Comparative study of photovoltaic technologies based on performance,cost and space requirement: Strategy for selection and application

The module performance is an important consideration for selecting PV technologies for electricity production, as well as the economic aspect. Also, PV energy yield under varying environmental conditions is largely dependent on the type of technology used. Therefore, this article presents a comparative analysis of different PV modules, of the same power, namely, monocrystalline, polycrystalline, amorphous silicon and hybrid, based on performance, cost and space requirement. The performance is evaluated in terms of module power output, yield, capture losses, fill factor and efficiency, according to the IEC 61724 standards, using Gwako, Nigeria as a case study. A novel technique called Fundamental PV Module Performance Analysis is used to analyze and compare the performance of the PV modules. The performance of a single module is then employed to calculate the overall performance of a PV array designed for a small off-grid house, and a suitable module is determined amongst the modules under study. Results provide insights into the behaviors of the different technologies with the environmental factors of the location, which have an impact on their power and kWh/kW outputs and the efficiency. This knowledge, coupled with the understanding of the constraints of cost and the module space requirements would be useful to researchers, engineers, installers etc. in Nigeria, for planning and developing photovoltaic electric systems for off-grid applications.     

Drought,water access,and urban agriculture: a case study from Silicon Valley

In California, the growing popularity of urban agriculture (UA) has unfolded against a backdrop of historic drought. While UA is often celebrated as an urban sustainability strategy, it must be able to persist during drought if it is to perform these functions. Using Santa Clara County – the geographic core of Silicon Valley – as a case study, we use interviews and surveys to explore the implications of drought for UA. We show how developing an understanding of water access for UA during a drought requires examining the social and institutional context of water management and use. In metropolitan California, the highly decentralised water supply system combined with the diverse institutional arrangements that support UA create an uneven landscape of water access. Consequently, the pressure to change water-consuming practices – that is, the stress that institutional drought responses place on different water users – is geographically and socially differentiated. Among UA water users, responses to drought have also varied, in part because the possibilities for change are constrained by the sociotechnical arrangements of UA sites and the different purposes of UA.     

The adoption of green energy technologies: The role of policies in Austria,Germany, and Switzerland

We contribute to the existing research about policy-induced technology adoption in several ways. First, we suggest a new survey design to measure the energy-related policy environment. Second, we simultaneously estimate the policy effects for the adoption propensity and the adoption intensity simultaneously and, third, we compare the policy effects in the three countries, Austria, Germany, and Switzerland. Based on a representative sample of firms for all three countries we find that policies essentially promote the adoption of technologies and they are practically ineffective for the intensity, which poses a great challenge to future policy designs. Voluntary agreements or demand-related factors are among the most important drivers for the adoption propensity of green energy technologies. Given the current institutional framework in the surveyed countries, subsidies are more effective in Austria, taxes are more effective in Germany, and demand-related factors are relatively more effective in Switzerland.     

Design study of a 150 kWth double loop circulating fluidized bed reactor system for chemical looping combustion with focus on industrial applicability and pressurization

Nowadays the lab scale feasibility of the chemical looping combustion technology has been proved. This article deals with many of the design requirements that need to be fulfilled to make this technology applicable at industrial scale. A design for a 150 kW_th chemical looping combustion reactor system is proposed. In the base case it is supposed to work with gaseous fuels and inexpensive oxygen carriers derived from industrial by-products or natural minerals. More specifically the fuel will be methane and a manganese ore will be the basis for the oxygen carrier. It is a double loop circulating fluidized bed where both the air reactor and the fuel reactor are capable to work in the fast fluidization regime in order to increase the gas solids contact along the reactor body. High operational flexibility is aimed, in this way it will be possible to run with different fuels and oxygen carriers as well as different operating conditions such as variation in air excess. Compactness is a major goal in order to reduce the required solid material and possibly to enclose the reactor body into a pressurized vessel to investigate the chemical looping combustion under pressurized conditions. The mass and heat balance are described, as well as the hydrodynamic investigations performed. Most design solutions presented are taken from industrial standards as one main objective is to meet commercial requirements.     

