Energy payback time of grid connected pv systems: comparison between tracking and fixed systems

A review of existing studies about LCA of PV systems has been carried out. The data from this review have been completed with our own figures in order to calculate the Energy Payback Time of double and horizontal axis tracking and fixed systems. The results of this metric span from 2 to 5 years for the latitude and global irradiation ranges of the geographical area comprised between −10◦ to 10◦ of longitude, and 30◦ to 45◦ of latitude. With the caution due to the uncertainty of the sources of information, these results mean that a GCPVS is able to produce back the energy required for its existence from 6 to 15 times during a life cycle of 30 years. When comparing tracking and fixed systems, the great importance of the PV generator makes advisable to dedicate more energy to some components of the system in order to increase the productivity and to obtain a higher performance of the component with the highest energy requirement. Both double axis and horizontal axis trackers follow this way, requiring more energy in metallic structure, foundations and wiring, but this higher contribution is widely compensated by the improved productivity of the system.

Nitrogen fertilizer rate management as a nitrous oxide mitigation strategy: Development of a nitrous oxide emission reduction protocol (NERP)

Nitrous oxide (N2O) is a potent agricultural greenhouse gas (GHG). More than 50% of the global anthropogenic N2O flux is attributable to emissions from soil, primarily due to large fertilizer nitrogen (N) applications to corn and other non-leguminous crops. Quantification of the trade–offs between N2O emissions, fertilizer N rate, and crop yield is an essential requirement for informing management strategies aiming to reduce the agricultural sector GHG burden, without compromising productivity and producer livelihood. There is currently great interest in developing and implementing agricultural GHG reduction offset projects for inclusion within carbon offset markets. Nitrous oxide, with a global warming potential (GWP) of 298, is a major target for these endeavours due to the high payback associated with its emission prevention. In this paper we use robust quantitative relationships between fertilizer N rate and N2O emissions, along with a recently developed approach for determining economically profitable N rates for optimized crop yield, to propose a simple, transparent, and robust N2O emission reduction protocol (NERP) for generating agricultural GHG emission reduction credits. This NERP has the advantage of providing an economic and environmental incentive for producers and other stakeholders, necessary requirements in the implementation of agricultural offset projects.

Research roadmap summary - Integrated Design and Delivery Solutions (IDDS)

Changes in the construction sector are creating opportunities in research to maximise the benefits of those changes and to continue the exciting developments in improved people skills, new processes and developing technologies. Many research centres around the world are investigating aspects of the current changes to drive their particular expertise forward. However, the CIB Integrated Design and Delivery Solutions (IDDS) priority research theme takes a higher-level view of the changes and then focuses down on a prioritised set of research targets. These targets have been investigated, re-focussed and validated over a period of four years through many workshops, conferences and meetings by a wide ranging group of representatives from approximately 90 industry and research organisations. The outcomes of such research, once put into practice should be significantly shortened timespans from conception of need to occupation of new or revised structures. As time is money, the owners will get their investments into productive use sooner, which means a shorter payback time. In addition, there will inevitably be a reduction in construction costs as productivity increases. The improvements in reliable delivery and improved quality currently being seen in relatively simplistic use of Building information Modelling (BIM) (compared to full IDDS) will inevitably continue its on-going trajectory of improvement. We should also consider the wider economic contribution to society that will stem from such improvements and, finally, and by no means unimportantly, the reliable modelling and delivery of sustainability at both the building and estate/ area scale will significantly improve carbon footprints and other sustainable outcomes. Whilst there are huge opportunities for early adopters, the primary risk will be the expansion of the gap between those working in this way and those who are not so advanced or who even refuse to progress . The opportunities to address the significant and widely varying wastes within the structure of the construction sector and within and across projects are huge and timely and industry is encouraged to become involved.

Research roadmap report : Integrated Design and Delivery Solutions (IDDS)

