Storage Investment Research Articles

Underground Gravity Energy Storage: A Solution for Long-Term Energy Storage

Low-carbon energy transitions taking place worldwide are primarily driven by the integration of renewable energy sources such as wind and solar power. These variable renewable energy (VRE) sources require energy storage options to match energy demand reliably at different time scales. This article suggests using a gravitational-based energy storage method by making use of decommissioned underground mines as storage reservoirs, using a vertical shaft and electric motor/generators for lifting and dumping large volumes of sand. The proposed technology, called Underground Gravity Energy Storage (UGES), can discharge electricity by lowering large volumes of sand into an underground mine through the mine shaft. When there is excess electrical energy in the grid, UGES can store electricity by elevating sand from the mine and depositing it in upper storage sites on top of the mine. Unlike battery energy storage, the energy storage medium of UGES is sand, which means the self-discharge rate of the system is zero, enabling ultra-long energy storage times. Furthermore, the use of sand as storage media alleviates any risk for contaminating underground water resources as opposed to an underground pumped hydro storage alternative. UGES offers weekly to pluriannual energy storage cycles with energy storage investment costs of about 1 to 10 USD/kWh. The technology is estimated to have a global energy storage potential of 7 to 70 TWh and can support sustainable development, mainly by providing seasonal energy storage services.

A novel investment strategy for renewable-dominated power distribution networks

Aiming at the problem of insufficient adaptability to the new elements of the new power system in the current distribution network investment method, this paper innovatively proposes a distribution network investment method based on the new power system. By constructing a source-grid-load-storage-side investment calculation model, the investment in the new power system can be accurately calculated. First, the distributed power investment is calculated from the two aspects of new construction and renovation. Secondly, construct the grid investment demand and grid investment capacity measurement model, and obtain the grid side investment model by weighted summation. Then, a model for calculating the scale of investment that can be saved due to demand-side response is constructed, and the cost of demand response is subtracted to obtain a model for calculating the scale of investment that can be saved on the load side. Finally, the energy storage side investment calculation model is constructed from the power supply side, grid side, user-side energy storage investment, and energy storage investment benefit. The research results are applied to the empirical area, and scientific guidance is provided to realize the precise investment in the area.

Research on Investment Economic Evaluation of Flexible Regulating Resources such as Energy Storage in High Proportion New Energy Environment

With a high percentage of new energy scenarios, it has become a trend for flexible resources such as energy storage systems to participate in long-term planning. In this context, it is important to explore how energy storage systems are configured. Therefore, it is necessary to analyse the economics of energy storage and other resources to ensure that investments in energy storage and other resources are economically valuable under different future models. This paper firstly analyses the current situation of a high percentage of new energy in China, and secondly constructs a model for analysing the economics of flexible regulation resources such as energy storage. Under partial data based on the scenery storage project, the economic analysis under four models is derived, including cost and benefit analysis, investment benefit analysis, and break-even point analysis. Finally, the economic evaluation of investment in energy storage projects under different models is summarized based on the calculation results.It is concluded that different scenario models have different economic benefits, and the operation capacity of the four scenarios is higher than that of the existing models.

Cloud Energy Storage Investment by Collaboration of Microgrids for Profit and Reliability Enhancement Considering a TSO-DSO Yearly Reward

A shared pool of grid-scale storage resources called Cloud Energy Storage (CES) can bring substantial benefits to the economical and reliable operation of MGs. However, the investment cost of CES may not be affordable for a single microgrid (MG). As a solution, we propose an approach in which neighboring microgrids in a distribution network collaborate and form a multi-microgrid (multi-MG) to install a shared CES to increase their profit and improve their reliability. Different investment scenarios are evaluated by considering the yearly reward from TSO and DSO. For each of the investment scenarios, TSO and DSO give a yearly reward based on the contribution of CES in peak-shaving and distribution network operation yearly cost reduction. Afterward, a decision table is provided in which, for all investment scenarios, profit, reliability index based on expected energy not supplied (ENS), and TSO-DSO yearly reward are determined. Finally, the microgrids select one of the investment scenarios using a multi-attribute decision-making approach. Simulation results of a case study validate the effectiveness of the proposed collaborative decision-making framework in increasing the economic value of CES investment, reliability enhancement in multi-MG, and peak-shaving.

