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According to the European-Green-Deal, the share of renewable energy sources (RES) in electricity generation is increased by e.g. solar/wind. This requires the deployment of effective energy storage solutions to compensate the fluctuating network supply of RES. A well-developed storage technology is pumped hydro energy storage (PHES), but especially in lowland countries, e.g. Denmark, typical high-head plant locations are missing. Therefore, new developments in low-head hydraulic turbomachineries and smart operation schemes are needed to shape LH-PHES towards a viable future technology through maximizing performance and minimizing investment costs. Hence, this study demonstrates a novel design of contra-rotating, variable-speed, reversible pump-turbines (CR-VS-RPT) for low-head operation with a peak efficiency above 90 % in pump/turbine mode. The results comparing shaft-driven with rim-driven CR-VS-RPT show the influences of chosen RPT type on the reservoir size/investment. The study also proves that hydraulic losses due to the bulb for shaft-driven CR-VS-RPT have a decisive impact on the head range, and thus on the required dam material volume. Despite the slightly less efficient performance of rim-driven CR-VS-RPT, the absence of the bulb increases the efficiency during operation at low L A T s. However, the L A T is the key factor for CR-VS-RPT type selection to minimize the investment for LH-PHES. • LH-PHES is powerful technology for grid stabilization while increasing the share of RES. • RPT bulb design controls the losses and thus the reservoir size, especially in the lower water depths. • The rim-driven CR-VS-RPT is thus more efficient than the shaft-driven CR-VS-RPT in the lower depths. • Above LAT 33 m shaft-driven RPT is advantageous over rim-driven RPT independent of bulb design. [ABSTRACT FROM AUTHOR]

With its European Green Deal, the European Union (EU) aims to substantially increase renewable electricity generation and decrease greenhouse gas emissions in the electricity sector by 2035. European countries independently set these targets, but might not account for cross-border infrastructure interdependencies that may facilitate or impede their implementation. This study quantifies regional interdependencies among 36 European countries aggregated to eight regions by applying electricity sector modeling, Modeling to Generate Alternatives, tree-based ensemble method, and scenario discovery. Cost-effectively reaching EU targets in 2035 allows for flexibility in uptake of electricity system infrastructure across European regions, with few exceptions. Reaching EU targets with low costs requires high renewable capacities in Central and Nordic Europe and France, steep reductions of fossil fuel capacities in Central and Eastern Europe, keeping existing nuclear capacities in France, and high storage capacities in Alpine and Central Europe. Regional targets are most influential for increasing renewable capacities, while EU targets are most influential for decreasing greenhouse gas emissions. If EU targets are met, reaching regional targets of Central Europe and keeping nuclear capacities in France substantially reduce infrastructure requirements in Eastern Europe, highlighting the importance of regional cooperation for electricity system planning and policy. • EU targets allows for flexibility in new electricity infrastructure in Europe • Renewables in Central and Nordic Europe are cost-effective to reach EU targets • Regional interdependencies highlight the importance of cooperation across Europe [ABSTRACT FROM AUTHOR]

The current research is motivated to arrange an innovative hybrid solar-geothermal system, where the geothermal-driven subsystem is used to give out a sustainable framework for the upstream subsystems. Thus, an integrated geothermal flash cycle combined with organic Rankine cycle 1 (ORC1) is utilized to supply the input electricity of the compressed air energy storage system (CAES) at charging periods. The stored stream is exposed to electricity generation by the use of parabolic trough solar collectors (PTSCs). In addition, ORC2 recovers the waste heat of air turbines. A multi-aspect study is considered from the thermodynamical and economical standpoints. In addition, the sensitivity analysis is carried out to evaluate the effect of different parameters on the performance of the system. Moreover, four optimization scenarios are defined and scrutinized using a multi-objective particle swarm optimization (MOPSO) algorithm. The present study exhibits that the most appropriate optimum solution from the thermodynamic facet is a consequence of a framework in which the energy efficiency of flash-ORC1 and its output electricity is the objective functions. In this situation, the optimum energetic and exergetic efficiencies of the flash-ORC1 unit are equal to 20.43% and 67.63%. Furthermore, the lower optimum payback period equals 3.07 years corresponding to the scenario in which objective functions are the exergy efficiency of flash-ORC1 and the payback period. • Design of a novel hybrid solar-geothermal combined power plant utilizing CAES. • Conduct a coherent parametric study at charging and discharging periods. • Investigation of the proposed system from thermodynamic and economic viewpoints. • Considering four different optimization methods using MOPSO/TOPSIS/LINMAP. • Obtaining The best optimum exergy efficiency and payback period of 67.63% and 3.07 years. [ABSTRACT FROM AUTHOR]

Abstract Demand response has proven to be a distributed energy resource of great potential over the last decades for electrical systems operation. However, small or medium size facilities generally have a very limited ability to participate in demand response programs. When a facility includes several generation resources, energy storage systems, or even demand flexibility, the decision-making becomes considerably harder because of the amount of variables to be considered. This paper presents a method to facilitate end users' decision-making in demand response participation. The method consists of an algorithm that uses demand and generation forecasts and costs of the available resources. Depending on the energy to be reduced in a program, the algorithm obtains the optimal schedule and facilitates decision making, helping end users to decide when and how to participate. With this method, end users' capability to participate in these programs is clearly increased. In addition, the method is contrasted by simulations based on real programs developed at the Campus de Vera of the Universitat Politècnica de València. The simulations carried out show that the developed method allows end users to take advantage of the potential of their facilities to provide demand response services and obtain the maximum possible benefit. Highlights • A method to facilitate decision-making in demand response is proposed. • The proposed algorithm enables facilities to participate in demand response programs. • The proposed method maximises the benefits that can be obtained with demand response. • A method to optimise demand response participation is tested. • Participation in demand response with distributed energy resources is facilitated. [ABSTRACT FROM AUTHOR]

