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This paper investigates the challenges isolated islands face in transitioning from fossil fuel-based electricity generation to renewable energy sources. The Canary Islands serve as a case study, where photovoltaic and wind power are the primary renewables, but their variability requires a deep techno-economic analysis. The island's energy demand is predicted to rise by 100% due to economic growth, electrification and electric vehicles. However, implementing renewable systems encounters obstacles, such as limited suitable sites and protected areas. The study uses Wilks' methodology and Monte Carlo sampling to explore 59 combinations of randomly selected inputs of the uncertain variables, aiming for a 95/95% coverage and confidence level in the results. In most cases, they experience energy shortages, failing to meet electric demand. Even though a new generation mix appears to cover demand under all circumstances, the uncertainty unveils a different reality, leading to an approximate 25% increase in system costs. Surpluses in energy generation, while seemingly positive, can pose challenges. The new system's Levelized Cost of Energy increases from around 14 to 17c€/kWh. These cost increases are contingent upon future performance and the variability of uncertain parameters, leading to excesses ranging from slightly below 25% to over 40%. • Demand coverage scenario designed to meet electric demand through renewable sources. • Uncertainty analysis of a scenario for the complete electrification of the economy. • Best Estimate Plus Uncertainty analysis implementing the Wilks' methodology. • Resizing the system to cover the demand with 95% coverage and confidence levels. • Differences in using deterministic and stochastic methods for electric demand coverage. [ABSTRACT FROM AUTHOR]

Abstract Tidal energy is one of the most abundant renewable energy sources. Due to its intermittent nature, the integration of tidal energy within a Microgrid (MG) requires appropriate energy management strategies. Some important considerations are tidal energy generation prediction, energy storage requirements, load profile and demand within the Microgrid, and energy pricing structures. This paper considers an MG scenario that includes a small scale tidal farm near Darwin in north of Australia. A tidal power prediction model is introduced using tidal current speed data. Then, for a fixed-size energy storage system (ESS), an optimal scheduling strategy is devised using Particle Swarm Optimization (PSO) to achieve minimum operating costs in the MG. The work presented in this paper provides a framework for the planning of MGs that include tidal generation in their energy mix. Highlights • Visibility of tidal power in the North of Australia. • Tidal power prediction based on tidal current speed observation. • Optimal scheduling for a tidal Micro-grid using Particle Swarm Optimisation. [ABSTRACT FROM AUTHOR]

Abstract The transition to a 100% renewable energy system based on variable renewable energy raises technical but also institutional questions. The smart energy system concept integrates variable renewable energy by addressing the technical challenges through the integration of different energy sectors, but integration of variable renewable energy also entails a change in the cost structures, especially related to electricity. The effect of this change in cost structures on market prices is investigated. This is done through simulation of a 100% renewable energy system that utilises a large degree of cross-sector integration but maintaining the current electricity market structure. The paper uses a 100% renewable energy system scenario for a 2050 Danish energy system. This is reflected in the use of wind energy as the primary renewable energy source. It is concluded that the current electricity market structure is not able to financially sustain the amounts of wind power necessary for the transition to a 100% renewable energy system. Since earlier research shows that neither electricity production costs nor the total system costs is higher for the renewable path than the fossil-based alternatives, the conclusion in this paper points towards a need for reshaping the institutional structure of electricity trade. Highlights • Calculates electricity prices in a renewable energy system with current market design. • Calculates private profitability of wind power investments within such system. • The market design cannot financially sustain wind power in a renewable energy system. [ABSTRACT FROM AUTHOR]