Optimal Storage and Solar Capacity of a Residential Household Under Net Metering and Time-of-Use Pricing

Incentive programs and ongoing reduction in costs are driving joint installation of solar PV panels and storage systems in residential households. There is a need for optimal investment decisions to reduce the electricity consumption costs of the households further. In this paper, we first develop analytical expression of storage investment decision and then of solar investment decision for a household which is under net metering billing mechanism with time of use pricing condition. Using real data of a residential household in Austin, TX, USA, we study how the investment decisions would provide benefit for a period of one year. Results show significant profit when using storage devices and solar panels optimally for the system. It is important to note that though our approach can help significantly to take investment decisions, the solution will still be sub-optimal for somebody who needs optimal investment jointly on both storage and solar systems.

Energy storage economy research and sensitivity analysis applied to photovoltaic primary frequency modulation scenario

In practical engineering applications, the investment, income, subsidies and other costs of energy storage batteries have a certain impact on the overall economic benefits of primary frequency modulation. The larger the capacity of the configured battery energy storage system, the better the primary frequency modulation effect will be, but at the same time, the problem is that the cost of investment in the energy storage system will increase, which will offset the benefits of primary frequency modulation loss reduction of its auxiliary photovoltaic station from an economic perspective. Therefore, this paper will clarify the benefits and costs of the primary frequency modulation application environment of the energy storage system, and establish an economic analysis model from delaying the investment of photovoltaic station equipment, reducing the cost of light waste, environmental benefits, direct benefits, government subsidies, energy storage investment costs and other aspects. Finally, a photovoltaic station is taken as an example to simulate and analyse the sensitivity.

Study on market mechanisms for participation of small-scale hydropower clusters in electricity energy and ancillary services

The problem of large-scale distributed new energy consumption is highlighted under the double carbon target. Based on the existing distributed small hydropower and local hydrological and geographical conditions, the pumping-storage linkage function of distributed small hydropower can be realized through small-scale transformation according to local conditions, which can significantly reduce the construction cost and improve the profitability of the power station. The development of small hydropower to pumped storage can effectively enhance the flexible regulation capacity of the power grid. Based on an analysis of the investment environment, profitability and option characteristics of small hydropower to pumped storage projects, this paper conducts a study on the operational mechanism of hydropower participation in the electricity energy market and auxiliary services market to provide support for small hydropower to pumped storage investments in the new situation.

A Bi-level optimization model of integrated energy system considering wind power uncertainty

To cope with the volatility of renewable energy and improve the efficiency of energy storage investment, a bi-level (B-L) optimization model of an integrated energy system (IES) with multiple types of energy storage is established by considering the uncertainty of wind power. The upper-level optimization model considers the lowest configuration cost of energy storage as the objective function and satisfies the constraints of the energy storage configuration. The lower-level optimization model considers the lowest operation cost of the IES as the objective function and satisfies the constraints of the system operation. Second, to overcome the fluctuation problem of wind power output, a robust optimization theory is introduced to describe the uncertainty. Robust coefficients are set to reflect different risk attitudes, which improves the adaptability of the system to uncertainty. Third, the B-L optimization model is solved using the Karush–Kuhn Tucker condition. Finally, a new park is used to implement the simulation. The conclusions are as follows: (1) The economic configuration strategy and optimal operation scheme can be obtained by applying the B-L optimization model, and the upper- and lower-levels interact with each other. The optimal targets of the upper- and lower-level models are −115,848 ¥ and 57,131,102 ¥, respectively. (2) The robust optimization theory improves the ability of a system to deal with risks. Robust optimization theory improves the ability of a system to deal with risks. With an increase in the robustness coefficient, the profit space of the upper-level model increases; however, the operation cost of the lower-level model increases.

