large scale deployment of renewables for electricity generation comparisons of resource assessments suggest that sufficient renewable energy resources are available to allow for large scale deployment of renewable energy technologies economic analysis identifies barriers to the adoption of renewable energy sources resulting from i market structure ii competition in an uneven playing field and iii various non marketplace barriers however even if these barriers are removed the problem of technology lock out remains the key policy response is strategic deployment coupled with increased r d support to accelerate the pace of improvement through market experience this paper suggests significant contributions from various technologies are possible but does not assess their optimal or maximal market share copyright 2005 oxford university press

frontiers of real time data analysis in the past ten years researchers have explored the impact of data revisions in many different contexts researchers have examined the properties of data revisions how structural modeling is affected by data revisions how data revisions affect forecasting the impact of data revisions on monetary policy analysis and the use of real time data in current analysis this paper summarizes many of the questions for which real time data analysis has provided answers in addition researchers and institutions have developed better real time data sets around the world still additional research is needed in key areas and research to date has uncovered even more fruitful areas worth exploring jel c52 c53 c80 e01

res and risk renewable energy s contribution to energy security a portfolio based approach abstract during the first decade of the 21st century renewable energy sources res had been gaining momentum due to environmental issues concerns about pollution and climate change have raised public awareness encouraging governments to adopt policies to preserve and protect the environment regarding energy res promotion together with energy efficiency measures has been the main policy response to address such concerns as a consequence res development during the first decade of the 21st century has been remarkable although res deployment has been mainly focused on achieving environmental goals its potential contribution to energy security went not unnoticed however it is worth noting that while the trade off between environmental goals and the use of res to accomplish them and competitiveness has been widely explored the relationship between energy security and res has received less attention both at the conceptual and energy policy levels this article tries to address such a relationship the present article focuses on renewable electricity imports as illustrated by the case of the mediterranean solar plan after introducing the energy security energy risk concept and its dimensions the article focuses on the contribution of res in terms of security of supply for a given energy mix using the portfolio theory most of the analyses of the interactions between res and energy security focus on the national level with res being mainly conceived as a substitute for fuel imports to produce electricity and reduce so called energy dependence however new transmission technologies allow the import of electricity directly from neighbouring countries far out of the range of regular electricity lines therefore this article tries to broaden the analysis of energy security to international res trade flows applying the previous discussion to the main project involving significant international green electricity trade the mediterranean solar plan

a portfolio risk analysis on electricity supply planning abstract conventional electricity planning selects from a range of alternative technologies based on the least cost method without assessing cost related risks the current approach to determining energy generation portfolios creates a preference for fossil fuel consequently this preference results in increased exposure to recent fluctuations in fossil fuel prices particularly for countries heavily depend on imported energy this paper applies portfolio theory in conventional electricity planning with taiwan as a case study the model objective is to minimize the risk weighted present value of total generation cost both the present value of generating cost and risk variance of the generating cost are considered risk of generating cost is introduced for volatile fuel prices and uncertainty of technological change and capital cost reduction the impact of risk levels on the portfolio of power generation technologies is also examined to provide some valuable policy suggestions study results indicate that replacing fossil fuel with renewable energy helps reduce generating cost risk however due to limited renewable development potential in taiwan there is an upper bound of 15 on the maximum share of renewable energy in the generating portfolio in the meantime reevaluating the current nuclear energy policy for reduced exposure to fossil fuel price fluctuations is worthwhile

establishing the role that wind generation may have in future generation portfolios assessing the correct future mix in generation portfolios has become more difficult given the introduction of emission trading schemes the recent fuel price rises and the increasing competitiveness of wind energy this paper combines analysis of generation economics load and wind generation characteristics generation adequacy and plant utilization to gain insight into the role of wind generation in desirable generation portfolios the unique characteristics of wind generation are accounted for in the analysis and sensitivity analysis is carried out with respect to discount rates carbon taxes and various fuel price scenarios results show that for a large range of future scenarios wind generation has a significant role to play in future generation portfolios in ireland mean variance portfolio theory is applied to examine the benefits of portfolio diversification in terms of avoiding exposure to volatile fuel prices analysis shows that wind generation has a further role to play in generation portfolios in this respect

examination performance in scottish secondary schools an ordered logit approach this paper analyses the determinants of educational outcomes for scottish secondary schools using an ordered logit model with data on school examination performance for pupils in the last year of compulsory education separate equations are estimated for 1993 1994 and 1998 1999 the empirical results in line with previous british studies underline the importance of family peer group and school influences in determining educational outcomes they cast doubt however on suggestions that there is an optimal size of school

