Power Pinch Analysis Research Articles

Power Pinch Analysis for optimal sizing of renewable-based isolated system with uncertainties

Isolated renewable energy system offers promising options to electrify communities located in remote areas where the utility grid is not available or extension of the grid is not economical. Proper sizing of renewable energy conversion system along with storage capacity is the key element to achieve the technical and economical feasibility of such renewable-based isolated system. In this paper, a methodology, based on the concept of Power Pinch Analysis, is proposed to determine the minimum renewable generator area, its extreme limits, and the corresponding storage capacity. The proposed methodology accounts for the uncertainties associated with the renewable resource to size the overall system with a predefined reliability. The concept of the chance constrained programming is applied within the Pinch Analysis framework to incorporate stochastic nature of the renewable energy resources. The applicability of the methodology is demonstrated with an illustrative example of photovoltaic-battery system and verified using sequential Monte-Carlo simulation approach as well as through annual simulation of the system with actual isolation data.

Optimal Design and Sizing of Integrated Centralized and Decentralized Energy Systems

Concerns over sustainability of fossil fuels, and increasing awareness for the environment have encouraged countries all over the world to shift from the heavy reliance on fossil fuel to renewable energy (RE) resources for electricity generation. Although implementation of RE has been on the rise, large-scale deployment of RE still remains a challenge, especially in terms of economic and technicality. This paper proposes the integration of the current energy system (centralised energy system, CEG running on mainly fossil fuels) with the new energy system (decentralised energy system, DEG). Numerical analysis is developed to solve and target the proposed multiple DEGs and CEG integrated system at its optimum design and sizing. Two existing numerical approaches in Power Pinch Analysis are applied, i.e. Power Pinch Analysis (PoPA) for a smaller scale decentralised energy systems while the net energy deficit will be satisfied in a centralised energy system via Electric System Cascade Analysis (ESCA). The designated combination of Power Pinch methodology in this study is based on an hourly scale operation of both systems. With case study of five (5) DEG(s), the analysis indicates that DEG 1 has 540 MWh for energy-related capacity and 70 MW for power-related capacity. DEG 2, 480 MWh and 70 MW, DEG 3, 480 MWh and 120 MW, DEG 4, 1,000 MWh and 150 MW, and DEG 5, 100 MWh and 90 MW. The CEG power plants should have a total capacity of 48.3 MW with energy storage of 270.6 MWh and 45.1 MW.

Popa-sharps: a New Framework for Cost-effective Design of Hybrid Power Systems

Development of Power Pinch Analysis (PoPA) for the design and optimisation of Hybrid Power Systems (HPS) is steadily progressing. Even though PoPA has been developed for widespread applications in HPS design analysis, the economic aspect still needs more attention. This work presents a new framework for the design of a cost-effective HPS by incorporating PoPA with a cost-screening tool known as the Systematic Hierarchical Approach for Resilient Process Screening (SHARPS). SHARPS which was originally developed to screen various process changes options in water network is adapted to imbed cost analysis and renewable energy (RE) technology screening in power network. Demonstration on an illustrative case study shows that the proposed framework can provide the best HPS scheme considering the system efficiency, while satisfying the desired payback period.

Modified Electric System Cascade Analysis for optimal sizing of an autonomous Hybrid Energy System

Ensuring sufficient generation for covering the power demand at minimum cost of the system are the goals of using renewable energy on isolated sites. Solar and wind capture are most widely used to generate clean electricity. Their availability is generally shifted in time. Therefore, it is advantageous to consider both sources simultaneously while designing an electrical power supply module of the studied system.A specific challenge in this context is to find the optimal sizes of the power generation and storage facilities, which would minimise the overall system cost and will still satisfy the demand. In this work, a new design algorithm is presented minimising the system cost, based on the Electric System Cascade Analysis and the Power Pinch Analysis. The algorithm takes as inputs the wind speed, solar irradiation, as well as cost data for the generation and storage facilities. It has also been applied to minimise the loss of power supply probability (LPSP) and to ensure the minimum of the used storage units without using outsourced electricity.The algorithm has been demonstrated on a case study with daily electrical energy demand of 18.7 kWh, resulting in a combination of PV Panels, wind turbine, and the batteries at minimal cost. For the conditions in Oujda city, the case study results indicate that it is possible to achieve 0.25 €/kWh Levelised Cost of Electricity for the generated power.