In the present context, energy access to remote rural households through local energy generating systems has been recognized as a cost effective and extent efficient option. With increased emphasis on eco-friendly technologies and high fuel cost associated with conventional energy generation, the use of renewable energy resources (small hydro, biomass, solar, wind energy etc.) are being explored. The present paper is focused on the optimal sizing of a stand-alone Integrated Renewable Energy System (IRES) which comprises the resources of micro hydro power (MHP), biogas, biomass, solar and wind energy. Initially, a demand response (DR) strategy based on energy consumption scheduling of appliances has been suggested and modelled in the paper. This strategy aims to minimize the peak hourly energy consumption of the study area. Further, different combinations of system components without and with DR strategy were considered and optimized for power reliability criteria of 0% and 5% unmet load. It has been found that significant amount of savings in system sizes and costs are obtained with DR strategy compared to system without DR. [ABSTRACT FROM AUTHOR]

Capacity expansion models for the power sector are used to project future decisions over the coming decades by simulating investment and operation decisions for the use of electricity. Due to model performance constraints, these models typically do not explicitly simulate every hour within a year, but instead simulate representative time segments (groups of hours). This paper evaluates different approaches for selecting time segments across three methods: sequential, categorical, and clustering, across a wide range of time-segment quantities, for a total of 204 temporal profiles. To measure the performance of each profile's ability to accurately represent data, the root-mean-square-error of each profile's time segments are compared to the data's original hourly data. The temporal alignment across regions is also measured (i.e., how often windy days align across regions). Different spatial resolutions were applied for a subset of the temporal selection methods to investigate the impact spatial resolution has on performance. This paper provides a framework for measuring the value of different temporal selection methods and of adding more granular data to energy system models. Overall, multi-criteria clustering yields the lowest root-mean-square-error across all datasets evaluated and provides a holistic view of the intertwined relationships between renewable generation and electricity demand. • Temporal selection methods analyzed across three commonly used techniques. • Measured performance of representing model data within representative hours. • Measured temporal performance across electric load and wind and solar generation. • Clustering techniques performed better than sequential or categorical techniques. [ABSTRACT FROM AUTHOR]

Growth of electricity generation from variable renewable resources like wind and solar has raised questions about future grid stability. This paper used several renewable energy penetration scenarios to determine when an electric grid might be more vulnerable to frequency contingencies, such as a generator outage. Unit commitment and dispatch modeling was used to quantify system inertia, an established proxy for grid stability. A case study of the Electric Reliability Council of Texas grid was used to illustrate the method. Results from the modeled scenarios showed that the Texas grid is resilient to major grid changes, even with relatively high penetrations (∼ 30% of annual energy generation compared to 18% in 2017) of renewable energy. However, retiring nuclear power plants and private-use networks in the model led to unstable inertia levels in our results. When the system inertia was constrained to meet a minimum threshold in our model, multiple coal and natural gas combined-cycle plants were dispatched at part-load or at their minimum operating level to maintain stable system inertia levels. This behavior is expected to expand with higher renewable energy penetrations and could occur on other electric grids that are reliant on synchronous generators for inertia support. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with modeling possible future paths for Lebanon’s electricity future and evaluating them. The baseline scenario (BS) reflects the business-as-usual state of affairs and thus describes the most likely evolution of the power sector in the absence of any climate change-related or other policies. Two alternative scenarios are examined in contrast to the BS; the renewable energy scenario (RES) and the natural gas scenario (NGS). Using the Long range Energy Alternatives Planning System (LEAP) software we conduct a full-fledged scenario analysis and examine the technical, economic, and environmental implications of all scenarios. From an economic standpoint as well as from an environmental perspective both alternative scenarios are superior to the baseline. Hence, the results of the simulation show that the alternative scenarios are more environmentally and economically attractive than the BS. They would help Lebanon meet its social, environmental, and economic development goals, while at the same time providing other unquantifiable benefits that are discussed further in the paper. Anticipated barriers to the shift in energy mix from conventional sources to renewable energy sources are also presented and discussed [Copyright &y& Elsevier]