Co-Optimization of Battery Storage Investment and Grid Expansion in Integrated Energy Systems

Battery storage is a flexible resource that can deliver a wide range of grid services quickly and efficiently. This article presents an investment planning model for battery storage, power transmission grid, and natural gas network in a stochastic gas–electric energy infrastructure. A bilevel stochastic optimization program is developed with an upper level investor and two interrelated lower level players. The investment decisions pertaining to the battery storage facilities and the expansion of power and gas systems are made by an independent investor anticipating the clearing results of gas and electricity markets, modeled as connected mixed-integer lower level programs. The nonconvexity of power generation and the randomness of power and gas demands, as well as renewable energy are considered in the formulation of the lower level problems. To compute this stochastic bilevel optimization with discrete decisions in both levels and interrelated lower level programs, we develop an exact solution methodology in a decomposed master-subproblem form. The application of the method is illustrated on two test systems. Experimental results show the modeling of gas and power grids’ interaction and the nonconvex nature of power production using the proposed methodology significantly affects the optimal costs and expansion plans.

Life-cycle economic analysis of thermal energy storage, new and second-life batteries in buildings for providing multiple flexibility services in electricity markets

More energy flexibility is required to alleviate the stress of power systems caused by intermittent and weather-dependent solar and wind power. The utilization of demand-side flexibility (e.g., flexibility management strategies and distributed storage technologies) can be considered a win-win approach for demand-side users and power grids. However, the economic benefits of distributed energy storage systems in buildings are usually underestimated without considering the full-scale flexibility utilization, which may impede storage investments. Meanwhile, the disposal problem of retired EV batteries is becoming more serious. Repurposing these batteries for stationary applications in buildings seems cost-effective and eco-friendly. Therefore, this study first proposes novel optimal dispatch strategies for different storage systems in buildings to maximize their benefits from providing multiple grid flexibility services simultaneously, and then conducts a comparative life-cycle economic analysis on thermal energy storage, new and second-life batteries. The optimal configuration of hybrid storage systems is also analyzed to facilitate the decision-making of building owners/operators. Test results show that thermal energy storage and electrical energy storage can increase the economic benefits by 13% and 2.6 times, respectively. Battery storage may no longer be an expensive option for building-scale investment due to downward trends in capacity costs and environmental impacts.

이산화탄소 저장소 탐사와 시추를 위한 법적 개선에 관한 연구

The global investment in carbon capture, utilization and storage (CCUS) is increasing in an attempt to reach carbon neutrality by 2050. Korea is pushing for a project to install the country's first commercial-scale carbon capture storage facilities in a gas field in the East Sea in 2021. Successfully deploying CCUS relies on the establishment of legal and regulatory frameworks to ensure the effective stewardship of CCUS activities and the safe and secure storage of CO₂But which are yet to establish a legal foundation for CCUS, and particularly for Regulations relating to exploitation of CO₂storage site. The CCUS Act requires separate provisions for exploration and drilling. CCUS cost is the most significant hurdle in investment for exploration and drilling of CO₂storage site. Article 140 of the Restriction of Special Taxation Act shall be amended to exempt tariffs and value-added taxes on equipment for exploration and drilling of carbon dioxide storage. The management agency of public waters shall collect occupancy or use fees of pubic waters each year from a person who has obtained an occupancy or use permit or the consultation or approval for occupancy or use of public waters, as prescribed by Presidential Decree: Provided, That reductions or exemptions of occupancy or use fees may be granted, as prescribed by Presidential Decree in any of the following cases. In reference to Article 13 of the Public Waters Management and Reclamation Act, Where who occupies or uses public waters to install or operate energy facilities falling under Article 2 of the Act on the Promotion of the Development, Use and Diffusion of New and Renewable Energy. By applying this provision, because exploration and drilling is not mining in the sea, occupancy fees imposed on holder of exploration licence for CO₂storage site should be reduced or exempted.