Abstract Due to slow response of conventional micro gas turbine(MGT) generator system, pulse power load(PPL) will cause large voltage sags and overshoot of direct current(DC) bus voltage, and even lead to instability. In this paper, super capacitor(SC) energy storage system(ESS) is applied to MGT to form a hybrid power generation system. Then the two cooperative control methods of hybrid generation system are proposed. One is the PI-based control algorithm, and the other is the fast power coordinated control method through MGT output power forecast. The fast power dynamic response of SC ESS can compensate for low dynamic response of MGT, which makes the hybrid generation system in equilibrium state of transient power in real time. Voltage of DC bus is smooth, and adaptability of MGT to PPL is enhanced. The second control algorithm is proposed according to power output characteristics of MGT, and has the advantages of fast and balanced power distribution. The algorithm of fast charging and exiting of SC ESS is proposed based on load conditions, and the charging process will not cause any impact. Finally, simulation model is established to verify the effectiveness of the two control algorithms, and the results are compared. Highlights • Supercapacitor energy storage system is applied to MGT to form hybrid generation system. • PI-based cooperative control algorithm of hybrid generation system is proposed. • Instantaneous power cooperative control based on power prediction of MGT is proposed. • Hybrid power generation system is designed seamlessly in frequency domain. • Soft operation of hybrid power generation system under pulse power load is ensured. [ABSTRACT FROM AUTHOR]

Abstract Based on weather and electricity demand data for the period 1984–2013, we develop a system model based on energy balance to determine the size of photovoltaic and wind generation combined with energy storage to provide a firm power supply for Great Britain. A simple graphical methodology is proposed where the required wind and PV generation capacities can be read off from a "system configuration diagram" as a function of the available storage size. We show, by way of illustration, that a reliable supply would be produced by a system based on PV and wind generators generating some 30% more electrical energy (approximately 100 TWh p.a.) than the current electricity supply system if supplemented with 30 days of storage. In terms of generation capacities, the current 82 GW of principally thermal generation would then be replaced by about 150 GW of wind turbines and 35 GW of PV arrays. Highlights • Great Britain power system consisting of wind turbines, photovoltaics and storage. • 100% renewable system producing 30% more electrical energy than the demand. • 30 storage days (25 TWh) for uninterrupted power supply over a 30 year design period. [ABSTRACT FROM AUTHOR]

This paper presents a framework for expansion planning studies of distributed energy storage systems (DESSs) in high wind penetrated power systems. The main objective is to find optimal location and capacity of DESSs in the viewpoint of independent system operator (ISO) while ensuring the maximum usage of wind farms output generation. Three different criteria are introduced for expansion planning studies. Minimizing wind curtailment cost together with transmission congestion cost are considered to properly deal with the issues associated with the curtailment of wind energy and constraints of transmission network. Furthermore, the minimum normalized profit for all DESSs' owners needs to be maximized to model the requirements of DESSs' owners in the studies. These all the crucial aspects of the DESSs expansion problem are treated via a well-organized posteriori multi-objective (MO) optimization algorithm, i.e. the Non-dominated Sorting Genetic Algorithm II (NSGA-II). The proposed method is applied to the modified IEEE 24-bus test system, and the results are presented to verify the applicability and efficiency of the proposed DESSs planning in a renewable-based power system. [ABSTRACT FROM AUTHOR]

The main purpose of a Transmission System Operator is to ensure stabile, reliable and efficient operation of its power system. Large-scale integration of renewable energy sources has introduced additional challenges to active control of transmission power systems. Traditionally, generation adequacy has been achieved through investments in generating units and transmission adequacy through investments in transmission lines. However, energy storage can be regarded as both the generation asset, as it reduces peak load and acts as a generator when injecting electricity into the network, and transmission asset, as it can move electricity in time thus reducing congestion and curtailment of renewable energy sources. This paper examines the role of energy storage in increasing power system adequacy and security. A method is proposed to define the charging/discharging schedule of energy storage after a contingency in order to preserve the system within the operating limits and to provide the system operator enough time to redispatch the system and relieve the overloaded lines. The method is applied to an actual part of the Croatian power system using scenarios that describe representative network states. The simulations are performed in a transmission operations and planning software using actual operating data. The results are analysed in details and conclusions on the role of the energy storage in providing transmission system adequacy and security is assessed. [ABSTRACT FROM AUTHOR]

With the rapid development of cascade reservoirs, the joint operation chart of cascade reservoirs and its optimization methods have been widely researched. Aimed at the defects of the conventional two-stage Progressive Optimality Algorithm (POA) in the optimization of energy storage operation chart, this paper proposed a new multi-stage POA optimization model. It took the traditional reverse calculation result as the initial solution, and expanded the two-stage optimization mode of conventional POA to three-stage mode, four-stage mode, or higher stages mode, and implemented the iterative calculation by taking the result of lower stages POA as the input of higher stages POA, until the result converged. In addition, enumeration method was used to iterate over all the possible combinations in local optimization to improve the efficiency of local search. In order to test and verify the rationality and validity of the proposed model, two cascade reservoirs had been taken as the instances of case study, compared with conventional two-stage POA, results showed that the power generation of Li Xianjiang and Three Gorges cascade reservoirs by the proposed multi-stage POA can respectively increase by 0.055% ($32000) and 0.077% ($3900000). So the economic benefits are remarkable, and the proposed model is reasonable and effective. [ABSTRACT FROM AUTHOR]

The main aim of this study is to present an energy transition roadmap for Pakistan in which the total energy demand by 2050 is met by electricity generated via renewable sources, in particular, solar photovoltaic. Efforts have been made to assess the energy and cost required for the transition towards a sustainable energy supply covering the demand for power, desalination and industrial gas sectors. Hourly resolved model was used and optimization was carried out for each time period (transition is modeled in 5-year steps) on the basis of assumed costs and technological status till 2050 for all energy technologies involved. Solar PV dominates the installed technologies and contributes 92.7% and 96.6% in power and integrated scenarios. Seawater desalination sector dominates the integrated scenario and clean water demand is found to be 2.8⋅10 11 m 3 by 2050. The levelised cost of electricity declines from 106.6 €/MWh in 2015 to 46.2 €/MWh in 2050 in power scenario. In country-wide scenario, gas storage rules from 2040 to 2050 in terms of total storage capacities while battery storage is prominent in terms of storage output. The results indicates that, 100% renewable system is cost competitive and least cost option for Pakistan's future energy transition. [ABSTRACT FROM AUTHOR]

Innovative technologies and strategies to decarbonize electricity generation, transport, and heat supply sector are key factors to achieve the global climate targets set by international organizations. One of these strategies implies a significant increase of the share of renewable electricity in the energy mix. Given the intermittent behaviour of renewable energy sources (RES), a detailed assessment of future energy scenarios is required to estimate the potential surplus in electricity production. To facilitate the penetration of renewable energy sources up to significant shares, massive long-term electricity storage technologies must be considered. Among these technologies, power-to-gas (PtG) systems may foster the fossil fuels switch by providing storage of surplus renewable electricity in the form of hydrogen or synthetic natural gas. Thus, this energy carrier could be reconverted to electrical power to cover peak demand periods. In this work, a study of the prospective Spanish scenario is presented and the potential of PtG technology is assessed in terms of expected renewable surplus. We found that the annual electricity surplus for 2050 might vary between 1.4 TWh and 13.5 TWh, and the required PtG capacity would be in the range 7.0–19.5 GW, depending on the renewable production pattern and the increment of demand. [ABSTRACT FROM AUTHOR]