Abstract The Brazilian electricity system is an important example of a large country relying on a high renewable energy matrix with a major focus on hydropower, which has historically allowed for low carbon electricity production. However, the increase in the demand and climate change impacts on the availability of these renewable resources represent important challenges for long-term power planning. The contribution of this paper is twofold: Firstly, a first attempt to use the EnergyPLAN model for the analysis of the Brazilian electricity sector and in particular to study future scenarios is presented. Secondly, the possibility of achieving a 100% RES system is also addressed. The 100% RES scenario is found to be theoretically possible but a substantial increase in the overall installed capacity would be required, to support the grid mainly during the spring and summer season. The results underline the importance of seasonal complementarity of hydro and wind power and reveal how an increase in RES would add exportation potential, reducing also the Brazilian external energy dependency. The study identifies risk factors for these high RES scenarios and outlines several avenues for future research to address cost, environmental and technical uncertainties of the system. Highlights • The Brazilian power sector is analysed with EnergyPLAN computer model. • Renewable scenarios are compared for technical, cost, emissions and risk parameters. • The importance of seasonal complementarity of hydro and wind power is outlined. • The 100% RES scenario results in full decarbonization of the system at higher cost. • The 100% RES scenario results in higher exportation and lower importation potential. [ABSTRACT FROM AUTHOR]

Bangladesh, currently a low middle-income economy aspires to become a high middle income country by 2021. To achieve such aspiration, the country will have to ensure adequate power supply for its fast growing economy. Bangladesh lacks energy resources for power generation. This paper explores some of the power supply scenarios with special focus on power imports and higher use of renewables. Using the technology rich, least cost optimization model 'The Integrated MARKAL-EFOM System (TIMES)', the authors developed four possible future power supply scenarios for Bangladesh. These scenarios include an energy security framework (based on the Power System Master Plan (PSMP) 2016 report), a high power import scenario, a scenario with higher use of renewables and a combined high power import - high renewables development scenario. The analysis indicates that the present energy security framework ensures energy security with diversifying fuels used for power generation, however, scenarios with high power imports and a high share of renewables (including the combined scenario) bring down the cost of supplying power along with a reduction in expensive fossil fuel imports while maintaining energy security as fuel sources for power generation still remain diversified. [ABSTRACT FROM AUTHOR]

synchronous generators are the most extensive generators used as electrical production component in a power plant. Many researches have been done to optimize their structure and their performances. This paper introduces a modern generation of synchronous machine. The introduced double-stator cup-rotor permanent-magnet synchronous generator (DSPMSG) was optimized, designed and simulated for high-power wind farms. Its structural features and operational principles were described and its specific equations have been extracted. Analytical hierarchy process (AHP) was used to optimize the designing parameters. The optimized parameters were used to simulate the generator on Maxwell based on Finite Element Method (FEM). The no-load and full load magnetic fields were computed by 2-D FEM and the simulation results were used to validate the whole designing processes. A comparison was made between the characteristics of the designed generator and a general permanent-magnet one. Finally, it was concluded that along with less electrical losses, less weight, length and diameter and simple structure, the most important feature of the proposed generator which is its more electrical energy production in a smaller size can resolve the limited performances of ordinary synchronous generators especially in high power wind applications besides other advantageous of doubled-stator ones. [ABSTRACT FROM AUTHOR]

Several influential energy systems models indicate that renewable energy must provide a significant share of the world's electricity to limit global temperature rises to below 2 °C this century. To better represent the costs and other implications of this shift, it is important that these models realistically characterise the technical and economic potential of renewable energy technologies. Towards this goal, this paper presents the first temporally-explicit Geospatial Information System (GIS) methodology to characterise the global onshore wind energy potential with respect to topographical features, land use and environmental constraints. The approach combines the hourly NASA MERRA-2 global wind speed data set with the spatially-resolved DTU Global Wind Atlas. This yields high resolution global capacity factors for onshore wind, binned into seasonal and diurnal time-slices to capture the important temporal variability. For each country, the wind power generation capacity available for various capacity factor ranges is produced, and made freely available to the community. This data set can be used to assess the economically viable wind energy potential on a global or per-country basis, and as an input to various energy systems models. [ABSTRACT FROM AUTHOR]