이산화탄소 저장소 탐사와 시추를 위한 법적 개선에 관한 연구

The global investment in carbon capture, utilization and storage (CCUS) is increasing in an attempt to reach carbon neutrality by 2050. Korea is pushing for a project to install the country's first commercial-scale carbon capture storage facilities in a gas field in the East Sea in 2021. Successfully deploying CCUS relies on the establishment of legal and regulatory frameworks to ensure the effective stewardship of CCUS activities and the safe and secure storage of CO₂But which are yet to establish a legal foundation for CCUS, and particularly for Regulations relating to exploitation of CO₂storage site. The CCUS Act requires separate provisions for exploration and drilling. CCUS cost is the most significant hurdle in investment for exploration and drilling of CO₂storage site. Article 140 of the Restriction of Special Taxation Act shall be amended to exempt tariffs and value-added taxes on equipment for exploration and drilling of carbon dioxide storage. The management agency of public waters shall collect occupancy or use fees of pubic waters each year from a person who has obtained an occupancy or use permit or the consultation or approval for occupancy or use of public waters, as prescribed by Presidential Decree: Provided, That reductions or exemptions of occupancy or use fees may be granted, as prescribed by Presidential Decree in any of the following cases. In reference to Article 13 of the Public Waters Management and Reclamation Act, Where who occupies or uses public waters to install or operate energy facilities falling under Article 2 of the Act on the Promotion of the Development, Use and Diffusion of New and Renewable Energy. By applying this provision, because exploration and drilling is not mining in the sea, occupancy fees imposed on holder of exploration licence for CO₂storage site should be reduced or exempted.

Energy Storage Investment and Operation in Efficient Electric Power Systems

We consider welfare-optimal investment in and operation of electric power systems with constant returns to scale in multiple available generation and storage technologies under perfect foresight. We extend a number of classic results on generation, derive conditions for investment and operations of storage technologies described by seven cost/performance parameters, and develop insights on power systems with multiple storage technologies. Simulation of a deeply decarbonized “Texas-like” power system with two available storage technologies shows both the non-existence of simple “merit-order” rules for storage operation and the value of frequency domain analysis to describe efficient operation. Our analysis points to the critical role of the capital cost of energy storage capacity in influencing efficient storage investment and operation.

Implications of intercontinental renewable electricity trade for energy systems and emissions

A rapid global energy transition, including the ramping up of electricity generation from renewables, is needed to limit global warming to 2 °C or 1.5 °C. However, renewable resource endowments vary widely between regions, and renewable electricity is currently mainly used locally. Here we use a global integrated assessment model to explore the implications of renewable electricity trade via a set of planned direct-current-type ultra-high-voltage (UHVDC) transmission lines for global energy transition and climate change. We find that renewable electricity trade across large world regions via the underlying UHVDC interconnection can boost renewable electricity production and reduce 2020–2100 cumulative CO2 emissions from the power sector up to 9.8%. Financial investments in the UHVDC lines are offset in the long term by reduced investments in other electricity-generation options, including nuclear and storage. Finally, we find that renewable electricity trade can substantially reduce air pollutant emissions in importing regions. Projects are under way for direct-current ultra-high-voltage transmission lines that would allow trading of renewable electricity across world regions. Guo et al. use integrated assessment models to explore different scenarios for the operation of these projects and assess their potential for decarbonization.

Benefit analysis and preliminary decision-making of electrical and thermal energy storage in the regional integrated energy system