Sensitivity analysis of hybrid power systems using Power Pinch Analysis considering Feed-in Tariff

Feed-in Tariff (FiT) has been one of the most effective policies in accelerating the development of renewable energy (RE) projects. The amount of RE electricity in the FiT purchase agreement is an important decision that has to be made by the RE project developers. They have to consider various crucial factors associated with RE system operation as well as its stochastic nature. The presented work aims to assess the sensitivity and profitability of a hybrid power system (HPS) in cases of RE system failure or shutdown. The amount of RE electricity for the FiT purchase agreement in various scenarios was determined using a novel tool called On-Grid Problem Table based on the Power Pinch Analysis (PoPA). A sensitivity table has also been introduced to assist planners to evaluate the effects of the RE system's failure on the profitability of the HPS. This table offers insights on the variance of the RE electricity. The sensitivity analysis of various possible scenarios shows that the RE projects can still provide financial benefits via the FiT, despite the losses incurred from the penalty levied.

Optimal hybrid renewable energy design in autonomous system using Modified Electric System Cascade Analysis and Homer software

In this paper, a method for designing hybrid electricity generation systems is presented. It is based on the Modified Electric System Cascade Analysis method. The Power Pinch analysis is used as a guideline for development of an isolated power supply system, which consists of photovoltaic panels, wind turbines and energy storage units. The design procedure uses a simulation model, developed using MATLAB/SIMULINK and applies the developed algorithms for obtaining an optimal design. A validation of the Modified Electric System Cascade Analysis method is performed by comparing the obtained results with those from the Homer Pro software. The procedure takes as inputs hourly wind speed, solar radiation, demands, as well as cost data, for the generation and storage facilities. It is also applied to minimize the loss of power supply probability and to minimize the number of storage units. The algorithm has been demonstrated with a case study on a site in Oujda city, with daily electrical energy demand of 18.7kWh, resulting in a combination of photovoltaic panels, wind turbine and batteries at minimal cost. The results from the Modified Electric System Cascade Analysis and HOMER Pro show that both tools successfully identified the optimal solution with difference of 0.04% in produced energy, 5.4% in potential excess of electricity and 0.07% in the cost of the energy.

An integrated Pinch Analysis framework for low CO2 emissions industrial site planning

The development of Process Integration has paved the way for many generic application avenues for the efficient management of energy and resources. However, there is a need to develop a framework to guide industrial site planners to most efficiently exploit and benefit from the suite of Pinch Analysis tools in an integrated manner towards systematically planning a low CO2 emissions, while strongly promoting cleaner production alternatives. This work presents an attempt to develop a systematic framework for low CO2 industrial site planning, using an integrated set of Pinch Analysis related tools with algebraic algorithms established to complement the graphical representation. The proposed framework consists of four main stages. The first stage involves the baseline study of resources. The second stage involves Total Site Heat Integration to maximise heat recovery among multiple units, while simultaneously targeting for cogeneration potential. The third stage involves application of Power Pinch Analysis to optimise power allocation and integration of hybrid renewable energy system. CO2 Emissions Pinch Analysis is applied in the final stage to achieve the minimum CO2 targets via implementation of a CO2 emissions management hierarchy (CMH) to systematically explore options to maximise CO2 reductions. Application of this systematic framework to an illustrative industrial site case study resulted in an overall reduction of 56.7% in heat, 74.3% in power, and 99.8% in CO2 emissions. This proposed tool for low CO2 industrial site planning is available for designers, planners and industrial site owners to optimise integrated energy and CO2 emissions for Total Sites, starting from the individual process units, and ready to be extended to Locally Integrated Energy Systems.