Review of socio-economic drivers of community acceptance and adoption of decentralised water systems

The aim of this paper is to highlight key social and economic drivers crucial to understanding community acceptance and adoption of decentralised water systems. The review focused on social science literature pertaining to alternative forms of household water, with an emphasis on research examining decentralised water acceptance. Researchers consistently reported that most communities were open to alternative water sources for domestic applications; however, this was highly dependent upon the level of personal contact with the water. Acceptance and adoption of alternative water technology, such as decentralised systems, was influenced by risk perception, water culture, and threat perception. Motivational drivers were also identified as potentially influencing adoption of decentralised systems. A clear limitation of the literature was found to be an over-reliance on measuring people's intentions to adopt alternative water systems and building a conceptual understanding of acceptance solely on hypothetical water supply scenarios. Further, within the social science literature there appears to be a skewing towards focusing on acceptance of centralised alternative water, such as recycled and desalinated water systems. Although there are some research outcomes that are generalizable to the decentralised water context, it is clear that there is a significant gap in the knowledge base of social drivers specific to the acceptance of decentralised water systems and the factors contributing to its widespread use. It is recommended that future research focus on examining public attitudes relevant to decentralised water systems, as well as adoption behaviours among current users of these systems. This will assist in developing policies specific to domestic decentralised water use.     

Barriers to the diffusion of renewable energy: studies of biogas for transport in two European cities

The diffusion of renewable energy – particularly in transport – in cities may facilitate the transition away from fossil fuels, improve air quality and reduce greenhouse gas emissions. Past studies on this topic have focused on system modelling of diffusion pathways, technology characteristics and also estimations of future availability of renewable energy, whilst neglecting the agency of producers and users. This article assesses barriers to the diffusion of biogas for transportation in cities from a system and actor perspective. Using document studies and interviews in the cities of Basel, Switzerland, and Odense, Denmark, we identify the presence of conflicting political priorities and shifting strategic objectives, resulting in mixed signals concerning the role and viability of biogas for transportation. This underlines the importance of public sector support and coherent design and implementation of strategy and policy enabling the diffusion of renewable energy.     

Evaluating the potential of biodiesel (via recycled cooking oil) use in Singapore,an urban city

Singapore has pledged to attain 7–11% Business-As-Usual carbon emissions reduction by 2020. About 19% of CO₂ contribution stemmed from road transport in 2005. Commercial vehicles, which uses mainly diesel, consumed 695 million litres diesel in 2012. An estimated 115,585 tonnes or 127 million litres cooking oils (derived from seeds/fruits) were consumed in 2010, in which the bulk of used cooking oil is re-incorporated into the food preparation process while only a small amount is being recycled into biodiesel or disposed into the sewerage. Nevertheless, the present research reveals that biodiesel derived from spent cooking oil has potential to be a viable fuel supplement. Surveys were carried out involving three market segments – suppliers, processors and end-users – to identify the barriers and obstacles in mass production of biodiesel. A key enabler of biodiesel as a fuel supplement towards a greener environment lies in government mandate/policies in promoting greater biodiesel usage.     

Security risks in nuclear waste management: Exceptionalism,opaqueness and vulnerability

This paper analyses some potential security risks, concerning terrorism or more mundane forms of crime, such as fraud, in management of nuclear waste using a PEST scan (of political, economic, social and technical issues) and some insights of criminologists on crime prevention. Nuclear waste arises as spent fuel from ongoing energy generation or other nuclear operations, operational contamination or emissions, and decommissioning of obsolescent facilities. In international and EU political contexts, nuclear waste management is a sensitive issue, regulated specifically as part of the nuclear industry as well as in terms of hazardous waste policies. The industry involves state, commercial and mixed public–private bodies. The social and cultural dimensions – risk, uncertainty, and future generations – resonate more deeply here than in any other aspect of waste management. The paper argues that certain tendencies in regulation of the industry, claimed to be justified on security grounds, are decreasing transparency and veracity of reporting, opening up invisible spaces for management frauds, and in doing allowing a culture of impunity in which more serious criminal or terrorist risks could arise. What is needed is analysis of this ‘exceptional’ industry in terms of the normal cannons of risk assessment – a task that this paper begins.     