The ambitious goal of decarbonization has promoted regional integrated energy system (RIES), which enables interaction between energy consumption and supply sectors with different characteristics to improve energy application efficiency. Compared with single energy storage, multiple energy storage (MES) may have the potential to provide better flexibility and lower costs, but the necessity of applying and the preliminary decision-making principles have not been very clear to users and investors. To solve this problem, this study based on the typical RIES framework on the demand-side, firstly proposes multi-dimensional evaluation indexes from the aspects of renewable energy consumption, carbon emission reduction, load shifting and economic property; then, taking a commercial area as a case, develop the optimal operation strategy of the minimum total daily cost to analyze the operation and synergistic benefits under four scenarios; influencing factors such as energy storage capacity, load demand and region types are considered though sensitivity analysis; finally, suggestions for the preliminary decision-making of MES are given. The results show that the combination of electricity and thermal energy storage can realize the complementary advantages of single energy storage technology, making the contribution of different kinds of energy storage benefits more balanced on the basis of reducing the total cost, which significantly improves the flexibility of the energy system; the electricity-thermal energy storage has obvious advantages in the four functional areas involved herein; however, as the storage capacity increases to the saturation value, the marginal effect appears, and the corresponding total benefits tend to stabilize gradually. The preliminary decision-making of applying energy storage is carried out according to the external and internal levels, respectively according to the control requirements of energy storage investment cost, the allocation of renewable energy in the target area, as well as the regional energy consumption structure and specific needs. This principle can provide a reasonable basis for decision-makers and promote the application and development of multiple energy storage.

Effect of storage temperature on quality parameters of liquid organic fertilizer prepared from Mexican sunflower (Tithonia diversifolia)

Objectives: To determine the effect of storage temperature on physical-chemical properties of tithonia liquid organic fertilizer. To determine the effect of storage temperature on microbial population in tithonia liquid organic fertilizer. To evaluate the effect of tithonia liquid organic fertilizer on kales crop. Problem Statement: Tithonia diversifolia has been used as green manure in soil fertilization and improvement of crop performance. Attempts have been made to extracts tithonia liquid organic fertilizer (LOF) to ease storage and transport. However, not much was known about quality parameters of liquid organic fertilizer (LOF) during storage. This study established the effect of storage temperature on the quality parameters of LOF from Tithonia diversifolia. Methodology: Tithonia LOF was prepared by fermenting 2 kg of tithonia leaves in 20litres of water for 2 weeks to maintain leaf water ratio of 1:10. The fermented extract was filtered using a clean cloth and transferred into 36 one litre specimen jars. Eighteen of the specimen jars were placed in the refrigerator at temperature of 00 C to 50 C while another batch of 18 in the specimen cabinet at room temperature at 230C. Specific laboratory analysis procedures were used to determine the nutritional chemical content of the sampled LOF. Total nitrogen(N) was analyzed by ISO 5315-trimetric method, phosphorus (P) by ultraviolet visible spectrophotometer at λ-420nm, and potassium (K) by AAS ISO17319:2015. Other chemical analysis done were Magnesium (Mg) using method EN 16197:2012 AAS, Calcium by ISO method 17025 AAS and total reducing sugars by normal- phase chromatography HPLC method. The pH of the LOF was analyzed by handheld pH meter. Microbial analysis used plate count agar for bacterial and potato dextrose agar (PDA) for fungus count. Kale plants were arranged in a randomized block design of 9 plots each with 9 potted plants. The treatment was replicated three times for samples stored in the refrigerator and three times for the room temperature storage repeatedly for six months. Plant parameters measured were; plant height, number of leaves and the plant girth. Key findings: The study established that there was a significant change in LOF pH during storage, however correlation was higher for room storage than fridge storage. The study also established that there was no significant change in chemical properties of LOF in both storage conditions however, the room stored LOF had negative correlation with storage time an indicating that plant nutrients in LOF reduced with increase in storage time. In regards to microbial properties, it was found that there was no significant change in microbial count in LOF in both storage temperature experiments. The study also established that treatment of kales with LOF stored at room temperature had higher growth variance than for the fridge stored and control treatment. Discussion There was a significant change in LOF pH during storage where p=0.012. Correlation was higher for room storage than fridge storage. Freshly prepared LOF was slightly acidic at pH 6.5 attaining pH 7.88 and 7.1 at room and fridge temperatures respectively. Change in chemical properties of LOF in both storage conditions was not significant whereas, the room stored LOF had negative correlation with storage time indicating how plant nutrients in LOF reduced with increase in storage time. The microbial count in LOF in both storage temperature experiments had no significant change. The relationship between microbial count and storage period was weak. Application: This study is useful to organic agriculture farmers, researchers and policy makers. Conclusion: The study established that the quality of LOF during storage deteriorated. LOF stored in room temperature reduced in quality faster than the refrigerated one. Therefore, the quality of the LOF is best when freshly prepared. Despite kales performing marginally better when treated with room stored LOF, there was no significant difference with fridge stored LOF. Investment in cold storage of LOF therefore does not make economic sense. Recommendation: The study recommends further research on effect of LOF concentration on crop growth to ensure optimum nutrients for production.

