practical operation strategies for pumped hydroelectric energy storage phes utilising electricity price arbitrage abstract in this paper three practical operation strategies 24optimal 24prognostic and 24hsitrocial are compared to the optimum profit feasible for a phes facility with a 360 mw pump 300 mw turbine and a 2 gwh storage utilising price arbitrage on 13 electricity spot markets the results indicate that almost all 97 of the profits can be obtained by a phes facility when it is optimised using the 24optimal strategy developed which optimises the energy storage based on the day ahead electricity prices however to maximise profits with the 24optimal strategy the day ahead electricity prices must be the actual prices which the phes facility is charged or the phes operator must have very accurate price predictions otherwise the predicted profit could be significantly reduced and even become a loss finally using the 24optimal strategy the phes profit can surpass the annual investment repayments required however over the 5 year period investigated 2005 2009 the annual profit from the phes facility varied by more than 50 on five out of six electricity markets considered considering the 40 year lifetime of phes even with low investment costs a low interest rate and a suitable electricity market phes is a risky investment without a more predictable profit

optimal allocation of primary reserve services in energy markets this paper presents an optimization algorithm which provides generation economic dispatch minimizing simultaneously the cost of primary reserve services while ensuring the secure operation of the power system in the presence of disturbances the algorithm takes into consideration security constraints which are extracted from the chain rules provided by decision trees the proposed method is easy to implement in day ahead and real time balancing markets and is characterized from accuracy versatility and flexibility examples demonstrating application of the method on an actual power system model are presented and discussed

on the benefits of behind the meter rooftop solar and energy storage the importance of retail rate design abstract we investigate the impact of retail rate design on the investment incentives avoided utility costs and cost shifting concerns associated with rooftop solar plus battery storage systems that are located behind the meter to illustrate these interactions we consider recently proposed changes to california s time of use pricing policy for commercial and industrial consumers which shifts on peak prices from midday to the constrained evening hours we find that these rate adjustments reduce cost shifting concerns across consumers considerably but also decreases solar pv investment and has an ambiguous effect on storage investment we demonstrate that storage reduces utility costs but the magnitude of this effect varies critically with the prevailing retail rate structure importantly we show that a shift in the on peak period to the constrained evening hours does not always elevate the avoided cost associated with a battery system when demand charges are imposed on a consumer s private maximum demand we illustrate that this issue can be alleviated by imposing demand charges on consumption that arises in system constrained hours we find that while storage reduces the utility s costs it can also increase cost shifting concerns these findings demonstrate the potential trade offs between maximizing avoided costs and minimizing cost shifting concerns under commonly employed retail rate structures

why market rules matter optimizing pumped hydroelectric storage when compensation rules differ abstract policies markets and technologies interact to create the modern electrical system integrating large amounts of electricity generated by variable renewable resources such as from wind and sunlight into electricity systems may require energy storage technologies to synchronize electricity production with electricity demand electricity markets compensate the performance of these energy storage technologies for the services they provide and these markets are often operated by regional independent system operators isos that specify the market rules for this compensation to examine how different iso rules can affect the operation and profitability an energy storage technology we develop a dynamic programming model of pumped hydroelectric storage phes facility operation under the market rules from the midcontinent iso and iso new england we present how differences in rules between these isos produced different operational strategies and profits and how important they are for phes profitability

optimal operation of pumped hydro storage plants with continuous time varying power prices abstract pumped hydro storage plants are increasingly considered as a complement to intermittent renewable energy sources hence a profound understanding of their underlying economics gains in importance to this end we derive efficient operation programs for storage plants which operate in an environment with time varying but deterministic power prices optimal control theory thereby provides a consistent framework for analysis in continuous time taking into account the different specifics of pumped hydro setups with large not restricting and small restricting reservoirs an empirical illustration discusses storage operation in the german market showing that the profit potential for storage plants decreased significantly between 2008 and 2011 affecting both large and small reservoir plants

market clearing with stochastic security part i formulation the first of this two paper series formulates a stochastic security constrained multi period electricity market clearing problem with unit commitment the stochastic security criterion accounts for a pre selected set of random generator and line outages with known historical failure rates and involuntary load shedding as optimization variables unlike the classical deterministic reserve constrained unit commitment here the reserve services are determined by economically penalizing the operation of the market by the expected load not served the proposed formulation is a stochastic programming problem that optimizes concurrently with the pre contingency social welfare the expected operating costs associated with the deployment of the reserves following the contingencies this stochastic programming formulation is solved in the second companion paper using mixed integer linear programming methods two cases are presented a small transmission constrained three bus network scheduled over a horizon of four hours and the ieee reliability test system scheduled over 24 h the impact on the resulting generation and reserve schedules of transmission constraints and generation ramp limits of demand side reserve of the value of load not served and of the constitution of the pre selected set of contingencies are assessed

capacity controlled demand side management a stochastic pricing analysis we consider a novel paradigm for demand side management assuming that an aggregator communicates with a household only at the meter imposing a capacity constraint i e a restriction on the total power consumption level within a given time frame consumers are then responsible to adjust the set points of the individual household devices accordingly to meet the imposed constraint we formulate the problem as a stochastic household energy management program with stochasticity arising due to local photovoltaic generation we show how a demand bidding curve for capacity increments can be constructed as a by product of the developed problem and provide a rigorous pricing analysis that results in a probabilistic shadow price envelope to evaluate the efficacy of the proposed approach we compare it with an idealized real time market price set up and show how our analysis can provide guidelines to consumers when selecting a service contract for load curtailment

