solar energy. Beyond question, the policies of the government will determine the direction of developmental momentum of energy industry in Turkey as whole world will. The present support to production of electric from solar energy is not enough, so it is needed to give much higher level of support to this sector. In this context, it is essential to enhance guarantied tariff cost and the power of unlicensed electric production.

CO2 Emission from Electricity Generation in Malaysia： A Decomposition Analysis

In tenth Malaysian Plan, Malaysian government had voluntarily targeted to reduce its emission intensity to 40% compared to the 2005 level by the year 2020 and recently re-pledge to reduce more and declared for 45% emission reduction by 2030. Looking at the country＇s high dependency to the fossil fuel generation it is a high concern on the increasing CO2 emission in Malaysia. This paper intends to analyze the current status of CO2 emissions from electricity generation in Malaysia during the period 1992-2014 by applying the LMDI （logarithmic mean Divisia index） technique to find the nature of the factors influencing the changes in CO2 emissions. The decomposition analysis observed three biggest factors contributed to the reduction of CO2 emission throughout the period which is thermal generation effect, electricity generation efficiency effect and electricity structure effect.

Towards an Ethical and Ecological Approach to Electricity Generation: A Comparative Analysis of Coal and Nuclear Power in the USA

According to the US Energy Information Administration, about 4118 billion kilowatt-hours (kWh) electricity was generated at large-scale generation facilities in 2019. About 63% of this was from fossil fuels, e.g., coal, natural gas, petroleum, and other gases. Environmental exposure to particulates, sulfur dioxide, nitrogen oxides, mercury, arsenic, radioactive fly ash, and other pollutants are extremely detrimental to the human cardiovascular, respiratory, and nervous systems. Such exposure increases the risk of lung cancer, stroke, heart disease, chronic respiratory diseases, respiratory infections, and other illnesses. In light of the challenges associated with renewables providing large quantities of base load power, as well as other factors, the benefits offered by nuclear power should be reexamined by policy makers to move the country towards a more ecological and ethical method of electric power production. This paper offers a concise analysis of many of the salient issues, comparing electricity generation from coal plants and light water nuclear reactors.

Insights into the role of oxygen-containing functional groups on carbon surface in water–electricity generation

A deep understanding of the electricity generation mechanism from the interaction between water molecules and carbon material surfaces is attractive for next-generation water-based energy conversion and storage systems.Herein,an asymmetric generator was assembled based on functionalized carbon nanotubes films to investigate the relative contribution from various oxygen functional groups on carbon surface to the water-electrical performance.Experiments and calculations demonstrate that the electricity mainly originates from the water molecule adsorption by carboxyl groups and dissociation of functional groups on carbon surface,which leads to the formation of electrical double layers at interfaces.This device allows the electricity generation with a variety of water sources,such as deionized water,tap water,as well as seawater.In particular,the generator based on carboxyl carbon nanotubes can induce a voltage of over 200 mV spontaneously in natural seawater with the power density of about 0.11 mW·g^(−1).High voltages can be achieved easily through the series-connection strategy to power electronic products such as a liquid crystal display.This work reveals the dominant role of carboxyl groups in carbon-based water–electricity conversion and is expected to offer inspiration for the preparation of carbon materials with high electrical performance.

Solar evaporation for simultaneous oil-water separation and electricity generation with Janus wood-based absorbers

Oily wastewater from ocean oil spills endangers marine ecosystems and human health. Therefore, developing an effective and sustainable solution for separating oil-water mixtures is urgent. Interfacial solar photothermal evaporation is a promising approach for the complete separation of two-phase mixtures using only solar energy. Herein, we report a carbonized wood-based absorber with Janus structure of comprising a hydrophobic top-layer and an oleophobic bottom-layer for simultaneous solar-driven oil-water separation and electricity generation. Under sunlight irradiation, the rapid evaporation of seawater will induce a separation of oil-water mixtures, and cause a high salt concentration region underlying the interface, while the bottom “bulk water” maintains in a low salt concentration, thus forming a salinity gradient. Electricity can be generated by salinity gradient power. Therefore, oil-water separation efficiency of > 99% and derived extra electricity power of ~0.1 W/m2 is achieved under solar radiation, demonstrating the feasibility of oil-water separation and electricity production synchronously directly using solar energy. This work provides a green and cost-effective path for the separation of oil-water mixtures.