Strategic energy storage investments: A case study of the CAISO electricity market

Energy storage can provide a range of revenue streams for investors in electricity markets. However, as their deployments continue to rise, storage will no longer be a player on the sidelines and remain a price-taker, rather, these assets will start to impact prices. In this study, accounting for energy storage as a price-maker and using data from CAISO, we investigate strategic market behavior among competing investors using a non-cooperative game. We establish a centralized optimization problem to compute the market equilibrium. In the game, each investor initially decides on how much to invest and then how to operate their asset over a time horizon. Investors are allowed to deploy different energy storage technologies. Analytically, we show that an increasing number of investors will increase the market competition thereby reducing profits while increasing the total capacity of storage deployed. Numerically, our key findings include: (a) the difference in optimal investments under price-taker and price-maker assumptions, (b) as wind and solar assets expand under different resource-mix scenarios, there is a corresponding non-monotonic variation in arbitrage potential for energy storage, (c) when competition is intense and investors are allowed to invest in different technologies, a slight increase in storage technology performance can significantly improve an investor’s profit share, (d) when the arbitrage opportunity increases with renewables, longer duration storage technologies may gain an advantage, (e) Li-ion batteries dominate the market under low-moderate renewable energy penetration or with steep energy-capacity cost reductions in the future.

An Integrated Decision-Making Approach with Golden Cut and Bipolar q-ROFSs to Renewable Energy Storage Investments

An Integrated Decision-Making Approach with Golden Cut and Bipolar q-ROFSs to Renewable Energy Storage Investments

Investment in CO2 capture and storage combined with enhanced oil recovery in China: A case study of China's first megaton-scale project

In recent years, China has accelerated the development of CCUS (CO2 capture, utilization and storage) technology and started construction of the first megaton-scale CCS-EOR (CO2 capture and storage combined with enhanced oil recovery) project. Taking China's first megaton-scale CCS-EOR project as an example, this study constructs a comprehensive evaluation method that integrates the decision rules of the real option approach and net present value approach to evaluate the economics and investment strategies of China's CCS-EOR projects under multiple uncertainties. The results show that the project investment in 2022 can create a profit of 2.94 million USD because of the introduction of a tax credit policy that will begin in 2030 with an initial amount of 10 USD/ton of CERs (certified emission reductions) and an annual increment of 2 USD/ton of CERs, but the optimal time to invest should be 2025. Without this incentive policy, the profit opportunity and ability of the case project will be greatly reduced. In addition, the decision-making of CCS-EOR project investment is extremely sensitive to capital cost, oil production, incentive policy start time, and incentive intensity. Therefore, China should formulate and implement tax credit incentives or similar policies with a high incentive intensity as soon as possible to improve the confidence of potential CCUS investors. Direct financial support for early CCS-EOR projects through government financial allocations should be an important addition. In addition, enterprises should strive to accurately calculate and forecast the capital cost and oil production.

Can Distributed Intermittent Renewable Generation Reduce Future Grid Investments? Evidence from France

Abstract This paper estimates the relationship between investments in five distributed generation technologies and hourly net withdrawals from over 2,000 electricity distribution networks in France between 2005 and 2018. We find that investments in distributed wind and solar generation have little or no impact on the annual peak of hourly net withdrawals from the distribution grid, while investments in hydroelectric and thermal distributed generation significantly reduce it. An optimistic analysis of the impact of investments in battery storage suggests that high levels are required for distributed wind and solar to deliver similar reductions in the annual peak of hourly net withdrawals. Our results imply that public policies favoring distributed wind and solar generation over utility-scale generation cannot be rationalized by savings in future grid investments.