High Share Of Renewable Energy Research Articles

Assessing Efficiency and Environmental Performance of a Nearly Zero-Energy University Building’s Energy System in Norway

Increasing awareness of climate issues in recent decades has led to new policies on buildings’ energy consumption and energy performance. The European Union (EU) directive 2010/31/EC, i.e., the energy performance of buildings directive (EPBD), is one of the measures initiated to achieve climate and energy goals by reducing energy use and greenhouse gas emissions in the building sector. The EPBD required all new buildings to be nearly zero-energy buildings (nZEBs) by 2021. Nearly zero-energy buildings (nZEBs) are buildings with a very-high-energy performance and nearly zero or low-energy requirements covered to a very significant extent by energy from renewable sources produced on-site or nearby. The utilisation of solar photovoltaic (PV) panels is a common approach for achieving the nZEB standard. The carbon footprint of PV panels is often not discussed as a parameter. This paper aimed to analyse the environmental performance of an existing nearly zero-energy university building in a Norwegian use case scenario. This analysis is performed by assessing annual electricity and heat consumption from both energetic and environmental perspectives. The energy required for the building during the studied period is then used to analyse the environmental and energy performance of the building. When it comes to the environmental assessment, the commercial software SimaPro was used. The proposed revision EPBD and nZEB definition from 2021 suggests that nZEBs should also consider operational greenhouse gas emissions and life-cycle global warming potential from 2027. The life cycle assessment (LCA) of the building’s energy sources looks at the global warming potential (GWP) and greenhouse gas (GHG) emissions, and how they compare to Norwegian grid electricity. The results of the analysis highlights potential challenges to justifying the use of alternative energy sources to fulfil the criteria of nZEBs. When installing solar PV, it is important to consider the energy mix of the country where the solar PVs are produced. To solely consider the energy performance of the building, the installation of solar PV panels in countries with a high share of renewable energy may result in a reduced impact in terms of emission reduction from a life cycle perspective.

Technoeconomic Analysis and Optimization of Hybrid Solar-Wind-Hydrodiesel Renewable Energy Systems Using Two Dispatch Strategies

Sustainable generation is impacted by the adoption of renewable energy, the growth of energy markets, and economic strategies. This paper offers a sustainable strategy and a technoeconomic analysis of off-grid hybrid energy systems (HES) in remote islands of Iran, including Lavan, Larak, and Failaka, utilizing PV module, wind turbine, and hydrokinetic turbines. Hourly wind speed, solar irradiation, and hydrovelocity have been implemented under load following (LF) and cycle charging (CC) dispatch strategies in order to ascertain the most appropriate systems. Lavan Island achieves the winning HES with a CC dispatch strategy, which consists of 3 hydroelectric turbines, 1 wind turbine, 349 kW of solar power, 150 kW of generator power, 316 kWh of batteries, and 287 kW of the converter. This ideal HES, which generates a consistent generation profile and reasonable net present cost (NPC) and cost of energy (COE) of M0.160$ and $0.013 kWh, respectively, can be practically attained in these areas. LF-controlled optimal solutions use less fuel than CC-based ones, leading to a higher share of renewable energy. Compared to Larak and Lavan, the CC- and LF-controlled options on Failaka Island generate cleaner electricity with emissions that are 57% and 44% lower. Regarding the ability to recoup the project’s initial investment costs, long-term energy production would be more financially viable than short-term. Short-term projects with higher financial uncertainty due to the salvage cost should use the CC method.