optimal wind power deployment in europe a portfolio approach geographic diversification of wind farms can smooth out the fluctuations in wind power generation and reduce the associated system balancing and reliability costs the paper uses historical wind production data from five european countries austria denmark france germany and spain and applies the mean variance portfolio theory to identify cross country portfolios that minimise the total variance of wind production for a given level of production theoretical unconstrained portfolios show that countries spain and denmark with the best wind resource or whose size contributes to smoothing out the country output variability dominate optimal portfolios the methodology is then elaborated to derive optimal constrained portfolios taking into account national wind resource potential and transmission constraints and compare them with the projected portfolios for 2020 such constraints limit the theoretical potential efficiency gains from geographical diversification but there is still considerable room to improve performance from actual or projected portfolios these results highlight the need for more cross border interconnection capacity for greater coordination of european renewable support policies and for renewable support mechanisms and electricity market designs providing locational incentives under these conditions a mechanism for renewables credits trading could help aligning wind power portfolios with the theoretically efficient geographic dispersion 2009 elsevier ltd

optimal investment portfolio in renewable energy the spanish case abstract this article presents a model for investing in renewable energies in the framework of the spanish electricity market in a way that risk is minimised for the investor while returns are maximised the model outlined here is based on an economic model for calculating cash flows intended to obtain the internal rate of return irr of the different energies being studied wind photovoltaic mini hydro and thermo electrical the irrs obtained are considered the returns on investments while their standard deviations are considered associated risks in order to minimise risk a comprehensive portfolio of investments is created that includes all of the available energies by means of a system of linear equations the solution of the linear system is graphically checked using the efficient frontier method for the different financing options several case studies within the renewable energies plan per is its spanish abbreviation that is in force in spain in the period 2005 2010 are analysed in order to illustrate the method as are other case studies using different types of financing helping us to reach the pertinent conclusions

on functions quality and timeliness of economic information economic decisions confront more uncertainty as they grow in scope and reach further into the future they are likely to do so increasingly in decentralized economies that expand and diversify the economic incentives to reduce uncertainty and improve predictions and decisions give rise to the demand for large amounts of diverse information this is not a new phenomenon of course but it is revealed more clearly than ever in the present era of great advances in informational technology for now the demand is to a large extent visibly satisfied the knowledge industries or services of inquiring comthe uncertainty about economic information increases with the probability of error in the underlying data and their processing and interpretation many errors cannot be promptly detected and eliminated but can be gradually reduced over time as attested by the revisions in economic statistics this paper presents substantial evidence on the accuracy of provisional estimates of quarterly and monthly changes in 18 important variables measures of several aspects of data quality and of average lags of data release and signal detection are provided for a collection of 110 widely used economic indicators these materials help identify the location of the more serious measurement errors by variables and period and they show that informational lags of 5 and more months are frequent this paper is part of the national bureau of economic research program on economic fluctuations it was presented at the first international symposium on forecasting in quebec city on may 27 1981 and at the ifo institute for economics research in munich on september 23 1981 financial support from the national science foundation and the aid of the graduate school of business of the university of chicago and nber are gratefully acknowledged i am indebted to louis lambros for helpful suggestions and efficient research and to john gould and geoffrey moore for useful comments 1 growth in the modem economy is motivated by the desire to accumulate human and physical resources capital in the most general sense and is accomplished by actions that necessarily have long term consequences the decisions to choose these particular courses of action strategies must therefore be based on similarly long expectations which are fallible as the risk is high so is the premium on any knowledge that might help the decision maker

energy security and improvements in the function of diversity indices taiwan energy supply structure case study abstract facing the risk and uncertainty inherent in social and economic development many countries have adopted an energy supply diversification strategy in their energy security policy to control the energy import risk and cost to ensure that sufficient energy can be obtained at an affordable price level diversification helps the energy system respond to external changes and shocks diversification can also lessen the vulnerability of a single energy source to supply shocks and the market power of various energy supply sources this study develops the diversity reliability index and co vary diversity reliability index based on the hirschman herfindahl and shannon wiener indices investigates the contribution of different energy sources to the energy system and analyzes the covariance between various energies and their impacts on energy security to determine the impact of energy diversity in reducing the risk of energy supply shortages and cost fluctuations