economic feasibility of stationary electrochemical storages for electric bill management applications the italian scenario battery energy storage systems besss are expected to become a fundamental element of the electricity infrastructure thanks to their ability to decouple generation and demand over time besss can also be used to store electricity during low price hours when the demand is low and to meet the demand during peak hours thus leading to savings for the consumer this work focuses on the economic viability of bess from the point of view of the electricity customer the analysis refers to a lithium ion li ion an advanced lead acid a zinc based a sodium sulphur nas and a flow battery the total investment and replacement costs are estimated in order to calculate the cumulated cash flow the net present value npv and the internal rate of return irr of the investment a parametric analysis is further carried out under two different assumptions a varying the difference between high and low electricity prices b varying the peak demand charges the analysis reveals that some electrochemical technologies are more suitable than others for electric bill management applications and that a profit for the customer can be reached only with a significant difference between high and low electricity prices or when high peak demand charges are applied

mean conditional value at risk optimal energy storage operation in the presence of transaction costs this paper addresses the formulation and solution of an optimal energy storage management problem under risk consideration and transaction costs of trading energy with the power grid the price evolves as a stochastic process capable of correctly explaining the seasonality effects as well as the tail fatness and spikiness in its distribution transaction costs capture the price impact of the storage operation on the electricity spot price a risk analysis of an optimal risk neutral deterministic policy as well as the simple myopic policy indicates that the realized operational cost may notably differ from the expected cost by a considerable probability this difference suggests that we need to consider risk using the downside risk measure of conditional value at risk an optimal risk averse conversion and transmission strategy among the grid the renewable power generation source and an energy storage is proposed to fully satisfy the electricity demand and minimize the expected operational cost as well as the risk our numerical study using data from nyiso demonstrates the impacts of risk consideration and the transaction cost parameters on the optimal strategy structure its expected cost and its risk

electricity trading and negative prices storage vs disposal electricity cannot yet be stored on a large scale but technological advances leading to cheaper and more efficient industrial batteries make grid level storage of electricity surpluses a natural choice because electricity prices can be negative it is unclear how the presence of negative prices might affect the storage policy structure known to be optimal when prices are only nonnegative or even how important it is to consider negative prices when managing an industrial battery for fast storage a storage facility that can both be fully emptied and filled up in one decision period we show analytically that negative prices can substantially alter the optimal storage policy structure e g all else being equal it can be optimal to empty an almost empty storage facility and fill up an almost full one for more typical slow grid level electricity storage we numerically establish that ignoring negative prices could result in a considerable loss of value when negative prices occur more than 5 of the t

pricing and the news vendor problem a review with extensions in the newsvendor problem a decision maker facing random demand for a perishable product decides how much of it to stock for a single selling period this simple problem with its intuitively appealing solution is a crucial building block of stochastic inventory theory which comprises a vast literature focusing on operational efficiency typically in this literature market parameters such as demand and selling price are exogenous however incorporating these factors into the mode l can provide an excellent vehicle for examining how operational problems interact with marketing issues to influence decision making at the firm level in this paper we examine an extension of the newsvendor problem in which stocking quantity and selling price are set simultaneously we provide a comprehensive review that synthesizes existing results for the single period problem and develop additional results to enrich the existing knowledge base we also review and develop insight into a dynamic inventory extension of this problem and motivate the applicability of such models

stochastic security for operations planning with significant wind power generation in their attempt to cut down on greenhouse gas emissions from electricity generation several countries are committed to install wind power generation up to and beyond the 10 20 penetration mark however the large scale integration of wind power represents a challenge for power system operations planning because wind power 1 cannot be dispatched in the classical sense and 2 its output varies as weather conditions change this warrants the investigation of alternative short term power system operations planning methods capable of better coping with the nature of wind generation while maintaining or even improving the current reliability and economic performance of power systems to this end this paper formulates a short term forward electricity market clearing problem with stochastic security capable of accounting for nondispatchable and variable wind power generation sources the principal benefit of this stochastic operation planning approach is that when compared to a deterministic worst case scenario planning philosophy it allows greater wind power penetration without sacrificing security

dispatch planning using newsvendor dual problems and occupation times application to hydropower abstract we consider price driven dispatch planning under price uncertainty a storable commodity is optimally sold and purchased over time first we consider models where the storage level is constrained in expectation the dual of the corresponding optimization problem is related to the newsvendor problem exact solutions of bang bang type are given the second methodology is for high frequency dispatch decisions in multistage stochastic programming models to overcome the curse of dimensionality prices are modeled by occupation times at price levels in a case study we consider a pumped storage hydropower plant numerical solutions are given which have similar patterns as for the first exactly solvable problems

financial storage rights should energy storage buy and sell power at wholesale prices like utilities and generators or should its physical and financial operation be asynchronyous as with transmission lines in the first case storage straightforwardly profits through intertemporal arbitrage also known as load shifting and peak shaving in this paper the latter case referred to as passive storage is examined because passive storage does not make nodal price transactions new mechanisms are necessary for its integration into electricity markets this issue is addressed by further developing the analogy between energy storage and transmission specifically financial rights are defined for storage and tracing is extended to multiperiod power flows linked by storage like flowgate transmission rights the new financial storage rights redistribute the system operator s merchandising surplus and enable risk averse market participants to hedge against nodal price volatility resulting from storage congestion simple examples are given demonstrating the implementation of the new mechanisms game theoretic analysis suggests that financial storage rights mitigate gaming when both the generator and load bid strategically