Feasibility and optimal sizing analysis of hybrid renewable energy systems: A case study of Al-Karak, Jordan

The aim of this research is to examine the techno-economic viability of both off-grid and on-grid hybrid renewable energy systems for Jordan's Al-Karak governorate. Hybrid Optimization of Multiple Energy Resources (HOMER) Pro software was used in this article to evaluate the carry feasibility to maximize the renewable energy (RE) integration in hybrid energy systems based on different configurations, grid-connected and stand-alone systems of the wind turbine, biogas plant, photovoltaic (PV) panels, flywheel, and batteries while minimizing the net present cost, the Levelized cost of energy and CO2 emissions mitigation. The results showed that the PV/Wind system, connected to the grid with batteries for storage is the optimal configuration for sustainable Al-Karak governorate electrification whilst achieving environmental benefits and guaranteeing reliable and continuous energy access with the lowest net present cost and the Levelized cost, 298,359 USD$ and 0.024 USD$/kWh respectively, and high RE share, 71.8% of electricity is generated from wind and 28.2% is purchased from the grid and emits 220 tons of CO2 per year, 53% less than a grid alone system. Such a system would provide advantages in terms of energy independence and improved environmental quality.

Towards 100% renewable energy systems: The role of hydrogen and batteries

New challenges arise for the accurate modelling of energy systems with a high share of renewable energy. In this context, energy storage technologies become key elements to manage fluctuations in renewable energy sources and electricity demand. The aim of this work is to investigate the role of batteries and hydrogen storage in achieving a 100% renewable energy system. First, the impact of time series clustering on the multi-year planning of energy systems that rely heavily on energy storage is assessed. The results show good accuracy, even for a small number of representative days, which is necessary to limit the computational burden of the optimisation problem. Then, different configurations of carbon-free energy systems are considered by varying the energy storage solution: only-battery, only‑hydrogen, and hybrid scenarios. An island energy system based on photovoltaics and floating offshore wind turbines is used as a demonstrative case study. It is shown that the cost of the only-battery configuration is 155% higher than the cost of the hydrogen-based scenarios. The reason is that the long-term hydrogen-based storage, despite its low round-trip efficiency, avoids costly oversizing of batteries and wind turbines throughout the analysed period. In the selected case study, hydrogen storage reduces the total rated power of the wind farm by about 5 times compared to the only-battery system. Hydrogen-based solutions are therefore crucial in 100% renewable energy systems to achieve energy self-sufficiency in a cost-effective way.

Have renewable energy leaders announced aggressive emission reduction goals? Examining variations in the stringency of country-level net-zero emission pledges

The 2015 Paris Agreement outlined the goal to limit temperature increases below 2°C, preferably to 1.5°C. In response, several countries have announced net-zero emission pledges (NZEP). The credibility of these pledges varies because countries have committed to different target years. Moreover, some pledges outline sectoral as opposed to economy-wide targets and vary in how they monitor progress. To assess the pledge’s credibility, we create a novel NZEP stringency score. We find that climate leaders with a higher share of renewable energy in final energy consumption are more likely to have announced more stringent NZEPs. However, economic development, the size of the economy, countries’ embeddedness in international environmental treaties, and the robustness of domestic civil society are not associated with NZEP stringency.

Hydrogen economy development in Brazil: An analysis of stakeholders' perception

The aim of this article is to explore stakeholders' experiences, perceptions, and expectations in Brazilian hydrogen economy development. This is an essential input to define efficient public policies and strategy and convince stakeholders to invest in the hydrogen chain value. In order to understand the vision of the main stakeholders of the Brazilian hydrogen economy, a literature and documental analysis, complemented by interviews and questionnaire-based surveys with 32 experts of five categories (companies, governmental entities, research centers, associations, and universities) were performed. The results showed that, in the long-term vision, interviewees highlighted decarbonization as a key strategic advantage for hydrogen economy development in Brazil. Interviewees affirmed that, as Brazil already has a high share of renewable energy in its electricity mix and potential renewable power capacity additions, production of competitive low-cost green hydrogen is possible. On the other hand, the potential of low-carbon hydrogen production from fossil fuels combined with carbon capture, utilization, and storage (CCUS) is still a limited technology in the country. Nevertheless, Brazil needs to address challenges such as scaling up, cost reduction, and adoption and sustainable growth of hydrogen-based technologies. A majority of the interviewees foresaw that a well-established Brazilian hydrogen economy would become a reality at medium term (between 6 and 10 years). Opportunities for green hydrogen were highlighted in the cement, mobility, and fertilizer sectors. Nonetheless, a strong difference can be observed among the different categories about the maturity of hydrogen in the national context. While government entities believe in the medium term (6–10 years), companies foresee that technical and economic maturity will be reached in the long term (more than 11 years) In addition, economic, technical, normative, and social barriers were identified. The results show that Brazilian government needs to create a long-term policy framework that could build up confidence in private investment, create market demand with policy interventions, develop standards and regulations to remove obstacles for the market growth and provide enhanced R&D support. If the current initiatives are driven by the interaction with foreign players, a program centered to the synergy with Brazilian energy matrix and long-term economy planning is recommended. In terms of R&D, the creation of a specific funding program can be considered a strong tool to approximate efficiently and rapidly the industry to the academy through the development of ad hoc solutions to develop the market of hydrogen commodities.