The new gold rush: fueling ethanol production while protecting water quality

Renewable fuel production, particularly grain-based ethanol, is expanding rapidly in the USA. Although subsidized grain-based ethanol may provide a competitively priced transportation fuel, concerns exist about potential environmental impacts. This contribution focuses on potential water quality implications of expanded grain-based ethanol production and potential impacts of perennial-grass-based cellulosic ethanol. Expanded grain-based ethanol will increase and intensify corn production. Even with recommended fertilizer and land conservation measures, corn acreage can be a major source of N loss to water (20-40 kg ha(-1) yr(-1)). A greater acreage of corn is estimated to increase N and P loss to water by 37% (117 million kg) and 25% (9 million kg), respectively, and measures to encourage adoption of conservation practices are essential to mitigate water quality impairments. Dried distiller's grains remaining after ethanol production from corn grain are used as animal feed and can increase manure P content and may increase N content. Cellulosic fuel-stocks from perennials such as switchgrass and woody materials have the potential to produce ethanol. Although production, storage, and handling of cellulosic materials and conversion technology are limitations, accelerating development of cellulosic ethanol has the potential to reduce dependence on grain fuel-stocks and provide water quality and other environmental benefits. All alternative fuel production technologies could have environmental impacts. There is a need to understand these impacts to help guide policy and help make programmatic and scientific decisions that avoid or mitigate unintended environmental consequences of biofuel production.     

Fuel poverty and vulnerability in the EU low-carbon transition: the case of renewable electricity

The European Union (EU) and member states alike are following a tradition of addressing fuel poverty and vulnerability at the point of purchase by final consumers by seeking to influence the impact of income, energy price and the built environment on the ability of household consumers to access the energy that they need. By focusing on the conditions of energy transmission in the most rapidly growing renewable electricity sector in the UK – offshore wind – this paper aims to question whether the regulatory socio-technological framing of renewable electricity transmission is reproducing conditions for fuel poverty and vulnerability in the UK. By drawing a comparison with renewable electricity transmission in Bulgaria, this paper argues that the problem might be symptomatic of the EU as a whole. While not arguing against the proliferation of renewable electricity and its importance in meeting the 2020 targets, this paper calls for expanding the scope of fuel poverty alleviation policy throughout the whole renewable electricity supply chain, building on Helm's argument that energy companies at the middle of the supply chain are better suited to deliver fuel policy.     

Controlling urban air pollution caused by households: uncertainty, prices, and income

We examine the control of air pollution caused by households burning wood for heating and cooking in the developing world. Since the problem is one of controlling emissions from nonpoint sources, regulations are likely to be directed at household choices of wood consumption and combustion technologies. Moreover, these choices are subtractions from, or contributions to, the pure public good of air quality. Consequently, the efficient policy design is not independent of the distribution of household income. Since it is unrealistic to assume that environmental authorities can make lump sum income transfers part of control policies, efficient control of air pollution caused by wood consumption entails a higher tax on wood consumption and a higher subsidy for more efficient combustion technologies for higher income households. Among other difficulties, implementing a policy to promote the adoption of cleaner combustion technologies must overcome the seemingly paradoxical result that efficient control calls for higher technology subsidies for higher income households.     

Simultaneous adoption of integrated soil fertility management technologies in the Chinyanja Triangle,Southern Africa

Empirical scientific evidence indicates that there is still room for increasing food production by improving land productivity. This study aimed at identifying the key determinants that govern farmers’ decisions to adopt multiple components of integrated soil fertility management (ISFM) in a maize mixed cropping system of the Chinyanja Triangle, Southern Africa. Revealed preferences of ISFM components were collected from 320 randomly selected households and multivariate probit (MVP) model was used to analyse the simultaneous effects on adoption based on biophysical plot and household‐level socioeconomic attributes. The results show that farmers’ choices of a set of ISFM components are determined by a mix of factors that address the trade‐offs and synergies among them. Non‐farm income, moderate land quality perception, and education influence simultaneous technology adoption, while gender and crop loss increase the likelihood of farmers’ decisions to adopt independent options. Having other sources of income supports co‐adoption of inorganic fertilizer, residue incorporation, and crop rotation. Input/output market access, access to information, financial sources, and climate variability also play pivotal role in technology adoption. These results indicate that resource availability, learning costs, finances, and risk aversion need to be considered when designing and promoting ISFM technologies as a package.     

