Energy Modeling Tools Research Articles

Developing an Integrated Energy–Economy Model Framework for Islands

This paper presents a new energy–economy system modelling approach, developed specifically for energy system planning in non-interconnected islands, aiming for decarbonization. Energy system planning is an essential tool to shape the energy transition to reach carbon neutrality in the medium- and long-term horizon. Islands, as small-scale energy systems, have a limited contribution to the global climate targets, but due to their geographical and natural limitations, they present the potential to become frontrunners in the clean energy transition, especially regarding the efficient use of resources. The specificities and complexities of geographical islands cannot be adequately covered by the available energy modelling tools and new advanced approaches need to be developed to provide the appropriate support in designing the future decarbonized energy systems at insular level. Our methodological approach follows the adaptation and customization of well-established energy–economy modelling tools towards the development of an integrated island-scale energy–economy system model, capturing energy demand and supply by sector, heating/cooling and mobility requirements, energy efficiency potentials and their complex interactions through energy prices, storage, flexibility services and sectoral integration. By soft-linking the energy and economy system modelling tools through the consistent exchange of model parameters and variables, we developed a fully fledged modelling framework called IntE3-ISL, designed for islands with a horizon up to 2050.

A Novel Approach for Optimizing Building Energy Models Using Machine Learning Algorithms

The current practice with building energy simulation software tools requires the manual entry of a large list of detailed inputs pertaining to the building characteristics, geographical region, schedule of operation, end users, occupancy, control aspects, and more. While these software tools allow the evaluation of the energy consumption of a building with various combinations of building parameters, with the manual information entry and considering the large number of parameters related to building design and operation, global optimization is extremely challenging. In the present paper, a novel approach is developed for the global optimization of building energy models (BEMs) using Python EnergyPlus. A Python-based script is developed to automate the data entry into the building energy modeling tool (EnergyPlus) and numerous possible designs that cover the desired ranges of multiple variables are simulated. The resulting datasets are then used to establish a surrogate BEM using an artificial neural network (ANN) which is optimized through two different approaches, including Bayesian optimization and a genetic algorithm. To demonstrate the proposed approach, a case study is performed for a building on the campus of the Florida Institute of Technology, located in Melbourne, FL, USA. Eight parameters are selected and 200 variations of them are supplied to EnergyPlus, and the produced results from the simulations are used to train an ANN-based surrogate model. The surrogate model achieved a maximum of 90% R2 through hyperparameter tuning. The two optimization approaches, including the genetic algorithm and the Bayesian method, were applied to the surrogate model, and the optimal designs achieved annual energy consumptions of 11.3 MWh and 12.7 MWh, respectively. It was shown that the approach presented bridges between the physics-based building energy models and the strong optimization tools available in Python, which can allow the achievement of global optimization in a computationally efficient fashion.

AutoBPS: A tool for urban building energy modeling to support energy efficiency improvement at city-scale

China has promised to peak carbon emissions by 2030 and become carbon neutral before 2060. Achieving this target requires actions from all sectors, especially the building sector, which accounts for 33 % of the total energy consumption in China. Within this scenario, this paper introduces a new urban building energy modeling tool, Automated Building Performance Simulation (AutoBPS), to calculate urban building energy demands and to analyze energy retrofit and rooftop photovoltaic (PV) potential. AutoBPS uses a building-by-building approach to automatically generate multi-zone (one zone per floor) models based on the city building dataset, considering the shading effect by surrounding buildings. The tool simulates building energy use and PV generation via EnergyPlus. A downtown district of 3633 buildings in Changsha, China, was selected as a case study to demonstrate the features of the tool. Firstly, annual baseline energy uses of 1793 GWh were simulated by inputting Geographic Information System (GIS) data. Then, different energy conservation measures (covering envelope, lighting, cooling system upgrade, etc.) and roof PV generation systems were adopted to explore energy saving potential. The results showed that the window upgrade was the most energy-efficient individual measure for residential buildings, while the lighting upgrade was that one for commercial buildings. Altogether three measures could save 2.7 ∼ 30.7 % of annual site energy use intensity per building. The total energy demand could be reduced by 18.5 % by combining all measures and saved by 38.6 % when PV installation was added. AutoBPS can be easily applied to other cities, supporting urban energy efficiency plans for carbon reduction goal implementation.