market clearing with stochastic security part ii case studies this paper analyzes the market clearing formulation with stochastic security developed in its companion paper through two case studies solved using mixed integer linear programming techniques the generation and reserve schedules as well as the nodal prices of energy and security are assessed under various conditions such as a line flow limits b when nonspinning reserve is excluded from the formulation c demand side valuation of energy not served d generator ramping limits and e the set of pre selected contingencies

stochastic joint optimization of wind generation and pumped storage units in an electricity market one of the main characteristics of wind power is the inherent variability and unpredictability of the generation source even in the short term to cope with this drawback hydro pumped storage units have been proposed in the literature as a good complement to wind generation due to their ability to manage positive and negative energy imbalances over time this paper investigates the combined optimization of a wind farm and a pumped storage facility from the point of view of a generation company in a market environment the optimization model is formulated as a two stage stochastic programming problem with two random parameters market prices and wind generation the optimal bids for the day ahead spot market are the ldquohere and nowrdquo decisions while the optimal operation of the facilities are the recourse variables a joint configuration is modeled and compared with an uncoordinated operation a realistic example case is presented where the developed models are tested with satisfactory results

optimization of pumped storage capacity in an isolated power system with large renewable penetration this work describes an economic analysis of the inclusion of pumped storage in a small island system that has abundant renewable energy available but that at times cannot accept all of this power because of limits imposed by security criteria the question of whether or how much pumped storage to include is addressed by formulating a linear programming optimization problem the stochastic nature of load and renewable production is addressed using scenarios developed through fuzzy clustering both the unit capacity in mw and the reservoir storage capacity in mwh are optimized and optimal operating strategies for the scenarios are produced results showed that including pumped storage can be an effective means of allowing larger penetration of intermittent renewable energy sources improving both the dynamic security and the economic operation of a test system including the dynamic security criteria in the economic question of dimensioning the pumped storage unit proved to make a significant difference in the optimal pumped storage capacity

electricity price arbitrage with plug in hybrid electric vehicle gain or loss abstract customers utilities and society can gain many benefits from distributed energy resources ders including plug in hybrid electric vehicles phevs using battery on phev to arbitrage electricity price is one of the potential benefits to phev owners there is however disagreement on the magnitude of such profit this study uses a stochastic optimization model to estimate the potential profit from electricity price arbitrage of two types of phevs phev 10 and phev 40 under three scenarios with variant electricity tariff and phev owners over a five year period the simulation results indicate that under current market structure even with significant improvement in battery technologies e g higher efficiency lower cost the phev owners can t achieve a positive arbitrage profit this finding implies that expected arbitrage profit solely is not a viable option to engage phevs larger adoption subsidy and combining phev arbitraging with alternative phev services are required

technical and economical assessment of distributed electrochemical storages for load shifting applications an italian case study abstract time of use tou energy cost management involves the use of energy storage systems esss by customers to reduce their electricity bills the ess is charged during off peak time periods when electricity energy prices are low and discharged during times when on peak energy prices are applied this article addresses the question whether it is economically viable to install medium scale distributed esss designed to lower the electricity cost for a customer side application assuming flexible electricity tariffs the technical economical evaluation is carried out referring to lithium ion li ion sodium sulfur nas and vanadium redox battery vrb technologies performing a parametric analysis by changing the capital cost of the batteries and the difference between the maximum and minimum electricity price a case study is performed to show the advantages disadvantages of the proposed approach the analysis reveals that at the current costs of esss the use of batteries for tou applications is economically advantageous for a public institution facility in italy only if there is a significant difference between the maximum and the minimum electricity price the decrease in the cost of storage stimulated by the implementation of support policies will make ess even more convenient for load shifting applications

stochastic valuation of energy storage in wholesale power markets abstract energy storage systems are well poised to mitigate uncertainties of renewable generation outputs grid scale energy storage projects are major investments which call for rigorous valuation and risk analysis this paper provides a stochastic energy storage valuation framework in wholesale power markets which considers all key revenue streams simultaneously as part of this framework an operational optimization model is developed to determine the energy storage system s optimal dispatch sequences a future curve model is built to capture the volatilities of electricity prices in addition a frequency regulation service price forecasting model is developed simulation results with a realistic battery storage system reveal that the majority of the market revenues comes from frequency regulation services simulation results also show that both round trip efficiency and power to energy ratio are crucial to the cost effectiveness of energy storage systems

labor intensity and employment creation in a constrained economy abstract when considered in a general equilibrium context this paper shows that sectoral labor intensity is a poor proxy for the employment effects of sectoral demand or export expansion we develop an open economy input output model with endogenous consumption and capital formation to measure the employment effects of these two sorts of exogenous increases in demand we show that in an open economy the employment effect of sectoral government spending programs is always less than the number of jobs created by the program and could well be negative while the opposite is true for sectoral export expansion

changing patterns of wealth distribution evidence from ghana a largely unexplored feature of structural transformation is the change in the composition of an economy s asset holdings in most poor economies assets are concentrated in land in rich economies

foreign trade and its impact on employment the mexican case abstract this paper discusses the relationship between foreign trade and employment in a small open economy and carries out some empirical work using mexican data it is argued that employment multipliers are not stable if intermediate inputs are imported actual employment multipliers will be given by the relationship between effective demand and installed capacity in each sector and will depend strongly on whether quotas or tariffs are in operation it is also found that mexican exports are capital intensive relative to its imports