With the increase of the production of power/energy from renewables it becomes much important to look at methods and techniques to store this energy. In principle, the renewable energy can be transformed into another form of storable energy and to be transformed back when needed. The main Energy storage techniques can be classified as: 1) Magnetic systems: Superconducting Magnetic Energy Storage, 2) Electrochemical systems: Batteries, fuel cells, Super-capacitors, 3) Hydro Systems: Water pumps, 4) Pneumatic systems: Air compressors, 5) Mechanical systems: Flywheels, 6) Thermal systems: Molten Salt, Water or oil heaters. When we are talking about energy storage systems, we should consider the criteria of selection for method and technique of storing this energy. Researchers and scientists have classified different criteria in selecting the energy storage techniques, the main points to be considered are: 1) the available energy resources, 2) energy requirement and application, 3) energy storage efficiency, 4) energy storage cost, 5) energy storage infrastructure, 6) other factors. This editorial describes articles presented at the 8th International Conference on Sustainable Energy and Environmental Protection SEEP2015. Main topics include renewable energy and energy storage systems and various articles related to the conference scope. [ABSTRACT FROM AUTHOR]

Large scale deployment of intermittent renewable energy induces new challenges for energy systems. They have to balance the volatile energy consumption with the variable power generation. Thus all other components of a renewable energy system are required to be more flexible than they are at present. Storing surplus energy to meet demands when required is one technical solution of balancing this demand. This study analyses the economic performance of an innovative storage technology, known as stored energy in the sea (StEnSea), and compares the findings of the economic analysis with the costs of alternative storage technology options, namely compressed air energy storage (CAES) and pumped hydro storage (PHES) plants, which are comparable in capacity and their balancing performances. Results have shown that the required price arbitrage for the economic operation of the StEnSea technology at a storage farm with 80 storage units and 400 MW ranges from 4 €ct kWh-1 to 20 €ct kWh-1 and strongly depends on the annual operation cycles. The comparison of costs for storing surplus electricity providing power during demand periods when using the StEnSea technology with the costs of CAES and PHES for equivalent services have shown that the StEnSea technology is cost competitive. [ABSTRACT FROM AUTHOR]

Redox flow batteries (RFB) showcase extremely long charge-discharge life cycle and outstanding quick response to alleviate the oscillations under sudden disturbances in power system. The assimilation of energy storage units in power system can curtail the oscillations energetically by contributing fast active power compensation. Hence, in this paper, RFB are tried to integrate into multi-source power systems and their efficacy in boosting automatic generation control (AGC) performance is executed. A new fractional order fuzzy PID (FOFPID) controller is employed to enhance the system performance. FOFPID controller parameters are optimized maidenly by utilizing imperialist competitive algorithm (ICA). The controller is designed and implemented on more realistic single/two-area multi-source hydrothermal gas system with/without RFB. The potency of FOFPID is established by contrasting its responses with optimal and lately developed hSFS-PS, DE, TLBO and IPSO optimized controllers. To check the efficacy of the approach, the study is further conducted under the presence of important non-linearites like GDB and GRC. Analysis of results reveals that the advocated approach with/without RFB improves the system performance significantly in comparison to the prevalent methods. The robustness of the method is demonstrated against wide variations in system parameters under the presence/absence of RFB/GDB-GRC and at higher and variable step load demands. [ABSTRACT FROM AUTHOR]

A network topology is required to solve the scheduling problems of power systems. These systems suffer from many problems such as limited generation resources, changing fuel prices, and inconsistent load demand. This paper proposes an optimal generation rescheduling method for a hybrid integrated system (HIS) that employ multi-terminal voltage source converter high voltage direct current (VSC-MTDC) systems and a battery energy storage system (BESS)-based voltage droop control with a power dead-band and voltage limits. The proposed process is based on the HIS station limits and charging/discharging cycles, and can be used to improve the HIS performance. An optimal power flow (OPF) problem is formulated by considering the grid code constraints within VSC-MTDC and BESS. Using Benders' decomposition, the proposed approach is formulated as a master problem and sub-problems, and is intended to enhance the overall operational efficiency by leveraging parallel processing. Moreover, the charging/discharging strategy employs an operational HIS algorithm over a 24 h demand profile. This strategy takes into account the actual demand conditions so that the optimal rescheduling algorithm can be implemented in a realistic manner. The results of simulations on a modified IEEE–39 bus system demonstrate and confirm the applicability, effectiveness, and suitability of the proposed approach. [ABSTRACT FROM AUTHOR]

In view of the impact load problems in the traditional micro gas turbine (MT) power generation system, this paper analyzes its working mechanism and finds the reason lies in the slow response of the micro turbine output power adjustment. In order to make up for the shortage of the instantaneous output power of micro turbine, the method of instantaneous power fast control is proposed. Control algorithm of instantaneous compensation power is raised by power response prediction of MT. The high power dynamic response of super-capacitor energy storage can compensate low dynamic response problem of MT output power, so the instantaneous power of the system is real balance to ensure that the DC bus voltage is smooth and adaptability of MT power generation system is enhanced for impact load. Finally, the correctness and feasibility of the proposed control strategy are verified by simulation results. [ABSTRACT FROM AUTHOR]

We have introduced a generic decision support tool for concurrent optimal selection, sizing, and operation scheduling of grid-connected or off-grid multi-generation/multi-storage distributed generation and storage (DGS) systems with respect to the dynamics of historical/projected periodical weather data, electricity price, DGS system cost, DGS aging, and the major critical design and operational parameters. This decision support program enables the consumer (ranging from a small house to large-scale industrial plants) to implement the most efficient electricity management strategy while achieving the goal of minimizing the electricity bill. [ABSTRACT FROM AUTHOR]

Transition to a low-emission society requires radical emissions reductions in the electricity generation sector. Imposing that hourly load has to be served solely by wind power, solar PV and an energy storage technology, it is shown, using optimization and simulations of re-analysis data, how the EU can design a completely CO 2 emission-free electricity generation sector. For such a system, the optimal battery energy capacity should be 32 times of average hourly consumption of electricity in the EU. However, total production of electricity over a 10 year period is as much as 43% above total consumption of electricity. • Modeling of a CO2 free electricity system in Europe. • Using optimization and simulations of spatial re-analysis data. • Battery capacity should be 32 times of average hourly consumption of electricity. • Total production of electricity has to exceed total consumption by 43%. [ABSTRACT FROM AUTHOR]