Empirical validation and analysis of the energy performance of an ecological Net Zero Energy Building (NZEB) in Benguerir-Morocco

Within the framework of the sustainable development and carbon-neutrality, the building sector is a key target of the national energy strategy towards zero-carbon economy in Morocco. This article comes in response to this need by assessing the energy performance of a solar-powered low-embodied-carbon building in the semi-arid climate of Benguerir-Morocco, which refers to the fifth climatic zone in the thermal regulation for constructions in Morocco (RTCM). To do so, we’ve used Openstudio as the building energy modeling tool to investigate the energy self-sufficiency of a detached Net Zero Energy Building (NZEB) that has a floor area of 47 m², uses earth-based material as the main component part of the building envelope and has a photovoltaic installation with a capacity of 4 kW. The accuracy of the building energy model was empirically validated following ASHRAE 14 guidelines by monitoring hourly indoor temperatures for 8 days during summer season. Results show that annual thermal needs for cooling and heating are 123.4 kWh/m²/year and the calculated annual self-sufficiency (SS) of the building is 1.25, which means that the solar technology greatly offsets the electrical needs of the building and rech the goal of Zero Energy Building.

An Overview of the Current Energy Situation of Pakistan and the Way Forward towards Green Energy Implementation

Pakistan has been facing energy crises for more than a decade as a result of its reliance on imported fossil fuels, circular debt, political instability, and absurd energy policies. However, the country has abundant renewable energy resources which, if harnessed, may help to effectively cope with ever-increasing energy demand. This review study investigates the country’s economic and energy situations, energy crises, and energy sector performance. A critical analysis of studies conducted on Pakistan’s energy planning since its independence in 1947 is, and policies announced to date are assessed. This review reveals that the economic situation of the country has remained severely stressed, and energy sector performance has been compromised over the years for various underlying reasons. The energy policy narrative in the early decades of the post-independence period focused on water resource management, whereas energy concerns were only realized in the late 1960s as demand grew. The first-ever energy and power planning study in Pakistan was conducted in 1967, and since then, various studies have been conducted to support the medium-term development plans of the government. These planning studies inspired further development, and in 1994, the first-ever electricity-focused power policy was announced by the government in response to industrial growth and subsequent electricity demand. However, this and subsequent policies were fossil-fuel-centric until 2006, when the government announced the first-ever renewable energy policy. This 2006 policy focused on increasing renewable energy penetration in the overall energy mix by setting specific targets. However, these targets have rarely been accomplished as a result of a lack of an effective planning paradigm, as most of studies have been conducted without sound demand forecasting and without considering renewable energy’s potential to meet growing demand. As such, planning efforts based on proven methodologies/modeling tools and the undertaking of demand forecasts and renewable energy assessments are inevitable for countries such as Pakistan. Therefore, we suggest that sectoral energy demand forecasting, estimation of renewable energy potential with end use, and modeling of optimal penetration of renewable energy using energy modeling tools will be helpful to develop sustainable energy policies in Pakistan to eradicate the energy crisis.

Tracking building operational energy and carbon emissions using S-curve trajectories—a prototype tool

New and refurbished non-domestic buildings are failing to live up to their anticipated performance. Shortfalls show in excess energy consumption, high carbon dioxide emissions and other failings in quantitative and qualitative performance metrics. This paper describes the component parts of the performance gap using evidence from building performance evaluations. It introduces a way of visualising the consequences of decisions and actions that are known to compromise performance outcomes using a performance curve methodology (the S-curve) which plots performance, and the root causes of underperformance, from project inception to initial operation and beyond. The paper tests the hypothesis with two case studies. It also covers the initial development of a prototype visualisation tool designed to enable live projects to track emerging operational energy and emissions against a high energy and emissions trajectory created from empirical evidence. The tool aims to help practitioners identify key risk factors that could compromise building performance and mitigate these risks at different stages of procurement. Practical application: The Operational Energy and Carbon (OpEC) visualisation tool is designed for wide industrial application, on all sizes of a non-domestic building project, large and small. It aims to visualise the likely outturn energy performance of a project by calculating the penalties for shortcomings in project delivery. The penalties are visualised as weighted trajectories of energy and carbon dioxide emissions. The prototype tool aims to fill a gap between the capabilities of powerful energy modelling tools used in design and the capacity of non-specialist stakeholders to understand the emerging energy characteristics of a project as it moves through procurement, design, construction, and delivery.

