Benefits Of Energy Storage Research Articles

Techno-economic analysis of oxy-combustion coal-fired power plant with cryogenic oxygen storage

Around 43% of the cumulative CO2 emissions from the power sector between 2012 and 2050 could be mitigated through implementation of carbon capture and storage, and utilisation of renewable energy sources. Energy storage technologies can increase the efficiency of energy utilisation and thus should be widely deployed along with low-emission technologies. This study evaluates the techno-economic performance of cryogenic O2 storage implemented in an oxy-combustion coal-fired power plant as a means of energy storage. Such system was found to have high energy density and specific energy that compare favourably with other energy storage technologies. The average daily efficiency penalty of the analysed system was 12.3–12.5%HHV points, which is higher than the value for the oxy-combustion coal-fired power plant without energy storage (11.2%HHV points). Yet, investment associated with cryogenic O2 storage has marginal effect on the specific capital cost, and thus the levelised cost of electricity and cost of CO2 avoided. Therefore, the benefits of energy storage can be incorporated into oxy-combustion coal-fired power plants at marginal capital investment. Importantly, implementation of cryogenic O2 storage was found to increase the daily profit by 3.8–4.1%. Such performance would result in higher daily profit from oxy-combustion compared to an air-combustion system if the carbon tax is higher than 29.1–29.2€/tCO2. Finally, utilisation of renewable energy sources for cryogenic O2 production can reduce the daily efficiency penalty by 4.7%HHV points and increase the daily profit by 11.6%. For this reason, a synergy between fossil fuel electricity generation and renewable energy sources via CO2 capture integrated with energy storage needs to be commercially established.

A techno-economic assessment of large scale wind-hydrogen production with energy storage in Western Canada

Hydrogen production via steam methane reforming (SMR) dominates the supply to refining complexes worldwide, resulting in significant greenhouse gas (GHG) emissions. There is a considerable demand for clean hydrogen pathways that are economically competitive with SMR. The development of a 563 MW integrated wind-hydrogen model with energy storage is proposed. The model utilizes real-time wind energy data to ascertain the optimal size of the electrolyser, the number of electrolyser units and the battery (energy storage) capacity that will yield a minimum hydrogen production cost, whilst functioning in a liberalized electricity market with dynamic prices. The optimal plant configuration consists of 81 units of a 3496 kW (760Nm3/hr) electrolyser and 360 MWh (60 units) of battery capacity. For the minimum hydrogen production cost determined ($9.00//kg H2), the wind farm accounts for 63% of this cost. Hence, if existing wind farm assets are used, such that the investment cost of building the wind-hydrogen plant does not include the wind farm costs, the hydrogen production cost is reduced to $3.37/kg H2. For a particular electrolyser-battery configuration, it was observed that the minimum hydrogen production cost occurs when their respective capacity factors are approximately equivalent. The benefits of energy storage are limited by the decrease in overall plant efficiency, which results from the use of the battery. For the techno-economic conditions considered in this paper, hydrogen production costs from wind powered electrolysis ($3.37 to $9.00/kg H2) are uncompetitive with SMR/SMR-CCS ($1.87 to $2.60/kg H2).

Reliability benefit of energy storage in wind integrated power system operation

Variability of wind power is one of the main concerns of power system operation with significant wind power. Energy storage can be employed in conjunction with wind power to reduce the uncertainty associated with wind power. This study assumes the storage facility being operated by the wind farm operator for the explicit purpose of minimising the risk of wind power commitment. A time-dependent wind power model is developed in conjunction with the energy storage model for short operating lead times that are conditional on the initial wind and storage conditions. This study presents a probabilistic method to assess the reliability contribution of energy storage using two probabilistic indices: the wind power commitment risk and the unit commitment risk.

Quantifying the Energy-Storage Benefits of Controlled Plug-in Electric Vehicle Charging

Quantifying the Energy-Storage Benefits of Controlled Plug-in Electric Vehicle Charging

Potential value of energy storage in the UK electricity system

This paper assesses the value of distributed energy storage and informs the business case for its multiple applications in the UK electricity system. In contrast to earlier studies that focus on the benefits of energy storage for system operation and development, this work analyses the value that it may deliver to the owner. For this purpose, three models are proposed and applied to analyse the benefit of energy storage with applications in energy and ancillary service markets, revenue maximisation in the context of feed-in tariffs and reduction of carbon dioxide emissions. A large set of studies is carried out to quantify the commercial and emissions benefits of energy storage for those applications. Sensitivity analysis across various scenarios is performed to understand the key drivers for the value of energy storage and how it is affected by energy storage parameters and other factors such as network constraints, prices of energy and ancillary services, and inherent energy system characteristics. A review of current and near-term storage technology costs and functionality is also presented.