uncertainty in the monetary aggregates sources measurement and policy effects for a variety of reasons observed data on the monetary aggregates are subject to uncertainty or error in some instances first published data are revised at a later date due to errors in preliminary data which can be observed and corrected in others the error persists in the final data cutting across this classification are the numerous sources of error including definitional error transitory error seasonal adjustment error sampling clerical or reporting error etc this survey paper deals with the sources and where possible magnitudes of uncertainties in monetary series the next three sections discuss conceptual and definitional issues and the current procedures for assembling the money supply data sections 5 through 7 then consider respectively uncertainty due to sampling and reporting transitory variation and seasonal adjustment some implications including possible consequences for monetary policy and the effects on relationships to other series are assessed in sections 8 and 9 and the concluding section presents some suggestions for dealing with errors in the aggregates

financial optimization in the turkish electricity market markowitz s mean variance approach abstract electricity constitutes the input into many products that produced by industry and used by people hence it can be considered as a product or service that has vital importance in human life and economy since it has such special properties of instantaneous production and consumption obligation and unfeasible storage electricity market is not like other markets in a competitive electricity market generation company faces price risks and delivery risks so that risk management is an important part of a generation company and can deeply effect companies profitability this paper focuses on electricity generation asset allocation between bilateral contracts such as forward contracts and daily spot market considering constraints of generating units and spot price risks the problem is to find the optimal portfolio based on known electricity generation total costs bilateral contract prices it employed turkish historical balanced market hourly system marginal and day ahead hourly market prices between of 2006 and 2011 there are limited studies about portfolio optimization in electricity markets in literature and this paper should be considered frontier study taking spot market s hourly prices separately as risky assets markowitz mean variance optimization which is claimed to be the beginning of modern portfolio theory in financial sector is used to demonstrate this approach mean variance optimization has been successfully applied to all cases that modeled for electricity market some suggestions for future work are also listed in this paper

rational expectations and macroeconomic forecasts the article presents extensive results from testing for bias and serially correlated errors in a collection of time series of quarterly multiperiod forecasts for six variables including real gnp growth inflation and unemployment the analysis covers responses by 79 frequent participants in economic outlook surveys conducted regularly since 1968 it shows much greater incidence of apparently systematic errors for inflation than for the other variables also the tests are more favorable to composite group forecasts than to most of the individual forecast sets

a more timely and useful index of leading indicators effectively predicting cyclical movements in the economy is a major challenge the u s leading index li has long been used to analyze and predict economic fluctuations we describe and test a new procedure for making the li more timely the new li significantly outperforms its older counterpart it offers substantial gains in real time out of sample forecasts of changes in aggregate economic activity real gdp the index of coincident indicators and industrial production and provides timely and accurate ex ante information for predicting not only business cycle turning points but also monthly changes in the economy

on optimal wage indexation the observed practice of contracting for labor services in advance introduces stickiness or friction into the economic system in the presence of monetary and real stochastic disturbances the stability of the levels of employment and output hinges on the nature of the wage contracts in this paper we demonstrate the existence of optimal indexation schemes that are capable of eliminating the aforementioned friction by duplicating the equilibrium that would obtain if labor services were contracted for after the stochastic disturbances were realized

the effect of data revisions and additional observations on time series estimates 1987 the effect of data revisions and additional observations on time series estimates applied economics vol 19 no 3 pp 347 353

power sector investment risk and renewable energy a japanese case study using portfolio risk optimization method the conventional pricing mechanism used for electricity systematically hides huge investment risks which are embedded in the overall cost of production although consumers are often unaware of these risks they present a large financial burden on the economy this study applies the portfolio optimization concepts from the field of finance to demonstrate the scope of greater utilization of renewable energies re while reducing the embedded investment risk in the conventional electricity sector and its related financial burden this study demonstrates that re investment can compensate for the risks associated with the total input costs such costs being external volatilities of fossil fuel prices capital costs operating and maintenance costs and the carbon costs by means of example this case study shows that japan could in theory obtain up to 9 of its electricity supply from green sources as compared to the present 1 37 based on the utilization of a portfolio risk analysis evaluation explicit comparison of the monetary values of the investment risks of conventional and renewable energy sources shows that renewable energies have high market competitiveness the study concludes with a recommendation that as a business objective investors would benefit by focusing on electricity supply portfolio risk minimization instead of cost this could also inherently increase the supply of renewable energy in the market