Changes in the construction sector are creating opportunities in research to maximise the benefits of those changes and to continue the exciting developments in improved people skills, new processes and developing technologies. There are many research centres around the world investigating aspects of the current changes to drive their particular expertise forward. However, the CIB Integrated Design and Delivery Solutions (IDDS) priority research theme takes a higher-level view of the changes and then focuses down on a prioritised set of research targets. These targets have been investigated, re-focussed and validated over a period of four years through many workshops, conferences and meetings by a wide ranging group of representatives from approximately 90 industry and research organisations. This roadmap prioritises and details the research to be performed, why and by whom. In particular, some 25 CIB Working Commissions and Task Groups are explained as having potential roles in the delivery of this research theme. We are extremely privileged to have been urged on by such distinguished construction professionals in their forewords and the case for research. The outcomes of such research, once put into practice should be significantly shortened timespans from conception of need to occupation of new or revised structures. As time is money, the owners will get their investments into productive use sooner, which means a shorter payback time. In addition, there will inevitably be a reduction in construction costs as productivity increases. The improvements in reliable delivery and improved quality currently being seen in relatively simplistic use of Building information Modelling (BIM) (compared to full IDDS) will inevitably continue its on-going trajectory of improvement. We should also consider the wider economic contribution to society that will stem from such improvements and, finally, and by no means unimportantly, the reliable modelling and delivery of sustainability at both the building and estate/ area scale will significantly improve carbon footprints and other sustainable outcomes. Whilst there are huge opportunities for early adopters, the primary risk will be the expansion of the gap between those working in this way and those who are not so advanced or who even refuse to progress1. However, a similar issue arises between industry, clients, educators and trainers; the latter have particular challenges, having existed for many years in a sector that has had relatively few technological changes. However, the opportunities to address the significant and widely varying wastes within the structure of the construction sector and within and across projects are huge and timely. Whilst this Roadmap is specifically targeted at the Standing Commissions and Task Groups of the CIB, it is hoped that there are elements for research and applied research across academia and industry.

Desalination with a solar-assisted heat pump : an economic optimization

The solar-assisted heat pump (SAHP) desalination, based on the Rankin cycle, operates in low temperature and utilizes both solar and ambient energy. An experimental SAHP desalination system has been constructed at the National University of Singapore, Singapore. The system consisted of two main sections: an SAHP and a water distillation section. Experiments were carried out under the different meteorological condition of Singapore and results showed that the system had a performance ratio close to 1.3. The heat pump has a coefficient of performance of about 8, with solar collector efficiencies of 80% and 60% for evaporator and liquid collectors, respectively. Economic analysis showed that at a production rate of 900 L/day and an evaporator collector area of around 70m2 will have a payback period of about 3.5 years.

Dewatering of microalgal culture for biodiesel production : exploring polymer flocculation and tangential flow filtration

Background: Conventional biodiesel production relies on trans-esterification of lipids extracted from vegetable crops. However, the use of valuable vegetable food stocks as raw material for biodiesel production makes it an unfeasibly expensive process. Used cooking oil is a finite resource and requires extra downstream processing, which affects the amount of biodiesel that can be produced and the economics of the process. Lipids extracted from microalgae are considered an alternative raw material for biodiesel production. This is primarily due to the fast growth rate of these species in a simple aquaculture environment. However, the dilute nature of microalgae culture puts a huge economic burden on the dewatering process especially on an industrial scale. This current study explores the performance and economic viability of chemical flocculation and tangential flow filtration (TFF) for the dewatering of Tetraselmis suecicamicroalgae culture. Results: Results show that TFF concentrates the microalgae feedstock up to 148 times by consuming 2.06 kWh m-3 of energy while flocculation consumes 14.81 kWhm-3 to concentrate the microalgae up to 357 times. Economic evaluation demonstrates that even though TFF has higher initial capital investment than polymer flocculation, the payback period for TFF at the upper extreme ofmicroalgae revenue is ∼1.5 years while that of flocculation is ∼3 years. Conclusion: These results illustrate that improved dewatering levels can be achieved more economically by employing TFF. The performances of these two techniques are also compared with other dewatering techniques.

Comparison of performance of solar photovoltaics on dual axis tracker with fixed axis at 13 degrees N latitude

Tracking systems, that continually orient photovoltaic (PV) panels towards the Sun, are expected to increase the power output from the PV panels. Tremendous amount of research is being done and funds are being spent in order to increase the efficiency of PV cells to generate more power. We report the performance of two almost identical PV systems; one at a fixed latitude tilt and the other on a two-axis tracker. We observed that the fixed axis PV panels generated 336.3 kWh, and the dual-axis Sun-tracked PV panels generated 407.2 kWh during August 2012 March 2013. The tracked panels generated 21.2% more electricity than the optimum tilt angle fixed-axis panels. The cost payback calculations indicate that the additional cost of the tracker can be recovered in 450 days.