Technical benefits of energy storage and electricity interconnections in future British power systems

There are concerns that the GB (Great Britain) electricity system may not be able to fully absorb increasing levels of variable renewables with consequent implications for emission reduction targets.1 This study considers the technical benefits of additional energy storage and interconnections in future GB electricity systems. Initially a reference model of the GB electricity system was developed using the EnergyPLAN tool. The model was validated against actual data and was confirmed to accurately represent the GB electricity system. Subsequently, an analysis of four possible scenarios, for the years 2020 and 2030, has been performed and the maximum technically feasible wind penetration calculated. Finally, the level of interconnection and energy storage has been varied to assess the technical benefits to the operation of a 2030 GB electricity system. We conclude that increasing levels of interconnection and energy storage allow a further reduction in the primary energy supply and an increase in maximum technically feasible wind penetration, permitting the system emissions intensity to be reduced from 483 gCO2/kWh in 2012 to 113 gCO2/kWh in 2030. Increasing the levels of interconnection and energy storage has significant technical benefits in the potential future GB systems considered.

Power System Reliability Impact of Energy Storage Integration With Intelligent Operation Strategy

Electric power industry is experiencing a movement from the existing conventional electric grid to a more reliable, efficient and secure smart grid. In order to achieve these goals, components such as energy storage will be included, and potentially in large scale. Many feasible applications of energy storage in power systems have been investigated. The major benefits of energy storage include electric energy time-shift, frequency regulation and transmission congestion relief. In this paper, we focus on the reliability improvement of the bulk power system brought by the utilization of energy storage in the local distribution systems integrated with renewable energy generation. An intelligent operation strategy for energy storage which improves reliability considering the renewable energy integration is presented. The smart grid communication and control network is utilized to implement the proposed energy storage operation. A bulk power system reliability evaluation framework is proposed to study the reliability impact brought by the energy storage integration and operation. A detailed case study and sensitivity analysis is performed to demonstrate the effectiveness of the presented operation strategy and evaluation framework, and to provide valuable insights on the power system reliability impact derived from the energy storage integration.

Energy Storage for Relief of Transmission Congestion

Recent investigations by EPRI have focused on the application of existing technologies to reduce power system carbon footprint. Research examined the technical feasibility and potential benefits of energy storage to increase transmission capability of congested transmission networks that serve regions of the country having large renewable generation assets. The use of storage to relieve thermal constraints has not yet been explored or validated in depth. This paper summarizes the results of this research. These include a brief overview of different applications of storage, and a survey of past work by EPRI and others that investigated the application of energy storage on the transmission system. An in-depth description on the potential use of batteries storage to increase transmission capability in thermal-limited transmission paths is presented. A case study on a generic power system model illustrates the concept, with an economic analysis on benefits and costs. Conclusions and future steps are given.

Sustainable Power Supply Using Solar Energy and Wind Power Combined with Energy Storage

The idea of integrating intermittent sources of energy such as solar and wind with energy storage has several benefits for the electricity grid. The first benefit is that energy storage can help the grid during the periods that grid is facing high peak demand. The second benefit is that using energy storage would help shifting the grid load from peak and busy time to a less demand time. And the third benefit is that using energy storage would help smoothing the variations in power generation fed into the grid by variable and intermittent renewable resources. The third benefit is of particular important because in future more renewable energy sources will be integrated into the electricity grid worldwide. The objective of this paper is to present the results of a study conducted to examine the potential role and potential benefits of energy storage integrated into intermittent sources. Using energy storage will provide an opportunity to create a sustainable power supply, and to make the electricity grid more reliable especially with large proportion of grid-connected renewable sources.

Multiple Benefits Analysis of Energy Storage with the Application in Large Enterprises

The high cost and low benefit of energy storage are affecting its large-scale development. In this paper, the economical status of ESS in different occasions is summarized. To explore multiple benefits of ESS, the cost/benefits using diesel generator or ESS are both calculated in large enterprises. The results show that ESS will play multiple roles in large enterprises and bring economical and environmental benefits. Therefore, we should be in search of proper business model by reducing cost and dig more benefits to promote the development of ESS.

Modeling of PV generation, battery and hydrogen storage to investigate the benefits of energy storage for single dwelling

This work presents the results of simulation of battery and hydrogen technologies for renewable energy management, load-leveling and peak-shaving in a single grid-connected house in Nottingham United Kingdom where three people live. The house has a PV installation of 4.5 kWp. A stochastic model which takes active occupancy into account is used for simulating the electricity demand. A 10-kWh lead-acid battery and a 1-kW fuel cell together, with a 600-l hydrogen (gas) storage tank at 15 bar (31.3 kWh) are used for these simulations for short (daily cycles) and mid-term (3-day cycles) storage, respectively. Energy balances on a representative summer and winter day for both storage technologies are presented, along with annual balances. The battery increases the local use of PV energy generated on-site by 171%, while the hydrogen increases it by 159%. According to the current feed-in tariff legislation in the UK, the increase of the local use of PV energy means an additional annual income of at least £112 and £102 for the battery and hydrogen storage, respectively.