renewable electricity in europe abstract renewable energy use is growing at a much faster pace than the rest of the economy in europe and world wide this and the dramatic oil price increases in 2005 have lead to a remarkable re evaluation of the renewable energy sector by politics and financing institutions despite the fact that there are still discrepancies between the european union and the usa how to deal with climate change renewable energies will play an important role for the implementation of the kyoto protocol and the world wide introduction of tradable green certificates apart from the electricity sector renewable energy sources for the generation of heat and the use of environmental friendly bio fuels for the transport sector will become more and more important in the future

economic welfare impacts from renewable energy consumption the china experience over the last years renewable energy sources have increased their share on electricity generation of china due to environmental and security of supply concerns in this work author assesses the role of both the amount and share of renewable energy consumption in economic welfare using cobb douglas type production functions this assessment is carried out by multivariate ols and spss software for china from 1978 to 2008 results indicate that a 1 increase in renewable energy consumption rec increases real gdp by 0 120 gdp per capita by 0 162 per capita annual income of rural households by 0 444 and per capita annual income of urban households by 0 368 respectively the impact of renewable energy consumption share srec on economic welfare is insignificant and an increasing share of rec negatively affects economic welfare growth to a certain extent in this paper the cost structural demand accounting mechanism and policy reasons of renewable energy development are interpreted marginal effects analysis show that the shape of sound and robust renewable energy institutions and policies would matter for increasing the standards of economic welfare in the context of speeding up renewable energy development and increasing share of renewable energy consumption especially the goal oriented policy refinement should be addressed efficiently in improvement households income while increasing share of renewable energy consumption c 2011 elsevier ltd all rights reserved

valuation for renewable energy a comparative review abstract environmental cost benefit analysis is applied for the evaluation of renewable energy projects since some benefits and costs do not have monetary values economic valuation techniques are applied to estimate them this paper reviews the literature on the valuation evaluation of renewable energy resources and summarizes the methods used in them it discerns four main streams of valuation in renewable energy the first is economic welfare oriented and comprises stated and revealed preference methods the second is the financial option analysis with a financial background the third is emergy analysis which is mostly an ecological engineering based method with capable economic links and the fourth is again economic but not welfare based the paper discusses the main directions discerned in these studies and recognizes first that proper valuation takes place only in the first method while the other methods describe only evaluation procedures and second that there is a research gap that has yet to be filled in as compared to other areas of environmental resource and energy economics

electricity generation cost in isolated system the complementarities of natural gas and renewables in the canary islands abstract the canary islands offer an example of an isolated electric grid of relative important size within the eu due to its peculiarities the role of renewable energies and their complementarity with fossil fuels offers a solid path to achieving the main energy policy goals of the islands the purpose of this paper is to assess the current situation and the energy objectives proposed in the energy plan of the canaries pecan 2006 for the electricity industry taking into account the average cost and the risk associated with the different alternatives for generating electricity by means of the mean variance portfolio theory our analysis highlights the inefficiency of the current electricity generating mix in terms of cost risk and lack of diversification shifting toward an efficient system would involve optimizing the use of endogenous energy sources and introducing natural gas to generate electricity this scenario would mean reducing both cost and risk by almost 30 each as well as atmospheric co 2 emissions our results agree with the pecan philosophy

the european low carbon mix for 2030 the role of renewable energy sources in an environmentally and socially efficient approach abstract the european union s commitment to increase the presence of renewable energy sources in its portfolio has resulted in better levels of security of supply competitiveness and environmental sustainability this proposed work reviews european legislation regarding the promotion of renewable energy sources as well as the bibliography that applies portfolio theory methodology to energy policy this double revision gives rise to the question whether the share limits of renewable energy technologies anticipated for the european power mix in 2020 and 2030 are actually efficient the optimization model corrects for the attractiveness of renewable energy sources as opposed to conventional sources in terms of costs risks and pollutant gas emissions this model successfully and explicitly identifies the positive effect on the environment that is represented by the inclusion of renewable energy sources in the portfolio the goal is to minimize the cost and risk that society must bear to produce electricity in addition to compliance with european pollutant gas co2 so2 nox and pm objectives the results for 2020 indicate that the eu would not be able to reach its emissions reduction goals with the anticipated shares of renewable energy sources in 2030 achieving a lower emissions portfolio would not mean taking on greater costs although it would be necessary to assume a greater level of risk the anticipated shares of renewable energy sources 5 and fossil fuel technologies 15 would be overdimensioned in the forecasts analyzed in terms of technologies both nuclear and wind energy stand out both with shares above 20 on the contrary biomass and solar photovoltaic energies would be unnecessary in order to reach efficiency in any case one thing is clear the eu would be the master of its energy future if it prioritizes the importance of renewable energy sources in its efficient portfolio