Renewable energy plays significant role in achieving energy savings and emissions reduction. As a sustainable and environmental friendly renewable energy source, concentrated solar power (CSP) is of interest for research and development. This is because CSP plants can be equipped with thermal storage systems, thereby producing electricity when sunlight is not available. The installation of CSP plants also leads to substantial ‘peak shaving effects’. However, the cost of CSP generation is an obstacle hampering the commercialization of this emerging industry. This paper constructs a mathematical model of the levelized cost of energy (LCOE) to calculate the power generation cost of CSP projects on the basis of lifetime cost structure analysis. A sensitivity analysis is conducted to examine the impact of different variables on the LCOE of CSP projects. The variables considered in this study are investment cost over the construction period, annual operation and maintenance cost, annual electricity production and the discount rate. Finally, the influence of incentive policies such as preferential loans, tax support and zero land cost for power stations is analyzed. This research offers a new method for power generation cost calculation of CSP projects and provides support for governments to formulate incentive policies for the industry. [ABSTRACT FROM AUTHOR]

Solar ponds have been widely utilised in providing low grade heat needed for industrial processes and for heating applications <100 °C. In this paper, a small scale passive electric power generation unit was devised for generating electricity from the heat available in the solar pond. The power generation unit proposed operates without the use of a pump and involves no moving parts. The design of the power generation unit was finalised after performing a comprehensive theoretical study on the possible geometrical arrangements. The power generation unit was fabricated and tested experimentally. The power generation unit consists of 120 commercially available thermoelectric cells accommodated in the outer and inner layers of this dual layer power generation unit. The power generation unit had produced a maximum power of 40.8 W under the condition of T h = 99 °C. Under the normal operation of solar pond, the lower convective zone will have a temperature that lies within in the range of 40 °C –80 °C. Thus, maximum output in the range of 19.5 W–27.4 W is more realistic for the system proposed with the heat to electric conversion efficiency ranges between 0.37%–0.68%. [ABSTRACT FROM AUTHOR]

This paper investigates the impacts of California, USA reaching its renewable electricity target of 33%, excluding large hydro, by 2020, which is set out in the state's RPS (Renewable Portfolio Standard). The emerging renewable electricity mix in California and surrounding states which form the WECC (Western Electricity Coordination Council) is analysed using the CEPA (Carbon Emission Pinch Analysis) and EROI (Energy Return on Energy Invested) methodologies. The reduction in emissions with increased renewables is illustrated and the challenge of maintaining high EROI levels for renewable generation is examined for low and high electricity demand growth. Results demonstrate that wind and solar PV collectively form an integral part of California reaching the 33% renewables target by 2020. Government interventions of tax rebates and subsidies, net electricity metering and a four tiered electricity price have accelerated the uptake of electricity generation from wind and solar PV. Residential uptake of solar PV is also reducing overall California electricity grid demand. Emphasis on new renewable generation is stimulating development of affordable wind and solar technology in California which has the added benefit of enhancing social sustainability through improved employment opportunities at a variety of technical levels. [ABSTRACT FROM AUTHOR]

Jordan is a country faced with several environmental and energy related issues. It is the Worlds' fourth most water deprived country with a water consumption of only 145 m 3 per capita annually, less than a third of the established severe water poverty line. Jordan is also a country rich in wind and solar potential but practically no utilization with 99% of the produced electricity coming from imported fossil fuels resulting in high CO 2 emissions and a potential security of supply issue. The utilization of reverse osmosis desalination in a combination with brine operated pump storage units and wind and (PV) photovoltaic plants can tackle both issues. The desalination plants can produce the much needed water and act as a flexible demand to increase the penetration of intermittent renewables supported by the brine operated pump storage units. This paper presents six scenarios for the development of the Jordanian energy system until the year 2050. The results have shown that the demonstrated configuration can increase the share of intermittent renewables in the production of electricity up to 76% resulting in a high reduction of fuel consumption, CO 2 emissions and costs. These analyses have been performed using the EnergyPLAN advanced energy system analyses tool. [ABSTRACT FROM AUTHOR]