Electricity systems with high penetrations of renewable energy require a mix of resources to balance supply with demand, and to maintain safe levels of system reliability. A load balancing methodology is developed to determine the optimal lowest-cost mix of renewable energy resources, demand response, and energy storage to replace conventional fuels in the Province of Ontario, Canada. Three successive cumulative scenarios are considered: the displacement of fossil fuel generation, the planned retirement of an existing nuclear reactor, and the electrification of the passenger vehicle fleet. The results show that each of these scenarios is achievable with energy generation costs that are not out of line with current and projected electricity generation costs. These transitions, especially that which proposes the electrification of the vehicle fleet, require significant investment in new generation, with installed capacities much higher than that of the current system. Transitions to mainly renewable energy systems require changes in our conceptualization of, and approach to, energy system planning. [ABSTRACT FROM AUTHOR]

The rapid increase in the share of electricity generation from renewable energy sources is having a profound impact on the power sector; one of the most relevant effects of this trend is the increased importance of energy storage systems, which can be used to smooth out peaks and troughs of production from renewable energy sources. Besides their role in balancing the electric grid, energy storage systems may provide also several other useful services, such as price arbitrage, stabilizing conventional generation, etc.; therefore, it is not surprising that many research projects are under way in order to explore the potentials of new technologies for electric energy storage. This paper presents a thermodynamic analysis of a cryogenic energy storage system, based on air liquefaction and storage in an insulated vessel. This technology is attractive thanks to its independence from geographical constraints and because it can be scaled up easily to grid-scale ratings, but it is affected by a low round-trip efficiency due to the energy intensive process of air liquefaction. The present work aims to assess the efficiency of such a system and to identify if and how it can achieve an acceptable round-trip efficiency (in the order of 50–60%). [ABSTRACT FROM AUTHOR]

With the rapid growth of the electricity produced by RES (renewable energy sources), especially those highly variable and unprogrammable (e.g. wind and solar power), the need of energy system flexibility increases significantly. Since RES currently represent a significant fraction of the power supply, their variable nature poses challenges to power grid operation, such as RES curtail and loss in global efficiency of thermoelectric plants, since they are often operated at part-load as fluctuating back-up power. In particular, thermoelectric plants recently moved their role from base-load power to fluctuating back-up power. Such a cycling operation represents a less obvious effect of grid flexibility requirement due to RES penetration. Main effect is the increment of both energetic costs, due to reduced efficiency operation, and wear-and-tear costs. This aspect is deeply analysed in reference to the Italian electricity generation mix in the period 2008–2012. Moreover, the possible coupling of energy storage systems with thermoelectric plants is highlighted as an alternative solution respect to retrofitting of existing plants. [ABSTRACT FROM AUTHOR]

The new frontier for hydropower electricity generation in Brazil, the Amazon region, cannot be used for energy storage as the construction of storage reservoirs would have deep environmental and social impacts, thus run-of-the-river dams have been built instead. If Brazil still wants to generate 80% of its electricity from hydropower, there is the need to increase the country's energy storage capacity so that the excess generation coming from the dams in the Amazon region during the wet period can be used during the dry period. This article presents four ways to increase the storage capacity of a watershed. The most innovative alternative involves a large-scale pumped-storage site combined with a series of hydropower dams in cascade, which could store energy by pumping water to a new reservoir during the wet period and generate energy by releasing the stored water during the dry period. Even though pumped storage schemes have an average efficiency of around 75%, it has been calculated that the combination of a pumped storage site and a series of hydroelectric dams in cascade can increase the overall storage efficiency up to 90% and double the storage capacity of a watershed. This scheme was called EPS (Enhanced-Pumped-Storage). [ABSTRACT FROM AUTHOR]

We have recently developed a simple yet powerful method to identify key properties of electricity systems with a high share of renewables. Here, our weather-driven methodology is described and applied to model the Danish power system with combined wind and solar energy gross shares of up to 100% of the total demand. We show that in a wind only scenario, surplus energy grows rapidly beyond gross shares of about 50%, while the potential for arbitrage of surplus renewable energy, i.e. demand-side management or high-efficiency storage, is very limited in this case. A scenario with a wind-solar energy mix of 80/20, on the other hand, both decreases the total amount of surplus and has a significantly higher potential for arbitrage of the remaining surplus. However, beyond gross shares of about 75%, only large-scale seasonal storage of, e.g. hydrogen, enables the use of Danish surplus wind and solar energy to cover the residual Danish electricity demand in both scenarios. [ABSTRACT FROM AUTHOR]

As the ground-based wind-turbine systems have steadily reached their performance peak due to turbine blade size limitations, generator size constraints, high investment costs, and relatively unpredictable nature of near-surface winds, the possibility of harnessing the energy of steady, high-altitude/high-speed winds has become increasingly attractive within the last decade. However, due to the intermittent nature of power production of a considered high-altitude wind energy system utilizing an airborne module tethered to a ground station, sufficiently large energy storage is required in order to provide steady power supply to the electrical power grid. This paper focuses on the sizing of typical low-to-medium scale energy storage systems (up to 10 MW), such as those based on flywheels, compressed air, batteries and ultracapacitors, considering the intermittent power production cycle, airborne module altitude range and ground-station generator power ratings. The assessment results are summarized in terms of investment/running costs, storage system size, and durability, thus providing practical guidelines for the selection of appropriate energy storage system. [ABSTRACT FROM AUTHOR]

Abstract: The interconnection between a renewable power generation facility and a power grid poses challenges because of volatility and intermittent characteristics. Energy storage is one of the best solutions for this problem. This paper presents an integrated energy storage system (ESS) based on hydrogen storage, and hydrogen–oxygen combined cycle, wherein energy efficiency in the range of 49%–55% can be achieved. The proposed integrated ESS and other means of energy storage are compared. The results show that the proposed integrated system cannot be constrained by geological conditions and availability of materials, and appears to be an appropriate tool for the development of renewable power. Moreover, a case study is conducted for a special wind power plant with a nominal power of 100 MW and that generates electricity of 225 GWh/y. The integrated system is designed based on the daily wind load. Energy efficiency and preliminary economic comparison studies for the integrated system operated in two modes show that up to 50% average net efficiency of the integrated ESS can be achieved and that the integrated ESS can stabilize the intermittent wind power. Therefore, the integrated ESS can be useful to mitigate the bottleneck of renewable power development. [Copyright &y& Elsevier]