Influence of the Industry’s Output on Electricity Prices: Comparison of the Nord Pool and HUPX Markets

Electricity markets are characterised by high sensitivity to variations in supply and demand conditions. However, they also exhibit a number of specific characteristics, including large daily, weekly, and seasonal price fluctuations. The aim of this article is to assess the impact of fluctuations in the industry’s output on wholesale electricity prices. Results were compared for the Nord Pool markets, with a high share of renewable energy supply, and the HUPX markets, where fossil fuel and/or nuclear energy supply dominates. The results obtained generally indicate the positive impact of changes in the industry’s output on wholesale electricity prices. This impact was stronger in the HUPX markets and for periods in daily and weekly cycles with higher energy demands. The results indicate that the sensitivity of electricity prices to fluctuations in the industry’s output is lower in markets with a higher share of renewable energy, especially for periods with higher energy demands.

Stability Improvement of a Transmission Grid With High Share of Renewable Energy Using TSCOPF and Inertia Emulation

This paper proposes a Transient Stability Constrained Optimal Power Flow (TSCOPF) formulation that models non-synchronous renewable generation equipped with synthetic inertia. The proposed optimization problem calculates the optimal operating point of the system, accommodating high shares of non-synchronous renewable generation while ensuring transient stability in the event of critical incidents. Synthetic inertia controllers are used to improve the dynamic stability of the system in cases of very high share of renewable generation. The proposed tool is tested in the North-West Spanish system, a network with a high penetration of wind energy that causes a reduction in the total system inertia. The results of the study show that 1) synthetic inertia in renewable power plants can diminish electromechanical oscillations after a severe contingency, reducing the cost of ensuring transient stability; 2) using synthetic inertia the system becomes more stable when conventional generation is decommissioned following de-carbonization and renewable promotion policies; and 3) the proposed model can be used to calculate the parameters of the synthetic inertia control.

Spatial analyses of smart energy system implementation through system dynamics and GIS modelling. Wind power case study in Latvia

Major concern in utilising renewable energy sources, such as solar or wind, is their intermittent nature. Therefore, whether they can be reliable energy sources to provide uninterrupted energy demand when reaching a high share of renewable energy in the system depends on the whole energy supply network. Higher flexibility of RES-based systems can be reached through the development of smart energy concepts.The system dynamics model coupled with a geographical information system platform has been used to analyse space and time dimensions of RES potential using geo-referenced information. This approach allows analysing the whole energy system by determining the best-suited development scenario for each region separately, based on their resource, economic, and technological capabilities. Furthermore, the system dynamics model is complemented with different policies to evaluate their impact on renewable and local energy resource development and economic potential. The results show that the potential for large-scale onshore wind farm capacities with suitable land conditions could be around 5.5 GW, but the forecasted necessary wind power capacity to reach climate neutrality in 2050 is 1.55 GW. Therefore, onshore wind turbines should be promoted to move toward a smart and renewable power system in Latvia.