There has been an intense debate on the quantification of the employment effects of renewable electricity deployment in the European Union. However, most studies carried out in the past have focused on specific countries and those with a European-wide scope have not provided disaggregated results per country. Furthermore, differences between importing and exporting countries have not been considered. This paper aims to cover those gaps. It presents a novel methodology which integrates the aforementioned considerations in order to calculate the employment effects of renewable energy deployment. The methodology is useful to calculate dynamic employment factors (considering technology learning effects) and the specific capacity (based on trade effects) to which these factors should be applied. It is applied to three renewable energy technologies – photovoltaics, wind on-shore and wind off-shore- in the European Union Member States in the 2008–2012 period. The results using this novel methodology broadly confirm the figures provided in other contributions in the literature. The proposed methodology can be instrumental in assessing the socio-economic effects of policies and investment programmes targeting the deployment of renewable energy technologies. [ABSTRACT FROM AUTHOR]

The China's electricity consumption was 4966 TWh in 2012, which is the world top electricity consumer. The low carbon electricity is one of the key issues of its sustainable development. IRSP (integrated resource strategic planning) is a useful tool to implement DSM (demand side management) and power planning on the supply side. However, the role of interconnected smart grids with fast growing cross-region transmission is not considered in the IRSP. Therefore, the paper proposes the model of IRSP with interconnected smart grids to integrate more renewable power generation to the grids and implement more DSM projects, which is called as IRSP-sgs (IRSP smart grids) model. Two scenarios are projected to study the impact of cross-region transmission on low carbon electricity by using the IRSP-sgs model until 2025 in China. Results show that the scenario with enhanced cross-region transmission helps to reduce electricity generation by 784.38 TWh and reduce CO 2 emission by 999.57 million tons during 2013–2025, since the multi-regional power operation can integrate more than 488.30 TWh renewable generation into the grids and implement more DSM projects to substitute generation. In addition, it also provides tremendous opportunities to improve the stable operation of the power system. [ABSTRACT FROM AUTHOR]

Abstract: The biomass wastes from the palm oil industry offer great potential for large-scale power generation in Malaysia. It has been estimated that 85.5% of available biomass in the country comes from oil palm agriculture. The introduction of the FiT (Feed-in Tariff) regime in 2011, which superseded the underperforming SREP (Small Renewable Energy Power) scheme, is expected to catalyse and accelerate the development of the renewable energy industry, including biomass technology. Despite a major overhaul of the market structure under the new scheme, the sustainability of the grid-connected oil palm biomass renewable energy industry downstream components remains questionable. Hence, this paper aims to investigate and analyse the market response to six sustainability-related topics. The research methods include electronic and conventional postal modes to disseminate questionnaires to all of the palm oil producers. The returned questionnaires were then analysed with a statistical tool and inferences were drawn to identify the gaps in the existing policy system. The survey identified several key factors for the government's consideration. [Copyright &y& Elsevier]

Abstract: Many governments worldwide have instituted incentive schemes for renewable electricity producers in order to meet carbon emissions targets. These schemes aim to boost investment and hence growth in renewable energy industries. This paper examines four such schemes: premium feed-in tariffs, fixed feed-in tariffs, feed-in tariffs with contract for difference and the renewable obligations scheme. A generalised mathematical model of industry growth is presented and fitted with data from the UK onshore wind industry. The model responds to subsidy from each of the four incentive schemes. A utility or ‘fitness’ function that maximises installed capacity at some fixed time in the future while minimising total cost of subsidy is postulated. Using this function, the optimal strategy for provision and timing of subsidy for each scheme is calculated. Finally, a comparison of the performance of each scheme, given that they use their optimal control strategy, is presented. This model indicates that the premium feed-in tariff and renewable obligation scheme produce the joint best results. [Copyright &y& Elsevier]