Assessing the value of storage in a future energy system with a high share of renewable electricity generation

Increasing the share of intermittent renewable electricity generation will require additional flexibility in the electricity system. While energy storage can provide such flexibility, studies about the economics of power storage often conclude that there is no business case for large-scale storage applications. In this paper, we present a new approach on how to assess the benefits of energy storage. Key improvements have been made in two areas: Firstly, the agent-based market simulation model PowerACE has been enhanced to make use of optimization methods (MILP) for the unit commitment of the agents, enabling us to quantify the economic benefit of flexibility at supply-agent level. Secondly, we have considerably extended the common unit commitment problem (Carrion and Arroyo, IEEE Trans Power Syst 21(3):1371–1378, 2006), so that we can now model the provision of positive and negative balancing power and the dispatch of storage units. We compare the flexibility offered by thermal power plants to that offered by storage units for the four major German electricity generating companies under two different scenarios. The results for 2030 indicate that it would be more profitable to build up to 4,800 MW storage capacity in the German market rather than investing in flexible combined cycle gas turbine plants or hard coal-fired units. The increasingly fluctuating residual load implies that inflexible power plants will be penalized. Using storage units, the power plants of an existing portfolio can be dispatched in a more efficient way, i.e. with less operation in part load and avoiding start-up or shutdown events.

The energetic implications of curtailing versus storing solar- and wind-generated electricity

We present a theoretical framework to calculate how storage affects the energy return on energy investment (EROI) ratios of wind and solar resources. Our methods identify conditions under which it is more energetically favorable to store energy than it is to simply curtail electricity production. Electrochemically based storage technologies result in much smaller EROI ratios than large-scale geologically based storage technologies like compressed air energy storage (CAES) and pumped hydroelectric storage (PHS). All storage technologies paired with solar photovoltaic (PV) generation yield EROI ratios that are greater than curtailment. Due to their low energy stored on electrical energy invested (ESOIe) ratios, conventional battery technologies reduce the EROI ratios of wind generation below curtailment EROI ratios. To yield a greater net energy return than curtailment, battery storage technologies paired with wind generation need an ESOIe > 80. We identify improvements in cycle life as the most feasible way to increase battery ESOIe. Depending upon the battery's embodied energy requirement, an increase of cycle life to 10 000–18 000 (2–20 times present values) is required for pairing with wind (assuming liberal round-trip efficiency [90%] and liberal depth-of-discharge [80%] values). Reducing embodied energy costs, increasing efficiency and increasing depth of discharge will also further improve the energetic performance of batteries. While this paper focuses on only one benefit of energy storage, the value of not curtailing electricity generation during periods of excess production, similar analyses could be used to draw conclusions about other benefits as well.

Applications of Phase Change Material in highly energy-efficient houses

Thermal mass combined with other passive strategies can play an important role in buildings energy efficiency, minimizing the need of space-conditioning mechanical systems. However, the use of lightweight materials with low thermal mass is becoming increasingly common. Phase Change Materials (PCMs) can add thermal energy storage benefits to lightweight constructions. There are many studies about the use of PCM in buildings, but there are still some difficulties for effective use and practical application of these materials. The study of applications used in real buildings could help us find solutions to these difficulties. This paper analyzed different PCM applications presented in highly efficient lightweight construction houses that have participated in the American Solar Decathlon, an international competition organized by U.S. Department of Energy. These houses have been tested and monitored in Washington DC, place with suitable climate conditions for short term thermal storage systems. The study started with a classification of the PCM applications and included an analysis of the systems, materials, switching temperatures, containments and design strategies used to improve the houses energy performance. Also, it included results of numerical simulations and experimentation that the participant team had done, complemented with information available in the literature about similar materials or applications.

A unit commitment study of the application of energy storage toward the integration of renewable generation

To examine the potential benefits of energy storage in the electric grid, a generalized unit commitment model of thermal generating units and energy storage facilities is developed. Three different storage scenarios were tested—two without limits to total storage assignment and one with a constrained maximum storage portfolio. Given a generation fleet based on the City of Austin’s renewable energy deployment plans, results from the unlimited energy storage deployment scenarios studied show that if capital costs are ignored, large quantities of seasonal storage are preferred. This operational approach enables storage of plentiful wind generation during winter months that can then be dispatched during high cost peak periods in the summer. These two scenarios yielded $70 million and $94 million in yearly operational cost savings but would cost hundreds of billions to implement. Conversely, yearly cost reductions of $40 million can be achieved with one compressed air energy storage facility and a small set of electrochemical storage devices totaling 13 GWh of capacity. Similarly sized storage fleets with capital costs, service lifetimes, and financing consistent with these operational cost savings can yield significant operational benefit by avoiding dispatch of expensive peaking generators and improving utilization of renewable generation throughout the year. Further study using a modified unit commitment model can help to clarify optimal storage portfolios, reveal appropriate market participation approaches, and determine the optimal siting of storage within the grid.