Abstract: This study presents the modeling and analysis of an ESS (energy storage system) for a TEC (tidal energy converter) to be installed in the Bay of Fundy, Canada. The electricity distribution grid that services the region has a minimum annual electricity demand of 0.9 MW. Policy limits the installation of renewable electricity generators to 0.9 MW at this site. An existing 0.9 MW WEC (wind energy converter) occupies this capacity, inhibiting further installations. The use of an ESS enables the installation of a 0.5 MW TEC by ensuring the combined electricity output from WEC and TEC does not exceed 0.9 MW. The objective of this study is to model the system and determine the characteristics of the ESS capacity, power, and cyclic nature. The WEC and TEC are modeled based on measured and simulated wind and tidal speed data respectively. An ESS is modeled to de-couple the TEC output from the grid demand. A curtailment analysis is conducted for various ESS capacity and power sizes to determine the economic benefit. Avoidance of all curtailment requires nearly 7 MWh of storage. Significant economic benefit may be found by reducing the ESS to less than 3 MWh, resulting in minor curtailment. [Copyright &y& Elsevier]

The rising share of Variable Renewable Energy Sources (VRES) in the electricity generation mix leads to new challenges for the whole energy system. It especially raises technological issues to handle variability and to match electricity load with supply at all times. This study introduces a new methodology to quantify the relevance of different electricity storage technologies, based on a time scale analysis. It additionally provides an understanding of how electricity storages work in combination to handle variable load and intermittent generation. First, we set up a simple model of variable production, fluctuating over a single time-scale. This analysis provides figures of merit for electricity storage and curtailment. Second, we simulate the collaboration and competition behavior of various storages with a dual time-scale signal. Then, results are compared with the optimization of an energy system with real variable electricity supply and consumption time-series. We eventually highlight the trade-off mechanisms between the storage efficiency and its investment cost. • A parametric study is conducted on electricity storage for intermittent production. • Long-term electricity storage requires very low-cost technologies. • Short-term storage can afford higher costs if efficiency is high. • The optimal solution can involve two different storages for long and short terms. • Oversizing & curtailing the production can be more relevant than long term storage. [ABSTRACT FROM AUTHOR]

More utilities, energy providers, and governments are considering the transition to 100% renewable or carbon-free generation to satisfy electricity demand. This transition requires consideration of numerous factors including cost, resource adequacy, and geographical location, among others. Therefore, models that can explore the optimality of tradeoffs between multiple factors are crucial for planning this transition. An optimization problem formulation is proposed to analyze the amount of renewable generation and energy storage required to balance 100% of a utility's electricity demand on an hourly timescale over multiple years, while minimizing a desired cost. This formulation accounts for geographical location and accommodates regional energy trading, and it enables analysis of important metrics for planning, such as firm capacity, capacity factors, land area requirements, and amount of curtailed generation. This optimization-based approach is used to explore case studies in New Mexico, which is an area with significant potential for solar and wind generation in the United States. Considering multiple years of historical meteorological data and electricity demand data, results show that the amount of renewable generation required is an order of magnitude larger than the average demand, and that most of the generation is curtailed, which motivates a regional energy trading approach. • Optimize size of distributed energy resources for 100% renewable operation. • Optimize geographical locations and regional energy trading. • Sufficient firm capacity requires resources several times larger than demand. • Peaker plants are not needed in 100% renewable systems. • Energy trading can drastically reduce size of resources and curtailment. [ABSTRACT FROM AUTHOR]

The trigeneration combined the electricity, cooling and heating makes adiabatic compressed air energy storage system (ACAES) popular as an energy storage technology. Based on thermodynamic analysis, this paper studies the influence on the system performance of four variable factors, including compression stages, expansion stages, water (heat storage medium) mass flow rates in charging process and discharging process to provide a guidance for the design of ACAES for different user demand. The results show that changing these four factors can achieve different energy output distributions in a very wide range (power supply ratio is 0.50–0.86, heating output ratio is 0.00–0.39, cooling supply ratio is 0.00–0.41). Simulation results also indicate that fewer compression and expansion stages are suggested for the cases requiring shorter running time. Furthermore, according to this study, less compression stages than expansion is good for electricity generation and more compression stages is good for cooling supply. And for large heating supply demand, less compression is suggest. Besides, the energy efficiencies for different configurations of trigenerative ACAES are also achieved which are changed from 0.62 to 0.87 and the best configurations with highest system efficiency are also presented. Finally, by economic analysis, the most economic condition is achieved. • Single ACAES is used for trigenerative application to meet different energy demands. • Thermodynamic, exergy and economic analysis are used to perform the trigenerative application. • The energy efficiency of trigenerative ACAES is changed from 0.62 to 0.87. • The payback period of trigenerative ACAES is 3.4–6.8 years with different configurations. • The design guidance of compression stage, expansion stage, thermal storage are provided. [ABSTRACT FROM AUTHOR]

Abstract: Renewable energy generation is expected to continue to increase globally due to renewable energy targets and obligations to reduce greenhouse gas emissions. Some renewable energy sources are variable power sources, for example wind, wave and solar. Energy storage technologies can manage the issues associated with variable renewable generation and align non-dispatchable renewable energy generation with load demands. Energy storage technologies can play different roles in each of the step of the electric power supply chain. Moreover, large scale energy storage systems can act as renewable energy integrators by smoothing the variability. Compressed air energy storage is one such technology. This paper examines the impacts of a compressed air energy storage facility in a pool based wholesale electricity market in a power system with a large renewable energy portfolio. [Copyright &y& Elsevier]

Abstract: This paper presents the experimental results from the operation of a proto-type green ship in Geoje island, South Korea. As Korea is a peninsula situated between the continent and the sea, its location is ideal for utilizing PV/diesel green ship. After ground testing with a stand-alone PV (photovoltaic) generation system, this PV system was added to a conventional diesel ship. The proto-type green ship consisted of a photovoltaic (PV) generation system, diesel engine, battery energy storage, hybrid control system, and a stand-alone and grid-connected inverter. The aim of the green ship was not only to minimize fuel consumption but also to support the power grid as DG (distributed generation) connected to the smart grid (in land) and micro-grid (in island) in the near future. At the end of this paper, environmental, economic and sensitivity analysis would be discussed mainly based on experimental results. [Copyright &y& Elsevier]