the impact of electricity storage on wholesale electricity prices this paper analyzes the impact of electricity storage on the production cost of a power system and the marginal cost of electricity electricity price using a unit commitment model also real world data has been analyzed to verify the effect of storage operation on the electricity price using econometric techniques the unit commitment model found that the deployment of a storage system reduces the fuel cost of the power system but increases the average electricity price through its effect on the power system operation however the reduction in the production cost was found to be less than the increase in the consumer s cost of electricity resulting in a net increase in costs due to storage different storage and co2 price scenarios were investigated to study the sensitivity of these results the regression analysis supports the unit commitment results and finds that the presence of storage increases average wholesale electricity prices for the case study system

policy based reserves for power systems this paper introduces the concept of affine reserve policies for accommodating large fluctuating renewable in feeds in power systems the approach uses robust optimization with recourse to determine operating rules for power system entities such as generators and storage units these rules or policies establish several hours in advance how these entities are to respond to errors in the prediction of loads and renewable infeeds once their values are discovered affine policies consist of a nominal power schedule plus a series of planned linear modifications that depend on the prediction errors that will become known at future times we describe how to choose optimal affine policies that respect the power network constraints namely matching supply and demand respecting transmission line ratings and the local operating limits of power system entities for all realizations of the prediction errors crucially these policies are time coupled exploiting the spatial and temporal correlation of these prediction errors affine policies are compared with existing reserve operation under standard modeling assumptions and operating cost reductions are reported for a multi day benchmark study featuring a poorly predicted wind infeed efficient prices for such policy based reserves are derived and we propose new reserve products that could be traded on electricity markets

the value of intra day markets in power systems with high wind power penetration in this paper the value of intra day markets in managing wind power uncertainty in competitive electricity markets is analyzed a competitive electricity market model consisting of a day ahead market and a number of intra day markets is considered real time operation adjustment is also taken into account stochastic programming is used to model decision making under wind power uncertainty numerical simulations based on two test systems are presented

estimating the value of electricity storage in pjm arbitrage and some welfare effects significant increases in prices and price volatility of natural gas and electricity have raised interest in the potential economic opportunities for electricity storage in this paper we analyze the arbitrage value of a price taking storage device in pjm during the six year period from 2002 to 2007 to understand the impact of fuel prices transmission constraints efficiency storage capacity and fuel mix the impact of load shifting for larger amounts of storage where reductions in arbitrage are offset by shifts in consumer and producer surplus as well as increases in social welfare from a variety of sources is also considered

arbitraging intraday wholesale energy market prices with aggregations of thermostatic loads we investigate the potential for aggregations of residential thermostatically controlled loads tcls such as air conditioners to arbitrage intraday wholesale electricity market prices via non disruptive load control we present two arbitrage approaches 1 a benchmark that gives us an optimal policy but requires local computation or real time communication and 2 an alternative based on a thermal energy storage model which relies on less computation communication infrastructure but is suboptimal we find that the alternative approach achieves around 60 80 of the optimal wholesale energy cost savings we use this approach to compute practical upper bounds for savings via arbitrage with air conditioners in california s intraday energy market we investigate six sites over four years and find that the savings range from 2 37 per tcl per year and depend upon outdoor temperature statistics and price volatility

online adaptive real time optimal dispatch of privately owned energy storage systems using public domain electricity market prices this paper aims to evaluate and improve the usefulness of publicly available electricity market prices for real time optimal dispatching rtod of a privately owned energy storage system ess in a competitive electricity market the rtod algorithm seeks to maximize the revenue by exploiting arbitrage opportunities available due to the inter temporal variation of electricity prices in the day ahead market the pre dispatch prices issued by the ontario independent electricity system operator and the corresponding ex post hourly ontario energy prices are employed as the forecast and the actual prices a compressed air ess is sized and employed for evaluations due to its lower capital expenditure and its ability to be positively influenced by the availability of waste heat first the conventional rtod algorithm is developed by formulating a mixed integer linear programming problem it is demonstrated that the forecast inaccuracy of publicly available market prices significantly reduces the ess revenue then a new adaptive algorithm is proposed and evaluated which adapts the objective function of the optimization problem online based on historical market prices available before real time the outcomes reveal that the proposed adaptive rtod can significantly increase the ess revenue compared to the conventional algorithm as well as the back casting method proposed in prior studies

unemployment and economic development during the past thirty five years opinions on unemployment have significantly influenced our thoughts about the process of economic development in low income countries the economic strategies appropriate for governments committed to accelerating that process and the best way for the rich nations to assist in that endeavour which of the many and sometimes conflicting opinions of economists regarding the magnitude causes and costs of unemployment in ldcs reigns as the conventional wisdom at any given time is not determined by purely scientific criteria the emergence of a particular set of hypotheses as dominant may be strongly influenced by the attitudes and political preoccupations of observers as well

competitive energy storage in the presence of renewables a large fraction of new distributed generation will use renewable sources and cannot be treated as conventional generators due to high variability energy storage is a natural mechanism for absorbing variability and hence minimizing costly reliance on generator reserves we consider a simple scenario in which energy imbalances are allocated to energy storage representing either cooperation with a renewable producer or competitive operation in markets the optimal storage scheduling strategy is shown to be an inventory control like policy which through mild approximation yields affine relationships with the state variables we develop and numerically evaluate suboptimal policies that approximately incorporate the effects of correlation further approximation enables us to characterize the nash equilibria arising between generation and storage which we use to analyze strategic effects specifically we find that inefficient storage can lead to non socially optimal behavior