Optimal planning of energy and water systems of a small island with a hourly OSeMOSYS model

Islands all over the world face common challenges connected to energy costs and greenhouse gas emissions. Thus, islands have been identified as perfect sites for implementing and testing innovative solutions to boost the green energy transition towards a sustainable and clean energy system. The supply of clean water is a major issue that affects small islands, and desalination, particularly Reverse Osmosis, represents a valid solution to this challenge. In this research, an energy system model is used to analyse long-term water and energy supply strategies of the tourist island of Favignana, Italy. The model is built with the Open Source long-term energy modelling tool OSeMOSYS at an hourly resolution. It considers both the potential synergies offered by Reverse Osmosis Desalination and the use of water storage to store the excess electricity when needed. The indirect emissions for the maritime transportation of goods and fuels (i.e., water and diesel) to the island are also accounted for. Different energy policies are compared to understand how a carbon tax, a limit on emissions and no policy would impact the long-term energy strategy of the island. The results show that a carbon tax that covers also the maritime transportation sector would lead to the lowest overall cumulative emissions. They additionally reveal that the contribution of emissions for maritime transportation of goods and fuels is relevant and cannot be neglected if a full decarbonisation has to be achieved. On the technological side, investment in a desalination plant is the most viable option in all cases. Finally, for the first time, OSeMOSYS is applied with hourly resolution and the results are compared with those obtained with lower time resolution showing that inaccuracies are found both for overall values and for the dispatching strategies.

A Systematic Literature Review of Physics-Based Urban Building Energy Modeling (UBEM) Tools, Data Sources, and Challenges for Energy Conservation

Urban building energy modeling (UBEM) is a practical approach in large-scale building energy modeling for stakeholders in the energy industry to predict energy use in the building sector under different design and retrofit scenarios. UBEM is a relatively new large-scale building energy modeling (BEM) approach which raises different challenges and requires more in-depth study to facilitate its application. This paper performs a systematic literature review on physics-based modeling techniques, focusing on assessing energy conservation measures. Different UBEM case studies are examined based on the number and type of buildings, building systems, occupancy schedule modeling, archetype development, weather data type, and model calibration methods. Outcomes show that the existing tools and techniques can successfully simulate and assess different energy conservation measures for a large number of buildings. It is also concluded that standard UBEM data acquisition and model development, high-resolution energy use data for calibration, and open-access data, especially in heating and cooling systems and occupancy schedules, are among the biggest challenges in UBEM adoption. UBEM research studies focused on developing auto-calibration routines, adding feedback loops for real-time updates, future climate data, and sensitivity analysis on the most impactful modeling inputs should be prioritized for future research.

Development of a simplified calibrated building simulation model of a supermarket for proposed ECMs and control strategies impact evaluation

Calibrated building energy simulation is an important pathway to more energy-efficient buildings, but the information requirements of some approaches to this problem are significant. This is particularly true for supermarkets and other so-called “big-box” retail stores. Another characteristic of supermarkets is the significant interaction between Heating Ventilating and Air Conditioning (HVAC) and refrigeration systems in these buildings. These buildings could contain a wide variety of systems and a degree of load diversity that makes calibrated modeling a challenge. This paper describes a simplified approach that uses OpenStudio and EnergyPlus to combine known building parameters with “typical” parameters, resulting in a simplified building that is amenable to calibration. This approach was applied to a big-box store located in Nashville, Tennessee, and a calibrated model was obtained that was used to study potential energy conservation measures. The paper also explores the capabilities of whole-building energy modeling tools, such as EnergyPlus, for modeling the HVAC controls and sequences and their impact evaluation. Although some measures are precluded by the model simplicity, several measures were found to improve the efficiency of the model and demonstrate that the simplified modeling approach is effective. Practical Application: This paper introduces a hybrid approach of building energy model calibration using limited information available from the actual building in combination with characteristics of a “typical” building of the same type. This hybrid approach would also be applicable for other building types than discussed in this paper to calibrate the building energy model using limited information from the actual building.