Abstract: Offshore applications allow to exploit different renewable energy sources (wave, wind, solar) that are complementary each other, due to their statistical yearly distributions. In this paper, we discuss an offshore platform for energy production from renewable energy sources coupled with three energy storage systems. The proposed offshore platforms uses a Compressed Air Energy Storage (CAES) to timely shift the electricity production from the demand. The performance of the system related to a north Tyrrhenian Sea location was evaluated by a simulation model developed integrating three different software packages (Matlab, EES, TRNSYS). The system was designed to produce 564 kWh on the 2 h a day where peak electricity demand takes place. The results showed that the system is able to produce 177,000 kWh per year. This offshore power plant is conceived for local users (tourist resorts, villages), especially if placed in small or medium islands, wishing to qualify for extensive use of renewable energy. [Copyright &y& Elsevier]

Abstract: Dwindling fossil fuel resources and pressures to reduce greenhouse gas emissions will result in a more diverse range of generation portfolios for future electricity systems. Irrespective of the portfolio mix the overarching requirement for all electricity suppliers and system operators is to instantaneously meet demand, to operate to standards and reduce greenhouse gas emissions. Therefore all electricity market participants will ultimately need to use a variety of tools to balance the power system. Thus the role of demand side management with energy storage will be paramount to integrate future diverse generation portfolios. Electric water heating has been studied previously, particularly at the domestic level to provide load control, peak shave and to benefit end-users financially with lower bills, particularly in vertically integrated monopolies. In this paper a number of continuous direct load control demand response based electric water heating algorithms are modelled to test the effectiveness of wholesale electricity market signals to study the system benefits. The results are compared and contrasted to determine which control algorithm showed the best potential for energy savings, system marginal price savings and wind integration. [Copyright &y& Elsevier]

Abstract: The increase in fluctuating power production requires an increase in flexibility in the system as well. Flexibility can be found in generation technologies with fast response times or in storage options. In the transport sector, the proportion of electric drive vehicles is expected to increase over the next decade or two. These vehicles can provide some of the flexibility needed in the power system, in terms of both flexible demand and electricity storage. However, what are the batteries worth to the power system? And does the value depend on battery capacity? This article presents an analysis of the integrated power and transport system, focusing on the sensitivity of the power system configuration according to battery capacity and price of the electric drive vehicle. The value of different battery capacities is estimated, given that the batteries are used for both driving and storage. Likewise, the prices at which the electric drive vehicles become of interest to the power system are found. Smart charge, including the opportunity to discharge (vehicle-to-grid) is used in all scenarios. Analyses show that the marginal benefits decrease the larger the battery. For very high battery prices, large batteries imply that diesel vehicles are preferable to electric drive vehicles. [Copyright &y& Elsevier]

Abstract: Biomass energy systems can be employed to meet the requirements of distributed energy systems in rural as well as urban contexts, whether this is an electrification or a microgeneration project. This work is focused on a mathematical programming approach applied to bio-based supply chains that use locally available biomass at or near the point of use in order to produce electricity or other bioproduct. The problem of designing and planning a regional biomass supply chain is formulated as a MO-MILP (multi-objective mixed integer linear program), which takes into account three main objectives: economic, environmental and social criteria. The model supports decision-making about location and capacity of technologies, connectivity between the supply entities, biomass storage periods, matter transportation and biomass utilisation. The advantages of this approach are highlighted by solving a case study of a specific district in Ghana. The aim is to determine the most suitable biomass and electricity network among the different communities. The technology considered to transform the biomass into electricity is gasification combined with a gas engine. [Copyright &y& Elsevier]

Abstract: This paper presents a mixed-integer linear programming (MILP) super-structure model for the optimal design of distributed energy generation systems that satisfy the heating and power demand at the level of a small neighborhood. The objective is the optimal selection of the system components among several candidate technologies (micro combined heat and power units, photovoltaic arrays, boilers, central power grid), including the optimal design of a heating pipeline network, that allows heat exchange among the different nodes. The objective function to be minimised contains the annualised overall investment cost and the annual operating cost of the system. We show that besides the usual energy balance and unit operations constraints, additional equations must be included in the model to guarantee correctness of the produced heating pipeline designs. A special instance of the problem where a single centralised combined heat and power unit is installed in the neighborhood is also considered. The efficiency of the proposed model is evaluated through illustrating examples. [Copyright &y& Elsevier]

Abstract: The intermittent nature of wind energy poses questions on how electricity production can match the demand. The present paper analyses possible ways of achieving this goal when a large share of the energy is provided by wind. The study considers a certain share of wind energy as a target to be reached, and analyses different avenues for reaching such a target. The possible role of electricity energy storage, wind curtailment and transmission grid reinforcement is highlighted and discussed. The results show that above a certain percentage of electricity produced by wind, electricity storage becomes an economical option for integrating wind energy by reducing wind curtailments. Also, the synergy of storage and grid interconnections is highlighted. [Copyright &y& Elsevier]

Abstract: Distributed Energy Resources (DER) scheduling in smart grids presents a new challenge to system operators. The increase of new resources, such as storage systems and demand response programs, results in additional computational efforts for optimization problems. On the other hand, since natural resources, such as wind and sun, can only be precisely forecasted with small anticipation, short-term scheduling is especially relevant requiring a very good performance on large dimension problems. Traditional techniques such as Mixed-Integer Non-Linear Programming (MINLP) do not cope well with large scale problems. This type of problems can be appropriately addressed by metaheuristics approaches. This paper proposes a new methodology called Signaled Particle Swarm Optimization (SiPSO) to address the energy resources management problem in the scope of smart grids, with intensive use of DER. The proposed methodology''s performance is illustrated by a case study with 99 distributed generators, 208 loads, and 27 storage units. The results are compared with those obtained in other methodologies, namely MINLP, Genetic Algorithm, original Particle Swarm Optimization (PSO), Evolutionary PSO, and New PSO. SiPSO performance is superior to the other tested PSO variants, demonstrating its adequacy to solve large dimension problems which require a decision in a short period of time. [Copyright &y& Elsevier]