Abstract: Denmark’s long-term energy goal is to develop an energy system solely based on renewable energy sources by 2050. To reach this goal, energy savings in buildings is essential. Therefore, the focus on energy efficient measures in buildings and net zero energy buildings (NZEBs) has increased. Most buildings in Denmark are connected to electricity grids and around half are connected to district heating (DH) systems. Connecting buildings to larger energy systems enables them to send and receive energy from these systems. This paper’s objective is to examine how excess heat production from NZEBs influences different types of DH systems. In the analysis three different types of DH systems are analyzed, and three technology development scenarios for each are created. The examination is from a technical perspective and looks into how the overall heat production within DH areas is affected by the NZEBs excess heat production from solar thermal collectors. The main findings are that the excess heat from NZEBs can benefit DH systems by decreasing the production from production units utilizing combustible fuels. In DH areas where the heat demand in summer months is already covered by renewable energy, adding seasonal heat storage is essential to utilize the NZEB production. [Copyright &y& Elsevier]

Abstract: The intermittent nature of wind energy poses questions on how electricity production can match the demand. The present paper analyses possible ways of achieving this goal when a large share of the energy is provided by wind. The study considers a certain share of wind energy as a target to be reached, and analyses different avenues for reaching such a target. The possible role of electricity energy storage, wind curtailment and transmission grid reinforcement is highlighted and discussed. The results show that above a certain percentage of electricity produced by wind, electricity storage becomes an economical option for integrating wind energy by reducing wind curtailments. Also, the synergy of storage and grid interconnections is highlighted. [Copyright &y& Elsevier]

Abstract: Currently, a wide range of strategies is implemented in different countries to increase the share of electricity from renewable energy sources (RES-E). A still controversial discussion is whether quantity-driven (like Tradable Green Certificates (TGCs) based on quotas) or price-driven (like feed-in-tariffs (FIT)) instruments lead to preferable solutions for society. The core objective of this paper is to compare the perspectives of quota-based certificate trading systems for an efficient and effective increase of RES-E with FIT. The major results of this analysis are: (i) The success stories of growth in RES-E in EU member states in recent years has been triggered by FIT implemented in a technology-specific manner at modest costs for European citizens; (ii) At present, TGC systems in most countries applied show a low effectiveness with respect to RES-E deployment of less mature technologies such as solar PV (with improving tendencies in e.g. the UK or Italy with respect to certain technologies); (iii) Compared to short term trading in TGC markets the intrinsic stability of FIT systems appears to be a key element for success; (iv) Hence, currently a well-designed (dynamic) FIT system provides a certain deployment of RES-E in the shortest time and at lowest costs for society. [Copyright &y& Elsevier]

Between 2009 and 2017 the share of wind and solar energy sources in the GB electricity generation mix increased from 2.5% to 17%. Due to the variable nature of these renewable sources, large thermal power stations designed for constant base-load operation have been required to operate more flexibly to compensate for fluctuations in renewable generation. This flexible operation results in increased thermal stress and reduced efficiency causing increased operation, maintenance and fuel costs for these assets. In this paper we present the results of what is, to the best of our knowledge, the first empirical study on the impact of renewables generation on startups, ramping and part-loading (collectively, 'cycling') of base-load generators. We develop regression models using half-hourly generation data from 2009 to 2017 that capture the impact of increased renewable penetration while taking into account confounding factors including seasonality and demand. We find that with 2009-levels of renewable generation, cycling in 2017 would have been less severe, with 20% fewer startups. We also present estimates for cycling under National Grid Future Energy Scenarios to 2030 with implications for investment in generation assets. Additionally, the dataset derived in this research is made available and comprises the first open-access dataset on cycling. • A dataset for base-load cycling in the GB power system from 2009 to 2017 is presented. • Base-load cycling is shown to have become stronger during the period 2009–2017. • Regression models for cycling variables are estimated using power system variables. • The models are used to predict cycling under Future Energy Scenarios to 2030. [ABSTRACT FROM AUTHOR]