Development of future-proof supply concepts for sector-coupled district heating systems based on scenario-analysis

Abstract Existing districts pose a particular challenge within the transition into a renewable energy system. Especially the heat supply requires innovative concepts. In many districts, renewable energy resources are limited, and district heat supply relies on energy imports from the upstream energy infrastructures, especially the gas and electricity grid. These upstream infrastructures are in an ongoing process of transformation into a renewable energy system with uncertain speed and depth. To design future-proof heat supply concepts, this work presents a scenario-based design approach considering different scenario paths for the upstream energy infrastructures as well as the development of the existing building stock. Therefore, a mixed-integer linear programming model is set up to optimize the energy converter and storage capacities of a generic district heat supply with respect to costs and emission. Additionally, three different refurbishment scenarios are considered for the existing buildings stock. From the results of the different scenarios, future-proof heat supply concepts are derived. The analysis shows that heat-pump capacities in combination with a thermal storage is of great importance for a future carbon-neutral heat supply. A combined heat and power unit helps to reduce emissions in short term. However, only if the gas network has a high share of renewable energies, this technology will compete with electricity based heating via heat-pumps. The results show that electrolysis is at least in short term not a viable option for designing a cost-efficient carbon-neutral district heat supply.

Performance analysis of a pumped hydro assisted near‐isothermal compressed carbon dioxide energy storage system with gas/liquid phase change process

The energy storage device is indispensable in future power system due to the high share of renewable energies. Compressed gas energy storage (CGES) technology, including the compressed air energy storage (CAES), has been widely recognized as one of the most promising solutions in energy storage domain. Among multiple CAES forms, the isothermal CAES is a potential type in which the ideal round trip efficiency (RTE) can be 100%. On the other hand, carbon dioxide (CO2) as an excellent working medium in CGES system owing to its favorable properties. However, the existing isothermal type CGES systems just employ the air as working medium, the potential of CO2 in such system is not evaluated yet. Therefore, an 800 kW pumped hydro assisted near-isothermal compressed carbon dioxide energy storage system with gas/liquid phase change process is proposed. In detail, the hydraulic machineries, the flexible rubber diaphragm and the helical coils are employed to realize the near-isothermal process and high RTE. The transient models are built and system performance is thus investigated. The results show that the system possesses 68.36% in RTE and 1.0914 kWh/m3 in energy density (ED) under the design condition. Meanwhile, the water temperature in helical coil, the initial and maximum pressures of vessel and the vessel volume are sensitive for system behavior.

Addressing sustainability issues in transition to carbon-neutral sustainable society with multi-criteria analysis

Creation of sustainable society and transition to low-carbon energy system are the main priorities of the EU policy. Energy poverty (EP) is one of the most important social problems linked to low-carbon transition as creation of carbon neutral societies requires to address other important sustainability issues linked with carbon-free future. Although assessment of EP is a prerequisite for designing policy initiatives to alleviate the problem. The article provides a methodological framework for the EP assessment taking into account goals of low-carbon energy transition and creation of sustainable carbon-neutral society. The proposed evaluation tool can be applied in different settings and used to track the relative progress of the countries in pursuing low-carbon transition and sustainable societies development. The Bellagio Sustainability Assessment and Measurement Principles (STAMP) were followed throughout the process of indicators selection and assessment. In order to determine countries’ achievements over time, the assessment was performed in 2010 and 2018 by applying two multi-criteria techniques. The results show that the Nordic countries stand out from other EU member states in terms of just low-carbon energy transition progress because of their low poverty indicators in households, high standard of living, and high share of renewable energy.

Renewables and Advanced Storage in Power Systems: The Iberian Case

Storage has many benefits for power systems with a high share of renewable energy. It reduces renewable curtailment, can participate in ancillary services and contributes to system adequacy. However, its business model is far from clear since most of its revenues come from arbitrage in energy markets, and this is usually not enough to recover the investment. Advanced storage can facilitate the profitability of storage and ease the integration of renewables in power systems by reducing costs and allowing an enhanced performance. The profitability requirements of future advanced storage systems (batteries) are assessed in this paper by means of an optimization method and an uncertainty analysis for an optimal Iberian (Spain and Portugal) power system that meets the targets of their National Energy and Climate Plans. Results show that needed storage capacity is only a small part of the demanded energy, but technical advances are required for optimal performance. High prospective storage cost leads to a wind-dominated renewable mix, while low storage cost favours photovoltaics. Arbitrage with storage may cover its investment costs under carbon prices close to the actual Social Cost of Carbon.