Abstract: The substantial increase in power generation from variable renewable sources has led to renewed interest in energy storage. Pumped hydropower remains the only mature and widely-adopted utility-scale energy storage technology. However, the selection and development of new pumped hydropower sites is heavily influenced by physical constraints such as terrain, as well as non-physical considerations such as the proximity of proposed reservoirs to settlements or environmentally or culturally sensitive sites. Hence, transforming existing reservoirs to pumped hydropower schemes is often considerably easier than developing completely new schemes. A model is proposed to calculate theoretical potential of a large area for the development of pumped hydropower schemes from existing conventional hydropower stations and from non-hydropower reservoirs. The methodology combines a new database of existing dams and reservoirs with a digital terrain model to identify suitable reservoirs for transformation, applies several constraints to eliminate unfeasible sites, then calculates the realisable potential in terms of power output and energy storage. The model is tested by applying it to the case of Turkey to produce country-level estimates of the theoretical and realisable potential for such transformations. In excess of 3800 GWh of realisable energy storage potential was identified from over 400 sites in the country. [Copyright &y& Elsevier]

Abstract: Increasing penetration of fluctuating energy sources for electricity generation, heating, cooling and transportation increase the need for flexibility of the energy system to accommodate the fluctuations of these energy sources. Controlling production, controlling demand and utilising storage options are the three general categories of measures that may be applied for ensuring balance between production and demand, however with fluctuating energy sources, options are limited, and flexible demand has also demonstrated limited perspective. This article takes its point of departure in an all-inclusive 100% renewable energy scenario developed for the Danish city Aalborg based on wind power, bio-resources and low-temperature geothermal heat. The article investigates the system impact of different types of energy storage systems including district heating storage, biogas storage and electricity storage. The system is modelled in the energy systems analyses model energyPRO with a view to investigating how the different storages marginally affect the amount of wind power that may be integrated applying the different storage options and the associated economic costs. Results show the largest system impact but also most costly potential are in the form of electricity storages. [Copyright &y& Elsevier]

Abstract: Classic storage utilisation is mainly based on charging/discharging strategies enabling a power generation company to generate revenues by buying electricity in low-price periods and selling it at higher prices. Within this paper another feasible way to gain arbitrage in storage utilisation is considered: Strategically increasing demand disregarding existing market prices. This means, charging electricity for storage is not only bought in low price periods, but in all periods where storage charging could influence demand so that market prices increase. This idea is expanded by focussing on another frequently discussed topic which could serve utilities for the same purpose: Automated Demand Side Management (DSM). By using data from Ontario’s electricity market and applying a particular storage and DSM strategy it is analysed to which extent a non-regulated dominant power generation company could influence hourly demand and corresponding prices. It turns out that both strategies analysed derive additional revenues for the dominant power generation company compared to a Business-as-Usual (BAU) case. The results provide an indicator of potential threats for misuse from particular storage or DSM utilisation. Therefore, especially in countries where DSM and/or storage applications are still in its fledgling stages, appropriate market surveillance has to be guaranteed. [Copyright &y& Elsevier]

Abstract: In this paper, energetic performance comparison of three trigeneration systems is presented. The systems considered are SOFC-trigeneration, biomass-trigeneration, and solar-trigeneration systems. This study compares the performance of the systems considered when there is only electrical power and the efficiency improvement of these systems when there is trigeneration. Different key output parameters are examined: energy efficiency, net electrical power, electrical to heating and cooling ratios, and (GHG) GHG (greenhouse gas) emissions. This study shows that the SOFC-trigeneration system has the highest electrical efficiency among the three systems. Alternatively, when trigeneration is used, the efficiencies of all three systems considered increase considerably. The maximum trigeneration efficiency of the SOFC-trigeneration system is around 76% while it is around 90% for the biomass-trigeneration system. On the other hand, the maximum trigeneration efficiencies of the solar-trigeneration system is around 90% for the solar mode, 45% for storage and storage mode, and 41% for the storage mode. In addition, this study shows that the emissions of CO2 in kg per MWh of electrical power are high for the biomass-trigeneration and SOFC-trigeneration systems. However, by considering the emissions per MWh of trigeneration, their values drop to less than one fourth. [Copyright &y& Elsevier]

Abstract: Microgrids usually operate in disparate locations and may not be connected to the national grid. The potential sources of electricity in microgrids are wind farms, solar energy, biomass, tidal energy, among others. However, microgrids that are connected to the national grid are gaining importance, because they can supply electricity to the national grid when they have an excess and buy from it when they are in shortage. Such a symbiotic relationship with the national grid helps reduce investment in storage capacity and minimizes other operational costs. In this work, we develop a mathematical model MILP – (mixed integer linear programming) for scheduling operations in microgrids connected to the national grid. We allow several realistic features such as time constraints for the purchase/sale of power from/to the national grid; round trip efficiency of batteries; hydrogen generation, and limits on storage and retrieval rates from batteries/hydrogen tanks/natural gas tanks. Furthermore, to maintain diversity in the generation of electricity from multiple resources, we develop and impose a novel linear diversity constraint on the production schedule without sacrificing the ease of schedule implementation. [Copyright &y& Elsevier]

Abstract: Due to better wind conditions at sea, offshore wind farms have the advantage of higher electricity production compared to onshore and inland wind farms. In contrast, a greater material input, leading to increased energy consumptions and emissions during the production phase, is required to build offshore wind farms. These contrary effects are investigated for the first German offshore wind farm alpha ventus in the North Sea. In a life cycle assessment its environmental influence is compared to that of Germany’s electricity mix. In comparison to the mix, alpha ventus had better indicators in nearly every investigated impact category. One kilowatt-hour electricity, generated by the wind farm, was burdened with 0.137 kWh Primary Energy-Equivalent and 32 g CO2-Equivalent, which represented only a small proportion of the accordant values for the mix. Furthermore, the offshore foundations as well as the submarine cable were the main energy intensive components. The energetic and greenhouse gas payback period was less than one year. Therefore, offshore wind power, even in deep water, is compatible with the switch to sustainable electricity production relying on renewable energies. Additional research, taking backup power plants as well as increasingly required energy storage systems into account, will allow further calculation. [Copyright &y& Elsevier]

Abstract: A wide range of literature streams and methods were examined for this research, including sustainability, integrated resource planning, and construction of portfolios of electricity generation technologies. The research then focused on current and emerging HPSTs (hydropower generation and storage technologies), and technical, economic, social, and environmental sustainability objectives associated with those technologies in the PNW (Pacific Northwest) region of the United States. Candidate technologies obtained from the literature were examined using the Delphi Method, and then rated according to their perceived impacts using the AHP (Analytical Hierarchy Process). GP (Goal Programming) was then used to determine an optimal mix of technologies to achieve sustainability objectives, using these weightings and assumptions related to specific scenarios regarding technology development, adoption, and availability. This research is important because few previous studies have systematically considered multiple objectives and criteria from multiple stakeholder experts for creating portfolios of sustainable electricity generation technologies. Previous research has also not comprehensively investigated the manner in which changing scenarios of technology development and availability rates may lead to various technological, economic, environmental, and social sustainability impacts with regard to planning of regional electrical generation and storage systems. [ABSTRACT FROM AUTHOR]