Sizing of Hybrid Power System with varying current type using numerical probabilistic approach

Power Pinch Analysis is an established method to target the design parameter of a Hybrid Power System. This study aims to develop an extended tool known as Probability-Power Pinch Analysis (P-PoPA) using probability theory to simplify the process of Power Pinch Analysis in considering efficiency losses. The method targets for a Hybrid Power System with various current type from generation to demand, generation to storage, or storage to demand. The procedure of the method is illustrated using an electricity-deficit scenario where both AC–DC generation and AC–DC demand are present. The new methodology which adapts the same concept as the Stand-Alone Hybrid System Power Pinch Analysis utilizes data extracted from an ideal (considering no efficiency losses) graphical Power Pinch Analysis and Power Cascade Table and multiplying the extracted data with a probability factor to obtain an estimated target (considering efficiency losses) for the power system. In this study, three design parameters are determined for a system with 208kWh AC source and 50kWh DC source and 170kWh AC demand and 98kWh DC demand. The external energy that is needed for the system is identified as 38.93kWh and the energy capacity of energy storage is 42.20kWh and power capacity of energy storage is 8.79kW. The result is then compared with the existing cascade analysis, Power Cascade Table and Storage Cascade Table. The determined sizing values have a close estimation to that from cascading analysis (considering efficiency losses), with a maximum percentage difference of 2.3%.

An MILP model for cost-optimal planning of an on-grid hybrid power system for an eco-industrial park

The application of on-grid hybrid power system (HPS) has been effective for harnessing renewable energy resources and ensuring environmental sustainability. A number of algebraic and mathematical modeling approaches have been introduced for the optimisation of on-grid HPS. While algebraic power pinch analysis (PoPA) tools have been developed to enable the selection of cost-effective energy storage technology, the available mathematical modeling approaches have yet to consider the economics and storage system selection in the design of an optimal on-grid HPS. This work presents a mixed-integer linear programming (MILP) for the optimal design of an on-grid HPS with the minimum net present value (NPV) of the overall electricity production cost and the selection of the optimum energy storage technology. Two case studies are presented in this work. In the former, the differences between the developed MILP model and previous methods are highlighted, with sensitivity analysis to investigate the impact of electricity tariff on the on-grid HPS. In the second case study, the developed MILP model was applied to an Eco-Industrial Park (EIP) case study with energy storage technology selection. Lead-acid battery system was found to be the optimal choice due to its low investment requirement.

Power Pinch Analysis supply side management: strategy on purchasing and selling of electricity

Pinch analysis concept has been recently stepped into the realm of design and optimisation of power systems. One well-established pinch analysis that has been used in power systems design and optimisation is called Power Pinch Analysis (PoPA). In PoPA, both graphical and numerical approaches have provided an insight on the systematic approach to target and design various power systems. By only visualising the minimum amount of outsource energy required by the power system, the graphical PoPA method as a whole does not show the purchasing of outsource energy based on the exact time intervals. Using graphical PoPA, the objective of this study is to determine a proper strategy to buy and sell outsource electricity to improve the overall performance of a hybrid power system comprising renewable power generators and energy storage system. The strategies are made based on three design parameters: energy-related capacity, power-related capacity of energy storage and maximum grid power rating between centralised grid and hybrid power system. While deciding on the best strategy and heuristics to be implemented, the effects on system operation and economy are indirectly analysed. It is experimented that the output can benefit electricity consumers or producers.

Integration of diesel plant into a hybrid power system using power pinch analysis

Diesel power systems are one of the schemes for energy supply generation. However, they are mostly associated with difficulties of emission control and cost of the maintenance on top of the diesel fuel cost. Some of these problems can be reduced by incorporating renewable energy such as wind turbines and solar PV along with the existing diesel station. Hybrid systems provide clean and reliable power supply, and can be more cost-effective than sole diesel systems. This paper assesses the feasibility of expanding an existing diesel power plant into a hybrid power system (HPS) using Power Pinch Analysis (PoPA). A HPS configuration developed using PoPA methodology can provide close-to-optimal solar and wind electricity supplies while minimising the diesel generation. Results show that a HPS that combines solar and wind system with diesel power generation can provide significant diesel fuel savings while satisfying the demands at a reasonable cost.