Exploring the roles of storage technologies in the Spanish electricity system with high share of renewable energy

At operational level, fossil fuel phase-out and high shares of non-dispatchable renewable energy resources (RES) will challenge the system operator’s (SO) ability to balance generation, and the demand at any time. The variability of RES output ranges from one hour to a season, and critical events such as low supply and high demand might occur more frequently and for more extended periods. When evaluating the role of Energy Storage Systems (ESSs) in this context, the need for a long time scope to capture the different RES variabilities must be reconciled with the need for modeling the hourly chronology. This paper presents a medium-term operation planning model, addressing both the energy dispatch and the balancing services. This study shows that representing the combined chronological variability of demand and RES production is essential to properly assess the roles of different kinds of ESSs in the future 2030 electricity mix. Otherwise, it would not be possible to appropriately capture the frequency, depth, and length of events for which ESSs are activated. The analysis also highlights the importance of considering balancing services, given the significant contribution of batteries to the reserve market. Finally, the results show that batteries and Pumped Storage Hydro (PSH) have different roles in the Spanish electricity system with a high renewable penetration. While PSH is mainly used to provide energy during critical periods, batteries mostly provide balancing services.

Comparative sustainability study of energy storage technologies using data envelopment analysis

The transition to energy systems with a high share of renewable energy depends on the availability of technologies that can connect the physical distances or bridge the time differences between the energy supply and demand points. This study focuses on energy storage technologies due to their expected role in liberating the energy sector from fossil fuels and facilitating the penetration of intermittent renewable sources. The performance of 27 energy storage alternatives is compared considering sustainability aspects by means of data envelopment analysis. To this end, storage alternatives are first classified into two clusters: fast-response and long-term. The levelized cost of energy, energy and water consumption, global warming potential, and employment are common indicators considered for both clusters, while energy density is used only for fast-response technologies, where it plays a key role in technology selection. Flywheel reveals the highest efficiency between all the fast-response technologies, while green ammonia powered with solar energy ranks first for long-term energy storage. An uncertainty analysis is incorporated to discuss the reliability of the results. Overall, results obtained, and guidelines provided can be helpful for both decision-making and research and development purposes. For the former, we identify the most appealing energy storage options to be promoted, while for the latter, we report quantitative improvement targets that would make inefficient technologies competitive if attained. This contribution paves the way for more comprehensive studies in the context of energy storage by presenting a powerful framework for comparing options according to multiple sustainability indicators.

Optimization of CSP Plants with Thermal Energy Storage for Electricity Price Stability in Spot Markets

This research presents a novel optimization strategy for concentrating solar power (CSP) plants with thermal energy storage (TES) systems that aims to stabilize and reduce electricity prices in spot markets. In the current international scenario of initiatives with regulatory changes aiming to reduce climate change effects and therefore CO2 emissions, many countries are reducing the fossil fuel share in their respective electrical systems and increasing electrical renewable energy systems. These carbon free generation systems have inherent problems such as their intermittence which, combined with the lack of high-scale energy storage systems, cause a stability risk in electrical grid systems and require conventional fuel systems to match demand and production. In this research, we analyze spot price markets using a marginal price system that relies on natural gas and is quite sensitive to an increase in fuel prices, causing a direct increase in the final energy cost in systems with a high renewable energy share, and we study how optimally sized CSP plants with TES can be used as manageable solar energy systems and contribute to both price and grid stability. For the Spanish market, we analyze the ongoing market situation and generation mix and we present an optimization scheme using the System Advisor Model (SAM) software that aims to maximize energy availability throughout the day and contribute to peak generation. The results show that the optimization strategy increases the profitability of CSP plants but also ensures a contribution to spot price stability and reduction. A sensibility analysis is presented, and a case study is analyzed in southern Spain. The results show the importance of optimized CSP plants in an energy transition and a strategy is proposed that can be extended to other locations worldwide.