Abstract: A suitable operational strategy for a power interchange operation using multiple residential solid oxide fuel cell (SOFC) cogeneration systems for saving energy is investigated by an optimization approach based on mixed-integer linear programming. In this power interchange operation, electricity generated by residential SOFC cogeneration systems is shared among households in a housing complex without allowing a reverse power flow to a commercial electric power system in order to increase electric load factors of the system. For an SOFC cogeneration system operated continuously with the minimum output, two types of operational strategies for the power interchange operation are adopted: an operation to meet the total demand for electricity in intended households by the electricity output of SOFC cogeneration systems and an operation to meet the demand for hot water in each household by the hot water output of the SOFC cogeneration system. To clarify a theoretical limit of the energy-saving effects of the two strategies, this study numerically analyzes optimal operation patterns for 20 households on three representative days. The results show that the former operational strategy, which takes advantage of the high electricity generating efficiency of the SOFC, is more suitable for saving energy as compared to the latter strategy. [Copyright &y& Elsevier]

Abstract: The recent development of small scale combined heat and power (CHP) systems has provided the opportunity for in-house power backup of residential-scale photovoltaic (PV) arrays. This paper investigates the potential of deploying a distributed network of PV+CHP hybrid systems in order to increase the PV penetration level in the U.S. The temporal distribution of solar flux, electrical and heating requirements for representative U.S. single family residences were analyzed and the results clearly show that hybridizing CHP with PV can enable additional PV deployment above what is possible with a conventional centralized electric generation system. The technical evolution of such PV+CHP hybrid systems was developed from the present (near market) technology through four generations, which enable high utilization rates of both PV-generated electricity and CHP-generated heat. A method to determine the maximum percent of PV-generated electricity on the grid without energy storage was derived and applied to an example area. The results show that a PV+CHP hybrid system not only has the potential to radically reduce energy waste in the status quo electrical and heating systems, but it also enables the share of solar PV to be expanded by about a factor of five. [Copyright &y& Elsevier]

Electrification of military vehicles offers the potential for extended stealth operation, enhanced vehicle performance, and onboard electric power. This study proposes a hybrid electric powertrain for a military tracked vehicle with hybrid energy storage (battery and capacitor) and multi-speed transmission. Initially, component sizing of the proposed powertrain and a series hybrid electric powertrain was done based on power and torque analysis of vehicle performance requirements on different operating terrains. A rule-based control strategy was then developed for the proposed powertrain to maintain high performance as well as reduce energy losses. The performance of the proposed powertrain and the series configuration was evaluated using AVL Cruise software over synthesized drive cycles that represent the real-world activities of military tracked vehicles. Comparative analysis during component sizing showed that the proposed powertrain provides a reduction in powertrain mass by 389 kg (2.72%). From the performance analysis, it was observed that the fuel economy of the proposed powertrain improved by almost 30.27% as compared to the series configuration while maintaining vehicle performance. [Display omitted] • Hybrid electric powertrain considering the mobility attributes of military vehicles. • A rule-based control strategy for the proposed powertrain. • Synthesized drive cycle to represent the real-world operation of military vehicles. • Evaluation in AVL Cruise software for performance analysis and comparison. • Proposed configuration reduced powertrain mass and improved fuel economy. [ABSTRACT FROM AUTHOR]

Packed-bed thermal energy storage (PBTES) has advantage of being relatively low cost, but suffers from low utility factor, compared with two-tank thermal energy storage (TTES). This paper proposes two new designs of hybrid thermal energy storage system (HTESS), consisting of PBTES and TTES, and corresponding operation strategies: HTESS-TS for thermocline storage and HTESS-OTC for outlet temperature control. Firstly, structures and operation strategies of HTESS-TS and HTESS-OTC are described in detail. Then, thermal and economic performances of HTESS and single-tank thermal energy storage system (STESS) only containing PBTES in stand-alone state are compared. Next, effects of cut-off temperature and thermal capacity of TTES are analyzed. Finally, under realistic solar radiation, annual performance of concentrated solar power plant (CSP) with different thermal energy storage systems are compared. Results show that compared with STESS, utility factors of HTESS-TS and HTESS-OTC are improved by 12.5% and 22.1% respectively. Meanwhile, unit cost of HTESS-OTC is 8.6% lower than that of STESS. In addition, for a broad range of outlet temperature limits, HTESS-OTC can maintain more stable outlet temperature, higher utility factor than STESS. Compared with STESS, annual generated electricity induced by HTESS-TS and HTESS-OTC increase by 9.8% and 14.1% respectively. • Hybrid thermal energy storage system and operation strategies (HTESS) are proposed. • Utility factor of hybrid systems are improved by 12.5–22.1%. • Unit cost for heat storage is reduced by 8.6% with new designs. • New designs can enhance annual electricity generation up to 14.1%. [ABSTRACT FROM AUTHOR]

Energy storage can store surplus electricity generation and provide power system flexibility. A Generation Integrated Energy Storage system (GIES) is a class of energy storage that stores energy at some point along with the transformation between the primary energy form and electricity. The investigation of the economic and financial merits of novel energy storage systems and GIES is relevant as these technologies are in their infancy, and there are multiple technological, economic, and financial uncertainties and opportunities. This paper presents and applies a state-of-the-art model to compare the economics and financial merits for GIES (with pumped-heat energy storage) and non-GIES (with a Lithium-ion battery) systems coupled with wind generation in the United Kingdom. The deterministic, risk, and sensitivity analyses show that, for GIES's economics, the key driver is the generator capital cost; for non-GIES, the energy storage capital cost is the most important factor. A Monte Carlo analysis shows that the levelized cost of electricity values for GIES and non-GIES are 0.05 £/kWh - 0.12 £/kWh and 0.07 £/kWh - 0.11 £/kWh, respectively, for a 100 MW wind power generator and 100 MWh energy storage. The internal rate of return values for GIES and non-GIES are uncertain and range between 2%-22% and 5%–14%, respectively. • State-of-the-art cash flow model for generation integrated energy storage (GIES). • Examined the technical, economic, and financial inputs with uncertainties. • First financial and economic comparison of GIES and non-GIES systems. • A UK study with wind energy and pumped thermal energy storage. • Wind farms without energy storage have better economic and financial performance. [ABSTRACT FROM AUTHOR]