optimal forward trading and battery control under renewable electricity generation abstract the increased market penetration of renewable energy sources and the rapid development of electric battery storage technologies yield a potential for reducing electricity price volatility while maintaining stability of the power grid this work presents an algorithmic approach to control battery levels and forward positions to optimally manage power output fluctuations caused by intermittent renewable energy generation this paper will also explore the effect of battery technology on the firm s optimal trading behaviour in the electricity spot market

can a wind farm with caes survive in the day ahead market abstract we investigate the economic viability of coupling a wind farm with compressed air energy storage caes to participate in the day ahead electricity market at a time when renewable portfolio standards are not binding and wind competes freely in the marketplace in our model the caes is used to reduce the risk of committing uncertain quantities of wind energy and to shift dispatch of wind generation to high price periods other sources of revenue capacity markets ancillary services price arbitrage are not included in the analysis we present a model to calculate profit maximizing day ahead dispatch schedules based on wind forecasts annual profits are determined with dispatch schedules and actual wind generation values we find that annual income for the modeled wind caes system would not cover annualized capital costs using market prices from the years 2006 to 2009 we also estimate market prices with a carbon price of 20 and 50 per tonne co2 and find that revenue would still not cover the capital costs the implied cost per tonne of avoided co2 to make a wind caes profitable from trading on the day ahead market is roughly 100 with large variability due to electric power prices

gender inequalities in ownership and control of land in africa myth and reality lack of clarity behind measurement and interpretation of statistics on gender and land leads to an inability to clearly articulate a policy response to the potential inequalities faced by women and men this article sets out to explore conceptually and empirically the levels and relative inequalities in land rights between women and men in african countries the first section of the article engages in a conceptual discussion of how to measure gendered land outcomes what ownership and control mean in different contexts and why attention to these factors is important for the development of gender and land statistics the second section of the article systematically reviews existing evidence from microlevel large sample studies to summarize recent trends in land access ownership and control by sex the third section presents new statistics from a variety of nationally representative and large scale unpublished data on gender and land in africa results provide not only a nuanced understanding of the importance of measuring land indicators for gendered development in africa and globally but also new statistics on a variety of land outcomes to aid stakeholders in the discussion of gender land inequalities

opportunity cost bidding by wind generators in forward markets analytical results wind generation must trade in forward electricity markets based on imperfect forecasts of its output and real time prices when the real time price differs for generators that are short and long the optimal forward strategy must be based on the opportunity costs of charges and payments in real time rather than a central estimate of wind output we present analytical results for wind s optimal forward strategy in the risk neutral case the optimal strategy is determined by the distribution of real time available wind capacity and the expected real time prices conditioned on the forward price and wind out turn our approach is simpler and more computationally efficient than formulations requiring specification of full joint distributions or a large set of scenarios informative closed form examples are derived for particular specifications of the wind price dependence structure in the usual case of uncertain forward prices the optimal bidding strategy generally consists of a bid curve for wind power rather than a fixed quantity bid a discussion of the risk averse problem is also provided an analytical result is available for aversion to production volume risk however we doubt whether wind owners should be risk averse with respect to the income from a single settlement period given the large number of such periods in a year

the private and social economics of bulk electricity storage the ability to store excess intermittent renewable electricity is increasingly being seen as a key option for integrating large quantities of renewable capacity however intermittent energy sources currently account for very small amounts of total generation despite this fact policymakers have begun implementing requirements that will dramatically increase the amount of bulk storage capacity this paper examines the social benefits provided by bulk storage in the texas electricity market which has a large amount of renewable capacity relative to other states but still quite limited renewable penetration we focus on the impact of arbitraging electricity across time a major service of bulk storage using current storage technologies we demonstrate that electricity arbitrage will increase daily co2 emissions by an average of 0 19 tons for each mwh stored in addition daily so2 emissions will increase by an average of 1 89 pounds mwh while nox emissions will fall by an average of 0 15 pounds mwh

the role of smart metering and decentralized electricity storage for smart grids the importance of positive externalities because of its fluctuating nature the feed in of renewable energy sources into low voltage distribution grids complicates the balancing of demand and supply this carries the risk of grid instabilities causing damage to electronic devices and power outages which eventually lead to deadweight losses in principle the problems arising from fluctuating feed in can be solved by increasing demand elasticity or decoupling generation and consumption for the first an advanced metering infrastructure and for the second decentralized electricity storage are considered core enablers however to date the diffusion of these future smart grids core components is low the present study provides new insights for understanding and overcoming diffusion barriers for this purpose a qualitative research approach was chosen the most important stakeholders as well as related private costs and benefits are identified the findings show that both of these smart grid components are widely considered beneficial to society by experts however because the numerous private benefits are widely distributed among distinct players socially desired investments are hampered by positive externalities the importance of well designed and consistent regulatory and legal frameworks that provide economic incentives to involved stakeholders is highlighted in the results

optimal planning to include storage devices in power systems it is difficult to forecast renewable energy resources due to their variability high uncertainty of the resources increases the concern about the reliable operation of the electric power system storage devices have been considered a candidate to control variable energy resources and most studies on storage devices are performed in the economic dispatch therefore electric power adequacy may be an issue in this paper a new approach in the optimal power flow framework is proposed for deploying storage devices and the feasibility and economic impact analyses are discussed