Study of the Effects of Seasonal Climate Variations on Hybrid Power Systems Using Power Pinch Analysis

The role of renewable energy (RE) resources as clean alternatives to fossil fuel in power generation has been increasing. Widespread deployment of RE sources in Hybrid Power Systems (HPS) however can be a challenging task due to the stochastic nature of RE. Solar and wind are intermittent with weather variations, and the end use demands are also climate dependant. In this paper, Power Pinch Analysis (PoPA) method is applied to assess the different RE generation and load profiles from two seasonal climates namely winter and summer. The minimum electricity targets established from PoPA allows the designer to visualise the feasible limits for the sizing of HPS. Results show that HPS operation during winter demands a substantial amount of outsourced electricity, while summer operation requires higher investment on the PV generator and storage.

Expansion of a Diesel Plant into a Hybrid Power System Using Power Pinch Analysis

Diesel power system is one of the popular schemes for energy supply generation. It is, however, typically associated with high costs of emission control and maintenance on top of the diesel fuel cost. These limitations can be overcome by incorporating renewable energy technologies such as wind turbines and solar PV along with the existing diesel station. Hybrid systems provide cleaner and reliable power supply, and can be more cost-effective than sole diesel systems. This paper assesses the feasibility of expanding an existing diesel power plant into a hybrid power system (HPS) using Power Pinch Analysis (PoPA). An HPS configuration developed with PoPA methodology can provide optimal solar and wind electricity supplies while minimising the diesel runtime. Results show that an HPS that combines solar and wind system with diesel power generation can provide significant diesel fuel savings while satisfying the demands at a reasonable cost.

Peak-off-peak load shifting for hybrid power systems based on Power Pinch Analysis

Electricity load distribution tends to vary throughout the day depending on the time of operations of equipment and processes and the ambient weather conditions. Load shifting from peak to off-peak hours changes the electricity load profile and allows users to control the peak electricity demand and optimise the electricity cost. Power Pinch Analysis (PoPA) has been used recently to guide load shifting aimed at reducing the electricity maximum demand. This work applies the PoPA to optimise the overall electricity cost for a hybrid power system by performing cost-effective load shifting that takes advantage of the peak and off-peak electricity tariffs. Two new heuristics for load shifting have been proposed in this work. The results show that the total outsourced electricity during the peak hours has been successfully distributed to the off-peak hours to minimise the electricity cost.

A process integration approach for design of hybrid power systems with energy storage

Selection of energy storage technology in hybrid power systems (HPS) is vital due to the unique advantages and capabilities offered by different storage technologies. For an optimal operation, the efficient and economical storage system for an HPS should be selected. This work introduces a new systematic generic framework to determine the most cost-effective storage technology for an HPS. A Power Pinch Analysis tool called the AC/DC modified storage cascade table has been developed to optimise the HPS by considering various storage technologies. The economics of the various types of storage modes was analysed, taking into account the associated energy losses, among others. The method was applied to two case studies with different power trends to evaluate the effect of storage efficiencies and storage form on the performance of HPS. A superconducting magnetic storage system of 26.12 kWh capacity, that gives an investment payback period of 3.6 years, is the most cost-effective storage technology for the small-scale household system in Case Study 1. For the large-scale industrial application presented in Case Study 2, the Lead–Acid battery with a capacity of 15.38 MWh gives the lowest payback period (1.43 years).