Investigation of sustainable energy alternatives for powering remote communities in northern Ontario

ABSTRACT

Remote communities in the North of Ontario survive in isolation as their proximity to the southern industrial sector of the province limits their accessibility to the major grid. The lack of grid connection has led to antiquated methods of power generation which pollute the environment and deplete the planet of its natural resources. Aside from the primary means of electricity generation being by diesel generators, generation infrastructure is deteriorating due to age and the stagnation of the power supply has led to communities facing load restrictions. These challenges may be resolved by introducing clean energy alternatives and providing a fuel blend option. The primary energy sources investigated in this research are solar, wind, and hydrogen. To assess the viability of these energy production methods in Northern communities, an exergy analysis is employed as it utilizes both the first and second law of thermodynamics to determine systems’ efficiency and performance in the surroundings. Local weather patterns were used to determine the viability of using wind turbines, solar panels and/or hydrogen fuel cells in a remote community. Through analysis of the resources available at the community, it was determined that the hydrogen fuel cell was best suited to provide clean energy to the community. Wind resulted in low efficiency in the range of 2–3% while solar efficiencies resulted in ranges of 18 – 19%, as the seasonal variations between the three years is not very great. Due to the higher operating efficiencies observed of the PV panels it would also be an attractive alternative to diesel generators however, the lack of consistent operation above 30% efficiency throughout the year, resulted in hydrogen fuel cells being a better alternative.     

Analysis of an intermediate-temperature proton-conducting SOFC hybrid system

The performance of an intermediate-temperature proton-conducting solid oxide fuel cell (pSOFC) hybrid system is investigated in this work. The hybrid system consists of a 20-kW pSOFC, a micro gas turbine (MGT), and heat exchangers. Heat exchangers are used to recover waste heat from pSOFC and MGT. The performance of the system is analyzed by using Matlab/Simulink/Thermolib. Flow rates of air and hydrogen are controlled by assigning different stoichiometric ratio (St). St considered in this study is between 2 and 3.5 for air, and between 1.25 and 1.45 for hydrogen. Results show that the combined heat and power (CHP) efficiency increases as the fuel St decreases or air St increases. This is because lowering fuel St means fewer fuel will be wasted from the fuel cell stack, so the CHP efficiency increases. On the other hand, as air St increases, the amount of recovered waste heat increases, so does the CHP efficiency.     

浅析国外军用组合机柜环境设计

本文主要介绍了一款海外军用组合机柜,它的结构和电气设计在可靠性方面具有突出的优点,具体在环境设计方面采用的技术值得我们借鉴.     

Garbage as fuel: pursuing incineration to counter stigma in postcolonial urban India

This paper explains why local leaders may adopt and promote forms of environmentalism that privilege aesthetic and class-based concerns, displacing environmentalisms of the poor, that promote more socially just and sustainable practices. Presenting a case study from Delhi, India, I ask why centralised and mechanised approaches to garbage services, which included incineration or “waste-to-energy,” were promoted over manual recycling systems despite their unproven efficacy and significant expense. I argue that Indian leaders saw incineration as a mechanism for decontaminating garbage, and by association, de-stigmatising the city’s reputation. Transforming a chaotic cluster of materials – garbage – into a singular object for incineration – fuel – allowed Indian bureaucrats and managers, who tend to be upper-caste men, claim and profit from materials that are recycled by lower-caste and Muslim informal workers. I analyze ethnographic and documentary evidence and find that these motivations became particularly legible during the 2010 Commonwealth Games in Delhi, when postcolonial desires for international recognition were made explicit.     

Effects of chaotic acclimation applied on performance of microbial fuel cells

Microbial fuel cells (MFCs) are one of the bioreactors that produce electrons by metabolizing substrate from microorganisms, and have the ability to both degrade waste solution and produce electrons. Recently, the activity of microorganisms has limited the power performance of MFCs. Chaos has been used to stimulate activity of microorganisms, but it has not been used previously in MFCs. In this study, three types of acclimations – native acclimation (NA), MFC acclimation (MFCA), and MFC embedded with chaotic electric field acclimation (CMFCA) – are applied to realize their performance and chemical oxygen demand (COD) removal in MFCs, respectively. Results show that the current density and the power density of CMFCA were improved by 1.33 and 1.25 times than MFCA, and the COD removal of CMFCA reached 85% after five days. In addition, the acclimation stage at the condition of CMFCA appeared after 10 days, but was not found for the MFCA system. These observations would provide positive information for improving the performance of MCFs in the future.     

From open access to access by all: restating challenges in designing groundwater management in Andhra Pradesh, India

In a village-based watershed in Andhra Pradesh, India, it is increasingly difficult for users to access and extract groundwater for irrigation: a 'pumping race' is taking place. A move from groundwater development towards groundwater management is required, with a new perspective on options for change. Through a study of borewell technology and groundwater use, and considering new local developments in electricity supply and participatory resource management, the article argues that groundwater is a resource with 'instructions for use'. The technological dimensions of groundwater irrigation urge its study as a socio-technical process in order to design sustainable and equitable groundwater management.