is inexpensive natural gas hindering the grid energy storage industry abstract grid energy storage is a maturing technology and forecasts of the industry s growth have been promising however recent years have realized little growth in actual deployments of grid level storage and several high profile storage companies and projects have failed we hypothesize that falling natural gas prices have significantly reduced the potential profit from many u s energy storage projects since 2009 and quantify that effect we use engineering economic models to calculate the monthly revenue to energy storage devices providing frequency regulation and energy arbitrage in several electricity markets and compare that revenue to prevailing natural gas prices we find that flywheel devices providing frequency regulation were profitable in months when natural gas prices were above 7 mcf but face difficulties at current prices around 4 mcf for energy arbitrage alone we find that the breakeven capital cost for large scale storage was around 300 kwh in several key locations in 2004 2008 but is around 100 kwh in the same locations today though cost and performance improvements have been continually decreasing the effective cost of energy services from storage fundamental market signals indicating the need for energy storage are at or near 10 year lows for both energy arbitrage and frequency regulation

optimal management and sizing of energy storage under dynamic pricing for the efficient integration of renewable energy we address the optimal energy storage management and sizing problem in the presence of renewable energy and dynamic pricing associated with electricity from the grid we formulate the problem as a stochastic dynamic program that aims to minimize the long run average cost of electricity used and investment in storage if any while satisfying all the demand we model storage with ramp constraints conversion losses dissipation losses and an investment cost we prove the existence of an optimal storage management policy under mild assumptions and show that it has a dual threshold structure under this policy we derive structural results which indicate that the marginal value from storage decreases with its size and that the optimal storage size can be computed efficiently we prove a rather surprising result as we characterize the maximum value of storage under constant prices and i i d net demand processes if the storage is a profitable investment then the ratio of the amortized cost of storage to the constant price is less than 1 4 we further perform sensitivity analysis on the size of optimal storage and its gain via a case study finally with a computational study on real data we demonstrate significant savings with energy storage

cloud energy storage for grid scale applications in the uk abstract in this paper the uk s electricity market and battery technologies were researched to determine the economics of aggregating domestic batteries for grid scale services a feasibility study was conducted under three scenarios in order to estimate the value of advanced lead acid ala and lithium ion li batteries for domestic households in the uk a profit optimization model was built using historical market data and technical parameters of the batteries an aggregated system of 5000 batteries was simulated and used to compare and stack value streams of seven different grid scale services in the uk including energy arbitrage reserve and frequency regulation services the results showed that using a battery system for domestic services is currently not economically viable however grid scale provision of dynamic frequency response and fast reserve services yield sufficient annual revenue to compensate for these losses the annual profit margin per household obtained was 532 692 for ala and li batteries respectively allowing a shared margin of 230 300 after accounting for household costs the promotion of an aggregated storage system is hindered by current regulatory barriers in the uk such as a double payment structure for storage operators lack of subsidy and lack of separate definition for storage devices

economic valuation of reserves in power systems with high penetration of wind power this paper proposes a methodology to determine the required level of spinning and nonspinning reserves in a power system with a high penetration of wind power the computation of the required reserve levels and their costs is achieved through a stochastic programming market clearing model spanning a daily time horizon this model considers the network constraints and takes into account the cost of both the load shedding and the wind spillage the methodology proposed is illustrated using an example and a realistic case study some conclusions are finally drawn

energy storage arbitrage under day ahead and real time price uncertainty electricity markets must match real time supply and demand of electricity with increasing penetration of renewable resources it is important that this balancing is done effectively considering the high uncertainty of wind and solar energy storing electrical energy can make the grid more reliable and efficient and energy storage is proposed as a complement to highly variable renewable energy sources however for investments in energy storage to increase participating in the market must become economically viable for owners this paper proposes a stochastic formulation of a storage owner s arbitrage profit maximization problem under uncertainty in day ahead and real time market prices the proposed model helps storage owners in market bidding and operational decisions and in estimation of the economic viability of energy storage case study results on realistic market price data show that the novel stochastic bidding approach does significantly better than the deterministic benchmark

multistage stochastic investment planning with multiscale representation of uncertainties and decisions we propose a multistage multiscale linear stochastic model to optimize electricity generation storage and transmission investments over a long planning horizon the multiscale structure captures large scale uncertainties such as investment and fuel cost changes and long run demand growth rates and small scale uncertainties such as hour to hour demand and renewable availability uncertainty the model also includes a detailed treatment of operating periods so that the effect of dispatch decisions on long term investments are captured the proposed model can be large in size the progressive hedging algorithm is applied to decompose the model by scenario greatly reducing computation times we also derive bounds on the optimal objective function value to assess solution quality we use a case study based on the state of texas to demonstrate the model and show the benefits of its detailed representation of the operating periods in making investment decisions

when energy storage reduces social welfare this paper examines the potential welfare effects of storage under different market structures this includes combinations of perfectly competitive and strategic generation and storage sectors and standalone and generator owned storage we demonstrate that if the generation sector is perfectly competitive and does not own storage then storage cannot be welfare diminishing otherwise generator owned storage or standalone storage in a market with strategic generating firms can reduce welfare compared to the no storage case this contradicts conventional wisdom that adding firms to an imperfectly competitive market typically reduces welfare losses

an hour ahead prediction model for heavy tailed spot prices abstract we propose an hour ahead prediction model for electricity prices that capture the heavy tailed behavior that we observe in the hourly spot market in the ercot texas and the pjm west hub grids we present a model according to which we separate the price process into a thin tailed trailing median process and a heavy tailed residual process whose probability distribution can be approximated by a cauchy distribution we show empirical evidence that supports our model