Tortuosity regulation of two-dimensional nanofluidic films for water evaporation-induced electricity generation

Water evaporation-induced electricity generation is a promising technology for renewable energy harvesting.However,the output power of some reported two-dimensional(2D)nanofluidic films is still restricted by the relatively weak water–solid interactions within the tortuous nanochannels.To further enhance the comprehension and utilization of water–solid interactions,it is of utmost importance to conduct an in-depth investigation and propose a regulatory concept encompassing ion transport.Herein,we propose tortuosity regulation of 2D nanofluidic titanium oxide(Ti_(0.87)O_(2))films to optimize the ion transport within the interlayer nanochannel for enhanced efficiency in water evaporation-induced electricity generation for the first time.The significance of tortuosity in ion transport is elucidated by designing three 2D nanofluidic films with different tortuosity.Tortuosity analysis and in situ Raman measurement demonstrate that low tortuosity can facilitate the formation of efficient pathways for hydrated proton transport and promote water–solid interactions.Consequently,devices fabricated with the optimized 2D nanofluidic films exhibited a significantly enhanced output power density of approximately 204.01μW·cm^(−2),far exceeding those prepared by the high-tortuosity 2D nanofluidic films.This work highlights the significance of the construction of low tortuosity channels for 2D nanofluidic films with excellent performance.

Effects of crop residues for animal consumption and soil enhancement on the electricity generation potential of residues:A case study of Sawla-Tuna-Kalba district,Ghana

Many studies have estimated the potential of crop residues for energy generation globally and recognized its great potential,especially in rural areas where on-grid electricity is uneconomical.However,crop residues have other equally important uses as animal feed and as mulch for soil enhancement,especially in rural farming communities.Nevertheless,most of the known studies have neglected the estimation of the quantity of crop residues that will be required for feeding animals and also for the enhancement of soil through mulching in their energy potential estimation from crop residues.Neglecting these two important uses can lead to the over-exploitation of the residues for energy generation at the expense of conservation agriculture practices as well as depriving animals of quality feed which can lead to low crop yield and animal production,with the ability to cause hunger and poverty.This study has assessed the potential of electricity generation from agricultural residues in the Sawla-Tuna-Kalba district of Ghana using gasification technology,taking cognizance of the proportion of residues needed for animal consumption and soil enhancement.The results of the study indicate that out of the 207646.22 t of residues that can be generated from maize,yam,cassava,millet,sorghum,and groundnut,26830.36 t(representing 13%)will be required by sheep,goats,and cows for consumption,and 13936.17 t(representing 7%)will be required for mulching soils where the crops are planted.Also,it was found that a total of 592.17 MW∙h of electricity can be generated from crop residues without animal consumption and soil enhancement needs,while 461.89 MW∙h could be generated from the residues,considering animal feed and soil enhancement.This study has indicated that it is not enough to consider soil enhancement and animal feeding in agricultural biomass power generation through recovery factors without the exact quantification of residues required for these purposes since this can lead to a violation of conservation agricultural practice.Hence,it is concluded that the proper estimation of residues required for soil enhancement needs and animal feeding must be considered in the estimation of crop residues available for electricity generation following the method proposed in this study.It is further concluded from this study that,the proper utilization of crop residues serve as an important resource for meeting the electricity demand of the inhabitants in the study location without compromising on the residues that will be required for the consumption of all the animals in the location as well as for enhancement of the soil.

Changes in the microbial community structure and diversity during the electricity generation process of a microbial fuel cell with algal-film cathode

A two-chamber microbial fuel cell(MFC)with algal-film cathode was constructed.It showed good electric-generating performance with three electric-generating stages:start-up,development,and stable.An average output voltage reached~0.412 V during the stable period.A maximum power density during continuous operation was 19.76 mW/m^(2).Bacterial samples were collected from the anode in the three stages(A1,A2,and A3),and their community structure and diversity were analyzed using Illumina MiSeq high-throughput sequencing technology.A total of 4238 operational taxonomic units were identified based on the number of taxa.At the phylum level,Proteobacteria and Bacteroidetes played a dominant role in the three stages and increased significantly during electricity generation.Compared with A1,the relative abundances of Proteobacteria in A2 and A3 increased by 23.30%and 32.06%,respectively,whereas those of Bacteroidetes in A2 and A3 increased by 5.56%and 14.50%,respectively.At the genus level,there were differences in the composition of bacterial communities among the three stages.Acinetobacter and Chlorobium became the dominant genera in A2,replacing Nitrospira and norank_f__Saprospiraceae in A1,and Sphingobacterium and Ochrobactrum became the dominant genera in A3.According to the sample cluster and principal component analyses,A1 was clustered into one class,and A2 and A3 were clustered into a second class.This work revealed bacterial community succession at the anode of an algal-film cathode MFC during the electricity generation process,which provides a theoretical basis for the subsequent promotion of electricity generation by algal-film cathode MFCs.