Energy investigation in buildings applying a solar adsorption chiller coupled with biofuel heaters and solar heating/cooling systems in different climates

Green building is a concept in sustainable development which aims to reduce energy consumption and carbon emission of buildings. This study attempts to design and introduce a novel green HVAC system which reduces both energy consumption and carbon production of buildings. This system uses solar absorption chillers to provide the cooling demands of buildings. In addition, biofuel (biogas) fired boilers are also added to provide the heating demands. By using the novel approach of the study, such HVAC system can be coupled with other renewable technologies like photovoltaics and develop green buildings. In order to design, model and simulate the operation of this system, famous energy modeling tools are compared with each other and Design Builder software is chosen as the appropriate one. The paper also introduces a plan for establishment of such systems which is applicable to any locations. The results of modeling this green HVAC system for 10 various climates indicated considerable advantages of this system over traditional systems. The green HVAC system can save the maximum energy of 50 MWh per year in a four stories building. The maximum amount of 31 tons carbon can also be saved if the said building is equipped with this novel HVAC system. The results also made it clear that the solar cooling system is a great choice for providing cooling needs in hot climates. By coupling this kind of cooling system with biofuel heaters, the sustainable HVAC system can develop green buildings even in cold or cool climates. Adding green electricity producers like photovoltaic panels to this system and the building was successful. The maximum produced green energy in buildings was calculated as the amount of 17.9 MWh/yr.

A Case Study about Energy and Cost Impacts for Different Community Scenarios Using a Community-Scale Building Energy Modeling Tool

The United States building sector consumed approximately 75% of electricity in 2019. By implementing renewable energy technologies and control strategies into buildings, future buildings will serve as energy generators as well as consumers. To accommodate this transition, communications among buildings and between buildings and the grid could provide more possibilities to optimize the energy performance of buildings. This paper develops a community-scale building energy model tool and conducts a case study adopting behind-the-meter distributed energy resources, sharing energy in different buildings, and using different electricity tariff structures. Three scenarios are studied: (1) electricity only supplied by the grid, (2) photovoltaic (PV) panels installed on and available to some but not all buildings, and (3) a connected community. To consider the impacts of locations and energy tariffs, this paper selects four cities and three electricity tariffs to evaluate the energy and cost performances of these three scenarios. The results show that the PV panels in Scenario 2 reduce 25% to 33% of the community-level electricity consumption and 20% to 30% of the community-level electricity cost compared with Scenario 1 in all studied locations and energy tariffs. By considering power management in the connected community (Scenario 3), the electricity consumption and cost can be further reduced by 6% to 7% and 5% to 11%, respectively, compared with Scenario 2.

Contextualizing the scope, scale, and speed of energy pathways toward sustainable development in Africa

SummaryFaced with interrelated challenges of climate change and energy crises, Africa’s future energy system orientation could be steered toward sustainable development. In this study, we contextualized diverging fossil fuels-dominated and renewable energy-based pathways toward sustainable development in Africa. A novel and sophisticated techno-economic energy modeling tool is used to describe the scope of the pathways in high geo-spatial and full hourly resolution for Africa covering the entire energy system. This study demonstrates that a renewable energy pathway is not only climate-compatible, but also delivers a lower cost system structure than alternative pathways. Our results show that Africa can leapfrog carbonization by using its low-cost renewable electricity and green hydrogen. Furthermore, Africa can become a self-sufficient green economy and an exporter of green fuels. Notably, solar photovoltaic-battery hybrid systems and electrolyzers are instrumental in achieving carbon-neutrality in Africa. This research presents a “true-zero emission” pathway for Africa.