the portfolio composition of asset holdings in the united kingdom an extensive literature has developed on theoretical aspects of portfolio selection one basic model which often serves as a convenient benchmark assumes that individuals choose their portfolio to maximise expected utility in a world of perfect information perfect capital markets and no taxes or transaction costs if these individuals exhibit constant relative risk aversion the optimal asset combination will be one in which the proportion of wealth invested in each type of asset is independent of total wealth the asset proportions are also independent of age if the analysis is extended to a lifecycle framework with an additively separable intertemporal utility function once the stringent preconditions of this benchmark model are relaxed it becomes progressively more difficult to derive any firm predictions regarding the structure of asset portfolios the recognition of such factors as transaction costs indivisibilities capital market imperfections and the vagaries of tax systems as well as the possibility that relative risk aversion may not be constant makes it unlikely that asset proportions will show stability across wealth and age groups but portfolio theory is generally ambiguous about how the pattern of asset holdings is affected 2 it follows that the further analysis of portfolio behaviour needs to be primarily empirically orientated unfortunately data on the asset holdings of individuals or households are notoriously poor in comparison with other important economic variables information is available from sample surveys but there are usually problems with the limited asset coverage suspect valuations and biases arising from the non randomness of response rates furthermore the sample sizes are generally low against these deficiencies has to be set the fact that the surveys contain a range of other economic variables and demographic characteristics whose relationship with asset holdings can be investigated projector and weiss i966 report asset shares for a sample of 2 557 households in the united states and these data have been subsequently used by feldstein i976 to examine the impact of the tax structures on asset holdings using another source uhler and cragg i97i present results on portfolio composition for 965 households focusing in particular on the holdings of money balances exploiting yet

optimal energy commitments with storage and intermittent supply we formulate and solve the problem of making advance energy commitments for wind farms in the presence of a storage device with conversion losses mean reverting price process and an autoregressive energy generation process from wind we derive an optimal commitment policy under the assumption that wind energy is uniformly distributed then the stationary distribution of the storage level corresponding to the optimal policy is obtained from which the economic value of the storage as the relative increase in the expected revenue due to the existence of storage is obtained

economic assessment of concentrated solar power technologies a review abstract this paper surveys economic assessments of concentrated solar power csp technologies and finds two dominant assessment methods a majority of studies reported in the literature are based on the levelized cost of electricity lcoe while a small subset of studies consider time varying meteorological and electricity market conditions several studies argue that lcoe undervalues dynamic flexibility provided by thermal energy storage and does not consider revenue opportunities provided by electricity markets at different time scales as a result some studies find that both lcoe and revenue can in fact be conflicting metrics for certain designs and market conditions this review finds strong variations in lcoe and revenue estimates in the literature as comparisons between csp and other generation technologies e g fossil wind and photovoltaic are dictated by the chosen economic metric it is imperative that policy and investment decisions should carefully consider time varying effects and flexibility finally research directions are proposed to increasing the fidelity of economic assessments and to mitigate discrepancies

electricity market clearing with improved scheduling of stochastic production abstract in this paper we consider an electricity market that consists of a day ahead and a balancing settlement and includes a number of stochastic producers we first introduce two reference procedures for scheduling and pricing energy in the day ahead market on the one hand a conventional network constrained auction purely based on the least cost merit order where stochastic generation enters with its expected production and a low marginal cost on the other a counterfactual auction that also accounts for the projected balancing costs using stochastic programming although the stochastic clearing procedure attains higher market efficiency in expectation than the conventional day ahead auction it suffers from fundamental drawbacks with a view to its practical implementation in particular it requires flexible producers those that make up for the lack or surplus of stochastic generation to accept losses in some scenarios using a bilevel programming framework we then show that the conventional auction if combined with a suitable day ahead dispatch of stochastic producers generally different from their expected production can substantially increase market efficiency and emulate the advantageous features of the stochastic optimization ideal while avoiding its major pitfalls a two node power system serves as both an illustrative example and a proof of concept finally a more realistic case study highlights the main advantages of a smart day ahead dispatch of stochastic producers

risk constrained bidding and offering strategy for a merchant compressed air energy storage plant electricity price forecasts are imperfect therefore a merchant energy storage facility requires a bidding and offering strategy for purchasing and selling the electricity to manage the risk associated with price forecast errors this paper proposes an information gap decision theory igdt based risk constrained bidding offering strategy for a merchant compressed air energy storage caes plant that participates in the day ahead energy markets considering price forecasting errors price uncertainty is modeled using igdt the igdt based self scheduling formulation is then used to construct separate hourly bidding and offering curves the theoretical approach to develop the proposed strategy is presented and validated using numerical simulations

economic and environmental implications of different approaches to hedge against wind production uncertainty in two settlement electricity markets a pjm case study abstract this paper examines the economic and environmental outcomes of four two settlement electricity market clearing designs the first design corresponds to a deterministic market clearing dmc similar to the mechanism currently used in organized wholesale electricity markets in the united states the other three designs account for the day ahead da wind power production uncertainty into the da market mechanisms either implicitly or explicitly an augmented deterministic market clearing admc design introduces da ramp capability products these products ensure adequate and ramp feasible electricity generation capacity commitments in the da stage to cope with the real time realization of wind power generation a hybrid deterministic market clearing hdmc design augments admc by explicitly integrating a characterization of wind power production uncertainty into the residual unit commitment ruc process which is run after the da market is closed using stochastic programming the last design referred to as stochastic market clearing smc uses stochastic optimization to explicitly account for wind power production uncertainty in the da market clearing mechanisms i e da unit commitment and economic dispatch the four market clearing designs are assessed by simulating the electricity market operations of a test system and comparing their results in terms of operating costs prices costs and revenues of different types of producers consumer s payments integration of wind power and air emissions the test system has 12 of the capacity of pjm s fossil fired power generation fleet and uses data on coincident demand and wind power production from the bonneville power administration bpa system during years 2010 2014 the simulations are performed hourly for a whole year results show that smc is superior as its costs reductions are more than two times the improvements attained by admc and hdmc also smc results in electricity prices that are better aligned with operation costs cuts the spread between the day ahead and real time prices by 40 reduces out of market short term revenue sufficiency payments by 58 reduces co2 emissions by 3 52 and decreases power plants cycling hdmc is a distant second best market design relative to dmc it achieves a reduction in total costs that is less than half the reduction achieved by smc a reduction in out of market payments that is 80 of the reduction attained by smc and an increase in wind power integration that is