Green energy security assessment in Morocco: green finance as a step toward sustainable energy transition.

Morocco is an energy-deficient country depending on almost 94% of energy imports to fuel its growing economy. Due to its fast-growing population, Morocco’s energy consumption is projected to increase significantly, adding more pressure on the energy system. On the other hand, the rising tension of scarcity of resources, energy price fluctuations, and environmental issues have all made energy security one of its top priorities. Therefore, Morocco launched the National Energy Strategy (NES) in 2009 to reach 42% renewable generation by 2020, which was renewed to up to 52% by 2050. This study analyzes Morocco’s energy security under the 4-As framework from 2000 to 2016.The 4-As methodology aims to assess and graphically illustrate the changes in Morocco’s energy security by mapping these changes into four key dimensions: the availability of energy resources, the applicability of technology, the acceptability by the environment and society, and the affordability of energy resources. The quantitative analysis shows that Morocco’s energy security performance was at its optimum during the first period of study (2000–2004) but then regressed for the remainder of the study period, as energy imports and prices increased, in addition to the low performance in applicability characterized by low energy efficiency. To improve Morocco’s energy security status and move toward a sustainable energy transition, this study suggests integrating a higher share of renewable energy into the energy mix and boosting efficient technologies through a large scale of green finance and green investment projects.

Demand response strategy for TCLs considering consumer utility

With the higher share of renewable energy, the flexibility of the power system needs to be improved. In recent years, the loads on the demand side can provide flexibility with the development of demand response technology. Thermostatically controlled loads (TCLs), as a kind of large-scale flexible load, have been a significant demand response resource. In this paper, a demand response strategy for TCLs considering consumer utility function is proposed. Firstly, a utility function is modeled to estimate the utility of TCLs. Then a model for estimating the potential of TCLs is built. On this foundation, the power system operators (PSOs) sort TCLs by consumer utility. TCLs with lower consumer utility will be called first. The study case adopts realistic data of an eastern city in China, which verifies the effectiveness of the proposed strategy.

Multi‐sectoral flexibility measures to facilitate wind and solar power integration

As power systems evolve towards integrating higher shares of renewables, the demand for additional levels of flexibility is increased. Meanwhile, o-ther energy consuming sectors, such as transport and heating, could provide flexibility when they move from fossil fuels to electricity. In this paper, the impact of a range of flexibility measures is assessed for the island system of Ireland, with a high share of renewable energy, particularly wind and solar. Flexibility measures studied include hybrid heating in domestic and industrial processes, smart charging of electric vehicles, renewable hydrogen, power to ammonia, peak shaving demand response and batteries. The novelty of this paper lies in directly quantifying the interactions and dependencies between different flexibility measures, with the objective of increasing the operational flexibility of an increasingly renewable energy-dominated power system. Four different scenarios are modeled to explore this interplay between the different flexibility measures. The costs and benefits of several sector-coupling measures. The scenarios have also been compared in terms of their influence on system inertia, renewable energy curtailment and non-synchronous penetration levels. The results indicate the potential importance of electricity-based heating in the industrial sector, smart charging of electric vehicles, batteries and power-to-ammonia, as part of achieving future targets

Long Duration Flexibility Planning Challenges and Solutions for Power System With Ultra High Share of Renewable Energy

The uncertainty of wind/photovoltaics (PV) power generation and load fluctuations highlight the urgent need for flexible yet stable power resources. With the increasing in the share of renewable energy, the fluctuation presents a trend toward the longer periods, larger amplitudes, and more drastic changes. Therefore, research on the long duration flexible resource planning for the scenarios of the ultra high share of renewable power system (UHRPS) has become the focus. In this work, the main structural and operating characteristics of UHRPS are introduced and analyzed, which is followed by the flexibility requirements and flexibility planning challenges of UHRPS scenarios. Then, the current research trends in flexibility planning schemes of renewable energy power systems are reviewed. Finally, the key problems and solutions for research on the long duration flexibility resource planning of UHRPS are proposed.