An assessment of strategies for sustainability priority challenges in Jordan using a water–energy–food Nexus approach

This study aimed at supporting robust decision-making for planning and management of water–energy–food Nexus systems in the country of Jordan. Nexus priority challenges in Jordan were identified as (1) water scarcity, (2) agricultural productivity and water quality, and (3) shift to energy independence. We created a water–energy–food Nexus model that integrates three modelling frameworks: (1) the Water Evaluation and Planning system WEAP model to estimate water demands, supplies and allocation; (2) the MABIA model to estimate crop production, and, (3) a GIS-based energy modelling tool to estimate energy requirements of the water system. Through a set of scenario runs, results show how desalination is needed to address water scarcity, but it has to be coupled with low-carbon electricity generation in order to not exacerbate climate change. Improving water productivity in agriculture improves most of the studied dimensions across the water–energy–food security nexus; however, it does little for water scarcity at the municipal level. Reducing non-revenue water can have positive effects on municipal unmet demand and reduction of energy for pumping, but it does not improve agricultural water productivity and may have negative feedback effects on the Jordan Valleys aquifer levels. Energy efficiency can support energy-intensive projects, like desalination, by substantially reducing the load on the energy system, preventing increased emissions and achieving a more resilient water system. Finally, when all interventions are considered together all of the major drawbacks are reduced and the benefits augmented, producing a more holistic solution to the WEF Nexus challenges in Jordan.

A fast calculation tool for assessing the shading effect of surrounding buildings on window transmitted solar radiation energy

• A parametric study with 2500 models using EnergyPlus was carried out. • A rapid method to assess the shading effect of surrounding buildings was developed. • The method can greatly shorten calculation time while keeping an acceptable accuracy. • Suggestions were provided for designers achieving energy-efficient design. Most existing Urban Building Energy Modeling (UBEM) tools cannot simultaneously achieve fast and accurate simulation of regional building energy consumption with the consideration of shading effect from surrounding buildings. This study explored how the different designs of surrounding buildings affect the window transmitted solar radiation energy (WTSRE) of the target building by performing a parametric study using EnergyPlus, and proposed one method that can rapidly assess the shading effect of surrounding buildings at the design stage based on the databases obtained from the parametric study. A SketchUp plug-in named MOOSAS-FastSolar was developed based on the proposed method. By comparing the calculation results of the MOOSAS-FastSolar with the simulation results of EnergyPlus, the method developed by this research can greatly shorten the calculation time from more than 1 h to tens of seconds while keeping the accuracy of the calculation results within an acceptable range (the computational error is less than 15%). In addition, from the parametric simulation results, some recommendations were provided to help building designers achieve energy-efficient design at the conceptional design stage.

Transition from fossilized to defossilized energy system in Pakistan

Pakistan's energy sector has been in crises since 2005. Major reasons behind crises include huge dependence on imported fossil assets and lack of integrated energy planning. These crises have challenged energy sector and require special attention to solve them through proper planning using energy modeling tools. In this research, Long-range Energy Alternatives Planning System (LEAP) is used for modeling Pakistan's energy sector for period 2020 to 2070. Energy demand, production and CO2 emissions are forecasted under the Progressive (PROG) and Renewable Energy Sources, Technologies and Efficiency Measures (RESTEM) scenarios by considering techno-economic parameters. Results of this study suggest that transition towards defossilized energy system is possible through RESTEM scenario. Model results shows that energy demand for 2020 is 112 TWh and for 2070 is 2684 TWh. On supply side, energy production for 2020 is 114 TWh and for 2070 it is 2696 TWh. Share of renewable sources in total energy mix is increased from 38.5% in 2021 to 59.1% in 2070 and share of non-renewable sources is reduced from 53.1% in 2021 to 40.9% in 2070. CO2 emissions are also reduced from 153,083.7 million tons to 56,152 million tons under RESTEM scenario.

Assessment of Impacts of Climate Change on Hydropower-Dominated Power System—The Case of Ethiopia

The Ethiopia energy mix is dominated by hydro-generation, which is largely reliant on water resources and their availability. This article aims to examine the impacts of severe drought on electric power generation by developing a Drought Scenario. OSeMOSYS (an open source energy modelling tool) was used to perform the analyses. The results were then compared with an existing reference scenario called “New Policy Scenario”. The study looked at how power generation and CO2 emissions would be altered in the future if reservoir capacity was halved due to drought. Taking this into account, the renewable energy share decreased from its 90% in 2050 to 81% in 2065, which had been 98% to 89% in the case of New Policy Scenario. In another case, CO2 emissions also increased from 0.42 Mt CO2 in 2015 to 7.3 Mt CO2 in 2065, a 3.3 Mt CO2 increase as compared to the New Scenario. The results showed how a prolonged period of drought would reduce the river flows and lead to an energy transition that may necessitate the installation of other concurrent alternative power plants. The study suggested ways to approach energy mix, particularly for countries with hydro-dominated power generation and those experiencing drought.