using storage capacity rights to overcome the cost recovery hurdle for energy storage energy storage is unique in that it can provide multiple services this feature raises cost recovery issues for storage due to the combination of competitive markets and ratebased cost recovery used in many power systems today this hybrid regulatory paradigm relies on classifying assets as providing competitively prices or unpriced services and handling cost recovery based on that classification some recent regulatory precedents suggest that storage developers must choose between classifying their assets as providing competitively priced or unpriced services in the former case storage costs must be recovered through the market if an asset is classified as providing only unpriced services costs can be recovered through the ratebase this regulatory design can hamper cost recovery for storage and may lead to inefficient storage investment and use we propose an alternate solution whereby storage capacity rights are auctioned to third parties that use their rights for priced or unpriced services storage capacity rights disentangle storage cost recovery from the regulatory treatment of its end use we formulate the storage capacity auction model and demonstrate how to efficiently price storage capacity rights we show that the revenues earned by the storage owner through the auction equals the imputed marginal value of storage capacity as revealed by the market bids

gender differences in risk behavior an analysis of asset allocation decisions in ghana abstract within a developing country context little is known about gender differences in risk preferences as reflected in asset allocation decisions much of the empirical literature within development studies on risk and investment in assets centers on risk coping and risk management strategies of households with some exceptions this literature primarily focuses on household and household level outcomes previous experimental studies have explored gender differences in risk preferences in developing countries with inconclusive results using unique national representative sex disaggregated data with self reported asset ownership and wealth information of individuals within households in ghana from a multi country project the gender asset gap project this paper explores men and women s risk preferences as reflected in asset allocation decisions through a decomposition method typically used to explore gender differences in wage employment the study finds that although women hold significantly fewer risky assets than men in absolute terms and as a proportion of their wealth in the sample men and women do not have systematically different risk preferences the results in this paper differ from the results in many empirical studies in developed countries where women are often found to be more risk averse than men as the first study to look at gender differences in risk aversion in terms of asset allocation with in the developing country context the results from this study provide evidence that gender differences in risk attitudes may vary by cultural context as the growing experimental literature in developing countries suggests

assessing the economic value and optimal structure of large scale electricity storage large scale electricity storage can enable arbitrage between periods when electricity is abundant and cheap and periods when it is scarce in principle this could enable greater use of baseload generation and encourage investments in intermittent capacity such as wind and solar if storage is to penetrate the system the marginal value of storage capacity must be high enough to enable investments in storage to have a significant impact on investments in intermittent technologies it must be large enough to affect the prices on the system this research develops a theoretical framework to evaluate the marginal values of the components of a storage system and to characterize the impact of storage on the price patterns in the system the theoretical approach is applied to an example system to illustrate the changes in marginal values as storage penetrates the system and the impact on system prices

a comparative analysis of the value of pure and hybrid electricity storage significant natural gas and electricity price variation and volatility especially during the past few years raise questions about understanding the value drivers behind electricity storage the impact of these drivers for pure storage such as pumped hydroelectric storage and compressed air energy storage caes are different and in this paper we explore these differences in operation and net revenue over a variety of timescales we also consider the arbitrage value that is attainable in practice and explain why simple forecasting techniques based on historical data will generally be less successful for caes the breakeven cost of storage and how this can depend on regulatory treatment of storage and market structure is also considered

optimal response of a thermal unit to an electricity spot market this paper addresses the optimal response of a thermal unit to an electricity spot market the objective is to maximize the unit profit from selling both energy and spinning reserve in the spot market the paper proposes a 0 1 mixed integer linear programming approach that allows a rigorous modeling of i nonconvex and nondifferentiable operating costs ii exponential start up costs iii available spinning reserve taking into account ramp rate restrictions and iv minimum up and down time constraints this approach overcomes the modeling limitations of dynamic programming approaches and is computationally efficient results from realistic case studies are reported

economics of electric energy storage for energy arbitrage and regulation in new york unlike markets for storable commodities electricity markets depend on the real time balance of supply and demand although much of the present day grid operates effectively without storage cost effective ways of storing electrical energy can help make the grid more efficient and reliable we investigate the economics of two emerging electric energy storage ees technologies sodium sulfur batteries and flywheel energy storage systems in new york state s electricity market the analysis indicates that there is a strong economic case for ees installations in the new york city region for applications such as energy arbitrage and that significant opportunities exist throughout new york state for regulation services benefits from deferral of system upgrades may be important in the decision to deploy ees market barriers currently make it difficult for energy limited ees such as flywheels to receive revenue for voltage regulation charging efficiency is more important to the economics of ees in a competitive electricity market than has generally been recognized