Experimental and numerical investigations on the effect of using phase change materials for energy conservation in residential buildings

Phase change materials, which melt and solidify at a specified temperature range, can be employed effectively to store energy as latent heat of melting in a large number of applications. They can be used to increase the thermal mass of buildings by mixing them with building materials such as gypsum or concrete. The constructed research facilities of this study show that the application of phase change materials could significantly reduce variation in the indoor temperature of buildings by absorbing heat during the day and releasing it at nright. The objective of this article was to show experimentally and through computer simulation using SUNREL that phase change material impregnated in building materials can provide thermal energy storage benefits. For these simulations paraffin (RT21), which is a mixture of paraffin, has been used as the phase change material because of its desirable thermal and physical attributes, including its melting temperature of 21°C (69.8°F), which is close to human comfort temperature. The simulated results show that the use of phase change material can effectively reduce the daily fluctuations of indoor air temperatures and maintains it at the desired comfort level for a longer period of time.

High-Value Energy Storage for the Grid: A Multi-Dimensional Look

The conceptual attractiveness of energy storage in the electrical power grid has grown in recent years with Smart Grid initiatives. But cost is a problem, interwoven with the complexity of quantifying the benefits of energy storage. This analysis builds toward a multi-dimensional picture of storage that is offered as a step toward identifying and removing the gaps and “friction” that permeate the delivery chain from research laboratory to grid deployment.

Editorial

This issue, our last for 2008, contains seven papers that cover some of the most important subjects of wind engineering. The first paper here is by Nicholas Cutler and a group of researchers from the University of New South Wales and the Bureau of Meteorology in Australia. Their paper presents a new approach to the characterization of uncertainty in wind power predictions using Numerical Weather Prediction (NWP) spatial fields. The next three papers concern subjects dealing with wind turbine aerodynamics. The first paper in this group is by Nando Timmer from TU Delft where the experimental two-dimensional flow characteristics of NACA 0018 airfoil are presented. This paper is important in the fact that it fills in missing low-Reynolds number data for this historically popular airfoil. Papers three and four contain computational fluid dynamic (CFD) investigations dealing with wind turbine airfoils or vertical axis machines. The first, by Guerri (Centre de Developpement des Energies Renouvelables, Algeria), and Hamdouni and Sakout (Univ. de La Rochelle, France) used a CFD analysis applied to flow inducted vibrations of two wind turbine blades. The fourth paper by Sankar and Tiryakioglu from Robert Morris University (USA) characterizes the power production performance of a novel vertical axis wind turbine design. Papers five and six summarize research in the general area of electrical engineering and wind turbine controls. The first one, paper number five, by Ekanayake, Jenkins, and Strbac (U.K.) investigated the frequency response from doubly fed induction generators (DFIG) and full power converters (FPC) during the first thirty seconds after a frequency event. Paper number six, by Schinas and Vovos from the University of Patras (Greece) presents control strategies for a variable speed pitch-controlled wind turbine that supplied an autonomous system using a small hydropower unit. The subject of energy storage is investigated in the seventh and final paper of this issue. This paper by Sullivan, Short, and Blair from the National Renewable Energy Laboratory (USA) modeled the potential benefits of energy storage for future large penetrations of wind power in the United States.

Load Leveling Reduces T&D Line Losses

The benefit of shifting load from the peak to the off-peak period is well known from the viewpoints of demand response and deferral of capacity upgrade. However, the impact of load leveling on reducing transmission and distribution (T&D) losses is often ignored or lightly mentioned in the literature. A detailed analysis of T&D loss reduction is very specific to the considered power system and cannot be readily generalized. Therefore, the objective of this paper is to identify the key parameters and quantify the saved T&D losses as a function of the size or power of the energy storage in a set of normalized charts to help assess the benefits of energy storage as a means to level a utility load. This is a benefit of utility-scale energy storage that is not fully recognized.

Optimization of a space radiator with energy storage

A simple model for heat transfer from a space radiator with latent heat thermal energy storage has been developed. For a given heat storage and dissipation capability, analytical results have been obtained for the optimum geometry of a radiator panel/fin based on a minimum mass criterion. Numerical results for a typical configuration show that mass reductions of 20–25% or more can be achieved for pulsed heating loads of durations of the order of 1 h or less. At the same time, the radiator sizes can be reduced by a factor of 4 or more. The results also suggest that the benefits of energy storage will be higher for operating conditions with lower heat dissipation rates.