Extended-power pinch analysis (EPoPA) for integration of renewable energy systems with battery/hydrogen storages

An extended-power pinch analysis (EPoPA) is proposed as a means of extending the power pinch analysis (PoPA) for optimal design of renewable energy systems with battery and hydrogen storage (RES-BH). The EPoPA concept is based on the storage of wasted electricity that cannot be stored by the battery bank designed by PoPA. This energy is stored in the form of hydrogen and is discharged in the form of electricity when the external electricity source is needed. EPoPA graphical and numerical tools are introduced to determine the minimum required external electricity source, wasted electricity sources, and appropriate hydrogen storage system capacity of the RES-BH system during first and normal operation years. Furthermore, the integration of the RES-BH system with a diesel generator as a high reliable system is investigated in view point of economic. The optimal sizes of diesel generator and hydrogen storage system components, such as electrolyzer, fuel cell and hydrogen tank are obtained with the minimization of the total annual cost (TAC) of the system. The implementation results of the EPoPA tools on three possible case studies indicate that EPoPA, unlike other process integration methodologies such as PoPA, is able to optimally design RES-BH systems.

Transshipment model-based linear programming formulation for targeting hybrid power systems with power loss considerations

This article aims at targeting the minimum electricity outsourced from the grid and the minimum battery capacity for temporal storage of surplus power in a HPS (hybrid power systems) with known power demands and RE (renewable energy) sources. The given continuous or intermittent power demands and RE supplies can be AC (alternating current) or DC (direct current) with known average power ratings without uncertainty. An ETM (expanded transshipment model) is proposed to determine the allocation of electricity generated from RE sources as well as the storage and outsourcing policies for electricity surplus and deficit. This model also considers possible power losses from the conversion between AC and DC, the charging (for storage) and discharging of electricity (to supplement RE supply), and self-discharge during storage. The problem of targeting the electricity outsourcing and storage for an HPS is formulated as a LP (linear program). A literature example is used to demonstrate the application of the proposed ETM. The promising results show that the proposed model can provide preliminary analysis for optimal power management in an HPS, and is an improved method compared to the PPA (power pinch analysis).

Cost-effective Load Shifting for Hybrid Power Systems Using Power Pinch Analysis

Load shifting from peak to off-peak hours changes the electricity load profile and allows users to control the peak electricity demand and optimise the electricity cost. Power Pinch Analysis (PoPA) has been used recently to guide load shifting aimed at reducing the electricity maximum demand. This work applies the PoPA to optimise the overall electricity cost for a hybrid power system by performing cost-effective load shifting that takes advantage of the peak and off-peak electricity tariff. Two new heuristics for load shifting are proposed in this work. The results show that the total outsourced electricity during the peak hours has been successfully distributed to the off-peak hours to minimise the electricity cost.

Optimal sizing of hybrid power systems using power pinch analysis

Hybrid Power Systems (HPS) consist of different renewable generators, which produce electricity from renewable energy (RE) sources required by the load. An optimal sizing method is the key factor to achieve the technical and economical feasibility of the HPS. Power Pinch Analysis (PoPA) method has been applied to set the guidelines for proper HPS sizing. Different scenarios for RE generators allow the designers to choose the best alternative for their systems. The scenarios considered are the reduction of (1) the size of the most expensive RE generator, (2) the size of generator with the most abundant RE sources available during the time interval with large electricity surplus and (3) the size of both the most expensive and abundant RE sources available during the time interval with large electricity surplus. The results show that the first option yields the minimum capital and operating costs and results in the lowest payback period for a given set of electricity targets.

SAHPPA: a novel power pinch analysis approach for the design of off-grid hybrid energy systems

This work proposes a novel approach called stand-alone hybrid system power pinch analysis (SAHPPA), which is particularly applicable for the design of off-grid distributed energy generation systems. The enhanced graphical tool employs new ways of utilising the recently introduced demand composite curve and supply composite curve while honouring and adapting fundamental energy systems engineering concepts. The SAHPPA method is capable of optimising the capacity of both the power generators and energy storage for biomass (i.e. non-intermittent) and solar photovoltaic (i.e. intermittent) energy technologies, which is a contribution to the emerging area of power pinch analysis. In addition, the procedure considers all possible efficiency losses in the overall system encompassing the charging–discharging and current inversion processes.