Assessing and Monitoring of Building Performance by Diverse Methods

Buildings are one of the largest contributors to energy consumption and greenhouse gas emissions (GHG) in the world. There is an increased interest in building performance evaluation as an essential practice to design a sustainable building. Building performance is influenced by various terms, for example, designs, construction-related factors such as building envelope and airtightness, and energy technologies with or without micro-generations. How well a building performs thermally is key to determining the level of energy demand and GHG emissions. Building standards and regulations, in combination with assessments (e.g., energy modeling tools) and certifications, provide sets of supports, guidelines and instructions for designers and building engineers to ensure users’ health and well-being, consistency in construction practices and environmental protection. This paper reviews, evaluates and suggests a sequence of building performance methods from the UK perspective. It shows the relationships between such methods, their evolutions and related tools, and further highlights the importance of post-occupancy analysis and how crucial such assessments could be for efficient buildings.

Integration of an Energy Modeling Tool in a State’s Power Sector Planning Process—A Tamil Nadu Case Study

In this paper, we discuss how integrating energy planning tools can help state level planners, policy makers and utilities to set policy targets and design long-term clean energy pathways by providing insights into the state’s medium- and long-term planning exercise. As a case study, we assess how Tamil Nadu can utilize Low Emissions Analysis Platform (LEAP) to inform potential renewable electricity– capacity additions until 2030 and what lessons this case study can offer for other state's power sector planning processes.

A Review of Energy Modeling Tools for Energy Efficiency in Smart Cities

Nowadays, modeling tools are a crucial part of best practice in the elaboration and implementation of a decarbonization plan in any organization, city, or country. The present review analyzes the different modeling tools available to assess energy systems in smart cities. It creates an updated overview of the modeling tools currently available, showing their capabilities and main potential outputs when considering the energy efficiency objective in the context of smart cities in Europe. A restricted set of 14 tools are identified which optimally fulfill the modeling mission of the energy sector, in a smart city context, for different time horizons. The selection considers the capability to include decarbonization assessments, namely, by considering the flexibility to use different external factors, energy policies, technologies, and mainly the implementation of Article 7 from the Energy Efficiency Directive and the “energy efficiency first” principle defined by the European Commission. The ELECTRE TRI method was used to implement a multi-criteria decision approach for sorting modeling tools, aiming at distributing the various alternatives by previously defined categories, and considering the performance criteria of each alternative modeling tool, the analysis suggests that the best options are the LEAP, MESSAGEix, and oemof tools.

Flexibility options and their representation in open energy modelling tools

To reach climate targets, future energy systems must rely heavily on variable renewable energy sources (VRES) such as wind and photovoltaic (PV). As the share of VRES increases, the topics of flexibility and the smart interplay of different flexibility options grow in importance. One way to analyse flexibility options and enhance the design of future energy systems is to use energy system modelling tools. Although a wide range of openly accessible models exist, there is no clear evaluation of how flexibility is represented in these tools. To bridge this gap, this paper extracts the key factors of flexibility representation and introduces a new classification for flexibility and influencing factors. To evaluate the current modelling landscape, a survey was sent to developers of open energy modelling tools and analysed with the newly introduced Open ESM Flexibility Evaluation Tool (OpFEl), an open source evaluation algorithm to assess the representation of different flexibility options in the tools. The results show a wide range of different tools covering most aspects of flexibility. A trend towards including sector coupling elements is visible. However, storage and network type flexibility, as well as aspects touching system operations, are still underrepresented in current models and should be included in more detail. No single model covers all categories of flexibility options to a high degree, but a combination of different models through soft coupling could serve as the basis for a holistic flexibility assessment. This, in turn, would allow for a detailed evaluation of energy systems based on VRES.