Economic analysis of utilizing Kainji gas kiln for fish smoking in the Kainji Lake Basin of Nigeria

Marketing of smoked fish in the Kainji Lake Basin (Nigeria) has been found to be complex, traditional and inefficient. It is also said to be limited in scope due to poor handling and processing techniques, lack of storage facilities and inadequate marketing informations. The invention of Kainji gas kiln has been found suitable to overcoming poor handling and processing techniques. This paper discusses the feasibility of operating Kainji gas kiln commercially supported with adequate storage facilities and competent management hands. The financial indicators of net present value (NPV), 47,481.11, Internal rate of return (IRR) 24% and payback period of 2.3 years that are calculated confirmed that the commercial use of Kainji gas kiln is indeed profitably feasible

The Determinants of Energy Efficiency Investments in the U.S.

31 p.

The Private Provision of International Impure Public Goods: the Case of Climate Policy

33 p.

Etxebizitza baten kalifikazio energetikoa. Hobekuntza proposamenak

[EU]Komunikabideetan hainbesteko oihartzuna izan zuen eta saldu edo alokatutako etxebizitzak energia eraginkortasunaren ziurtagiria izatera derrigortzen zituen dekretuak urtebete eskas bete du. Proiektu honetan aipatutako legea 2020. urterako ezarritako europar helburu energetikoak betetzeko bidean kokatu egiten da, ziurtapenerako jarraitu beharreko metodologian gehiago sakonduz eta aipaturiko helburuentzako duen garrantzia azpimarratuz. Proiektuak bi zati nagusi ditu. Lehenengo zatian, proiektuaren helburu nagusia den etxebizitza baten kalifikazio energetikoa burutzen da, G letrako kalifikaziorik baxuena lortuz. Ondoren, kalifikatutako etxebizitzaren energia eraginkortasuna hobetzeko neurri posible batzuek bideragarritasuna aztertzen da. E letra erraztasun nahikoz lor daiteke, inbertsioaren berreskuratze aldi oso onargarriekin. C letraraino igotzea ere posible da aztertutako neurriak bateratuz, baina berreskuratze aldiak handiagoak izango lirateke.

Etxebizitza baten kalifikazio energetikoa eta hobekuntzak.

[EU]Garatutako txosten honekin, etxebizitza baten kalifikazio energetikoa burutuko da. Izan ere, gai honek orain dela bi urte sartu zen dekretuaren ondorioz berebiziko garrantzia hartu du etxe bat saldu edo alokatzeko orduan. Aipatutako kalifikazio energetikoa lortu ahal izateko CE3X programa erabiliko da. Horretarako, beharrezko izango da aztertutako etxearen datu aipagarrienak izatea (neurriak, materialak, leihoak...). Lehenik eta behin, proiektuaren helburu den etxebizitzaren kalifikazio energetikoa lortuko da, F letra eskuratuz, oso kalifikazio baxua dena. Ondoren, hobekuntza batzuk aplikatuko zaizkio etxeari energia eraginkortasuna hobetzeko asmoarekin. Hori eginez gero, E letra bat lortzea posible izango da amortizazio epe eta inbertsio nahiko onargarriekin.

Estudio de viabilidad financiera de un proyecto de inversión en energías alternativas

A través de este estudio se ha querido buscar una alternativa a la dependencia de la red eléctrica dada la escasez de combustible fósil y el encarecimiento de las tarifas eléctricas. Es por ello, que tras una larga búsqueda de energías renovables y eligiendo la energía solar y eólica como las más factibles, se ha hecho un estudio sobre la viabilidad financiera que supondría una instalación de bien paneles solares o bien un aerogenerador. En cuanto al proceso que conlleva la instalación, ha sido necesaria una rigurosa revisión de las legislaciones vigentes referentes a la instalación de este tipo de sistemas, para así, poder estimar el coste del procedimiento de la instalación, incluidas las tasas además de los costes de legalización. También se ha evaluado el consumo de la familia en una vivienda unifamiliar con el fin de estimar la potencia necesaria para hacer frente a dicho consumo. Una vez obtenido el consumo y la necesidad energética se ha realizado una compra de paneles solares y un aerogenerador. Para hacer frente a la suma de gastos se ha recurrido a un préstamo como única fuente de financiación. Por último, con el fin de estimar la viabilidad financiera, se han creado dos escenarios en los cuales por una parte estimaremos los rendimientos bajo el supuesto de que nos abasteceremos únicamente a través de los paneles solares o aerogenerador, y por la otra suponiendo que durante cuatro meses al año no vamos a recibir toda la electricidad necesaria y tendremos que recurrir a la red eléctrica; y como métodos de valoración se han utilizado el payback y TIR. Idioma: castellano.